/**
 * pugixml parser - version 1.8
 * --------------------------------------------------------
 * Copyright (C) 2006-2016, by Arseny Kapoulkine (arseny.kapoulkine@gmail.com)
 * Report bugs and download new versions at http://pugixml.org/
 *
 * This library is distributed under the MIT License. See notice at the end
 * of this file.
 *
 * This work is based on the pugxml parser, which is:
 * Copyright (C) 2003, by Kristen Wegner (kristen@tima.net)
 */

#ifndef SOURCE_PUGIXML_CPP
#define SOURCE_PUGIXML_CPP

#include "pugixml.hpp"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <limits.h>

#ifdef PUGIXML_WCHAR_MODE
#include <wchar.h>
#endif

#ifndef PUGIXML_NO_XPATH
#include <math.h>
#include <float.h>
#ifdef PUGIXML_NO_EXCEPTIONS
#include <setjmp.h>
#endif
#endif

#ifndef PUGIXML_NO_STL
#include <istream>
#include <ostream>
#include <string>
#endif

// For placement new
#include <new>

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable : 4127)  // conditional expression is constant
#pragma warning( \
    disable : 4324)  // structure was padded due to __declspec(align())
#pragma warning(disable : 4611)  // interaction between '_setjmp' and C++ object
                                 // destruction is non-portable
#pragma warning(disable : 4702)  // unreachable code
#pragma warning(disable : 4996)  // this function or variable may be unsafe
#pragma warning(disable : 4793)  // function compiled as native: presence of
                                 // '_setjmp' makes a function unmanaged
#endif

#ifdef __INTEL_COMPILER
#pragma warning(disable : 177)  // function was declared but never referenced
#pragma warning(disable : 279)  // controlling expression is constant
#pragma warning(disable : 1478 1786)  // function was declared "deprecated"
#pragma warning( \
    disable : 1684)  // conversion from pointer to same-sized integral type
#endif

#if defined(__BORLANDC__) && defined(PUGIXML_HEADER_ONLY)
#pragma warn - 8080  // symbol is declared but never used; disabling this inside
                     // push/pop bracket does not make the warning go away
#endif

#ifdef __BORLANDC__
#pragma option push
#pragma warn - 8008  // condition is always false
#pragma warn - 8066  // unreachable code
#endif

#ifdef __SNC__
// Using diag_push/diag_pop does not disable the warnings inside templates due
// to a compiler bug
#pragma diag_suppress = 178  // function was declared but never referenced
#pragma diag_suppress = 237  // controlling expression is constant
#endif

// Inlining controls
#if defined(_MSC_VER) && _MSC_VER >= 1300
#define PUGI__NO_INLINE __declspec(noinline)
#elif defined(__GNUC__)
#define PUGI__NO_INLINE __attribute__((noinline))
#else
#define PUGI__NO_INLINE
#endif

// Branch weight controls
#if defined(__GNUC__)
#define PUGI__UNLIKELY(cond) __builtin_expect(cond, 0)
#else
#define PUGI__UNLIKELY(cond) (cond)
#endif

// Simple static assertion
#define PUGI__STATIC_ASSERT(cond)                              \
  {                                                            \
    static const char condition_failed[(cond) ? 1 : -1] = {0}; \
    (void)condition_failed[0];                                 \
  }

// Digital Mars C++ bug workaround for passing char loaded from memory via stack
#ifdef __DMC__
#define PUGI__DMC_VOLATILE volatile
#else
#define PUGI__DMC_VOLATILE
#endif

// Borland C++ bug workaround for not defining ::memcpy depending on header
// include order (can't always use std::memcpy because some compilers don't have
// it at all)
#if defined(__BORLANDC__) && !defined(__MEM_H_USING_LIST)
using std::memcpy;
using std::memmove;
using std::memset;
#endif

// Some MinGW versions have headers that erroneously omit
// LLONG_MIN/LLONG_MAX/ULLONG_MAX definitions in strict ANSI mode
#if defined(PUGIXML_HAS_LONG_LONG) && defined(__MINGW32__) &&                 \
    defined(__STRICT_ANSI__) && !defined(LLONG_MAX) && !defined(LLONG_MIN) && \
    !defined(ULLONG_MAX)
#define LLONG_MAX 9223372036854775807LL
#define LLONG_MIN (-LLONG_MAX - 1)
#define ULLONG_MAX (2ULL * LLONG_MAX + 1)
#endif

// In some environments MSVC is a compiler but the CRT lacks certain
// MSVC-specific features
#if defined(_MSC_VER) && !defined(__S3E__)
#define PUGI__MSVC_CRT_VERSION _MSC_VER
#endif

#ifdef PUGIXML_HEADER_ONLY
#define PUGI__NS_BEGIN \
  namespace pugi {     \
  namespace impl {
#define PUGI__NS_END \
  }                  \
  }
#define PUGI__FN inline
#define PUGI__FN_NO_INLINE inline
#else
#if defined(_MSC_VER) && \
    _MSC_VER < 1300  // MSVC6 seems to have an amusing bug with anonymous
                     // namespaces inside namespaces
#define PUGI__NS_BEGIN \
  namespace pugi {     \
  namespace impl {
#define PUGI__NS_END \
  }                  \
  }
#else
#define PUGI__NS_BEGIN \
  namespace pugi {     \
  namespace impl {     \
  namespace {
#define PUGI__NS_END \
  }                  \
  }                  \
  }
#endif
#define PUGI__FN
#define PUGI__FN_NO_INLINE PUGI__NO_INLINE
#endif

// uintptr_t
#if (defined(_MSC_VER) && _MSC_VER < 1600) || \
    (defined(__BORLANDC__) && __BORLANDC__ < 0x561)
namespace pugi {
#ifndef _UINTPTR_T_DEFINED
typedef size_t uintptr_t;
#endif

typedef unsigned __int8 uint8_t;
typedef unsigned __int16 uint16_t;
typedef unsigned __int32 uint32_t;
}  // namespace pugi
#else
#include <stdint.h>
#endif

// Memory allocation
PUGI__NS_BEGIN
PUGI__FN void* default_allocate(size_t size) { return malloc(size); }

PUGI__FN void default_deallocate(void* ptr) { free(ptr); }

template <typename T>
struct xml_memory_management_function_storage {
  static allocation_function allocate;
  static deallocation_function deallocate;
};

// Global allocation functions are stored in class statics so that in header
// mode linker deduplicates them Without a template<> we'll get multiple
// definitions of the same static
template <typename T>
allocation_function xml_memory_management_function_storage<T>::allocate =
    default_allocate;
template <typename T>
deallocation_function xml_memory_management_function_storage<T>::deallocate =
    default_deallocate;

typedef xml_memory_management_function_storage<int> xml_memory;
PUGI__NS_END

// String utilities
PUGI__NS_BEGIN
// Get string length
PUGI__FN size_t strlength(const char_t* s) {
  assert(s);

#ifdef PUGIXML_WCHAR_MODE
  return wcslen(s);
#else
  return strlen(s);
#endif
}

// Compare two strings
PUGI__FN bool strequal(const char_t* src, const char_t* dst) {
  assert(src && dst);

#ifdef PUGIXML_WCHAR_MODE
  return wcscmp(src, dst) == 0;
#else
  return strcmp(src, dst) == 0;
#endif
}

// Compare lhs with [rhs_begin, rhs_end)
PUGI__FN bool strequalrange(const char_t* lhs, const char_t* rhs,
                            size_t count) {
  for (size_t i = 0; i < count; ++i)
    if (lhs[i] != rhs[i]) return false;

  return lhs[count] == 0;
}

// Get length of wide string, even if CRT lacks wide character support
PUGI__FN size_t strlength_wide(const wchar_t* s) {
  assert(s);

#ifdef PUGIXML_WCHAR_MODE
  return wcslen(s);
#else
  const wchar_t* end = s;
  while (*end) end++;
  return static_cast<size_t>(end - s);
#endif
}
PUGI__NS_END

// auto_ptr-like object for exception recovery
PUGI__NS_BEGIN
template <typename T>
struct auto_deleter {
  typedef void (*D)(T*);

  T* data;
  D deleter;

  auto_deleter(T* data_, D deleter_) : data(data_), deleter(deleter_) {}

  ~auto_deleter() {
    if (data) deleter(data);
  }

  T* release() {
    T* result = data;
    data = 0;
    return result;
  }
};
PUGI__NS_END

#ifdef PUGIXML_COMPACT
PUGI__NS_BEGIN
class compact_hash_table {
public:
  compact_hash_table() : _items(0), _capacity(0), _count(0) {}

  void clear() {
    if (_items) {
      xml_memory::deallocate(_items);
      _items = 0;
      _capacity = 0;
      _count = 0;
    }
  }

  void** find(const void* key) {
    assert(key);

    if (_capacity == 0) return 0;

    size_t hashmod = _capacity - 1;
    size_t bucket = hash(key) & hashmod;

    for (size_t probe = 0; probe <= hashmod; ++probe) {
      item_t& probe_item = _items[bucket];

      if (probe_item.key == key) return &probe_item.value;

      if (probe_item.key == 0) return 0;

      // hash collision, quadratic probing
      bucket = (bucket + probe + 1) & hashmod;
    }

    assert(false && "Hash table is full");
    return 0;
  }

  void** insert(const void* key) {
    assert(key);
    assert(_capacity != 0 && _count < _capacity - _capacity / 4);

    size_t hashmod = _capacity - 1;
    size_t bucket = hash(key) & hashmod;

    for (size_t probe = 0; probe <= hashmod; ++probe) {
      item_t& probe_item = _items[bucket];

      if (probe_item.key == 0) {
        probe_item.key = key;
        _count++;
        return &probe_item.value;
      }

      if (probe_item.key == key) return &probe_item.value;

      // hash collision, quadratic probing
      bucket = (bucket + probe + 1) & hashmod;
    }

    assert(false && "Hash table is full");
    return 0;
  }

  bool reserve() {
    if (_count + 16 >= _capacity - _capacity / 4) return rehash();

    return true;
  }

private:
  struct item_t {
    const void* key;
    void* value;
  };

  item_t* _items;
  size_t _capacity;

  size_t _count;

  bool rehash();

  static unsigned int hash(const void* key) {
    unsigned int h =
        static_cast<unsigned int>(reinterpret_cast<uintptr_t>(key));

    // MurmurHash3 32-bit finalizer
    h ^= h >> 16;
    h *= 0x85ebca6bu;
    h ^= h >> 13;
    h *= 0xc2b2ae35u;
    h ^= h >> 16;

    return h;
  }
};

PUGI__FN_NO_INLINE bool compact_hash_table::rehash() {
  compact_hash_table rt;
  rt._capacity = (_capacity == 0) ? 32 : _capacity * 2;
  rt._items =
      static_cast<item_t*>(xml_memory::allocate(sizeof(item_t) * rt._capacity));

  if (!rt._items) return false;

  memset(rt._items, 0, sizeof(item_t) * rt._capacity);

  for (size_t i = 0; i < _capacity; ++i)
    if (_items[i].key) *rt.insert(_items[i].key) = _items[i].value;

  if (_items) xml_memory::deallocate(_items);

  _capacity = rt._capacity;
  _items = rt._items;

  assert(_count == rt._count);

  return true;
}

PUGI__NS_END
#endif

PUGI__NS_BEGIN
#ifdef PUGIXML_COMPACT
static const uintptr_t xml_memory_block_alignment = 4;
#else
static const uintptr_t xml_memory_block_alignment = sizeof(void*);
#endif

// extra metadata bits
static const uintptr_t xml_memory_page_contents_shared_mask = 64;
static const uintptr_t xml_memory_page_name_allocated_mask = 32;
static const uintptr_t xml_memory_page_value_allocated_mask = 16;
static const uintptr_t xml_memory_page_type_mask = 15;

// combined masks for string uniqueness
static const uintptr_t xml_memory_page_name_allocated_or_shared_mask =
    xml_memory_page_name_allocated_mask | xml_memory_page_contents_shared_mask;
static const uintptr_t xml_memory_page_value_allocated_or_shared_mask =
    xml_memory_page_value_allocated_mask | xml_memory_page_contents_shared_mask;

#ifdef PUGIXML_COMPACT
#define PUGI__GETHEADER_IMPL(object, page, flags)  // unused
#define PUGI__GETPAGE_IMPL(header) (header).get_page()
#else
#define PUGI__GETHEADER_IMPL(object, page, flags)                             \
  (((reinterpret_cast<char*>(object) - reinterpret_cast<char*>(page)) << 8) | \
   (flags))
// this macro casts pointers through void* to avoid 'cast increases required
// alignment of target type' warnings
#define PUGI__GETPAGE_IMPL(header)                \
  static_cast<impl::xml_memory_page*>(            \
      const_cast<void*>(static_cast<const void*>( \
          reinterpret_cast<const char*>(&header) - (header >> 8))))
#endif

#define PUGI__GETPAGE(n) PUGI__GETPAGE_IMPL((n)->header)
#define PUGI__NODETYPE(n) \
  static_cast<xml_node_type>((n)->header & impl::xml_memory_page_type_mask)

struct xml_allocator;

struct xml_memory_page {
  static xml_memory_page* construct(void* memory) {
    xml_memory_page* result = static_cast<xml_memory_page*>(memory);

    result->allocator = 0;
    result->prev = 0;
    result->next = 0;
    result->busy_size = 0;
    result->freed_size = 0;

#ifdef PUGIXML_COMPACT
    result->compact_string_base = 0;
    result->compact_shared_parent = 0;
    result->compact_page_marker = 0;
#endif

    return result;
  }

  xml_allocator* allocator;

  xml_memory_page* prev;
  xml_memory_page* next;

  size_t busy_size;
  size_t freed_size;

#ifdef PUGIXML_COMPACT
  char_t* compact_string_base;
  void* compact_shared_parent;
  uint32_t* compact_page_marker;
#endif
};

static const size_t xml_memory_page_size =
#ifdef PUGIXML_MEMORY_PAGE_SIZE
    (PUGIXML_MEMORY_PAGE_SIZE)
#else
    32768
#endif
    - sizeof(xml_memory_page);

struct xml_memory_string_header {
  uint16_t page_offset;  // offset from page->data
  uint16_t full_size;    // 0 if string occupies whole page
};

struct xml_allocator {
  xml_allocator(xml_memory_page* root)
      : _root(root), _busy_size(root->busy_size) {
#ifdef PUGIXML_COMPACT
    _hash = 0;
#endif
  }

  xml_memory_page* allocate_page(size_t data_size) {
    size_t size = sizeof(xml_memory_page) + data_size;

    // allocate block with some alignment, leaving memory for worst-case padding
    void* memory = xml_memory::allocate(size);
    if (!memory) return 0;

    // prepare page structure
    xml_memory_page* page = xml_memory_page::construct(memory);
    assert(page);

    page->allocator = _root->allocator;

    return page;
  }

  static void deallocate_page(xml_memory_page* page) {
    xml_memory::deallocate(page);
  }

  void* allocate_memory_oob(size_t size, xml_memory_page*& out_page);

  void* allocate_memory(size_t size, xml_memory_page*& out_page) {
    if (PUGI__UNLIKELY(_busy_size + size > xml_memory_page_size))
      return allocate_memory_oob(size, out_page);

    void* buf =
        reinterpret_cast<char*>(_root) + sizeof(xml_memory_page) + _busy_size;

    _busy_size += size;

    out_page = _root;

    return buf;
  }

#ifdef PUGIXML_COMPACT
  void* allocate_object(size_t size, xml_memory_page*& out_page) {
    void* result = allocate_memory(size + sizeof(uint32_t), out_page);
    if (!result) return 0;

    // adjust for marker
    ptrdiff_t offset = static_cast<char*>(result) -
                       reinterpret_cast<char*>(out_page->compact_page_marker);

    if (PUGI__UNLIKELY(static_cast<uintptr_t>(offset) >=
                       256 * xml_memory_block_alignment)) {
      // insert new marker
      uint32_t* marker = static_cast<uint32_t*>(result);

      *marker = static_cast<uint32_t>(reinterpret_cast<char*>(marker) -
                                      reinterpret_cast<char*>(out_page));
      out_page->compact_page_marker = marker;

      // since we don't reuse the page space until we reallocate it, we can just
      // pretend that we freed the marker block this will make sure
      // deallocate_memory correctly tracks the size
      out_page->freed_size += sizeof(uint32_t);

      return marker + 1;
    } else {
      // roll back uint32_t part
      _busy_size -= sizeof(uint32_t);

      return result;
    }
  }
#else
  void* allocate_object(size_t size, xml_memory_page*& out_page) {
    return allocate_memory(size, out_page);
  }
#endif

  void deallocate_memory(void* ptr, size_t size, xml_memory_page* page) {
    if (page == _root) page->busy_size = _busy_size;

    assert(ptr >= reinterpret_cast<char*>(page) + sizeof(xml_memory_page) &&
           ptr < reinterpret_cast<char*>(page) + sizeof(xml_memory_page) +
                     page->busy_size);
    (void)!ptr;

    page->freed_size += size;
    assert(page->freed_size <= page->busy_size);

    if (page->freed_size == page->busy_size) {
      if (page->next == 0) {
        assert(_root == page);

        // top page freed, just reset sizes
        page->busy_size = 0;
        page->freed_size = 0;

#ifdef PUGIXML_COMPACT
        // reset compact state to maximize efficiency
        page->compact_string_base = 0;
        page->compact_shared_parent = 0;
        page->compact_page_marker = 0;
#endif

        _busy_size = 0;
      } else {
        assert(_root != page);
        assert(page->prev);

        // remove from the list
        page->prev->next = page->next;
        page->next->prev = page->prev;

        // deallocate
        deallocate_page(page);
      }
    }
  }

  char_t* allocate_string(size_t length) {
    static const size_t max_encoded_offset =
        (1 << 16) * xml_memory_block_alignment;

    PUGI__STATIC_ASSERT(xml_memory_page_size <= max_encoded_offset);

    // allocate memory for string and header block
    size_t size = sizeof(xml_memory_string_header) + length * sizeof(char_t);

    // round size up to block alignment boundary
    size_t full_size = (size + (xml_memory_block_alignment - 1)) &
                       ~(xml_memory_block_alignment - 1);

    xml_memory_page* page;
    xml_memory_string_header* header = static_cast<xml_memory_string_header*>(
        allocate_memory(full_size, page));

    if (!header) return 0;

    // setup header
    ptrdiff_t page_offset = reinterpret_cast<char*>(header) -
                            reinterpret_cast<char*>(page) -
                            sizeof(xml_memory_page);

    assert(page_offset % xml_memory_block_alignment == 0);
    assert(page_offset >= 0 &&
           static_cast<size_t>(page_offset) < max_encoded_offset);
    header->page_offset = static_cast<uint16_t>(
        static_cast<size_t>(page_offset) / xml_memory_block_alignment);

    // full_size == 0 for large strings that occupy the whole page
    assert(full_size % xml_memory_block_alignment == 0);
    assert(full_size < max_encoded_offset ||
           (page->busy_size == full_size && page_offset == 0));
    header->full_size = static_cast<uint16_t>(
        full_size < max_encoded_offset ? full_size / xml_memory_block_alignment
                                       : 0);

    // round-trip through void* to avoid 'cast increases required alignment of
    // target type' warning header is guaranteed a pointer-sized alignment,
    // which should be enough for char_t
    return static_cast<char_t*>(static_cast<void*>(header + 1));
  }

  void deallocate_string(char_t* string) {
    // this function casts pointers through void* to avoid 'cast increases
    // required alignment of target type' warnings we're guaranteed the proper
    // (pointer-sized) alignment on the input string if it was allocated via
    // allocate_string

    // get header
    xml_memory_string_header* header =
        static_cast<xml_memory_string_header*>(static_cast<void*>(string)) - 1;
    assert(header);

    // deallocate
    size_t page_offset = sizeof(xml_memory_page) +
                         header->page_offset * xml_memory_block_alignment;
    xml_memory_page* page = reinterpret_cast<xml_memory_page*>(
        static_cast<void*>(reinterpret_cast<char*>(header) - page_offset));

    // if full_size == 0 then this string occupies the whole page
    size_t full_size = header->full_size == 0
                           ? page->busy_size
                           : header->full_size * xml_memory_block_alignment;

    deallocate_memory(header, full_size, page);
  }

  bool reserve() {
#ifdef PUGIXML_COMPACT
    return _hash->reserve();
#else
    return true;
#endif
  }

  xml_memory_page* _root;
  size_t _busy_size;

#ifdef PUGIXML_COMPACT
  compact_hash_table* _hash;
#endif
};

PUGI__FN_NO_INLINE void* xml_allocator::allocate_memory_oob(
    size_t size, xml_memory_page*& out_page) {
  const size_t large_allocation_threshold = xml_memory_page_size / 4;

  xml_memory_page* page = allocate_page(
      size <= large_allocation_threshold ? xml_memory_page_size : size);
  out_page = page;

  if (!page) return 0;

  if (size <= large_allocation_threshold) {
    _root->busy_size = _busy_size;

    // insert page at the end of linked list
    page->prev = _root;
    _root->next = page;
    _root = page;

    _busy_size = size;
  } else {
    // insert page before the end of linked list, so that it is deleted as soon
    // as possible the last page is not deleted even if it's empty (see
    // deallocate_memory)
    assert(_root->prev);

    page->prev = _root->prev;
    page->next = _root;

    _root->prev->next = page;
    _root->prev = page;

    page->busy_size = size;
  }

  return reinterpret_cast<char*>(page) + sizeof(xml_memory_page);
}
PUGI__NS_END

#ifdef PUGIXML_COMPACT
PUGI__NS_BEGIN
static const uintptr_t compact_alignment_log2 = 2;
static const uintptr_t compact_alignment = 1 << compact_alignment_log2;

class compact_header {
public:
  compact_header(xml_memory_page* page, unsigned int flags) {
    PUGI__STATIC_ASSERT(xml_memory_block_alignment == compact_alignment);

    ptrdiff_t offset = (reinterpret_cast<char*>(this) -
                        reinterpret_cast<char*>(page->compact_page_marker));
    assert(offset % compact_alignment == 0 &&
           static_cast<uintptr_t>(offset) < 256 * compact_alignment);

    _page = static_cast<unsigned char>(offset >> compact_alignment_log2);
    _flags = static_cast<unsigned char>(flags);
  }

  void operator&=(uintptr_t mod) { _flags &= static_cast<unsigned char>(mod); }

  void operator|=(uintptr_t mod) { _flags |= static_cast<unsigned char>(mod); }

  uintptr_t operator&(uintptr_t mod) const { return _flags & mod; }

  xml_memory_page* get_page() const {
    // round-trip through void* to silence 'cast increases required alignment of
    // target type' warnings
    const char* page_marker =
        reinterpret_cast<const char*>(this) - (_page << compact_alignment_log2);
    const char* page = page_marker - *reinterpret_cast<const uint32_t*>(
                                         static_cast<const void*>(page_marker));

    return const_cast<xml_memory_page*>(
        reinterpret_cast<const xml_memory_page*>(
            static_cast<const void*>(page)));
  }

private:
  unsigned char _page;
  unsigned char _flags;
};

PUGI__FN xml_memory_page* compact_get_page(const void* object,
                                           int header_offset) {
  const compact_header* header = reinterpret_cast<const compact_header*>(
      static_cast<const char*>(object) - header_offset);

  return header->get_page();
}

template <int header_offset, typename T>
PUGI__FN_NO_INLINE T* compact_get_value(const void* object) {
  return static_cast<T*>(
      *compact_get_page(object, header_offset)->allocator->_hash->find(object));
}

template <int header_offset, typename T>
PUGI__FN_NO_INLINE void compact_set_value(const void* object, T* value) {
  *compact_get_page(object, header_offset)->allocator->_hash->insert(object) =
      value;
}

template <typename T, int header_offset, int start = -126>
class compact_pointer {
public:
  compact_pointer() : _data(0) {}

  void operator=(const compact_pointer& rhs) { *this = rhs + 0; }

  void operator=(T* value) {
    if (value) {
      // value is guaranteed to be compact-aligned; 'this' is not
      // our decoding is based on 'this' aligned to compact alignment downwards
      // (see operator T*) so for negative offsets (e.g. -3) we need to adjust
      // the diff by compact_alignment - 1 to compensate for arithmetic shift
      // rounding for negative values
      ptrdiff_t diff =
          reinterpret_cast<char*>(value) - reinterpret_cast<char*>(this);
      ptrdiff_t offset =
          ((diff + int(compact_alignment - 1)) >> compact_alignment_log2) -
          start;

      if (static_cast<uintptr_t>(offset) <= 253)
        _data = static_cast<unsigned char>(offset + 1);
      else {
        compact_set_value<header_offset>(this, value);

        _data = 255;
      }
    } else
      _data = 0;
  }

  operator T*() const {
    if (_data) {
      if (_data < 255) {
        uintptr_t base =
            reinterpret_cast<uintptr_t>(this) & ~(compact_alignment - 1);

        return reinterpret_cast<T*>(
            base + ((_data - 1 + start) << compact_alignment_log2));
      } else
        return compact_get_value<header_offset, T>(this);
    } else
      return 0;
  }

  T* operator->() const { return *this; }

private:
  unsigned char _data;
};

template <typename T, int header_offset>
class compact_pointer_parent {
public:
  compact_pointer_parent() : _data(0) {}

  void operator=(const compact_pointer_parent& rhs) { *this = rhs + 0; }

  void operator=(T* value) {
    if (value) {
      // value is guaranteed to be compact-aligned; 'this' is not
      // our decoding is based on 'this' aligned to compact alignment downwards
      // (see operator T*) so for negative offsets (e.g. -3) we need to adjust
      // the diff by compact_alignment - 1 to compensate for arithmetic shift
      // behavior for negative values
      ptrdiff_t diff =
          reinterpret_cast<char*>(value) - reinterpret_cast<char*>(this);
      ptrdiff_t offset =
          ((diff + int(compact_alignment - 1)) >> compact_alignment_log2) +
          65533;

      if (static_cast<uintptr_t>(offset) <= 65533) {
        _data = static_cast<unsigned short>(offset + 1);
      } else {
        xml_memory_page* page = compact_get_page(this, header_offset);

        if (PUGI__UNLIKELY(page->compact_shared_parent == 0))
          page->compact_shared_parent = value;

        if (page->compact_shared_parent == value) {
          _data = 65534;
        } else {
          compact_set_value<header_offset>(this, value);

          _data = 65535;
        }
      }
    } else {
      _data = 0;
    }
  }

  operator T*() const {
    if (_data) {
      if (_data < 65534) {
        uintptr_t base =
            reinterpret_cast<uintptr_t>(this) & ~(compact_alignment - 1);

        return reinterpret_cast<T*>(
            base + ((_data - 1 - 65533) << compact_alignment_log2));
      } else if (_data == 65534)
        return static_cast<T*>(
            compact_get_page(this, header_offset)->compact_shared_parent);
      else
        return compact_get_value<header_offset, T>(this);
    } else
      return 0;
  }

  T* operator->() const { return *this; }

private:
  uint16_t _data;
};

template <int header_offset, int base_offset>
class compact_string {
public:
  compact_string() : _data(0) {}

  void operator=(const compact_string& rhs) { *this = rhs + 0; }

  void operator=(char_t* value) {
    if (value) {
      xml_memory_page* page = compact_get_page(this, header_offset);

      if (PUGI__UNLIKELY(page->compact_string_base == 0))
        page->compact_string_base = value;

      ptrdiff_t offset = value - page->compact_string_base;

      if (static_cast<uintptr_t>(offset) < (65535 << 7)) {
        // round-trip through void* to silence 'cast increases required
        // alignment of target type' warnings
        uint16_t* base = reinterpret_cast<uint16_t*>(
            static_cast<void*>(reinterpret_cast<char*>(this) - base_offset));

        if (*base == 0) {
          *base = static_cast<uint16_t>((offset >> 7) + 1);
          _data = static_cast<unsigned char>((offset & 127) + 1);
        } else {
          ptrdiff_t remainder = offset - ((*base - 1) << 7);

          if (static_cast<uintptr_t>(remainder) <= 253) {
            _data = static_cast<unsigned char>(remainder + 1);
          } else {
            compact_set_value<header_offset>(this, value);

            _data = 255;
          }
        }
      } else {
        compact_set_value<header_offset>(this, value);

        _data = 255;
      }
    } else {
      _data = 0;
    }
  }

  operator char_t*() const {
    if (_data) {
      if (_data < 255) {
        xml_memory_page* page = compact_get_page(this, header_offset);

        // round-trip through void* to silence 'cast increases required
        // alignment of target type' warnings
        const uint16_t* base =
            reinterpret_cast<const uint16_t*>(static_cast<const void*>(
                reinterpret_cast<const char*>(this) - base_offset));
        assert(*base);

        ptrdiff_t offset = ((*base - 1) << 7) + (_data - 1);

        return page->compact_string_base + offset;
      } else {
        return compact_get_value<header_offset, char_t>(this);
      }
    } else
      return 0;
  }

private:
  unsigned char _data;
};
PUGI__NS_END
#endif

#ifdef PUGIXML_COMPACT
namespace pugi {
struct xml_attribute_struct {
  xml_attribute_struct(impl::xml_memory_page* page)
      : header(page, 0), namevalue_base(0) {
    PUGI__STATIC_ASSERT(sizeof(xml_attribute_struct) == 8);
  }

  impl::compact_header header;

  uint16_t namevalue_base;

  impl::compact_string<4, 2> name;
  impl::compact_string<5, 3> value;

  impl::compact_pointer<xml_attribute_struct, 6> prev_attribute_c;
  impl::compact_pointer<xml_attribute_struct, 7, 0> next_attribute;
};

struct xml_node_struct {
  xml_node_struct(impl::xml_memory_page* page, xml_node_type type)
      : header(page, type), namevalue_base(0) {
    PUGI__STATIC_ASSERT(sizeof(xml_node_struct) == 12);
  }

  impl::compact_header header;

  uint16_t namevalue_base;

  impl::compact_string<4, 2> name;
  impl::compact_string<5, 3> value;

  impl::compact_pointer_parent<xml_node_struct, 6> parent;

  impl::compact_pointer<xml_node_struct, 8, 0> first_child;

  impl::compact_pointer<xml_node_struct, 9> prev_sibling_c;
  impl::compact_pointer<xml_node_struct, 10, 0> next_sibling;

  impl::compact_pointer<xml_attribute_struct, 11, 0> first_attribute;
};
}  // namespace pugi
#else
namespace pugi {
struct xml_attribute_struct {
  xml_attribute_struct(impl::xml_memory_page* page)
      : name(0), value(0), prev_attribute_c(0), next_attribute(0) {
    header = PUGI__GETHEADER_IMPL(this, page, 0);
  }

  uintptr_t header;

  char_t* name;
  char_t* value;

  xml_attribute_struct* prev_attribute_c;
  xml_attribute_struct* next_attribute;
};

struct xml_node_struct {
  xml_node_struct(impl::xml_memory_page* page, xml_node_type type)
      : name(0),
        value(0),
        parent(0),
        first_child(0),
        prev_sibling_c(0),
        next_sibling(0),
        first_attribute(0) {
    header = PUGI__GETHEADER_IMPL(this, page, type);
  }

  uintptr_t header;

  char_t* name;
  char_t* value;

  xml_node_struct* parent;

  xml_node_struct* first_child;

  xml_node_struct* prev_sibling_c;
  xml_node_struct* next_sibling;

  xml_attribute_struct* first_attribute;
};
}  // namespace pugi
#endif

PUGI__NS_BEGIN
struct xml_extra_buffer {
  char_t* buffer;
  xml_extra_buffer* next;
};

struct xml_document_struct : public xml_node_struct, public xml_allocator {
  xml_document_struct(xml_memory_page* page)
      : xml_node_struct(page, node_document),
        xml_allocator(page),
        buffer(0),
        extra_buffers(0) {}

  const char_t* buffer;

  xml_extra_buffer* extra_buffers;

#ifdef PUGIXML_COMPACT
  compact_hash_table hash;
#endif
};

template <typename Object>
inline xml_allocator& get_allocator(const Object* object) {
  assert(object);

  return *PUGI__GETPAGE(object)->allocator;
}

template <typename Object>
inline xml_document_struct& get_document(const Object* object) {
  assert(object);

  return *static_cast<xml_document_struct*>(PUGI__GETPAGE(object)->allocator);
}
PUGI__NS_END

// Low-level DOM operations
PUGI__NS_BEGIN
inline xml_attribute_struct* allocate_attribute(xml_allocator& alloc) {
  xml_memory_page* page;
  void* memory = alloc.allocate_object(sizeof(xml_attribute_struct), page);
  if (!memory) return 0;

  return new (memory) xml_attribute_struct(page);
}

inline xml_node_struct* allocate_node(xml_allocator& alloc,
                                      xml_node_type type) {
  xml_memory_page* page;
  void* memory = alloc.allocate_object(sizeof(xml_node_struct), page);
  if (!memory) return 0;

  return new (memory) xml_node_struct(page, type);
}

inline void destroy_attribute(xml_attribute_struct* a, xml_allocator& alloc) {
  if (a->header & impl::xml_memory_page_name_allocated_mask)
    alloc.deallocate_string(a->name);

  if (a->header & impl::xml_memory_page_value_allocated_mask)
    alloc.deallocate_string(a->value);

  alloc.deallocate_memory(a, sizeof(xml_attribute_struct), PUGI__GETPAGE(a));
}

inline void destroy_node(xml_node_struct* n, xml_allocator& alloc) {
  if (n->header & impl::xml_memory_page_name_allocated_mask)
    alloc.deallocate_string(n->name);

  if (n->header & impl::xml_memory_page_value_allocated_mask)
    alloc.deallocate_string(n->value);

  for (xml_attribute_struct* attr = n->first_attribute; attr;) {
    xml_attribute_struct* next = attr->next_attribute;

    destroy_attribute(attr, alloc);

    attr = next;
  }

  for (xml_node_struct* child = n->first_child; child;) {
    xml_node_struct* next = child->next_sibling;

    destroy_node(child, alloc);

    child = next;
  }

  alloc.deallocate_memory(n, sizeof(xml_node_struct), PUGI__GETPAGE(n));
}

inline void append_node(xml_node_struct* child, xml_node_struct* node) {
  child->parent = node;

  xml_node_struct* head = node->first_child;

  if (head) {
    xml_node_struct* tail = head->prev_sibling_c;

    tail->next_sibling = child;
    child->prev_sibling_c = tail;
    head->prev_sibling_c = child;
  } else {
    node->first_child = child;
    child->prev_sibling_c = child;
  }
}

inline void prepend_node(xml_node_struct* child, xml_node_struct* node) {
  child->parent = node;

  xml_node_struct* head = node->first_child;

  if (head) {
    child->prev_sibling_c = head->prev_sibling_c;
    head->prev_sibling_c = child;
  } else
    child->prev_sibling_c = child;

  child->next_sibling = head;
  node->first_child = child;
}

inline void insert_node_after(xml_node_struct* child, xml_node_struct* node) {
  xml_node_struct* parent = node->parent;

  child->parent = parent;

  if (node->next_sibling)
    node->next_sibling->prev_sibling_c = child;
  else
    parent->first_child->prev_sibling_c = child;

  child->next_sibling = node->next_sibling;
  child->prev_sibling_c = node;

  node->next_sibling = child;
}

inline void insert_node_before(xml_node_struct* child, xml_node_struct* node) {
  xml_node_struct* parent = node->parent;

  child->parent = parent;

  if (node->prev_sibling_c->next_sibling)
    node->prev_sibling_c->next_sibling = child;
  else
    parent->first_child = child;

  child->prev_sibling_c = node->prev_sibling_c;
  child->next_sibling = node;

  node->prev_sibling_c = child;
}

inline void remove_node(xml_node_struct* node) {
  xml_node_struct* parent = node->parent;

  if (node->next_sibling)
    node->next_sibling->prev_sibling_c = node->prev_sibling_c;
  else
    parent->first_child->prev_sibling_c = node->prev_sibling_c;

  if (node->prev_sibling_c->next_sibling)
    node->prev_sibling_c->next_sibling = node->next_sibling;
  else
    parent->first_child = node->next_sibling;

  node->parent = 0;
  node->prev_sibling_c = 0;
  node->next_sibling = 0;
}

inline void append_attribute(xml_attribute_struct* attr,
                             xml_node_struct* node) {
  xml_attribute_struct* head = node->first_attribute;

  if (head) {
    xml_attribute_struct* tail = head->prev_attribute_c;

    tail->next_attribute = attr;
    attr->prev_attribute_c = tail;
    head->prev_attribute_c = attr;
  } else {
    node->first_attribute = attr;
    attr->prev_attribute_c = attr;
  }
}

inline void prepend_attribute(xml_attribute_struct* attr,
                              xml_node_struct* node) {
  xml_attribute_struct* head = node->first_attribute;

  if (head) {
    attr->prev_attribute_c = head->prev_attribute_c;
    head->prev_attribute_c = attr;
  } else
    attr->prev_attribute_c = attr;

  attr->next_attribute = head;
  node->first_attribute = attr;
}

inline void insert_attribute_after(xml_attribute_struct* attr,
                                   xml_attribute_struct* place,
                                   xml_node_struct* node) {
  if (place->next_attribute)
    place->next_attribute->prev_attribute_c = attr;
  else
    node->first_attribute->prev_attribute_c = attr;

  attr->next_attribute = place->next_attribute;
  attr->prev_attribute_c = place;
  place->next_attribute = attr;
}

inline void insert_attribute_before(xml_attribute_struct* attr,
                                    xml_attribute_struct* place,
                                    xml_node_struct* node) {
  if (place->prev_attribute_c->next_attribute)
    place->prev_attribute_c->next_attribute = attr;
  else
    node->first_attribute = attr;

  attr->prev_attribute_c = place->prev_attribute_c;
  attr->next_attribute = place;
  place->prev_attribute_c = attr;
}

inline void remove_attribute(xml_attribute_struct* attr,
                             xml_node_struct* node) {
  if (attr->next_attribute)
    attr->next_attribute->prev_attribute_c = attr->prev_attribute_c;
  else
    node->first_attribute->prev_attribute_c = attr->prev_attribute_c;

  if (attr->prev_attribute_c->next_attribute)
    attr->prev_attribute_c->next_attribute = attr->next_attribute;
  else
    node->first_attribute = attr->next_attribute;

  attr->prev_attribute_c = 0;
  attr->next_attribute = 0;
}

PUGI__FN_NO_INLINE xml_node_struct* append_new_node(
    xml_node_struct* node, xml_allocator& alloc,
    xml_node_type type = node_element) {
  if (!alloc.reserve()) return 0;

  xml_node_struct* child = allocate_node(alloc, type);
  if (!child) return 0;

  append_node(child, node);

  return child;
}

PUGI__FN_NO_INLINE xml_attribute_struct* append_new_attribute(
    xml_node_struct* node, xml_allocator& alloc) {
  if (!alloc.reserve()) return 0;

  xml_attribute_struct* attr = allocate_attribute(alloc);
  if (!attr) return 0;

  append_attribute(attr, node);

  return attr;
}
PUGI__NS_END

// Helper classes for code generation
PUGI__NS_BEGIN
struct opt_false {
  enum { value = 0 };
};

struct opt_true {
  enum { value = 1 };
};
PUGI__NS_END

// Unicode utilities
PUGI__NS_BEGIN
inline uint16_t endian_swap(uint16_t value) {
  return static_cast<uint16_t>(((value & 0xff) << 8) | (value >> 8));
}

inline uint32_t endian_swap(uint32_t value) {
  return ((value & 0xff) << 24) | ((value & 0xff00) << 8) |
         ((value & 0xff0000) >> 8) | (value >> 24);
}

struct utf8_counter {
  typedef size_t value_type;

  static value_type low(value_type result, uint32_t ch) {
    // U+0000..U+007F
    if (ch < 0x80) return result + 1;
    // U+0080..U+07FF
    else if (ch < 0x800)
      return result + 2;
    // U+0800..U+FFFF
    else
      return result + 3;
  }

  static value_type high(value_type result, uint32_t) {
    // U+10000..U+10FFFF
    return result + 4;
  }
};

struct utf8_writer {
  typedef uint8_t* value_type;

  static value_type low(value_type result, uint32_t ch) {
    // U+0000..U+007F
    if (ch < 0x80) {
      *result = static_cast<uint8_t>(ch);
      return result + 1;
    }
    // U+0080..U+07FF
    else if (ch < 0x800) {
      result[0] = static_cast<uint8_t>(0xC0 | (ch >> 6));
      result[1] = static_cast<uint8_t>(0x80 | (ch & 0x3F));
      return result + 2;
    }
    // U+0800..U+FFFF
    else {
      result[0] = static_cast<uint8_t>(0xE0 | (ch >> 12));
      result[1] = static_cast<uint8_t>(0x80 | ((ch >> 6) & 0x3F));
      result[2] = static_cast<uint8_t>(0x80 | (ch & 0x3F));
      return result + 3;
    }
  }

  static value_type high(value_type result, uint32_t ch) {
    // U+10000..U+10FFFF
    result[0] = static_cast<uint8_t>(0xF0 | (ch >> 18));
    result[1] = static_cast<uint8_t>(0x80 | ((ch >> 12) & 0x3F));
    result[2] = static_cast<uint8_t>(0x80 | ((ch >> 6) & 0x3F));
    result[3] = static_cast<uint8_t>(0x80 | (ch & 0x3F));
    return result + 4;
  }

  static value_type any(value_type result, uint32_t ch) {
    return (ch < 0x10000) ? low(result, ch) : high(result, ch);
  }
};

struct utf16_counter {
  typedef size_t value_type;

  static value_type low(value_type result, uint32_t) { return result + 1; }

  static value_type high(value_type result, uint32_t) { return result + 2; }
};

struct utf16_writer {
  typedef uint16_t* value_type;

  static value_type low(value_type result, uint32_t ch) {
    *result = static_cast<uint16_t>(ch);

    return result + 1;
  }

  static value_type high(value_type result, uint32_t ch) {
    uint32_t msh = static_cast<uint32_t>(ch - 0x10000) >> 10;
    uint32_t lsh = static_cast<uint32_t>(ch - 0x10000) & 0x3ff;

    result[0] = static_cast<uint16_t>(0xD800 + msh);
    result[1] = static_cast<uint16_t>(0xDC00 + lsh);

    return result + 2;
  }

  static value_type any(value_type result, uint32_t ch) {
    return (ch < 0x10000) ? low(result, ch) : high(result, ch);
  }
};

struct utf32_counter {
  typedef size_t value_type;

  static value_type low(value_type result, uint32_t) { return result + 1; }

  static value_type high(value_type result, uint32_t) { return result + 1; }
};

struct utf32_writer {
  typedef uint32_t* value_type;

  static value_type low(value_type result, uint32_t ch) {
    *result = ch;

    return result + 1;
  }

  static value_type high(value_type result, uint32_t ch) {
    *result = ch;

    return result + 1;
  }

  static value_type any(value_type result, uint32_t ch) {
    *result = ch;

    return result + 1;
  }
};

struct latin1_writer {
  typedef uint8_t* value_type;

  static value_type low(value_type result, uint32_t ch) {
    *result = static_cast<uint8_t>(ch > 255 ? '?' : ch);

    return result + 1;
  }

  static value_type high(value_type result, uint32_t ch) {
    (void)ch;

    *result = '?';

    return result + 1;
  }
};

struct utf8_decoder {
  typedef uint8_t type;

  template <typename Traits>
  static inline typename Traits::value_type process(
      const uint8_t* data, size_t size, typename Traits::value_type result,
      Traits) {
    const uint8_t utf8_byte_mask = 0x3f;

    while (size) {
      uint8_t lead = *data;

      // 0xxxxxxx -> U+0000..U+007F
      if (lead < 0x80) {
        result = Traits::low(result, lead);
        data += 1;
        size -= 1;

        // process aligned single-byte (ascii) blocks
        if ((reinterpret_cast<uintptr_t>(data) & 3) == 0) {
          // round-trip through void* to silence 'cast increases required
          // alignment of target type' warnings
          while (size >= 4 && (*static_cast<const uint32_t*>(
                                   static_cast<const void*>(data)) &
                               0x80808080) == 0) {
            result = Traits::low(result, data[0]);
            result = Traits::low(result, data[1]);
            result = Traits::low(result, data[2]);
            result = Traits::low(result, data[3]);
            data += 4;
            size -= 4;
          }
        }
      }
      // 110xxxxx -> U+0080..U+07FF
      else if (static_cast<unsigned int>(lead - 0xC0) < 0x20 && size >= 2 &&
               (data[1] & 0xc0) == 0x80) {
        result = Traits::low(
            result, ((lead & ~0xC0) << 6) | (data[1] & utf8_byte_mask));
        data += 2;
        size -= 2;
      }
      // 1110xxxx -> U+0800-U+FFFF
      else if (static_cast<unsigned int>(lead - 0xE0) < 0x10 && size >= 3 &&
               (data[1] & 0xc0) == 0x80 && (data[2] & 0xc0) == 0x80) {
        result = Traits::low(result, ((lead & ~0xE0) << 12) |
                                         ((data[1] & utf8_byte_mask) << 6) |
                                         (data[2] & utf8_byte_mask));
        data += 3;
        size -= 3;
      }
      // 11110xxx -> U+10000..U+10FFFF
      else if (static_cast<unsigned int>(lead - 0xF0) < 0x08 && size >= 4 &&
               (data[1] & 0xc0) == 0x80 && (data[2] & 0xc0) == 0x80 &&
               (data[3] & 0xc0) == 0x80) {
        result = Traits::high(result, ((lead & ~0xF0) << 18) |
                                          ((data[1] & utf8_byte_mask) << 12) |
                                          ((data[2] & utf8_byte_mask) << 6) |
                                          (data[3] & utf8_byte_mask));
        data += 4;
        size -= 4;
      }
      // 10xxxxxx or 11111xxx -> invalid
      else {
        data += 1;
        size -= 1;
      }
    }

    return result;
  }
};

template <typename opt_swap>
struct utf16_decoder {
  typedef uint16_t type;

  template <typename Traits>
  static inline typename Traits::value_type process(
      const uint16_t* data, size_t size, typename Traits::value_type result,
      Traits) {
    while (size) {
      uint16_t lead = opt_swap::value ? endian_swap(*data) : *data;

      // U+0000..U+D7FF
      if (lead < 0xD800) {
        result = Traits::low(result, lead);
        data += 1;
        size -= 1;
      }
      // U+E000..U+FFFF
      else if (static_cast<unsigned int>(lead - 0xE000) < 0x2000) {
        result = Traits::low(result, lead);
        data += 1;
        size -= 1;
      }
      // surrogate pair lead
      else if (static_cast<unsigned int>(lead - 0xD800) < 0x400 && size >= 2) {
        uint16_t next = opt_swap::value ? endian_swap(data[1]) : data[1];

        if (static_cast<unsigned int>(next - 0xDC00) < 0x400) {
          result = Traits::high(
              result, 0x10000 + ((lead & 0x3ff) << 10) + (next & 0x3ff));
          data += 2;
          size -= 2;
        } else {
          data += 1;
          size -= 1;
        }
      } else {
        data += 1;
        size -= 1;
      }
    }

    return result;
  }
};

template <typename opt_swap>
struct utf32_decoder {
  typedef uint32_t type;

  template <typename Traits>
  static inline typename Traits::value_type process(
      const uint32_t* data, size_t size, typename Traits::value_type result,
      Traits) {
    while (size) {
      uint32_t lead = opt_swap::value ? endian_swap(*data) : *data;

      // U+0000..U+FFFF
      if (lead < 0x10000) {
        result = Traits::low(result, lead);
        data += 1;
        size -= 1;
      }
      // U+10000..U+10FFFF
      else {
        result = Traits::high(result, lead);
        data += 1;
        size -= 1;
      }
    }

    return result;
  }
};

struct latin1_decoder {
  typedef uint8_t type;

  template <typename Traits>
  static inline typename Traits::value_type process(
      const uint8_t* data, size_t size, typename Traits::value_type result,
      Traits) {
    while (size) {
      result = Traits::low(result, *data);
      data += 1;
      size -= 1;
    }

    return result;
  }
};

template <size_t size>
struct wchar_selector;

template <>
struct wchar_selector<2> {
  typedef uint16_t type;
  typedef utf16_counter counter;
  typedef utf16_writer writer;
  typedef utf16_decoder<opt_false> decoder;
};

template <>
struct wchar_selector<4> {
  typedef uint32_t type;
  typedef utf32_counter counter;
  typedef utf32_writer writer;
  typedef utf32_decoder<opt_false> decoder;
};

typedef wchar_selector<sizeof(wchar_t)>::counter wchar_counter;
typedef wchar_selector<sizeof(wchar_t)>::writer wchar_writer;

struct wchar_decoder {
  typedef wchar_t type;

  template <typename Traits>
  static inline typename Traits::value_type process(
      const wchar_t* data, size_t size, typename Traits::value_type result,
      Traits traits) {
    typedef wchar_selector<sizeof(wchar_t)>::decoder decoder;

    return decoder::process(
        reinterpret_cast<const typename decoder::type*>(data), size, result,
        traits);
  }
};

#ifdef PUGIXML_WCHAR_MODE
PUGI__FN void convert_wchar_endian_swap(wchar_t* result, const wchar_t* data,
                                        size_t length) {
  for (size_t i = 0; i < length; ++i)
    result[i] = static_cast<wchar_t>(endian_swap(
        static_cast<wchar_selector<sizeof(wchar_t)>::type>(data[i])));
}
#endif
PUGI__NS_END

PUGI__NS_BEGIN
enum chartype_t {
  ct_parse_pcdata = 1,    // \0, &, \r, <
  ct_parse_attr = 2,      // \0, &, \r, ', "
  ct_parse_attr_ws = 4,   // \0, &, \r, ', ", \n, tab
  ct_space = 8,           // \r, \n, space, tab
  ct_parse_cdata = 16,    // \0, ], >, \r
  ct_parse_comment = 32,  // \0, -, >, \r
  ct_symbol = 64,         // Any symbol > 127, a-z, A-Z, 0-9, _, :, -, .
  ct_start_symbol = 128   // Any symbol > 127, a-z, A-Z, _, :
};

static const unsigned char chartype_table[256] = {
    55,  0,   0,   0,   0,   0,   0,   0,   0,   12,  12,  0,   0,   63,
    0,   0,  // 0-15
    0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
    0,   0,  // 16-31
    8,   0,   6,   0,   0,   0,   7,   6,   0,   0,   0,   0,   0,   96,
    64,  0,  // 32-47
    64,  64,  64,  64,  64,  64,  64,  64,  64,  64,  192, 0,   1,   0,
    48,  0,  // 48-63
    0,   192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192,  // 64-79
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 0,   0,   16,
    0,   192,  // 80-95
    0,   192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192,  // 96-111
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 0,   0,   0,
    0,   0,  // 112-127

    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192,  // 128+
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192,
    192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192};

enum chartypex_t {
  ctx_special_pcdata =
      1,  // Any symbol >= 0 and < 32 (except \t, \r, \n), &, <, >
  ctx_special_attr = 2,  // Any symbol >= 0 and < 32 (except \t), &, <, >, "
  ctx_start_symbol = 4,  // Any symbol > 127, a-z, A-Z, _
  ctx_digit = 8,         // 0-9
  ctx_symbol = 16        // Any symbol > 127, a-z, A-Z, 0-9, _, -, .
};

static const unsigned char chartypex_table[256] = {
    3,  3,  3,  3,  3,  3,  3,  3,  3,  0,  2,  3,  3,  2,  3,  3,  // 0-15
    3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  // 16-31
    0,  0,  2,  0,  0,  0,  3,  0,  0,  0,  0,  0,  0,  16, 16, 0,  // 32-47
    24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 0,  0,  3,  0,  3,  0,  // 48-63

    0,  20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,  // 64-79
    20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 0,  0,  0,  0,  20,  // 80-95
    0,  20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,  // 96-111
    20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 0,  0,  0,  0,  0,   // 112-127

    20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,  // 128+
    20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,
    20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,
    20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,
    20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,
    20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,
    20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20};

#ifdef PUGIXML_WCHAR_MODE
#define PUGI__IS_CHARTYPE_IMPL(c, ct, table)                                 \
  ((static_cast<unsigned int>(c) < 128 ? table[static_cast<unsigned int>(c)] \
                                       : table[128]) &                       \
   (ct))
#else
#define PUGI__IS_CHARTYPE_IMPL(c, ct, table) \
  (table[static_cast<unsigned char>(c)] & (ct))
#endif

#define PUGI__IS_CHARTYPE(c, ct) PUGI__IS_CHARTYPE_IMPL(c, ct, chartype_table)
#define PUGI__IS_CHARTYPEX(c, ct) PUGI__IS_CHARTYPE_IMPL(c, ct, chartypex_table)

PUGI__FN bool is_little_endian() {
  unsigned int ui = 1;

  return *reinterpret_cast<unsigned char*>(&ui) == 1;
}

PUGI__FN xml_encoding get_wchar_encoding() {
  PUGI__STATIC_ASSERT(sizeof(wchar_t) == 2 || sizeof(wchar_t) == 4);

  if (sizeof(wchar_t) == 2)
    return is_little_endian() ? encoding_utf16_le : encoding_utf16_be;
  else
    return is_little_endian() ? encoding_utf32_le : encoding_utf32_be;
}

PUGI__FN bool parse_declaration_encoding(const uint8_t* data, size_t size,
                                         const uint8_t*& out_encoding,
                                         size_t& out_length) {
#define PUGI__SCANCHAR(ch)                                  \
  {                                                         \
    if (offset >= size || data[offset] != ch) return false; \
    offset++;                                               \
  }
#define PUGI__SCANCHARTYPE(ct)                                             \
  {                                                                        \
    while (offset < size && PUGI__IS_CHARTYPE(data[offset], ct)) offset++; \
  }

  // check if we have a non-empty XML declaration
  if (size < 6 || !((data[0] == '<') & (data[1] == '?') & (data[2] == 'x') &
                        (data[3] == 'm') & (data[4] == 'l') &&
                    PUGI__IS_CHARTYPE(data[5], ct_space)))
    return false;

  // scan XML declaration until the encoding field
  for (size_t i = 6; i + 1 < size; ++i) {
    // declaration can not contain ? in quoted values
    if (data[i] == '?') return false;

    if (data[i] == 'e' && data[i + 1] == 'n') {
      size_t offset = i;

      // encoding follows the version field which can't contain 'en' so this has
      // to be the encoding if XML is well formed
      PUGI__SCANCHAR('e');
      PUGI__SCANCHAR('n');
      PUGI__SCANCHAR('c');
      PUGI__SCANCHAR('o');
      PUGI__SCANCHAR('d');
      PUGI__SCANCHAR('i');
      PUGI__SCANCHAR('n');
      PUGI__SCANCHAR('g');

      // S? = S?
      PUGI__SCANCHARTYPE(ct_space);
      PUGI__SCANCHAR('=');
      PUGI__SCANCHARTYPE(ct_space);

      // the only two valid delimiters are ' and "
      uint8_t delimiter = (offset < size && data[offset] == '"') ? '"' : '\'';

      PUGI__SCANCHAR(delimiter);

      size_t start = offset;

      out_encoding = data + offset;

      PUGI__SCANCHARTYPE(ct_symbol);

      out_length = offset - start;

      PUGI__SCANCHAR(delimiter);

      return true;
    }
  }

  return false;

#undef PUGI__SCANCHAR
#undef PUGI__SCANCHARTYPE
}

PUGI__FN xml_encoding guess_buffer_encoding(const uint8_t* data, size_t size) {
  // skip encoding autodetection if input buffer is too small
  if (size < 4) return encoding_utf8;

  uint8_t d0 = data[0], d1 = data[1], d2 = data[2], d3 = data[3];

  // look for BOM in first few bytes
  if (d0 == 0 && d1 == 0 && d2 == 0xfe && d3 == 0xff) return encoding_utf32_be;
  if (d0 == 0xff && d1 == 0xfe && d2 == 0 && d3 == 0) return encoding_utf32_le;
  if (d0 == 0xfe && d1 == 0xff) return encoding_utf16_be;
  if (d0 == 0xff && d1 == 0xfe) return encoding_utf16_le;
  if (d0 == 0xef && d1 == 0xbb && d2 == 0xbf) return encoding_utf8;

  // look for <, <? or <?xm in various encodings
  if (d0 == 0 && d1 == 0 && d2 == 0 && d3 == 0x3c) return encoding_utf32_be;
  if (d0 == 0x3c && d1 == 0 && d2 == 0 && d3 == 0) return encoding_utf32_le;
  if (d0 == 0 && d1 == 0x3c && d2 == 0 && d3 == 0x3f) return encoding_utf16_be;
  if (d0 == 0x3c && d1 == 0 && d2 == 0x3f && d3 == 0) return encoding_utf16_le;

  // look for utf16 < followed by node name (this may fail, but is better than
  // utf8 since it's zero terminated so early)
  if (d0 == 0 && d1 == 0x3c) return encoding_utf16_be;
  if (d0 == 0x3c && d1 == 0) return encoding_utf16_le;

  // no known BOM detected; parse declaration
  const uint8_t* enc = 0;
  size_t enc_length = 0;

  if (d0 == 0x3c && d1 == 0x3f && d2 == 0x78 && d3 == 0x6d &&
      parse_declaration_encoding(data, size, enc, enc_length)) {
    // iso-8859-1 (case-insensitive)
    if (enc_length == 10 && (enc[0] | ' ') == 'i' && (enc[1] | ' ') == 's' &&
        (enc[2] | ' ') == 'o' && enc[3] == '-' && enc[4] == '8' &&
        enc[5] == '8' && enc[6] == '5' && enc[7] == '9' && enc[8] == '-' &&
        enc[9] == '1')
      return encoding_latin1;

    // latin1 (case-insensitive)
    if (enc_length == 6 && (enc[0] | ' ') == 'l' && (enc[1] | ' ') == 'a' &&
        (enc[2] | ' ') == 't' && (enc[3] | ' ') == 'i' &&
        (enc[4] | ' ') == 'n' && enc[5] == '1')
      return encoding_latin1;
  }

  return encoding_utf8;
}

PUGI__FN xml_encoding get_buffer_encoding(xml_encoding encoding,
                                          const void* contents, size_t size) {
  // replace wchar encoding with utf implementation
  if (encoding == encoding_wchar) return get_wchar_encoding();

  // replace utf16 encoding with utf16 with specific endianness
  if (encoding == encoding_utf16)
    return is_little_endian() ? encoding_utf16_le : encoding_utf16_be;

  // replace utf32 encoding with utf32 with specific endianness
  if (encoding == encoding_utf32)
    return is_little_endian() ? encoding_utf32_le : encoding_utf32_be;

  // only do autodetection if no explicit encoding is requested
  if (encoding != encoding_auto) return encoding;

  // try to guess encoding (based on XML specification, Appendix F.1)
  const uint8_t* data = static_cast<const uint8_t*>(contents);

  return guess_buffer_encoding(data, size);
}

PUGI__FN bool get_mutable_buffer(char_t*& out_buffer, size_t& out_length,
                                 const void* contents, size_t size,
                                 bool is_mutable) {
  size_t length = size / sizeof(char_t);

  if (is_mutable) {
    out_buffer = static_cast<char_t*>(const_cast<void*>(contents));
    out_length = length;
  } else {
    char_t* buffer = static_cast<char_t*>(
        xml_memory::allocate((length + 1) * sizeof(char_t)));
    if (!buffer) return false;

    if (contents)
      memcpy(buffer, contents, length * sizeof(char_t));
    else
      assert(length == 0);

    buffer[length] = 0;

    out_buffer = buffer;
    out_length = length + 1;
  }

  return true;
}

#ifdef PUGIXML_WCHAR_MODE
PUGI__FN bool need_endian_swap_utf(xml_encoding le, xml_encoding re) {
  return (le == encoding_utf16_be && re == encoding_utf16_le) ||
         (le == encoding_utf16_le && re == encoding_utf16_be) ||
         (le == encoding_utf32_be && re == encoding_utf32_le) ||
         (le == encoding_utf32_le && re == encoding_utf32_be);
}

PUGI__FN bool convert_buffer_endian_swap(char_t*& out_buffer,
                                         size_t& out_length,
                                         const void* contents, size_t size,
                                         bool is_mutable) {
  const char_t* data = static_cast<const char_t*>(contents);
  size_t length = size / sizeof(char_t);

  if (is_mutable) {
    char_t* buffer = const_cast<char_t*>(data);

    convert_wchar_endian_swap(buffer, data, length);

    out_buffer = buffer;
    out_length = length;
  } else {
    char_t* buffer = static_cast<char_t*>(
        xml_memory::allocate((length + 1) * sizeof(char_t)));
    if (!buffer) return false;

    convert_wchar_endian_swap(buffer, data, length);
    buffer[length] = 0;

    out_buffer = buffer;
    out_length = length + 1;
  }

  return true;
}

template <typename D>
PUGI__FN bool convert_buffer_generic(char_t*& out_buffer, size_t& out_length,
                                     const void* contents, size_t size, D) {
  const typename D::type* data = static_cast<const typename D::type*>(contents);
  size_t data_length = size / sizeof(typename D::type);

  // first pass: get length in wchar_t units
  size_t length = D::process(data, data_length, 0, wchar_counter());

  // allocate buffer of suitable length
  char_t* buffer =
      static_cast<char_t*>(xml_memory::allocate((length + 1) * sizeof(char_t)));
  if (!buffer) return false;

  // second pass: convert utf16 input to wchar_t
  wchar_writer::value_type obegin =
      reinterpret_cast<wchar_writer::value_type>(buffer);
  wchar_writer::value_type oend =
      D::process(data, data_length, obegin, wchar_writer());

  assert(oend == obegin + length);
  *oend = 0;

  out_buffer = buffer;
  out_length = length + 1;

  return true;
}

PUGI__FN bool convert_buffer(char_t*& out_buffer, size_t& out_length,
                             xml_encoding encoding, const void* contents,
                             size_t size, bool is_mutable) {
  // get native encoding
  xml_encoding wchar_encoding = get_wchar_encoding();

  // fast path: no conversion required
  if (encoding == wchar_encoding)
    return get_mutable_buffer(out_buffer, out_length, contents, size,
                              is_mutable);

  // only endian-swapping is required
  if (need_endian_swap_utf(encoding, wchar_encoding))
    return convert_buffer_endian_swap(out_buffer, out_length, contents, size,
                                      is_mutable);

  // source encoding is utf8
  if (encoding == encoding_utf8)
    return convert_buffer_generic(out_buffer, out_length, contents, size,
                                  utf8_decoder());

  // source encoding is utf16
  if (encoding == encoding_utf16_be || encoding == encoding_utf16_le) {
    xml_encoding native_encoding =
        is_little_endian() ? encoding_utf16_le : encoding_utf16_be;

    return (native_encoding == encoding)
               ? convert_buffer_generic(out_buffer, out_length, contents, size,
                                        utf16_decoder<opt_false>())
               : convert_buffer_generic(out_buffer, out_length, contents, size,
                                        utf16_decoder<opt_true>());
  }

  // source encoding is utf32
  if (encoding == encoding_utf32_be || encoding == encoding_utf32_le) {
    xml_encoding native_encoding =
        is_little_endian() ? encoding_utf32_le : encoding_utf32_be;

    return (native_encoding == encoding)
               ? convert_buffer_generic(out_buffer, out_length, contents, size,
                                        utf32_decoder<opt_false>())
               : convert_buffer_generic(out_buffer, out_length, contents, size,
                                        utf32_decoder<opt_true>());
  }

  // source encoding is latin1
  if (encoding == encoding_latin1)
    return convert_buffer_generic(out_buffer, out_length, contents, size,
                                  latin1_decoder());

  assert(false && "Invalid encoding");
  return false;
}
#else
template <typename D>
PUGI__FN bool convert_buffer_generic(char_t*& out_buffer, size_t& out_length,
                                     const void* contents, size_t size, D) {
  const typename D::type* data = static_cast<const typename D::type*>(contents);
  size_t data_length = size / sizeof(typename D::type);

  // first pass: get length in utf8 units
  size_t length = D::process(data, data_length, 0, utf8_counter());

  // allocate buffer of suitable length
  char_t* buffer =
      static_cast<char_t*>(xml_memory::allocate((length + 1) * sizeof(char_t)));
  if (!buffer) return false;

  // second pass: convert utf16 input to utf8
  uint8_t* obegin = reinterpret_cast<uint8_t*>(buffer);
  uint8_t* oend = D::process(data, data_length, obegin, utf8_writer());

  assert(oend == obegin + length);
  *oend = 0;

  out_buffer = buffer;
  out_length = length + 1;

  return true;
}

PUGI__FN size_t get_latin1_7bit_prefix_length(const uint8_t* data,
                                              size_t size) {
  for (size_t i = 0; i < size; ++i)
    if (data[i] > 127) return i;

  return size;
}

PUGI__FN bool convert_buffer_latin1(char_t*& out_buffer, size_t& out_length,
                                    const void* contents, size_t size,
                                    bool is_mutable) {
  const uint8_t* data = static_cast<const uint8_t*>(contents);
  size_t data_length = size;

  // get size of prefix that does not need utf8 conversion
  size_t prefix_length = get_latin1_7bit_prefix_length(data, data_length);
  assert(prefix_length <= data_length);

  const uint8_t* postfix = data + prefix_length;
  size_t postfix_length = data_length - prefix_length;

  // if no conversion is needed, just return the original buffer
  if (postfix_length == 0)
    return get_mutable_buffer(out_buffer, out_length, contents, size,
                              is_mutable);

  // first pass: get length in utf8 units
  size_t length =
      prefix_length +
      latin1_decoder::process(postfix, postfix_length, 0, utf8_counter());

  // allocate buffer of suitable length
  char_t* buffer =
      static_cast<char_t*>(xml_memory::allocate((length + 1) * sizeof(char_t)));
  if (!buffer) return false;

  // second pass: convert latin1 input to utf8
  memcpy(buffer, data, prefix_length);

  uint8_t* obegin = reinterpret_cast<uint8_t*>(buffer);
  uint8_t* oend = latin1_decoder::process(
      postfix, postfix_length, obegin + prefix_length, utf8_writer());

  assert(oend == obegin + length);
  *oend = 0;

  out_buffer = buffer;
  out_length = length + 1;

  return true;
}

PUGI__FN bool convert_buffer(char_t*& out_buffer, size_t& out_length,
                             xml_encoding encoding, const void* contents,
                             size_t size, bool is_mutable) {
  // fast path: no conversion required
  if (encoding == encoding_utf8)
    return get_mutable_buffer(out_buffer, out_length, contents, size,
                              is_mutable);

  // source encoding is utf16
  if (encoding == encoding_utf16_be || encoding == encoding_utf16_le) {
    xml_encoding native_encoding =
        is_little_endian() ? encoding_utf16_le : encoding_utf16_be;

    return (native_encoding == encoding)
               ? convert_buffer_generic(out_buffer, out_length, contents, size,
                                        utf16_decoder<opt_false>())
               : convert_buffer_generic(out_buffer, out_length, contents, size,
                                        utf16_decoder<opt_true>());
  }

  // source encoding is utf32
  if (encoding == encoding_utf32_be || encoding == encoding_utf32_le) {
    xml_encoding native_encoding =
        is_little_endian() ? encoding_utf32_le : encoding_utf32_be;

    return (native_encoding == encoding)
               ? convert_buffer_generic(out_buffer, out_length, contents, size,
                                        utf32_decoder<opt_false>())
               : convert_buffer_generic(out_buffer, out_length, contents, size,
                                        utf32_decoder<opt_true>());
  }

  // source encoding is latin1
  if (encoding == encoding_latin1)
    return convert_buffer_latin1(out_buffer, out_length, contents, size,
                                 is_mutable);

  assert(false && "Invalid encoding");
  return false;
}
#endif

PUGI__FN size_t as_utf8_begin(const wchar_t* str, size_t length) {
  // get length in utf8 characters
  return wchar_decoder::process(str, length, 0, utf8_counter());
}

PUGI__FN void as_utf8_end(char* buffer, size_t size, const wchar_t* str,
                          size_t length) {
  // convert to utf8
  uint8_t* begin = reinterpret_cast<uint8_t*>(buffer);
  uint8_t* end = wchar_decoder::process(str, length, begin, utf8_writer());

  assert(begin + size == end);
  (void)!end;
  (void)!size;
}

#ifndef PUGIXML_NO_STL
PUGI__FN std::string as_utf8_impl(const wchar_t* str, size_t length) {
  // first pass: get length in utf8 characters
  size_t size = as_utf8_begin(str, length);

  // allocate resulting string
  std::string result;
  result.resize(size);

  // second pass: convert to utf8
  if (size > 0) as_utf8_end(&result[0], size, str, length);

  return result;
}

PUGI__FN std::basic_string<wchar_t> as_wide_impl(const char* str, size_t size) {
  const uint8_t* data = reinterpret_cast<const uint8_t*>(str);

  // first pass: get length in wchar_t units
  size_t length = utf8_decoder::process(data, size, 0, wchar_counter());

  // allocate resulting string
  std::basic_string<wchar_t> result;
  result.resize(length);

  // second pass: convert to wchar_t
  if (length > 0) {
    wchar_writer::value_type begin =
        reinterpret_cast<wchar_writer::value_type>(&result[0]);
    wchar_writer::value_type end =
        utf8_decoder::process(data, size, begin, wchar_writer());

    assert(begin + length == end);
    (void)!end;
  }

  return result;
}
#endif

template <typename Header>
inline bool strcpy_insitu_allow(size_t length, const Header& header,
                                uintptr_t header_mask, char_t* target) {
  // never reuse shared memory
  if (header & xml_memory_page_contents_shared_mask) return false;

  size_t target_length = strlength(target);

  // always reuse document buffer memory if possible
  if ((header & header_mask) == 0) return target_length >= length;

  // reuse heap memory if waste is not too great
  const size_t reuse_threshold = 32;

  return target_length >= length &&
         (target_length < reuse_threshold ||
          target_length - length < target_length / 2);
}

template <typename String, typename Header>
PUGI__FN bool strcpy_insitu(String& dest, Header& header, uintptr_t header_mask,
                            const char_t* source, size_t source_length) {
  if (source_length == 0) {
    // empty string and null pointer are equivalent, so just deallocate old
    // memory
    xml_allocator* alloc = PUGI__GETPAGE_IMPL(header)->allocator;

    if (header & header_mask) alloc->deallocate_string(dest);

    // mark the string as not allocated
    dest = 0;
    header &= ~header_mask;

    return true;
  } else if (dest &&
             strcpy_insitu_allow(source_length, header, header_mask, dest)) {
    // we can reuse old buffer, so just copy the new data (including zero
    // terminator)
    memcpy(dest, source, source_length * sizeof(char_t));
    dest[source_length] = 0;

    return true;
  } else {
    xml_allocator* alloc = PUGI__GETPAGE_IMPL(header)->allocator;

    if (!alloc->reserve()) return false;

    // allocate new buffer
    char_t* buf = alloc->allocate_string(source_length + 1);
    if (!buf) return false;

    // copy the string (including zero terminator)
    memcpy(buf, source, source_length * sizeof(char_t));
    buf[source_length] = 0;

    // deallocate old buffer (*after* the above to protect against overlapping
    // memory and/or allocation failures)
    if (header & header_mask) alloc->deallocate_string(dest);

    // the string is now allocated, so set the flag
    dest = buf;
    header |= header_mask;

    return true;
  }
}

struct gap {
  char_t* end;
  size_t size;

  gap() : end(0), size(0) {}

  // Push new gap, move s count bytes further (skipping the gap).
  // Collapse previous gap.
  void push(char_t*& s, size_t count) {
    if (end)  // there was a gap already; collapse it
    {
      // Move [old_gap_end, new_gap_start) to [old_gap_start, ...)
      assert(s >= end);
      memmove(end - size, end,
              reinterpret_cast<char*>(s) - reinterpret_cast<char*>(end));
    }

    s += count;  // end of current gap

    // "merge" two gaps
    end = s;
    size += count;
  }

  // Collapse all gaps, return past-the-end pointer
  char_t* flush(char_t* s) {
    if (end) {
      // Move [old_gap_end, current_pos) to [old_gap_start, ...)
      assert(s >= end);
      memmove(end - size, end,
              reinterpret_cast<char*>(s) - reinterpret_cast<char*>(end));

      return s - size;
    } else
      return s;
  }
};

PUGI__FN char_t* strconv_escape(char_t* s, gap& g) {
  char_t* stre = s + 1;

  switch (*stre) {
    case '#':  // &#...
    {
      unsigned int ucsc = 0;

      if (stre[1] == 'x')  // &#x... (hex code)
      {
        stre += 2;

        char_t ch = *stre;

        if (ch == ';') return stre;

        for (;;) {
          if (static_cast<unsigned int>(ch - '0') <= 9)
            ucsc = 16 * ucsc + (ch - '0');
          else if (static_cast<unsigned int>((ch | ' ') - 'a') <= 5)
            ucsc = 16 * ucsc + ((ch | ' ') - 'a' + 10);
          else if (ch == ';')
            break;
          else  // cancel
            return stre;

          ch = *++stre;
        }

        ++stre;
      } else  // &#... (dec code)
      {
        char_t ch = *++stre;

        if (ch == ';') return stre;

        for (;;) {
          if (static_cast<unsigned int>(static_cast<unsigned int>(ch) - '0') <=
              9)
            ucsc = 10 * ucsc + (ch - '0');
          else if (ch == ';')
            break;
          else  // cancel
            return stre;

          ch = *++stre;
        }

        ++stre;
      }

#ifdef PUGIXML_WCHAR_MODE
      s = reinterpret_cast<char_t*>(wchar_writer::any(
          reinterpret_cast<wchar_writer::value_type>(s), ucsc));
#else
      s = reinterpret_cast<char_t*>(
          utf8_writer::any(reinterpret_cast<uint8_t*>(s), ucsc));
#endif

      g.push(s, stre - s);
      return stre;
    }

    case 'a':  // &a
    {
      ++stre;

      if (*stre == 'm')  // &am
      {
        if (*++stre == 'p' && *++stre == ';')  // &amp;
        {
          *s++ = '&';
          ++stre;

          g.push(s, stre - s);
          return stre;
        }
      } else if (*stre == 'p')  // &ap
      {
        if (*++stre == 'o' && *++stre == 's' && *++stre == ';')  // &apos;
        {
          *s++ = '\'';
          ++stre;

          g.push(s, stre - s);
          return stre;
        }
      }
      break;
    }

    case 'g':  // &g
    {
      if (*++stre == 't' && *++stre == ';')  // &gt;
      {
        *s++ = '>';
        ++stre;

        g.push(s, stre - s);
        return stre;
      }
      break;
    }

    case 'l':  // &l
    {
      if (*++stre == 't' && *++stre == ';')  // &lt;
      {
        *s++ = '<';
        ++stre;

        g.push(s, stre - s);
        return stre;
      }
      break;
    }

    case 'q':  // &q
    {
      if (*++stre == 'u' && *++stre == 'o' && *++stre == 't' &&
          *++stre == ';')  // &quot;
      {
        *s++ = '"';
        ++stre;

        g.push(s, stre - s);
        return stre;
      }
      break;
    }

    default:
      break;
  }

  return stre;
}

// Parser utilities
#define PUGI__ENDSWITH(c, e) ((c) == (e) || ((c) == 0 && endch == (e)))
#define PUGI__SKIPWS()                           \
  {                                              \
    while (PUGI__IS_CHARTYPE(*s, ct_space)) ++s; \
  }
#define PUGI__OPTSET(OPT) (optmsk & (OPT))
#define PUGI__PUSHNODE(TYPE)                                 \
  {                                                          \
    cursor = append_new_node(cursor, *alloc, TYPE);          \
    if (!cursor) PUGI__THROW_ERROR(status_out_of_memory, s); \
  }
#define PUGI__POPNODE() \
  { cursor = cursor->parent; }
#define PUGI__SCANFOR(X)         \
  {                              \
    while (*s != 0 && !(X)) ++s; \
  }
#define PUGI__SCANWHILE(X) \
  {                        \
    while (X) ++s;         \
  }
#define PUGI__SCANWHILE_UNROLL(X) \
  {                               \
    for (;;) {                    \
      char_t ss = s[0];           \
      if (PUGI__UNLIKELY(!(X))) { \
        break;                    \
      }                           \
      ss = s[1];                  \
      if (PUGI__UNLIKELY(!(X))) { \
        s += 1;                   \
        break;                    \
      }                           \
      ss = s[2];                  \
      if (PUGI__UNLIKELY(!(X))) { \
        s += 2;                   \
        break;                    \
      }                           \
      ss = s[3];                  \
      if (PUGI__UNLIKELY(!(X))) { \
        s += 3;                   \
        break;                    \
      }                           \
      s += 4;                     \
    }                             \
  }
#define PUGI__ENDSEG() \
  {                    \
    ch = *s;           \
    *s = 0;            \
    ++s;               \
  }
#define PUGI__THROW_ERROR(err, m) \
  return error_offset = m, error_status = err, static_cast<char_t*>(0)
#define PUGI__CHECK_ERROR(err, m)           \
  {                                         \
    if (*s == 0) PUGI__THROW_ERROR(err, m); \
  }

PUGI__FN char_t* strconv_comment(char_t* s, char_t endch) {
  gap g;

  while (true) {
    PUGI__SCANWHILE_UNROLL(!PUGI__IS_CHARTYPE(ss, ct_parse_comment));

    if (*s == '\r')  // Either a single 0x0d or 0x0d 0x0a pair
    {
      *s++ = '\n';  // replace first one with 0x0a

      if (*s == '\n') g.push(s, 1);
    } else if (s[0] == '-' && s[1] == '-' &&
               PUGI__ENDSWITH(s[2], '>'))  // comment ends here
    {
      *g.flush(s) = 0;

      return s + (s[2] == '>' ? 3 : 2);
    } else if (*s == 0) {
      return 0;
    } else
      ++s;
  }
}

PUGI__FN char_t* strconv_cdata(char_t* s, char_t endch) {
  gap g;

  while (true) {
    PUGI__SCANWHILE_UNROLL(!PUGI__IS_CHARTYPE(ss, ct_parse_cdata));

    if (*s == '\r')  // Either a single 0x0d or 0x0d 0x0a pair
    {
      *s++ = '\n';  // replace first one with 0x0a

      if (*s == '\n') g.push(s, 1);
    } else if (s[0] == ']' && s[1] == ']' &&
               PUGI__ENDSWITH(s[2], '>'))  // CDATA ends here
    {
      *g.flush(s) = 0;

      return s + 1;
    } else if (*s == 0) {
      return 0;
    } else
      ++s;
  }
}

typedef char_t* (*strconv_pcdata_t)(char_t*);

template <typename opt_trim, typename opt_eol, typename opt_escape>
struct strconv_pcdata_impl {
  static char_t* parse(char_t* s) {
    gap g;

    char_t* begin = s;

    while (true) {
      PUGI__SCANWHILE_UNROLL(!PUGI__IS_CHARTYPE(ss, ct_parse_pcdata));

      if (*s == '<')  // PCDATA ends here
      {
        char_t* end = g.flush(s);

        if (opt_trim::value)
          while (end > begin && PUGI__IS_CHARTYPE(end[-1], ct_space)) --end;

        *end = 0;

        return s + 1;
      } else if (opt_eol::value &&
                 *s == '\r')  // Either a single 0x0d or 0x0d 0x0a pair
      {
        *s++ = '\n';  // replace first one with 0x0a

        if (*s == '\n') g.push(s, 1);
      } else if (opt_escape::value && *s == '&') {
        s = strconv_escape(s, g);
      } else if (*s == 0) {
        char_t* end = g.flush(s);

        if (opt_trim::value)
          while (end > begin && PUGI__IS_CHARTYPE(end[-1], ct_space)) --end;

        *end = 0;

        return s;
      } else
        ++s;
    }
  }
};

PUGI__FN strconv_pcdata_t get_strconv_pcdata(unsigned int optmask) {
  PUGI__STATIC_ASSERT(parse_escapes == 0x10 && parse_eol == 0x20 &&
                      parse_trim_pcdata == 0x0800);

  switch (((optmask >> 4) & 3) |
          ((optmask >> 9) & 4))  // get bitmask for flags (eol escapes trim)
  {
    case 0:
      return strconv_pcdata_impl<opt_false, opt_false, opt_false>::parse;
    case 1:
      return strconv_pcdata_impl<opt_false, opt_false, opt_true>::parse;
    case 2:
      return strconv_pcdata_impl<opt_false, opt_true, opt_false>::parse;
    case 3:
      return strconv_pcdata_impl<opt_false, opt_true, opt_true>::parse;
    case 4:
      return strconv_pcdata_impl<opt_true, opt_false, opt_false>::parse;
    case 5:
      return strconv_pcdata_impl<opt_true, opt_false, opt_true>::parse;
    case 6:
      return strconv_pcdata_impl<opt_true, opt_true, opt_false>::parse;
    case 7:
      return strconv_pcdata_impl<opt_true, opt_true, opt_true>::parse;
    default:
      assert(false);
      return 0;  // should not get here
  }
}

typedef char_t* (*strconv_attribute_t)(char_t*, char_t);

template <typename opt_escape>
struct strconv_attribute_impl {
  static char_t* parse_wnorm(char_t* s, char_t end_quote) {
    gap g;

    // trim leading whitespaces
    if (PUGI__IS_CHARTYPE(*s, ct_space)) {
      char_t* str = s;

      do ++str;
      while (PUGI__IS_CHARTYPE(*str, ct_space));

      g.push(s, str - s);
    }

    while (true) {
      PUGI__SCANWHILE_UNROLL(
          !PUGI__IS_CHARTYPE(ss, ct_parse_attr_ws | ct_space));

      if (*s == end_quote) {
        char_t* str = g.flush(s);

        do *str-- = 0;
        while (PUGI__IS_CHARTYPE(*str, ct_space));

        return s + 1;
      } else if (PUGI__IS_CHARTYPE(*s, ct_space)) {
        *s++ = ' ';

        if (PUGI__IS_CHARTYPE(*s, ct_space)) {
          char_t* str = s + 1;
          while (PUGI__IS_CHARTYPE(*str, ct_space)) ++str;

          g.push(s, str - s);
        }
      } else if (opt_escape::value && *s == '&') {
        s = strconv_escape(s, g);
      } else if (!*s) {
        return 0;
      } else
        ++s;
    }
  }

  static char_t* parse_wconv(char_t* s, char_t end_quote) {
    gap g;

    while (true) {
      PUGI__SCANWHILE_UNROLL(!PUGI__IS_CHARTYPE(ss, ct_parse_attr_ws));

      if (*s == end_quote) {
        *g.flush(s) = 0;

        return s + 1;
      } else if (PUGI__IS_CHARTYPE(*s, ct_space)) {
        if (*s == '\r') {
          *s++ = ' ';

          if (*s == '\n') g.push(s, 1);
        } else
          *s++ = ' ';
      } else if (opt_escape::value && *s == '&') {
        s = strconv_escape(s, g);
      } else if (!*s) {
        return 0;
      } else
        ++s;
    }
  }

  static char_t* parse_eol(char_t* s, char_t end_quote) {
    gap g;

    while (true) {
      PUGI__SCANWHILE_UNROLL(!PUGI__IS_CHARTYPE(ss, ct_parse_attr));

      if (*s == end_quote) {
        *g.flush(s) = 0;

        return s + 1;
      } else if (*s == '\r') {
        *s++ = '\n';

        if (*s == '\n') g.push(s, 1);
      } else if (opt_escape::value && *s == '&') {
        s = strconv_escape(s, g);
      } else if (!*s) {
        return 0;
      } else
        ++s;
    }
  }

  static char_t* parse_simple(char_t* s, char_t end_quote) {
    gap g;

    while (true) {
      PUGI__SCANWHILE_UNROLL(!PUGI__IS_CHARTYPE(ss, ct_parse_attr));

      if (*s == end_quote) {
        *g.flush(s) = 0;

        return s + 1;
      } else if (opt_escape::value && *s == '&') {
        s = strconv_escape(s, g);
      } else if (!*s) {
        return 0;
      } else
        ++s;
    }
  }
};

PUGI__FN strconv_attribute_t get_strconv_attribute(unsigned int optmask) {
  PUGI__STATIC_ASSERT(parse_escapes == 0x10 && parse_eol == 0x20 &&
                      parse_wconv_attribute == 0x40 &&
                      parse_wnorm_attribute == 0x80);

  switch ((optmask >> 4) &
          15)  // get bitmask for flags (wconv wnorm eol escapes)
  {
    case 0:
      return strconv_attribute_impl<opt_false>::parse_simple;
    case 1:
      return strconv_attribute_impl<opt_true>::parse_simple;
    case 2:
      return strconv_attribute_impl<opt_false>::parse_eol;
    case 3:
      return strconv_attribute_impl<opt_true>::parse_eol;
    case 4:
      return strconv_attribute_impl<opt_false>::parse_wconv;
    case 5:
      return strconv_attribute_impl<opt_true>::parse_wconv;
    case 6:
      return strconv_attribute_impl<opt_false>::parse_wconv;
    case 7:
      return strconv_attribute_impl<opt_true>::parse_wconv;
    case 8:
      return strconv_attribute_impl<opt_false>::parse_wnorm;
    case 9:
      return strconv_attribute_impl<opt_true>::parse_wnorm;
    case 10:
      return strconv_attribute_impl<opt_false>::parse_wnorm;
    case 11:
      return strconv_attribute_impl<opt_true>::parse_wnorm;
    case 12:
      return strconv_attribute_impl<opt_false>::parse_wnorm;
    case 13:
      return strconv_attribute_impl<opt_true>::parse_wnorm;
    case 14:
      return strconv_attribute_impl<opt_false>::parse_wnorm;
    case 15:
      return strconv_attribute_impl<opt_true>::parse_wnorm;
    default:
      assert(false);
      return 0;  // should not get here
  }
}

inline xml_parse_result make_parse_result(xml_parse_status status,
                                          ptrdiff_t offset = 0) {
  xml_parse_result result;
  result.status = status;
  result.offset = offset;

  return result;
}

struct xml_parser {
  xml_allocator* alloc;
  char_t* error_offset;
  xml_parse_status error_status;

  xml_parser(xml_allocator* alloc_)
      : alloc(alloc_), error_offset(0), error_status(status_ok) {}

  // DOCTYPE consists of nested sections of the following possible types:
  // <!-- ... -->, <? ... ?>, "...", '...'
  // <![...]]>
  // <!...>
  // First group can not contain nested groups
  // Second group can contain nested groups of the same type
  // Third group can contain all other groups
  char_t* parse_doctype_primitive(char_t* s) {
    if (*s == '"' || *s == '\'') {
      // quoted string
      char_t ch = *s++;
      PUGI__SCANFOR(*s == ch);
      if (!*s) PUGI__THROW_ERROR(status_bad_doctype, s);

      s++;
    } else if (s[0] == '<' && s[1] == '?') {
      // <? ... ?>
      s += 2;
      PUGI__SCANFOR(s[0] == '?' &&
                    s[1] == '>');  // no need for ENDSWITH because ?> can't
                                   // terminate proper doctype
      if (!*s) PUGI__THROW_ERROR(status_bad_doctype, s);

      s += 2;
    } else if (s[0] == '<' && s[1] == '!' && s[2] == '-' && s[3] == '-') {
      s += 4;
      PUGI__SCANFOR(s[0] == '-' && s[1] == '-' &&
                    s[2] == '>');  // no need for ENDSWITH because --> can't
                                   // terminate proper doctype
      if (!*s) PUGI__THROW_ERROR(status_bad_doctype, s);

      s += 3;
    } else
      PUGI__THROW_ERROR(status_bad_doctype, s);

    return s;
  }

  char_t* parse_doctype_ignore(char_t* s) {
    size_t depth = 0;

    assert(s[0] == '<' && s[1] == '!' && s[2] == '[');
    s += 3;

    while (*s) {
      if (s[0] == '<' && s[1] == '!' && s[2] == '[') {
        // nested ignore section
        s += 3;
        depth++;
      } else if (s[0] == ']' && s[1] == ']' && s[2] == '>') {
        // ignore section end
        s += 3;

        if (depth == 0) return s;

        depth--;
      } else
        s++;
    }

    PUGI__THROW_ERROR(status_bad_doctype, s);
  }

  char_t* parse_doctype_group(char_t* s, char_t endch) {
    size_t depth = 0;

    assert((s[0] == '<' || s[0] == 0) && s[1] == '!');
    s += 2;

    while (*s) {
      if (s[0] == '<' && s[1] == '!' && s[2] != '-') {
        if (s[2] == '[') {
          // ignore
          s = parse_doctype_ignore(s);
          if (!s) return s;
        } else {
          // some control group
          s += 2;
          depth++;
        }
      } else if (s[0] == '<' || s[0] == '"' || s[0] == '\'') {
        // unknown tag (forbidden), or some primitive group
        s = parse_doctype_primitive(s);
        if (!s) return s;
      } else if (*s == '>') {
        if (depth == 0) return s;

        depth--;
        s++;
      } else
        s++;
    }

    if (depth != 0 || endch != '>') PUGI__THROW_ERROR(status_bad_doctype, s);

    return s;
  }

  char_t* parse_exclamation(char_t* s, xml_node_struct* cursor,
                            unsigned int optmsk, char_t endch) {
    // parse node contents, starting with exclamation mark
    ++s;

    if (*s == '-')  // '<!-...'
    {
      ++s;

      if (*s == '-')  // '<!--...'
      {
        ++s;

        if (PUGI__OPTSET(parse_comments)) {
          PUGI__PUSHNODE(node_comment);  // Append a new node on the tree.
          cursor->value = s;             // Save the offset.
        }

        if (PUGI__OPTSET(parse_eol) && PUGI__OPTSET(parse_comments)) {
          s = strconv_comment(s, endch);

          if (!s) PUGI__THROW_ERROR(status_bad_comment, cursor->value);
        } else {
          // Scan for terminating '-->'.
          PUGI__SCANFOR(s[0] == '-' && s[1] == '-' &&
                        PUGI__ENDSWITH(s[2], '>'));
          PUGI__CHECK_ERROR(status_bad_comment, s);

          if (PUGI__OPTSET(parse_comments))
            *s =
                0;  // Zero-terminate this segment at the first terminating '-'.

          s += (s[2] == '>' ? 3 : 2);  // Step over the '\0->'.
        }
      } else
        PUGI__THROW_ERROR(status_bad_comment, s);
    } else if (*s == '[') {
      // '<![CDATA[...'
      if (*++s == 'C' && *++s == 'D' && *++s == 'A' && *++s == 'T' &&
          *++s == 'A' && *++s == '[') {
        ++s;

        if (PUGI__OPTSET(parse_cdata)) {
          PUGI__PUSHNODE(node_cdata);  // Append a new node on the tree.
          cursor->value = s;           // Save the offset.

          if (PUGI__OPTSET(parse_eol)) {
            s = strconv_cdata(s, endch);

            if (!s) PUGI__THROW_ERROR(status_bad_cdata, cursor->value);
          } else {
            // Scan for terminating ']]>'.
            PUGI__SCANFOR(s[0] == ']' && s[1] == ']' &&
                          PUGI__ENDSWITH(s[2], '>'));
            PUGI__CHECK_ERROR(status_bad_cdata, s);

            *s++ = 0;  // Zero-terminate this segment.
          }
        } else  // Flagged for discard, but we still have to scan for the
                // terminator.
        {
          // Scan for terminating ']]>'.
          PUGI__SCANFOR(s[0] == ']' && s[1] == ']' &&
                        PUGI__ENDSWITH(s[2], '>'));
          PUGI__CHECK_ERROR(status_bad_cdata, s);

          ++s;
        }

        s += (s[1] == '>' ? 2 : 1);  // Step over the last ']>'.
      } else
        PUGI__THROW_ERROR(status_bad_cdata, s);
    } else if (s[0] == 'D' && s[1] == 'O' && s[2] == 'C' && s[3] == 'T' &&
               s[4] == 'Y' && s[5] == 'P' && PUGI__ENDSWITH(s[6], 'E')) {
      s -= 2;

      if (cursor->parent) PUGI__THROW_ERROR(status_bad_doctype, s);

      char_t* mark = s + 9;

      s = parse_doctype_group(s, endch);
      if (!s) return s;

      assert((*s == 0 && endch == '>') || *s == '>');
      if (*s) *s++ = 0;

      if (PUGI__OPTSET(parse_doctype)) {
        while (PUGI__IS_CHARTYPE(*mark, ct_space)) ++mark;

        PUGI__PUSHNODE(node_doctype);

        cursor->value = mark;
      }
    } else if (*s == 0 && endch == '-')
      PUGI__THROW_ERROR(status_bad_comment, s);
    else if (*s == 0 && endch == '[')
      PUGI__THROW_ERROR(status_bad_cdata, s);
    else
      PUGI__THROW_ERROR(status_unrecognized_tag, s);

    return s;
  }

  char_t* parse_question(char_t* s, xml_node_struct*& ref_cursor,
                         unsigned int optmsk, char_t endch) {
    // load into registers
    xml_node_struct* cursor = ref_cursor;
    char_t ch = 0;

    // parse node contents, starting with question mark
    ++s;

    // read PI target
    char_t* target = s;

    if (!PUGI__IS_CHARTYPE(*s, ct_start_symbol))
      PUGI__THROW_ERROR(status_bad_pi, s);

    PUGI__SCANWHILE(PUGI__IS_CHARTYPE(*s, ct_symbol));
    PUGI__CHECK_ERROR(status_bad_pi, s);

    // determine node type; stricmp / strcasecmp is not portable
    bool declaration = (target[0] | ' ') == 'x' && (target[1] | ' ') == 'm' &&
                       (target[2] | ' ') == 'l' && target + 3 == s;

    if (declaration ? PUGI__OPTSET(parse_declaration)
                    : PUGI__OPTSET(parse_pi)) {
      if (declaration) {
        // disallow non top-level declarations
        if (cursor->parent) PUGI__THROW_ERROR(status_bad_pi, s);

        PUGI__PUSHNODE(node_declaration);
      } else {
        PUGI__PUSHNODE(node_pi);
      }

      cursor->name = target;

      PUGI__ENDSEG();

      // parse value/attributes
      if (ch == '?') {
        // empty node
        if (!PUGI__ENDSWITH(*s, '>')) PUGI__THROW_ERROR(status_bad_pi, s);
        s += (*s == '>');

        PUGI__POPNODE();
      } else if (PUGI__IS_CHARTYPE(ch, ct_space)) {
        PUGI__SKIPWS();

        // scan for tag end
        char_t* value = s;

        PUGI__SCANFOR(s[0] == '?' && PUGI__ENDSWITH(s[1], '>'));
        PUGI__CHECK_ERROR(status_bad_pi, s);

        if (declaration) {
          // replace ending ? with / so that 'element' terminates properly
          *s = '/';

          // we exit from this function with cursor at node_declaration, which
          // is a signal to parse() to go to LOC_ATTRIBUTES
          s = value;
        } else {
          // store value and step over >
          cursor->value = value;

          PUGI__POPNODE();

          PUGI__ENDSEG();

          s += (*s == '>');
        }
      } else
        PUGI__THROW_ERROR(status_bad_pi, s);
    } else {
      // scan for tag end
      PUGI__SCANFOR(s[0] == '?' && PUGI__ENDSWITH(s[1], '>'));
      PUGI__CHECK_ERROR(status_bad_pi, s);

      s += (s[1] == '>' ? 2 : 1);
    }

    // store from registers
    ref_cursor = cursor;

    return s;
  }

  char_t* parse_tree(char_t* s, xml_node_struct* root, unsigned int optmsk,
                     char_t endch) {
    strconv_attribute_t strconv_attribute = get_strconv_attribute(optmsk);
    strconv_pcdata_t strconv_pcdata = get_strconv_pcdata(optmsk);

    char_t ch = 0;
    xml_node_struct* cursor = root;
    char_t* mark = s;

    while (*s != 0) {
      if (*s == '<') {
        ++s;

      LOC_TAG:
        if (PUGI__IS_CHARTYPE(*s, ct_start_symbol))  // '<#...'
        {
          PUGI__PUSHNODE(node_element);  // Append a new node to the tree.

          cursor->name = s;

          PUGI__SCANWHILE_UNROLL(
              PUGI__IS_CHARTYPE(ss, ct_symbol));  // Scan for a terminator.
          PUGI__ENDSEG();  // Save char in 'ch', terminate & step over.

          if (ch == '>') {
            // end of tag
          } else if (PUGI__IS_CHARTYPE(ch, ct_space)) {
          LOC_ATTRIBUTES:
            while (true) {
              PUGI__SKIPWS();  // Eat any whitespace.

              if (PUGI__IS_CHARTYPE(*s, ct_start_symbol))  // <... #...
              {
                xml_attribute_struct* a = append_new_attribute(
                    cursor, *alloc);  // Make space for this attribute.
                if (!a) PUGI__THROW_ERROR(status_out_of_memory, s);

                a->name = s;  // Save the offset.

                PUGI__SCANWHILE_UNROLL(PUGI__IS_CHARTYPE(
                    ss, ct_symbol));  // Scan for a terminator.
                PUGI__ENDSEG();  // Save char in 'ch', terminate & step over.

                if (PUGI__IS_CHARTYPE(ch, ct_space)) {
                  PUGI__SKIPWS();  // Eat any whitespace.

                  ch = *s;
                  ++s;
                }

                if (ch == '=')  // '<... #=...'
                {
                  PUGI__SKIPWS();  // Eat any whitespace.

                  if (*s == '"' || *s == '\'')  // '<... #="...'
                  {
                    ch = *s;  // Save quote char to avoid breaking on "''" -or-
                              // '""'.
                    ++s;      // Step over the quote.
                    a->value = s;  // Save the offset.

                    s = strconv_attribute(s, ch);

                    if (!s) PUGI__THROW_ERROR(status_bad_attribute, a->value);

                    // After this line the loop continues from the start;
                    // Whitespaces, / and > are ok, symbols and EOF are wrong,
                    // everything else will be detected
                    if (PUGI__IS_CHARTYPE(*s, ct_start_symbol))
                      PUGI__THROW_ERROR(status_bad_attribute, s);
                  } else
                    PUGI__THROW_ERROR(status_bad_attribute, s);
                } else
                  PUGI__THROW_ERROR(status_bad_attribute, s);
              } else if (*s == '/') {
                ++s;

                if (*s == '>') {
                  PUGI__POPNODE();
                  s++;
                  break;
                } else if (*s == 0 && endch == '>') {
                  PUGI__POPNODE();
                  break;
                } else
                  PUGI__THROW_ERROR(status_bad_start_element, s);
              } else if (*s == '>') {
                ++s;

                break;
              } else if (*s == 0 && endch == '>') {
                break;
              } else
                PUGI__THROW_ERROR(status_bad_start_element, s);
            }

            // !!!
          } else if (ch == '/')  // '<#.../'
          {
            if (!PUGI__ENDSWITH(*s, '>'))
              PUGI__THROW_ERROR(status_bad_start_element, s);

            PUGI__POPNODE();  // Pop.

            s += (*s == '>');
          } else if (ch == 0) {
            // we stepped over null terminator, backtrack & handle closing tag
            --s;

            if (endch != '>') PUGI__THROW_ERROR(status_bad_start_element, s);
          } else
            PUGI__THROW_ERROR(status_bad_start_element, s);
        } else if (*s == '/') {
          ++s;

          mark = s;

          char_t* name = cursor->name;
          if (!name) PUGI__THROW_ERROR(status_end_element_mismatch, mark);

          while (PUGI__IS_CHARTYPE(*s, ct_symbol)) {
            if (*s++ != *name++)
              PUGI__THROW_ERROR(status_end_element_mismatch, mark);
          }

          if (*name) {
            if (*s == 0 && name[0] == endch && name[1] == 0)
              PUGI__THROW_ERROR(status_bad_end_element, s);
            else
              PUGI__THROW_ERROR(status_end_element_mismatch, mark);
          }

          PUGI__POPNODE();  // Pop.

          PUGI__SKIPWS();

          if (*s == 0) {
            if (endch != '>') PUGI__THROW_ERROR(status_bad_end_element, s);
          } else {
            if (*s != '>') PUGI__THROW_ERROR(status_bad_end_element, s);
            ++s;
          }
        } else if (*s == '?')  // '<?...'
        {
          s = parse_question(s, cursor, optmsk, endch);
          if (!s) return s;

          assert(cursor);
          if (PUGI__NODETYPE(cursor) == node_declaration) goto LOC_ATTRIBUTES;
        } else if (*s == '!')  // '<!...'
        {
          s = parse_exclamation(s, cursor, optmsk, endch);
          if (!s) return s;
        } else if (*s == 0 && endch == '?')
          PUGI__THROW_ERROR(status_bad_pi, s);
        else
          PUGI__THROW_ERROR(status_unrecognized_tag, s);
      } else {
        mark = s;  // Save this offset while searching for a terminator.

        PUGI__SKIPWS();  // Eat whitespace if no genuine PCDATA here.

        if (*s == '<' || !*s) {
          // We skipped some whitespace characters because otherwise we would
          // take the tag branch instead of PCDATA one
          assert(mark != s);

          if (!PUGI__OPTSET(parse_ws_pcdata | parse_ws_pcdata_single) ||
              PUGI__OPTSET(parse_trim_pcdata)) {
            continue;
          } else if (PUGI__OPTSET(parse_ws_pcdata_single)) {
            if (s[0] != '<' || s[1] != '/' || cursor->first_child) continue;
          }
        }

        if (!PUGI__OPTSET(parse_trim_pcdata)) s = mark;

        if (cursor->parent || PUGI__OPTSET(parse_fragment)) {
          if (PUGI__OPTSET(parse_embed_pcdata) && cursor->parent &&
              !cursor->first_child && !cursor->value) {
            cursor->value = s;  // Save the offset.
          } else {
            PUGI__PUSHNODE(node_pcdata);  // Append a new node on the tree.

            cursor->value = s;  // Save the offset.

            PUGI__POPNODE();  // Pop since this is a standalone.
          }

          s = strconv_pcdata(s);

          if (!*s) break;
        } else {
          PUGI__SCANFOR(*s == '<');  // '...<'
          if (!*s) break;

          ++s;
        }

        // We're after '<'
        goto LOC_TAG;
      }
    }

    // check that last tag is closed
    if (cursor != root) PUGI__THROW_ERROR(status_end_element_mismatch, s);

    return s;
  }

#ifdef PUGIXML_WCHAR_MODE
  static char_t* parse_skip_bom(char_t* s) {
    unsigned int bom = 0xfeff;
    return (s[0] == static_cast<wchar_t>(bom)) ? s + 1 : s;
  }
#else
  static char_t* parse_skip_bom(char_t* s) {
    return (s[0] == '\xef' && s[1] == '\xbb' && s[2] == '\xbf') ? s + 3 : s;
  }
#endif

  static bool has_element_node_siblings(xml_node_struct* node) {
    while (node) {
      if (PUGI__NODETYPE(node) == node_element) return true;

      node = node->next_sibling;
    }

    return false;
  }

  static xml_parse_result parse(char_t* buffer, size_t length,
                                xml_document_struct* xmldoc,
                                xml_node_struct* root, unsigned int optmsk) {
    // early-out for empty documents
    if (length == 0)
      return make_parse_result(PUGI__OPTSET(parse_fragment)
                                   ? status_ok
                                   : status_no_document_element);

    // get last child of the root before parsing
    xml_node_struct* last_root_child =
        root->first_child ? root->first_child->prev_sibling_c + 0 : 0;

    // create parser on stack
    xml_parser parser(static_cast<xml_allocator*>(xmldoc));

    // save last character and make buffer zero-terminated (speeds up parsing)
    char_t endch = buffer[length - 1];
    buffer[length - 1] = 0;

    // skip BOM to make sure it does not end up as part of parse output
    char_t* buffer_data = parse_skip_bom(buffer);

    // perform actual parsing
    parser.parse_tree(buffer_data, root, optmsk, endch);

    xml_parse_result result = make_parse_result(
        parser.error_status,
        parser.error_offset ? parser.error_offset - buffer : 0);
    assert(result.offset >= 0 && static_cast<size_t>(result.offset) <= length);

    if (result) {
      // since we removed last character, we have to handle the only possible
      // false positive (stray <)
      if (endch == '<')
        return make_parse_result(status_unrecognized_tag, length - 1);

      // check if there are any element nodes parsed
      xml_node_struct* first_root_child_parsed =
          last_root_child ? last_root_child->next_sibling + 0
                          : root->first_child + 0;

      if (!PUGI__OPTSET(parse_fragment) &&
          !has_element_node_siblings(first_root_child_parsed))
        return make_parse_result(status_no_document_element, length - 1);
    } else {
      // roll back offset if it occurs on a null terminator in the source buffer
      if (result.offset > 0 &&
          static_cast<size_t>(result.offset) == length - 1 && endch == 0)
        result.offset--;
    }

    return result;
  }
};

// Output facilities
PUGI__FN xml_encoding get_write_native_encoding() {
#ifdef PUGIXML_WCHAR_MODE
  return get_wchar_encoding();
#else
  return encoding_utf8;
#endif
}

PUGI__FN xml_encoding get_write_encoding(xml_encoding encoding) {
  // replace wchar encoding with utf implementation
  if (encoding == encoding_wchar) return get_wchar_encoding();

  // replace utf16 encoding with utf16 with specific endianness
  if (encoding == encoding_utf16)
    return is_little_endian() ? encoding_utf16_le : encoding_utf16_be;

  // replace utf32 encoding with utf32 with specific endianness
  if (encoding == encoding_utf32)
    return is_little_endian() ? encoding_utf32_le : encoding_utf32_be;

  // only do autodetection if no explicit encoding is requested
  if (encoding != encoding_auto) return encoding;

  // assume utf8 encoding
  return encoding_utf8;
}

template <typename D, typename T>
PUGI__FN size_t convert_buffer_output_generic(typename T::value_type dest,
                                              const char_t* data, size_t length,
                                              D, T) {
  PUGI__STATIC_ASSERT(sizeof(char_t) == sizeof(typename D::type));

  typename T::value_type end = D::process(
      reinterpret_cast<const typename D::type*>(data), length, dest, T());

  return static_cast<size_t>(end - dest) * sizeof(*dest);
}

template <typename D, typename T>
PUGI__FN size_t convert_buffer_output_generic(typename T::value_type dest,
                                              const char_t* data, size_t length,
                                              D, T, bool opt_swap) {
  PUGI__STATIC_ASSERT(sizeof(char_t) == sizeof(typename D::type));

  typename T::value_type end = D::process(
      reinterpret_cast<const typename D::type*>(data), length, dest, T());

  if (opt_swap) {
    for (typename T::value_type i = dest; i != end; ++i) *i = endian_swap(*i);
  }

  return static_cast<size_t>(end - dest) * sizeof(*dest);
}

#ifdef PUGIXML_WCHAR_MODE
PUGI__FN size_t get_valid_length(const char_t* data, size_t length) {
  if (length < 1) return 0;

  // discard last character if it's the lead of a surrogate pair
  return (sizeof(wchar_t) == 2 &&
          static_cast<unsigned int>(static_cast<uint16_t>(data[length - 1]) -
                                    0xD800) < 0x400)
             ? length - 1
             : length;
}

PUGI__FN size_t convert_buffer_output(char_t* r_char, uint8_t* r_u8,
                                      uint16_t* r_u16, uint32_t* r_u32,
                                      const char_t* data, size_t length,
                                      xml_encoding encoding) {
  // only endian-swapping is required
  if (need_endian_swap_utf(encoding, get_wchar_encoding())) {
    convert_wchar_endian_swap(r_char, data, length);

    return length * sizeof(char_t);
  }

  // convert to utf8
  if (encoding == encoding_utf8)
    return convert_buffer_output_generic(r_u8, data, length, wchar_decoder(),
                                         utf8_writer());

  // convert to utf16
  if (encoding == encoding_utf16_be || encoding == encoding_utf16_le) {
    xml_encoding native_encoding =
        is_little_endian() ? encoding_utf16_le : encoding_utf16_be;

    return convert_buffer_output_generic(r_u16, data, length, wchar_decoder(),
                                         utf16_writer(),
                                         native_encoding != encoding);
  }

  // convert to utf32
  if (encoding == encoding_utf32_be || encoding == encoding_utf32_le) {
    xml_encoding native_encoding =
        is_little_endian() ? encoding_utf32_le : encoding_utf32_be;

    return convert_buffer_output_generic(r_u32, data, length, wchar_decoder(),
                                         utf32_writer(),
                                         native_encoding != encoding);
  }

  // convert to latin1
  if (encoding == encoding_latin1)
    return convert_buffer_output_generic(r_u8, data, length, wchar_decoder(),
                                         latin1_writer());

  assert(false && "Invalid encoding");
  return 0;
}
#else
PUGI__FN size_t get_valid_length(const char_t* data, size_t length) {
  if (length < 5) return 0;

  for (size_t i = 1; i <= 4; ++i) {
    uint8_t ch = static_cast<uint8_t>(data[length - i]);

    // either a standalone character or a leading one
    if ((ch & 0xc0) != 0x80) return length - i;
  }

  // there are four non-leading characters at the end, sequence tail is broken
  // so might as well process the whole chunk
  return length;
}

PUGI__FN size_t convert_buffer_output(char_t* /* r_char */, uint8_t* r_u8,
                                      uint16_t* r_u16, uint32_t* r_u32,
                                      const char_t* data, size_t length,
                                      xml_encoding encoding) {
  if (encoding == encoding_utf16_be || encoding == encoding_utf16_le) {
    xml_encoding native_encoding =
        is_little_endian() ? encoding_utf16_le : encoding_utf16_be;

    return convert_buffer_output_generic(r_u16, data, length, utf8_decoder(),
                                         utf16_writer(),
                                         native_encoding != encoding);
  }

  if (encoding == encoding_utf32_be || encoding == encoding_utf32_le) {
    xml_encoding native_encoding =
        is_little_endian() ? encoding_utf32_le : encoding_utf32_be;

    return convert_buffer_output_generic(r_u32, data, length, utf8_decoder(),
                                         utf32_writer(),
                                         native_encoding != encoding);
  }

  if (encoding == encoding_latin1)
    return convert_buffer_output_generic(r_u8, data, length, utf8_decoder(),
                                         latin1_writer());

  assert(false && "Invalid encoding");
  return 0;
}
#endif

class xml_buffered_writer {
  xml_buffered_writer(const xml_buffered_writer&);
  xml_buffered_writer& operator=(const xml_buffered_writer&);

public:
  xml_buffered_writer(xml_writer& writer_, xml_encoding user_encoding)
      : writer(writer_),
        bufsize(0),
        encoding(get_write_encoding(user_encoding)) {
    PUGI__STATIC_ASSERT(bufcapacity >= 8);
  }

  size_t flush() {
    flush(buffer, bufsize);
    bufsize = 0;
    return 0;
  }

  void flush(const char_t* data, size_t size) {
    if (size == 0) return;

    // fast path, just write data
    if (encoding == get_write_native_encoding())
      writer.write(data, size * sizeof(char_t));
    else {
      // convert chunk
      size_t result = convert_buffer_output(scratch.data_char, scratch.data_u8,
                                            scratch.data_u16, scratch.data_u32,
                                            data, size, encoding);
      assert(result <= sizeof(scratch));

      // write data
      writer.write(scratch.data_u8, result);
    }
  }

  void write_direct(const char_t* data, size_t length) {
    // flush the remaining buffer contents
    flush();

    // handle large chunks
    if (length > bufcapacity) {
      if (encoding == get_write_native_encoding()) {
        // fast path, can just write data chunk
        writer.write(data, length * sizeof(char_t));
        return;
      }

      // need to convert in suitable chunks
      while (length > bufcapacity) {
        // get chunk size by selecting such number of characters that are
        // guaranteed to fit into scratch buffer and form a complete codepoint
        // sequence (i.e. discard start of last codepoint if necessary)
        size_t chunk_size = get_valid_length(data, bufcapacity);
        assert(chunk_size);

        // convert chunk and write
        flush(data, chunk_size);

        // iterate
        data += chunk_size;
        length -= chunk_size;
      }

      // small tail is copied below
      bufsize = 0;
    }

    memcpy(buffer + bufsize, data, length * sizeof(char_t));
    bufsize += length;
  }

  void write_buffer(const char_t* data, size_t length) {
    size_t offset = bufsize;

    if (offset + length <= bufcapacity) {
      memcpy(buffer + offset, data, length * sizeof(char_t));
      bufsize = offset + length;
    } else {
      write_direct(data, length);
    }
  }

  void write_string(const char_t* data) {
    // write the part of the string that fits in the buffer
    size_t offset = bufsize;

    while (*data && offset < bufcapacity) buffer[offset++] = *data++;

    // write the rest
    if (offset < bufcapacity) {
      bufsize = offset;
    } else {
      // backtrack a bit if we have split the codepoint
      size_t length = offset - bufsize;
      size_t extra = length - get_valid_length(data - length, length);

      bufsize = offset - extra;

      write_direct(data - extra, strlength(data) + extra);
    }
  }

  void write(char_t d0) {
    size_t offset = bufsize;
    if (offset > bufcapacity - 1) offset = flush();

    buffer[offset + 0] = d0;
    bufsize = offset + 1;
  }

  void write(char_t d0, char_t d1) {
    size_t offset = bufsize;
    if (offset > bufcapacity - 2) offset = flush();

    buffer[offset + 0] = d0;
    buffer[offset + 1] = d1;
    bufsize = offset + 2;
  }

  void write(char_t d0, char_t d1, char_t d2) {
    size_t offset = bufsize;
    if (offset > bufcapacity - 3) offset = flush();

    buffer[offset + 0] = d0;
    buffer[offset + 1] = d1;
    buffer[offset + 2] = d2;
    bufsize = offset + 3;
  }

  void write(char_t d0, char_t d1, char_t d2, char_t d3) {
    size_t offset = bufsize;
    if (offset > bufcapacity - 4) offset = flush();

    buffer[offset + 0] = d0;
    buffer[offset + 1] = d1;
    buffer[offset + 2] = d2;
    buffer[offset + 3] = d3;
    bufsize = offset + 4;
  }

  void write(char_t d0, char_t d1, char_t d2, char_t d3, char_t d4) {
    size_t offset = bufsize;
    if (offset > bufcapacity - 5) offset = flush();

    buffer[offset + 0] = d0;
    buffer[offset + 1] = d1;
    buffer[offset + 2] = d2;
    buffer[offset + 3] = d3;
    buffer[offset + 4] = d4;
    bufsize = offset + 5;
  }

  void write(char_t d0, char_t d1, char_t d2, char_t d3, char_t d4, char_t d5) {
    size_t offset = bufsize;
    if (offset > bufcapacity - 6) offset = flush();

    buffer[offset + 0] = d0;
    buffer[offset + 1] = d1;
    buffer[offset + 2] = d2;
    buffer[offset + 3] = d3;
    buffer[offset + 4] = d4;
    buffer[offset + 5] = d5;
    bufsize = offset + 6;
  }

  // utf8 maximum expansion: x4 (-> utf32)
  // utf16 maximum expansion: x2 (-> utf32)
  // utf32 maximum expansion: x1
  enum {
    bufcapacitybytes =
#ifdef PUGIXML_MEMORY_OUTPUT_STACK
        PUGIXML_MEMORY_OUTPUT_STACK
#else
        10240
#endif
    ,
    bufcapacity = bufcapacitybytes / (sizeof(char_t) + 4)
  };

  char_t buffer[bufcapacity];

  union {
    uint8_t data_u8[4 * bufcapacity];
    uint16_t data_u16[2 * bufcapacity];
    uint32_t data_u32[bufcapacity];
    char_t data_char[bufcapacity];
  } scratch;

  xml_writer& writer;
  size_t bufsize;
  xml_encoding encoding;
};

PUGI__FN void text_output_escaped(xml_buffered_writer& writer, const char_t* s,
                                  chartypex_t type) {
  while (*s) {
    const char_t* prev = s;

    // While *s is a usual symbol
    PUGI__SCANWHILE_UNROLL(!PUGI__IS_CHARTYPEX(ss, type));

    writer.write_buffer(prev, static_cast<size_t>(s - prev));

    switch (*s) {
      case 0:
        break;
      case '&':
        writer.write('&', 'a', 'm', 'p', ';');
        ++s;
        break;
      case '<':
        writer.write('&', 'l', 't', ';');
        ++s;
        break;
      case '>':
        writer.write('&', 'g', 't', ';');
        ++s;
        break;
      case '"':
        writer.write('&', 'q', 'u', 'o', 't', ';');
        ++s;
        break;
      default:  // s is not a usual symbol
      {
        unsigned int ch = static_cast<unsigned int>(*s++);
        assert(ch < 32);

        writer.write('&', '#', static_cast<char_t>((ch / 10) + '0'),
                     static_cast<char_t>((ch % 10) + '0'), ';');
      }
    }
  }
}

PUGI__FN void text_output(xml_buffered_writer& writer, const char_t* s,
                          chartypex_t type, unsigned int flags) {
  if (flags & format_no_escapes)
    writer.write_string(s);
  else
    text_output_escaped(writer, s, type);
}

PUGI__FN void text_output_cdata(xml_buffered_writer& writer, const char_t* s) {
  do {
    writer.write('<', '!', '[', 'C', 'D');
    writer.write('A', 'T', 'A', '[');

    const char_t* prev = s;

    // look for ]]> sequence - we can't output it as is since it terminates
    // CDATA
    while (*s && !(s[0] == ']' && s[1] == ']' && s[2] == '>')) ++s;

    // skip ]] if we stopped at ]]>, > will go to the next CDATA section
    if (*s) s += 2;

    writer.write_buffer(prev, static_cast<size_t>(s - prev));

    writer.write(']', ']', '>');
  } while (*s);
}

PUGI__FN void text_output_indent(xml_buffered_writer& writer,
                                 const char_t* indent, size_t indent_length,
                                 unsigned int depth) {
  switch (indent_length) {
    case 1: {
      for (unsigned int i = 0; i < depth; ++i) writer.write(indent[0]);
      break;
    }

    case 2: {
      for (unsigned int i = 0; i < depth; ++i)
        writer.write(indent[0], indent[1]);
      break;
    }

    case 3: {
      for (unsigned int i = 0; i < depth; ++i)
        writer.write(indent[0], indent[1], indent[2]);
      break;
    }

    case 4: {
      for (unsigned int i = 0; i < depth; ++i)
        writer.write(indent[0], indent[1], indent[2], indent[3]);
      break;
    }

    default: {
      for (unsigned int i = 0; i < depth; ++i)
        writer.write_buffer(indent, indent_length);
    }
  }
}

PUGI__FN void node_output_comment(xml_buffered_writer& writer,
                                  const char_t* s) {
  writer.write('<', '!', '-', '-');

  while (*s) {
    const char_t* prev = s;

    // look for -\0 or -- sequence - we can't output it since -- is illegal in
    // comment body
    while (*s && !(s[0] == '-' && (s[1] == '-' || s[1] == 0))) ++s;

    writer.write_buffer(prev, static_cast<size_t>(s - prev));

    if (*s) {
      assert(*s == '-');

      writer.write('-', ' ');
      ++s;
    }
  }

  writer.write('-', '-', '>');
}

PUGI__FN void node_output_pi_value(xml_buffered_writer& writer,
                                   const char_t* s) {
  while (*s) {
    const char_t* prev = s;

    // look for ?> sequence - we can't output it since ?> terminates PI
    while (*s && !(s[0] == '?' && s[1] == '>')) ++s;

    writer.write_buffer(prev, static_cast<size_t>(s - prev));

    if (*s) {
      assert(s[0] == '?' && s[1] == '>');

      writer.write('?', ' ', '>');
      s += 2;
    }
  }
}

PUGI__FN void node_output_attributes(xml_buffered_writer& writer,
                                     xml_node_struct* node,
                                     const char_t* indent, size_t indent_length,
                                     unsigned int flags, unsigned int depth) {
  const char_t* default_name = PUGIXML_TEXT(":anonymous");

  for (xml_attribute_struct* a = node->first_attribute; a;
       a = a->next_attribute) {
    if ((flags & (format_indent_attributes | format_raw)) ==
        format_indent_attributes) {
      writer.write('\n');

      text_output_indent(writer, indent, indent_length, depth + 1);
    } else {
      writer.write(' ');
    }

    writer.write_string(a->name ? a->name + 0 : default_name);
    writer.write('=', '"');

    if (a->value) text_output(writer, a->value, ctx_special_attr, flags);

    writer.write('"');
  }
}

PUGI__FN bool node_output_start(xml_buffered_writer& writer,
                                xml_node_struct* node, const char_t* indent,
                                size_t indent_length, unsigned int flags,
                                unsigned int depth) {
  const char_t* default_name = PUGIXML_TEXT(":anonymous");
  const char_t* name = node->name ? node->name + 0 : default_name;

  writer.write('<');
  writer.write_string(name);

  if (node->first_attribute)
    node_output_attributes(writer, node, indent, indent_length, flags, depth);

  // element nodes can have value if parse_embed_pcdata was used
  if (!node->value) {
    if (!node->first_child) {
      if (flags & format_no_empty_element_tags) {
        writer.write('>', '<', '/');
        writer.write_string(name);
        writer.write('>');

        return false;
      } else {
        if ((flags & format_raw) == 0) writer.write(' ');

        writer.write('/', '>');

        return false;
      }
    } else {
      writer.write('>');

      return true;
    }
  } else {
    writer.write('>');

    text_output(writer, node->value, ctx_special_pcdata, flags);

    if (!node->first_child) {
      writer.write('<', '/');
      writer.write_string(name);
      writer.write('>');

      return false;
    } else {
      return true;
    }
  }
}

PUGI__FN void node_output_end(xml_buffered_writer& writer,
                              xml_node_struct* node) {
  const char_t* default_name = PUGIXML_TEXT(":anonymous");
  const char_t* name = node->name ? node->name + 0 : default_name;

  writer.write('<', '/');
  writer.write_string(name);
  writer.write('>');
}

PUGI__FN void node_output_simple(xml_buffered_writer& writer,
                                 xml_node_struct* node, unsigned int flags) {
  const char_t* default_name = PUGIXML_TEXT(":anonymous");

  switch (PUGI__NODETYPE(node)) {
    case node_pcdata:
      text_output(writer, node->value ? node->value + 0 : PUGIXML_TEXT(""),
                  ctx_special_pcdata, flags);
      break;

    case node_cdata:
      text_output_cdata(writer,
                        node->value ? node->value + 0 : PUGIXML_TEXT(""));
      break;

    case node_comment:
      node_output_comment(writer,
                          node->value ? node->value + 0 : PUGIXML_TEXT(""));
      break;

    case node_pi:
      writer.write('<', '?');
      writer.write_string(node->name ? node->name + 0 : default_name);

      if (node->value) {
        writer.write(' ');
        node_output_pi_value(writer, node->value);
      }

      writer.write('?', '>');
      break;

    case node_declaration:
      writer.write('<', '?');
      writer.write_string(node->name ? node->name + 0 : default_name);
      node_output_attributes(writer, node, PUGIXML_TEXT(""), 0,
                             flags | format_raw, 0);
      writer.write('?', '>');
      break;

    case node_doctype:
      writer.write('<', '!', 'D', 'O', 'C');
      writer.write('T', 'Y', 'P', 'E');

      if (node->value) {
        writer.write(' ');
        writer.write_string(node->value);
      }

      writer.write('>');
      break;

    default:
      assert(false && "Invalid node type");
  }
}

enum indent_flags_t { indent_newline = 1, indent_indent = 2 };

PUGI__FN void node_output(xml_buffered_writer& writer, xml_node_struct* root,
                          const char_t* indent, unsigned int flags,
                          unsigned int depth) {
  size_t indent_length =
      ((flags & (format_indent | format_indent_attributes)) &&
       (flags & format_raw) == 0)
          ? strlength(indent)
          : 0;
  unsigned int indent_flags = indent_indent;

  xml_node_struct* node = root;

  do {
    assert(node);

    // begin writing current node
    if (PUGI__NODETYPE(node) == node_pcdata ||
        PUGI__NODETYPE(node) == node_cdata) {
      node_output_simple(writer, node, flags);

      indent_flags = 0;
    } else {
      if ((indent_flags & indent_newline) && (flags & format_raw) == 0)
        writer.write('\n');

      if ((indent_flags & indent_indent) && indent_length)
        text_output_indent(writer, indent, indent_length, depth);

      if (PUGI__NODETYPE(node) == node_element) {
        indent_flags = indent_newline | indent_indent;

        if (node_output_start(writer, node, indent, indent_length, flags,
                              depth)) {
          // element nodes can have value if parse_embed_pcdata was used
          if (node->value) indent_flags = 0;

          node = node->first_child;
          depth++;
          continue;
        }
      } else if (PUGI__NODETYPE(node) == node_document) {
        indent_flags = indent_indent;

        if (node->first_child) {
          node = node->first_child;
          continue;
        }
      } else {
        node_output_simple(writer, node, flags);

        indent_flags = indent_newline | indent_indent;
      }
    }

    // continue to the next node
    while (node != root) {
      if (node->next_sibling) {
        node = node->next_sibling;
        break;
      }

      node = node->parent;

      // write closing node
      if (PUGI__NODETYPE(node) == node_element) {
        depth--;

        if ((indent_flags & indent_newline) && (flags & format_raw) == 0)
          writer.write('\n');

        if ((indent_flags & indent_indent) && indent_length)
          text_output_indent(writer, indent, indent_length, depth);

        node_output_end(writer, node);

        indent_flags = indent_newline | indent_indent;
      }
    }
  } while (node != root);

  if ((indent_flags & indent_newline) && (flags & format_raw) == 0)
    writer.write('\n');
}

PUGI__FN bool has_declaration(xml_node_struct* node) {
  for (xml_node_struct* child = node->first_child; child;
       child = child->next_sibling) {
    xml_node_type type = PUGI__NODETYPE(child);

    if (type == node_declaration) return true;
    if (type == node_element) return false;
  }

  return false;
}

PUGI__FN bool is_attribute_of(xml_attribute_struct* attr,
                              xml_node_struct* node) {
  for (xml_attribute_struct* a = node->first_attribute; a;
       a = a->next_attribute)
    if (a == attr) return true;

  return false;
}

PUGI__FN bool allow_insert_attribute(xml_node_type parent) {
  return parent == node_element || parent == node_declaration;
}

PUGI__FN bool allow_insert_child(xml_node_type parent, xml_node_type child) {
  if (parent != node_document && parent != node_element) return false;
  if (child == node_document || child == node_null) return false;
  if (parent != node_document &&
      (child == node_declaration || child == node_doctype))
    return false;

  return true;
}

PUGI__FN bool allow_move(xml_node parent, xml_node child) {
  // check that child can be a child of parent
  if (!allow_insert_child(parent.type(), child.type())) return false;

  // check that node is not moved between documents
  if (parent.root() != child.root()) return false;

  // check that new parent is not in the child subtree
  xml_node cur = parent;

  while (cur) {
    if (cur == child) return false;

    cur = cur.parent();
  }

  return true;
}

template <typename String, typename Header>
PUGI__FN void node_copy_string(String& dest, Header& header,
                               uintptr_t header_mask, char_t* source,
                               Header& source_header, xml_allocator* alloc) {
  assert(!dest && (header & header_mask) == 0);

  if (source) {
    if (alloc && (source_header & header_mask) == 0) {
      dest = source;

      // since strcpy_insitu can reuse document buffer memory we need to mark
      // both source and dest as shared
      header |= xml_memory_page_contents_shared_mask;
      source_header |= xml_memory_page_contents_shared_mask;
    } else
      strcpy_insitu(dest, header, header_mask, source, strlength(source));
  }
}

PUGI__FN void node_copy_contents(xml_node_struct* dn, xml_node_struct* sn,
                                 xml_allocator* shared_alloc) {
  node_copy_string(dn->name, dn->header, xml_memory_page_name_allocated_mask,
                   sn->name, sn->header, shared_alloc);
  node_copy_string(dn->value, dn->header, xml_memory_page_value_allocated_mask,
                   sn->value, sn->header, shared_alloc);

  for (xml_attribute_struct* sa = sn->first_attribute; sa;
       sa = sa->next_attribute) {
    xml_attribute_struct* da = append_new_attribute(dn, get_allocator(dn));

    if (da) {
      node_copy_string(da->name, da->header,
                       xml_memory_page_name_allocated_mask, sa->name,
                       sa->header, shared_alloc);
      node_copy_string(da->value, da->header,
                       xml_memory_page_value_allocated_mask, sa->value,
                       sa->header, shared_alloc);
    }
  }
}

PUGI__FN void node_copy_tree(xml_node_struct* dn, xml_node_struct* sn) {
  xml_allocator& alloc = get_allocator(dn);
  xml_allocator* shared_alloc = (&alloc == &get_allocator(sn)) ? &alloc : 0;

  node_copy_contents(dn, sn, shared_alloc);

  xml_node_struct* dit = dn;
  xml_node_struct* sit = sn->first_child;

  while (sit && sit != sn) {
    if (sit != dn) {
      xml_node_struct* copy = append_new_node(dit, alloc, PUGI__NODETYPE(sit));

      if (copy) {
        node_copy_contents(copy, sit, shared_alloc);

        if (sit->first_child) {
          dit = copy;
          sit = sit->first_child;
          continue;
        }
      }
    }

    // continue to the next node
    do {
      if (sit->next_sibling) {
        sit = sit->next_sibling;
        break;
      }

      sit = sit->parent;
      dit = dit->parent;
    } while (sit != sn);
  }
}

PUGI__FN void node_copy_attribute(xml_attribute_struct* da,
                                  xml_attribute_struct* sa) {
  xml_allocator& alloc = get_allocator(da);
  xml_allocator* shared_alloc = (&alloc == &get_allocator(sa)) ? &alloc : 0;

  node_copy_string(da->name, da->header, xml_memory_page_name_allocated_mask,
                   sa->name, sa->header, shared_alloc);
  node_copy_string(da->value, da->header, xml_memory_page_value_allocated_mask,
                   sa->value, sa->header, shared_alloc);
}

inline bool is_text_node(xml_node_struct* node) {
  xml_node_type type = PUGI__NODETYPE(node);

  return type == node_pcdata || type == node_cdata;
}

// get value with conversion functions
template <typename U>
U string_to_integer(const char_t* value, U minneg, U maxpos) {
  U result = 0;
  const char_t* s = value;

  while (PUGI__IS_CHARTYPE(*s, ct_space)) s++;

  bool negative = (*s == '-');

  s += (*s == '+' || *s == '-');

  bool overflow = false;

  if (s[0] == '0' && (s[1] | ' ') == 'x') {
    s += 2;

    // since overflow detection relies on length of the sequence skip leading
    // zeros
    while (*s == '0') s++;

    const char_t* start = s;

    for (;;) {
      if (static_cast<unsigned>(*s - '0') < 10)
        result = result * 16 + (*s - '0');
      else if (static_cast<unsigned>((*s | ' ') - 'a') < 6)
        result = result * 16 + ((*s | ' ') - 'a' + 10);
      else
        break;

      s++;
    }

    size_t digits = static_cast<size_t>(s - start);

    overflow = digits > sizeof(U) * 2;
  } else {
    // since overflow detection relies on length of the sequence skip leading
    // zeros
    while (*s == '0') s++;

    const char_t* start = s;

    for (;;) {
      if (static_cast<unsigned>(*s - '0') < 10)
        result = result * 10 + (*s - '0');
      else
        break;

      s++;
    }

    size_t digits = static_cast<size_t>(s - start);

    PUGI__STATIC_ASSERT(sizeof(U) == 8 || sizeof(U) == 4 || sizeof(U) == 2);

    const size_t max_digits10 = sizeof(U) == 8 ? 20 : sizeof(U) == 4 ? 10 : 5;
    const char_t max_lead = sizeof(U) == 8 ? '1' : sizeof(U) == 4 ? '4' : '6';
    const size_t high_bit = sizeof(U) * 8 - 1;

    overflow =
        digits >= max_digits10 &&
        !(digits == max_digits10 &&
          (*start < max_lead || (*start == max_lead && result >> high_bit)));
  }

  if (negative)
    return (overflow || result > minneg) ? 0 - minneg : 0 - result;
  else
    return (overflow || result > maxpos) ? maxpos : result;
}

PUGI__FN int get_value_int(const char_t* value) {
  return string_to_integer<unsigned int>(
      value, 0 - static_cast<unsigned int>(INT_MIN), INT_MAX);
}

PUGI__FN unsigned int get_value_uint(const char_t* value) {
  return string_to_integer<unsigned int>(value, 0, UINT_MAX);
}

PUGI__FN double get_value_double(const char_t* value) {
#ifdef PUGIXML_WCHAR_MODE
  return wcstod(value, 0);
#else
  return strtod(value, 0);
#endif
}

PUGI__FN float get_value_float(const char_t* value) {
#ifdef PUGIXML_WCHAR_MODE
  return static_cast<float>(wcstod(value, 0));
#else
  return static_cast<float>(strtod(value, 0));
#endif
}

PUGI__FN bool get_value_bool(const char_t* value) {
  // only look at first char
  char_t first = *value;

  // 1*, t* (true), T* (True), y* (yes), Y* (YES)
  return (first == '1' || first == 't' || first == 'T' || first == 'y' ||
          first == 'Y');
}

#ifdef PUGIXML_HAS_LONG_LONG
PUGI__FN long long get_value_llong(const char_t* value) {
  return string_to_integer<unsigned long long>(
      value, 0 - static_cast<unsigned long long>(LLONG_MIN), LLONG_MAX);
}

PUGI__FN unsigned long long get_value_ullong(const char_t* value) {
  return string_to_integer<unsigned long long>(value, 0, ULLONG_MAX);
}
#endif

template <typename U>
PUGI__FN char_t* integer_to_string(char_t* begin, char_t* end, U value,
                                   bool negative) {
  char_t* result = end - 1;
  U rest = negative ? 0 - value : value;

  do {
    *result-- = static_cast<char_t>('0' + (rest % 10));
    rest /= 10;
  } while (rest);

  assert(result >= begin);
  (void)begin;

  *result = '-';

  return result + !negative;
}

// set value with conversion functions
template <typename String, typename Header>
PUGI__FN bool set_value_ascii(String& dest, Header& header,
                              uintptr_t header_mask, char* buf) {
#ifdef PUGIXML_WCHAR_MODE
  char_t wbuf[128];
  assert(strlen(buf) < sizeof(wbuf) / sizeof(wbuf[0]));

  size_t offset = 0;
  for (; buf[offset]; ++offset) wbuf[offset] = buf[offset];

  return strcpy_insitu(dest, header, header_mask, wbuf, offset);
#else
  return strcpy_insitu(dest, header, header_mask, buf, strlen(buf));
#endif
}

template <typename U, typename String, typename Header>
PUGI__FN bool set_value_integer(String& dest, Header& header,
                                uintptr_t header_mask, U value, bool negative) {
  char_t buf[64];
  char_t* end = buf + sizeof(buf) / sizeof(buf[0]);
  char_t* begin = integer_to_string(buf, end, value, negative);

  return strcpy_insitu(dest, header, header_mask, begin, end - begin);
}

template <typename String, typename Header>
PUGI__FN bool set_value_convert(String& dest, Header& header,
                                uintptr_t header_mask, float value) {
  char buf[128];
  sprintf(buf, "%.9g", value);

  return set_value_ascii(dest, header, header_mask, buf);
}

template <typename String, typename Header>
PUGI__FN bool set_value_convert(String& dest, Header& header,
                                uintptr_t header_mask, double value) {
  char buf[128];
  sprintf(buf, "%.17g", value);

  return set_value_ascii(dest, header, header_mask, buf);
}

template <typename String, typename Header>
PUGI__FN bool set_value_bool(String& dest, Header& header,
                             uintptr_t header_mask, bool value) {
  return strcpy_insitu(dest, header, header_mask,
                       value ? PUGIXML_TEXT("true") : PUGIXML_TEXT("false"),
                       value ? 4 : 5);
}

PUGI__FN xml_parse_result load_buffer_impl(
    xml_document_struct* doc, xml_node_struct* root, void* contents,
    size_t size, unsigned int options, xml_encoding encoding, bool is_mutable,
    bool own, char_t** out_buffer) {
  // check input buffer
  if (!contents && size) return make_parse_result(status_io_error);

  // get actual encoding
  xml_encoding buffer_encoding =
      impl::get_buffer_encoding(encoding, contents, size);

  // get private buffer
  char_t* buffer = 0;
  size_t length = 0;

  if (!impl::convert_buffer(buffer, length, buffer_encoding, contents, size,
                            is_mutable))
    return impl::make_parse_result(status_out_of_memory);

  // delete original buffer if we performed a conversion
  if (own && buffer != contents && contents)
    impl::xml_memory::deallocate(contents);

  // grab onto buffer if it's our buffer, user is responsible for deallocating
  // contents himself
  if (own || buffer != contents) *out_buffer = buffer;

  // store buffer for offset_debug
  doc->buffer = buffer;

  // parse
  xml_parse_result res =
      impl::xml_parser::parse(buffer, length, doc, root, options);

  // remember encoding
  res.encoding = buffer_encoding;

  return res;
}

// we need to get length of entire file to load it in memory; the only
// (relatively) sane way to do it is via seek/tell trick
PUGI__FN xml_parse_status get_file_size(FILE* file, size_t& out_result) {
#if defined(PUGI__MSVC_CRT_VERSION) && PUGI__MSVC_CRT_VERSION >= 1400 && \
    !defined(_WIN32_WCE)
  // there are 64-bit versions of fseek/ftell, let's use them
  typedef __int64 length_type;

  _fseeki64(file, 0, SEEK_END);
  length_type length = _ftelli64(file);
  _fseeki64(file, 0, SEEK_SET);
#elif defined(__MINGW32__) && !defined(__NO_MINGW_LFS) && \
    (!defined(__STRICT_ANSI__) || defined(__MINGW64_VERSION_MAJOR))
  // there are 64-bit versions of fseek/ftell, let's use them
  typedef off64_t length_type;

  fseeko64(file, 0, SEEK_END);
  length_type length = ftello64(file);
  fseeko64(file, 0, SEEK_SET);
#else
  // if this is a 32-bit OS, long is enough; if this is a unix system, long is
  // 64-bit, which is enough; otherwise we can't do anything anyway.
  typedef long length_type;

  fseek(file, 0, SEEK_END);
  length_type length = ftell(file);
  fseek(file, 0, SEEK_SET);
#endif

  // check for I/O errors
  if (length < 0) return status_io_error;

  // check for overflow
  size_t result = static_cast<size_t>(length);

  if (static_cast<length_type>(result) != length) return status_out_of_memory;

  // finalize
  out_result = result;

  return status_ok;
}

// This function assumes that buffer has extra sizeof(char_t) writable bytes
// after size
PUGI__FN size_t zero_terminate_buffer(void* buffer, size_t size,
                                      xml_encoding encoding) {
  // We only need to zero-terminate if encoding conversion does not do it for us
#ifdef PUGIXML_WCHAR_MODE
  xml_encoding wchar_encoding = get_wchar_encoding();

  if (encoding == wchar_encoding ||
      need_endian_swap_utf(encoding, wchar_encoding)) {
    size_t length = size / sizeof(char_t);

    static_cast<char_t*>(buffer)[length] = 0;
    return (length + 1) * sizeof(char_t);
  }
#else
  if (encoding == encoding_utf8) {
    static_cast<char*>(buffer)[size] = 0;
    return size + 1;
  }
#endif

  return size;
}

PUGI__FN xml_parse_result load_file_impl(xml_document_struct* doc, FILE* file,
                                         unsigned int options,
                                         xml_encoding encoding,
                                         char_t** out_buffer) {
  if (!file) return make_parse_result(status_file_not_found);

  // get file size (can result in I/O errors)
  size_t size = 0;
  xml_parse_status size_status = get_file_size(file, size);
  if (size_status != status_ok) return make_parse_result(size_status);

  size_t max_suffix_size = sizeof(char_t);

  // allocate buffer for the whole file
  char* contents =
      static_cast<char*>(xml_memory::allocate(size + max_suffix_size));
  if (!contents) return make_parse_result(status_out_of_memory);

  // read file in memory
  size_t read_size = fread(contents, 1, size, file);

  if (read_size != size) {
    xml_memory::deallocate(contents);
    return make_parse_result(status_io_error);
  }

  xml_encoding real_encoding = get_buffer_encoding(encoding, contents, size);

  return load_buffer_impl(doc, doc, contents,
                          zero_terminate_buffer(contents, size, real_encoding),
                          options, real_encoding, true, true, out_buffer);
}

PUGI__FN void close_file(FILE* file) { fclose(file); }

#ifndef PUGIXML_NO_STL
template <typename T>
struct xml_stream_chunk {
  static xml_stream_chunk* create() {
    void* memory = xml_memory::allocate(sizeof(xml_stream_chunk));
    if (!memory) return 0;

    return new (memory) xml_stream_chunk();
  }

  static void destroy(xml_stream_chunk* chunk) {
    // free chunk chain
    while (chunk) {
      xml_stream_chunk* next_ = chunk->next;

      xml_memory::deallocate(chunk);

      chunk = next_;
    }
  }

  xml_stream_chunk() : next(0), size(0) {}

  xml_stream_chunk* next;
  size_t size;

  T data[xml_memory_page_size / sizeof(T)];
};

template <typename T>
PUGI__FN xml_parse_status load_stream_data_noseek(std::basic_istream<T>& stream,
                                                  void** out_buffer,
                                                  size_t* out_size) {
  auto_deleter<xml_stream_chunk<T> > chunks(0, xml_stream_chunk<T>::destroy);

  // read file to a chunk list
  size_t total = 0;
  xml_stream_chunk<T>* last = 0;

  while (!stream.eof()) {
    // allocate new chunk
    xml_stream_chunk<T>* chunk = xml_stream_chunk<T>::create();
    if (!chunk) return status_out_of_memory;

    // append chunk to list
    if (last)
      last = last->next = chunk;
    else
      chunks.data = last = chunk;

    // read data to chunk
    stream.read(chunk->data,
                static_cast<std::streamsize>(sizeof(chunk->data) / sizeof(T)));
    chunk->size = static_cast<size_t>(stream.gcount()) * sizeof(T);

    // read may set failbit | eofbit in case gcount() is less than read length,
    // so check for other I/O errors
    if (stream.bad() || (!stream.eof() && stream.fail()))
      return status_io_error;

    // guard against huge files (chunk size is small enough to make this
    // overflow check work)
    if (total + chunk->size < total) return status_out_of_memory;
    total += chunk->size;
  }

  size_t max_suffix_size = sizeof(char_t);

  // copy chunk list to a contiguous buffer
  char* buffer =
      static_cast<char*>(xml_memory::allocate(total + max_suffix_size));
  if (!buffer) return status_out_of_memory;

  char* write = buffer;

  for (xml_stream_chunk<T>* chunk = chunks.data; chunk; chunk = chunk->next) {
    assert(write + chunk->size <= buffer + total);
    memcpy(write, chunk->data, chunk->size);
    write += chunk->size;
  }

  assert(write == buffer + total);

  // return buffer
  *out_buffer = buffer;
  *out_size = total;

  return status_ok;
}

template <typename T>
PUGI__FN xml_parse_status load_stream_data_seek(std::basic_istream<T>& stream,
                                                void** out_buffer,
                                                size_t* out_size) {
  // get length of remaining data in stream
  typename std::basic_istream<T>::pos_type pos = stream.tellg();
  stream.seekg(0, std::ios::end);
  std::streamoff length = stream.tellg() - pos;
  stream.seekg(pos);

  if (stream.fail() || pos < 0) return status_io_error;

  // guard against huge files
  size_t read_length = static_cast<size_t>(length);

  if (static_cast<std::streamsize>(read_length) != length || length < 0)
    return status_out_of_memory;

  size_t max_suffix_size = sizeof(char_t);

  // read stream data into memory (guard against stream exceptions with buffer
  // holder)
  auto_deleter<void> buffer(
      xml_memory::allocate(read_length * sizeof(T) + max_suffix_size),
      xml_memory::deallocate);
  if (!buffer.data) return status_out_of_memory;

  stream.read(static_cast<T*>(buffer.data),
              static_cast<std::streamsize>(read_length));

  // read may set failbit | eofbit in case gcount() is less than read_length
  // (i.e. line ending conversion), so check for other I/O errors
  if (stream.bad() || (!stream.eof() && stream.fail())) return status_io_error;

  // return buffer
  size_t actual_length = static_cast<size_t>(stream.gcount());
  assert(actual_length <= read_length);

  *out_buffer = buffer.release();
  *out_size = actual_length * sizeof(T);

  return status_ok;
}

template <typename T>
PUGI__FN xml_parse_result load_stream_impl(xml_document_struct* doc,
                                           std::basic_istream<T>& stream,
                                           unsigned int options,
                                           xml_encoding encoding,
                                           char_t** out_buffer) {
  void* buffer = 0;
  size_t size = 0;
  xml_parse_status status = status_ok;

  // if stream has an error bit set, bail out (otherwise tellg() can fail and
  // we'll clear error bits)
  if (stream.fail()) return make_parse_result(status_io_error);

  // load stream to memory (using seek-based implementation if possible, since
  // it's faster and takes less memory)
  if (stream.tellg() < 0) {
    stream.clear();  // clear error flags that could be set by a failing tellg
    status = load_stream_data_noseek(stream, &buffer, &size);
  } else
    status = load_stream_data_seek(stream, &buffer, &size);

  if (status != status_ok) return make_parse_result(status);

  xml_encoding real_encoding = get_buffer_encoding(encoding, buffer, size);

  return load_buffer_impl(doc, doc, buffer,
                          zero_terminate_buffer(buffer, size, real_encoding),
                          options, real_encoding, true, true, out_buffer);
}
#endif

#if defined(PUGI__MSVC_CRT_VERSION) || defined(__BORLANDC__) || \
    (defined(__MINGW32__) &&                                    \
     (!defined(__STRICT_ANSI__) || defined(__MINGW64_VERSION_MAJOR)))
PUGI__FN FILE* open_file_wide(const wchar_t* path, const wchar_t* mode) {
  return _wfopen(path, mode);
}
#else
PUGI__FN char* convert_path_heap(const wchar_t* str) {
  assert(str);

  // first pass: get length in utf8 characters
  size_t length = strlength_wide(str);
  size_t size = as_utf8_begin(str, length);

  // allocate resulting string
  char* result = static_cast<char*>(xml_memory::allocate(size + 1));
  if (!result) return 0;

  // second pass: convert to utf8
  as_utf8_end(result, size, str, length);

  // zero-terminate
  result[size] = 0;

  return result;
}

PUGI__FN FILE* open_file_wide(const wchar_t* path, const wchar_t* mode) {
  // there is no standard function to open wide paths, so our best bet is to try
  // utf8 path
  char* path_utf8 = convert_path_heap(path);
  if (!path_utf8) return 0;

  // convert mode to ASCII (we mirror _wfopen interface)
  char mode_ascii[4] = {0};
  for (size_t i = 0; mode[i]; ++i) mode_ascii[i] = static_cast<char>(mode[i]);

  // try to open the utf8 path
  FILE* result = fopen(path_utf8, mode_ascii);

  // free dummy buffer
  xml_memory::deallocate(path_utf8);

  return result;
}
#endif

PUGI__FN bool save_file_impl(const xml_document& doc, FILE* file,
                             const char_t* indent, unsigned int flags,
                             xml_encoding encoding) {
  if (!file) return false;

  xml_writer_file writer(file);
  doc.save(writer, indent, flags, encoding);

  return ferror(file) == 0;
}

struct name_null_sentry {
  xml_node_struct* node;
  char_t* name;

  name_null_sentry(xml_node_struct* node_) : node(node_), name(node_->name) {
    node->name = 0;
  }

  ~name_null_sentry() { node->name = name; }
};
PUGI__NS_END

namespace pugi {
PUGI__FN xml_writer_file::xml_writer_file(void* file_) : file(file_) {}

PUGI__FN void xml_writer_file::write(const void* data, size_t size) {
  size_t result = fwrite(data, 1, size, static_cast<FILE*>(file));
  (void)!result;  // unfortunately we can't do proper error handling here
}

#ifndef PUGIXML_NO_STL
PUGI__FN xml_writer_stream::xml_writer_stream(
    std::basic_ostream<char, std::char_traits<char> >& stream)
    : narrow_stream(&stream), wide_stream(0) {}

PUGI__FN xml_writer_stream::xml_writer_stream(
    std::basic_ostream<wchar_t, std::char_traits<wchar_t> >& stream)
    : narrow_stream(0), wide_stream(&stream) {}

PUGI__FN void xml_writer_stream::write(const void* data, size_t size) {
  if (narrow_stream) {
    assert(!wide_stream);
    narrow_stream->write(reinterpret_cast<const char*>(data),
                         static_cast<std::streamsize>(size));
  } else {
    assert(wide_stream);
    assert(size % sizeof(wchar_t) == 0);

    wide_stream->write(reinterpret_cast<const wchar_t*>(data),
                       static_cast<std::streamsize>(size / sizeof(wchar_t)));
  }
}
#endif

PUGI__FN xml_tree_walker::xml_tree_walker() : _depth(0) {}

PUGI__FN xml_tree_walker::~xml_tree_walker() {}

PUGI__FN int xml_tree_walker::depth() const { return _depth; }

PUGI__FN bool xml_tree_walker::begin(xml_node&) { return true; }

PUGI__FN bool xml_tree_walker::end(xml_node&) { return true; }

PUGI__FN xml_attribute::xml_attribute() : _attr(0) {}

PUGI__FN xml_attribute::xml_attribute(xml_attribute_struct* attr)
    : _attr(attr) {}

PUGI__FN static void unspecified_bool_xml_attribute(xml_attribute***) {}

PUGI__FN xml_attribute::operator xml_attribute::unspecified_bool_type() const {
  return _attr ? unspecified_bool_xml_attribute : 0;
}

PUGI__FN bool xml_attribute::operator!() const { return !_attr; }

PUGI__FN bool xml_attribute::operator==(const xml_attribute& r) const {
  return (_attr == r._attr);
}

PUGI__FN bool xml_attribute::operator!=(const xml_attribute& r) const {
  return (_attr != r._attr);
}

PUGI__FN bool xml_attribute::operator<(const xml_attribute& r) const {
  return (_attr < r._attr);
}

PUGI__FN bool xml_attribute::operator>(const xml_attribute& r) const {
  return (_attr > r._attr);
}

PUGI__FN bool xml_attribute::operator<=(const xml_attribute& r) const {
  return (_attr <= r._attr);
}

PUGI__FN bool xml_attribute::operator>=(const xml_attribute& r) const {
  return (_attr >= r._attr);
}

PUGI__FN xml_attribute xml_attribute::next_attribute() const {
  return _attr ? xml_attribute(_attr->next_attribute) : xml_attribute();
}

PUGI__FN xml_attribute xml_attribute::previous_attribute() const {
  return _attr && _attr->prev_attribute_c->next_attribute
             ? xml_attribute(_attr->prev_attribute_c)
             : xml_attribute();
}

PUGI__FN const char_t* xml_attribute::as_string(const char_t* def) const {
  return (_attr && _attr->value) ? _attr->value + 0 : def;
}

PUGI__FN int xml_attribute::as_int(int def) const {
  return (_attr && _attr->value) ? impl::get_value_int(_attr->value) : def;
}

PUGI__FN unsigned int xml_attribute::as_uint(unsigned int def) const {
  return (_attr && _attr->value) ? impl::get_value_uint(_attr->value) : def;
}

PUGI__FN double xml_attribute::as_double(double def) const {
  return (_attr && _attr->value) ? impl::get_value_double(_attr->value) : def;
}

PUGI__FN float xml_attribute::as_float(float def) const {
  return (_attr && _attr->value) ? impl::get_value_float(_attr->value) : def;
}

PUGI__FN bool xml_attribute::as_bool(bool def) const {
  return (_attr && _attr->value) ? impl::get_value_bool(_attr->value) : def;
}

#ifdef PUGIXML_HAS_LONG_LONG
PUGI__FN long long xml_attribute::as_llong(long long def) const {
  return (_attr && _attr->value) ? impl::get_value_llong(_attr->value) : def;
}

PUGI__FN unsigned long long xml_attribute::as_ullong(
    unsigned long long def) const {
  return (_attr && _attr->value) ? impl::get_value_ullong(_attr->value) : def;
}
#endif

PUGI__FN bool xml_attribute::empty() const { return !_attr; }

PUGI__FN const char_t* xml_attribute::name() const {
  return (_attr && _attr->name) ? _attr->name + 0 : PUGIXML_TEXT("");
}

PUGI__FN const char_t* xml_attribute::value() const {
  return (_attr && _attr->value) ? _attr->value + 0 : PUGIXML_TEXT("");
}

PUGI__FN size_t xml_attribute::hash_value() const {
  return static_cast<size_t>(reinterpret_cast<uintptr_t>(_attr) /
                             sizeof(xml_attribute_struct));
}

PUGI__FN xml_attribute_struct* xml_attribute::internal_object() const {
  return _attr;
}

PUGI__FN xml_attribute& xml_attribute::operator=(const char_t* rhs) {
  set_value(rhs);
  return *this;
}

PUGI__FN xml_attribute& xml_attribute::operator=(int rhs) {
  set_value(rhs);
  return *this;
}

PUGI__FN xml_attribute& xml_attribute::operator=(unsigned int rhs) {
  set_value(rhs);
  return *this;
}

PUGI__FN xml_attribute& xml_attribute::operator=(long rhs) {
  set_value(rhs);
  return *this;
}

PUGI__FN xml_attribute& xml_attribute::operator=(unsigned long rhs) {
  set_value(rhs);
  return *this;
}

PUGI__FN xml_attribute& xml_attribute::operator=(double rhs) {
  set_value(rhs);
  return *this;
}

PUGI__FN xml_attribute& xml_attribute::operator=(float rhs) {
  set_value(rhs);
  return *this;
}

PUGI__FN xml_attribute& xml_attribute::operator=(bool rhs) {
  set_value(rhs);
  return *this;
}

#ifdef PUGIXML_HAS_LONG_LONG
PUGI__FN xml_attribute& xml_attribute::operator=(long long rhs) {
  set_value(rhs);
  return *this;
}

PUGI__FN xml_attribute& xml_attribute::operator=(unsigned long long rhs) {
  set_value(rhs);
  return *this;
}
#endif

PUGI__FN bool xml_attribute::set_name(const char_t* rhs) {
  if (!_attr) return false;

  return impl::strcpy_insitu(_attr->name, _attr->header,
                             impl::xml_memory_page_name_allocated_mask, rhs,
                             impl::strlength(rhs));
}

PUGI__FN bool xml_attribute::set_value(const char_t* rhs) {
  if (!_attr) return false;

  return impl::strcpy_insitu(_attr->value, _attr->header,
                             impl::xml_memory_page_value_allocated_mask, rhs,
                             impl::strlength(rhs));
}

PUGI__FN bool xml_attribute::set_value(int rhs) {
  if (!_attr) return false;

  return impl::set_value_integer<unsigned int>(
      _attr->value, _attr->header, impl::xml_memory_page_value_allocated_mask,
      rhs, rhs < 0);
}

PUGI__FN bool xml_attribute::set_value(unsigned int rhs) {
  if (!_attr) return false;

  return impl::set_value_integer<unsigned int>(
      _attr->value, _attr->header, impl::xml_memory_page_value_allocated_mask,
      rhs, false);
}

PUGI__FN bool xml_attribute::set_value(long rhs) {
  if (!_attr) return false;

  return impl::set_value_integer<unsigned long>(
      _attr->value, _attr->header, impl::xml_memory_page_value_allocated_mask,
      rhs, rhs < 0);
}

PUGI__FN bool xml_attribute::set_value(unsigned long rhs) {
  if (!_attr) return false;

  return impl::set_value_integer<unsigned long>(
      _attr->value, _attr->header, impl::xml_memory_page_value_allocated_mask,
      rhs, false);
}

PUGI__FN bool xml_attribute::set_value(double rhs) {
  if (!_attr) return false;

  return impl::set_value_convert(_attr->value, _attr->header,
                                 impl::xml_memory_page_value_allocated_mask,
                                 rhs);
}

PUGI__FN bool xml_attribute::set_value(float rhs) {
  if (!_attr) return false;

  return impl::set_value_convert(_attr->value, _attr->header,
                                 impl::xml_memory_page_value_allocated_mask,
                                 rhs);
}

PUGI__FN bool xml_attribute::set_value(bool rhs) {
  if (!_attr) return false;

  return impl::set_value_bool(_attr->value, _attr->header,
                              impl::xml_memory_page_value_allocated_mask, rhs);
}

#ifdef PUGIXML_HAS_LONG_LONG
PUGI__FN bool xml_attribute::set_value(long long rhs) {
  if (!_attr) return false;

  return impl::set_value_integer<unsigned long long>(
      _attr->value, _attr->header, impl::xml_memory_page_value_allocated_mask,
      rhs, rhs < 0);
}

PUGI__FN bool xml_attribute::set_value(unsigned long long rhs) {
  if (!_attr) return false;

  return impl::set_value_integer<unsigned long long>(
      _attr->value, _attr->header, impl::xml_memory_page_value_allocated_mask,
      rhs, false);
}
#endif

#ifdef __BORLANDC__
PUGI__FN bool operator&&(const xml_attribute& lhs, bool rhs) {
  return (bool)lhs && rhs;
}

PUGI__FN bool operator||(const xml_attribute& lhs, bool rhs) {
  return (bool)lhs || rhs;
}
#endif

PUGI__FN xml_node::xml_node() : _root(0) {}

PUGI__FN xml_node::xml_node(xml_node_struct* p) : _root(p) {}

PUGI__FN static void unspecified_bool_xml_node(xml_node***) {}

PUGI__FN xml_node::operator xml_node::unspecified_bool_type() const {
  return _root ? unspecified_bool_xml_node : 0;
}

PUGI__FN bool xml_node::operator!() const { return !_root; }

PUGI__FN xml_node::iterator xml_node::begin() const {
  return iterator(_root ? _root->first_child + 0 : 0, _root);
}

PUGI__FN xml_node::iterator xml_node::end() const { return iterator(0, _root); }

PUGI__FN xml_node::attribute_iterator xml_node::attributes_begin() const {
  return attribute_iterator(_root ? _root->first_attribute + 0 : 0, _root);
}

PUGI__FN xml_node::attribute_iterator xml_node::attributes_end() const {
  return attribute_iterator(0, _root);
}

PUGI__FN xml_object_range<xml_node_iterator> xml_node::children() const {
  return xml_object_range<xml_node_iterator>(begin(), end());
}

PUGI__FN xml_object_range<xml_named_node_iterator> xml_node::children(
    const char_t* name_) const {
  return xml_object_range<xml_named_node_iterator>(
      xml_named_node_iterator(child(name_)._root, _root, name_),
      xml_named_node_iterator(0, _root, name_));
}

PUGI__FN xml_object_range<xml_attribute_iterator> xml_node::attributes() const {
  return xml_object_range<xml_attribute_iterator>(attributes_begin(),
                                                  attributes_end());
}

PUGI__FN bool xml_node::operator==(const xml_node& r) const {
  return (_root == r._root);
}

PUGI__FN bool xml_node::operator!=(const xml_node& r) const {
  return (_root != r._root);
}

PUGI__FN bool xml_node::operator<(const xml_node& r) const {
  return (_root < r._root);
}

PUGI__FN bool xml_node::operator>(const xml_node& r) const {
  return (_root > r._root);
}

PUGI__FN bool xml_node::operator<=(const xml_node& r) const {
  return (_root <= r._root);
}

PUGI__FN bool xml_node::operator>=(const xml_node& r) const {
  return (_root >= r._root);
}

PUGI__FN bool xml_node::empty() const { return !_root; }

PUGI__FN const char_t* xml_node::name() const {
  return (_root && _root->name) ? _root->name + 0 : PUGIXML_TEXT("");
}

PUGI__FN xml_node_type xml_node::type() const {
  return _root ? PUGI__NODETYPE(_root) : node_null;
}

PUGI__FN const char_t* xml_node::value() const {
  return (_root && _root->value) ? _root->value + 0 : PUGIXML_TEXT("");
}

PUGI__FN xml_node xml_node::child(const char_t* name_) const {
  if (!_root) return xml_node();

  for (xml_node_struct* i = _root->first_child; i; i = i->next_sibling)
    if (i->name && impl::strequal(name_, i->name)) return xml_node(i);

  return xml_node();
}

PUGI__FN xml_attribute xml_node::attribute(const char_t* name_) const {
  if (!_root) return xml_attribute();

  for (xml_attribute_struct* i = _root->first_attribute; i;
       i = i->next_attribute)
    if (i->name && impl::strequal(name_, i->name)) return xml_attribute(i);

  return xml_attribute();
}

PUGI__FN xml_node xml_node::next_sibling(const char_t* name_) const {
  if (!_root) return xml_node();

  for (xml_node_struct* i = _root->next_sibling; i; i = i->next_sibling)
    if (i->name && impl::strequal(name_, i->name)) return xml_node(i);

  return xml_node();
}

PUGI__FN xml_node xml_node::next_sibling() const {
  return _root ? xml_node(_root->next_sibling) : xml_node();
}

PUGI__FN xml_node xml_node::previous_sibling(const char_t* name_) const {
  if (!_root) return xml_node();

  for (xml_node_struct* i = _root->prev_sibling_c; i->next_sibling;
       i = i->prev_sibling_c)
    if (i->name && impl::strequal(name_, i->name)) return xml_node(i);

  return xml_node();
}

PUGI__FN xml_attribute xml_node::attribute(const char_t* name_,
                                           xml_attribute& hint_) const {
  xml_attribute_struct* hint = hint_._attr;

  // if hint is not an attribute of node, behavior is not defined
  assert(!hint || (_root && impl::is_attribute_of(hint, _root)));

  if (!_root) return xml_attribute();

  // optimistically search from hint up until the end
  for (xml_attribute_struct* i = hint; i; i = i->next_attribute)
    if (i->name && impl::strequal(name_, i->name)) {
      // update hint to maximize efficiency of searching for consecutive
      // attributes
      hint_._attr = i->next_attribute;

      return xml_attribute(i);
    }

  // wrap around and search from the first attribute until the hint
  // 'j' null pointer check is technically redundant, but it prevents a crash in
  // case the assertion above fails
  for (xml_attribute_struct* j = _root->first_attribute; j && j != hint;
       j = j->next_attribute)
    if (j->name && impl::strequal(name_, j->name)) {
      // update hint to maximize efficiency of searching for consecutive
      // attributes
      hint_._attr = j->next_attribute;

      return xml_attribute(j);
    }

  return xml_attribute();
}

PUGI__FN xml_node xml_node::previous_sibling() const {
  if (!_root) return xml_node();

  if (_root->prev_sibling_c->next_sibling)
    return xml_node(_root->prev_sibling_c);
  else
    return xml_node();
}

PUGI__FN xml_node xml_node::parent() const {
  return _root ? xml_node(_root->parent) : xml_node();
}

PUGI__FN xml_node xml_node::root() const {
  return _root ? xml_node(&impl::get_document(_root)) : xml_node();
}

PUGI__FN xml_text xml_node::text() const { return xml_text(_root); }

PUGI__FN const char_t* xml_node::child_value() const {
  if (!_root) return PUGIXML_TEXT("");

  // element nodes can have value if parse_embed_pcdata was used
  if (PUGI__NODETYPE(_root) == node_element && _root->value)
    return _root->value;

  for (xml_node_struct* i = _root->first_child; i; i = i->next_sibling)
    if (impl::is_text_node(i) && i->value) return i->value;

  return PUGIXML_TEXT("");
}

PUGI__FN const char_t* xml_node::child_value(const char_t* name_) const {
  return child(name_).child_value();
}

PUGI__FN xml_attribute xml_node::first_attribute() const {
  return _root ? xml_attribute(_root->first_attribute) : xml_attribute();
}

PUGI__FN xml_attribute xml_node::last_attribute() const {
  return _root && _root->first_attribute
             ? xml_attribute(_root->first_attribute->prev_attribute_c)
             : xml_attribute();
}

PUGI__FN xml_node xml_node::first_child() const {
  return _root ? xml_node(_root->first_child) : xml_node();
}

PUGI__FN xml_node xml_node::last_child() const {
  return _root && _root->first_child
             ? xml_node(_root->first_child->prev_sibling_c)
             : xml_node();
}

PUGI__FN bool xml_node::set_name(const char_t* rhs) {
  xml_node_type type_ = _root ? PUGI__NODETYPE(_root) : node_null;

  if (type_ != node_element && type_ != node_pi && type_ != node_declaration)
    return false;

  return impl::strcpy_insitu(_root->name, _root->header,
                             impl::xml_memory_page_name_allocated_mask, rhs,
                             impl::strlength(rhs));
}

PUGI__FN bool xml_node::set_value(const char_t* rhs) {
  xml_node_type type_ = _root ? PUGI__NODETYPE(_root) : node_null;

  if (type_ != node_pcdata && type_ != node_cdata && type_ != node_comment &&
      type_ != node_pi && type_ != node_doctype)
    return false;

  return impl::strcpy_insitu(_root->value, _root->header,
                             impl::xml_memory_page_value_allocated_mask, rhs,
                             impl::strlength(rhs));
}

PUGI__FN xml_attribute xml_node::append_attribute(const char_t* name_) {
  if (!impl::allow_insert_attribute(type())) return xml_attribute();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_attribute();

  xml_attribute a(impl::allocate_attribute(alloc));
  if (!a) return xml_attribute();

  impl::append_attribute(a._attr, _root);

  a.set_name(name_);

  return a;
}

PUGI__FN xml_attribute xml_node::prepend_attribute(const char_t* name_) {
  if (!impl::allow_insert_attribute(type())) return xml_attribute();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_attribute();

  xml_attribute a(impl::allocate_attribute(alloc));
  if (!a) return xml_attribute();

  impl::prepend_attribute(a._attr, _root);

  a.set_name(name_);

  return a;
}

PUGI__FN xml_attribute xml_node::insert_attribute_after(
    const char_t* name_, const xml_attribute& attr) {
  if (!impl::allow_insert_attribute(type())) return xml_attribute();
  if (!attr || !impl::is_attribute_of(attr._attr, _root))
    return xml_attribute();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_attribute();

  xml_attribute a(impl::allocate_attribute(alloc));
  if (!a) return xml_attribute();

  impl::insert_attribute_after(a._attr, attr._attr, _root);

  a.set_name(name_);

  return a;
}

PUGI__FN xml_attribute xml_node::insert_attribute_before(
    const char_t* name_, const xml_attribute& attr) {
  if (!impl::allow_insert_attribute(type())) return xml_attribute();
  if (!attr || !impl::is_attribute_of(attr._attr, _root))
    return xml_attribute();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_attribute();

  xml_attribute a(impl::allocate_attribute(alloc));
  if (!a) return xml_attribute();

  impl::insert_attribute_before(a._attr, attr._attr, _root);

  a.set_name(name_);

  return a;
}

PUGI__FN xml_attribute xml_node::append_copy(const xml_attribute& proto) {
  if (!proto) return xml_attribute();
  if (!impl::allow_insert_attribute(type())) return xml_attribute();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_attribute();

  xml_attribute a(impl::allocate_attribute(alloc));
  if (!a) return xml_attribute();

  impl::append_attribute(a._attr, _root);
  impl::node_copy_attribute(a._attr, proto._attr);

  return a;
}

PUGI__FN xml_attribute xml_node::prepend_copy(const xml_attribute& proto) {
  if (!proto) return xml_attribute();
  if (!impl::allow_insert_attribute(type())) return xml_attribute();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_attribute();

  xml_attribute a(impl::allocate_attribute(alloc));
  if (!a) return xml_attribute();

  impl::prepend_attribute(a._attr, _root);
  impl::node_copy_attribute(a._attr, proto._attr);

  return a;
}

PUGI__FN xml_attribute xml_node::insert_copy_after(const xml_attribute& proto,
                                                   const xml_attribute& attr) {
  if (!proto) return xml_attribute();
  if (!impl::allow_insert_attribute(type())) return xml_attribute();
  if (!attr || !impl::is_attribute_of(attr._attr, _root))
    return xml_attribute();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_attribute();

  xml_attribute a(impl::allocate_attribute(alloc));
  if (!a) return xml_attribute();

  impl::insert_attribute_after(a._attr, attr._attr, _root);
  impl::node_copy_attribute(a._attr, proto._attr);

  return a;
}

PUGI__FN xml_attribute xml_node::insert_copy_before(const xml_attribute& proto,
                                                    const xml_attribute& attr) {
  if (!proto) return xml_attribute();
  if (!impl::allow_insert_attribute(type())) return xml_attribute();
  if (!attr || !impl::is_attribute_of(attr._attr, _root))
    return xml_attribute();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_attribute();

  xml_attribute a(impl::allocate_attribute(alloc));
  if (!a) return xml_attribute();

  impl::insert_attribute_before(a._attr, attr._attr, _root);
  impl::node_copy_attribute(a._attr, proto._attr);

  return a;
}

PUGI__FN xml_node xml_node::append_child(xml_node_type type_) {
  if (!impl::allow_insert_child(type(), type_)) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  xml_node n(impl::allocate_node(alloc, type_));
  if (!n) return xml_node();

  impl::append_node(n._root, _root);

  if (type_ == node_declaration) n.set_name(PUGIXML_TEXT("xml"));

  return n;
}

PUGI__FN xml_node xml_node::prepend_child(xml_node_type type_) {
  if (!impl::allow_insert_child(type(), type_)) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  xml_node n(impl::allocate_node(alloc, type_));
  if (!n) return xml_node();

  impl::prepend_node(n._root, _root);

  if (type_ == node_declaration) n.set_name(PUGIXML_TEXT("xml"));

  return n;
}

PUGI__FN xml_node xml_node::insert_child_before(xml_node_type type_,
                                                const xml_node& node) {
  if (!impl::allow_insert_child(type(), type_)) return xml_node();
  if (!node._root || node._root->parent != _root) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  xml_node n(impl::allocate_node(alloc, type_));
  if (!n) return xml_node();

  impl::insert_node_before(n._root, node._root);

  if (type_ == node_declaration) n.set_name(PUGIXML_TEXT("xml"));

  return n;
}

PUGI__FN xml_node xml_node::insert_child_after(xml_node_type type_,
                                               const xml_node& node) {
  if (!impl::allow_insert_child(type(), type_)) return xml_node();
  if (!node._root || node._root->parent != _root) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  xml_node n(impl::allocate_node(alloc, type_));
  if (!n) return xml_node();

  impl::insert_node_after(n._root, node._root);

  if (type_ == node_declaration) n.set_name(PUGIXML_TEXT("xml"));

  return n;
}

PUGI__FN xml_node xml_node::append_child(const char_t* name_) {
  xml_node result = append_child(node_element);

  result.set_name(name_);

  return result;
}

PUGI__FN xml_node xml_node::prepend_child(const char_t* name_) {
  xml_node result = prepend_child(node_element);

  result.set_name(name_);

  return result;
}

PUGI__FN xml_node xml_node::insert_child_after(const char_t* name_,
                                               const xml_node& node) {
  xml_node result = insert_child_after(node_element, node);

  result.set_name(name_);

  return result;
}

PUGI__FN xml_node xml_node::insert_child_before(const char_t* name_,
                                                const xml_node& node) {
  xml_node result = insert_child_before(node_element, node);

  result.set_name(name_);

  return result;
}

PUGI__FN xml_node xml_node::append_copy(const xml_node& proto) {
  xml_node_type type_ = proto.type();
  if (!impl::allow_insert_child(type(), type_)) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  xml_node n(impl::allocate_node(alloc, type_));
  if (!n) return xml_node();

  impl::append_node(n._root, _root);
  impl::node_copy_tree(n._root, proto._root);

  return n;
}

PUGI__FN xml_node xml_node::prepend_copy(const xml_node& proto) {
  xml_node_type type_ = proto.type();
  if (!impl::allow_insert_child(type(), type_)) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  xml_node n(impl::allocate_node(alloc, type_));
  if (!n) return xml_node();

  impl::prepend_node(n._root, _root);
  impl::node_copy_tree(n._root, proto._root);

  return n;
}

PUGI__FN xml_node xml_node::insert_copy_after(const xml_node& proto,
                                              const xml_node& node) {
  xml_node_type type_ = proto.type();
  if (!impl::allow_insert_child(type(), type_)) return xml_node();
  if (!node._root || node._root->parent != _root) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  xml_node n(impl::allocate_node(alloc, type_));
  if (!n) return xml_node();

  impl::insert_node_after(n._root, node._root);
  impl::node_copy_tree(n._root, proto._root);

  return n;
}

PUGI__FN xml_node xml_node::insert_copy_before(const xml_node& proto,
                                               const xml_node& node) {
  xml_node_type type_ = proto.type();
  if (!impl::allow_insert_child(type(), type_)) return xml_node();
  if (!node._root || node._root->parent != _root) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  xml_node n(impl::allocate_node(alloc, type_));
  if (!n) return xml_node();

  impl::insert_node_before(n._root, node._root);
  impl::node_copy_tree(n._root, proto._root);

  return n;
}

PUGI__FN xml_node xml_node::append_move(const xml_node& moved) {
  if (!impl::allow_move(*this, moved)) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  // disable document_buffer_order optimization since moving nodes around
  // changes document order without changing buffer pointers
  impl::get_document(_root).header |=
      impl::xml_memory_page_contents_shared_mask;

  impl::remove_node(moved._root);
  impl::append_node(moved._root, _root);

  return moved;
}

PUGI__FN xml_node xml_node::prepend_move(const xml_node& moved) {
  if (!impl::allow_move(*this, moved)) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  // disable document_buffer_order optimization since moving nodes around
  // changes document order without changing buffer pointers
  impl::get_document(_root).header |=
      impl::xml_memory_page_contents_shared_mask;

  impl::remove_node(moved._root);
  impl::prepend_node(moved._root, _root);

  return moved;
}

PUGI__FN xml_node xml_node::insert_move_after(const xml_node& moved,
                                              const xml_node& node) {
  if (!impl::allow_move(*this, moved)) return xml_node();
  if (!node._root || node._root->parent != _root) return xml_node();
  if (moved._root == node._root) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  // disable document_buffer_order optimization since moving nodes around
  // changes document order without changing buffer pointers
  impl::get_document(_root).header |=
      impl::xml_memory_page_contents_shared_mask;

  impl::remove_node(moved._root);
  impl::insert_node_after(moved._root, node._root);

  return moved;
}

PUGI__FN xml_node xml_node::insert_move_before(const xml_node& moved,
                                               const xml_node& node) {
  if (!impl::allow_move(*this, moved)) return xml_node();
  if (!node._root || node._root->parent != _root) return xml_node();
  if (moved._root == node._root) return xml_node();

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return xml_node();

  // disable document_buffer_order optimization since moving nodes around
  // changes document order without changing buffer pointers
  impl::get_document(_root).header |=
      impl::xml_memory_page_contents_shared_mask;

  impl::remove_node(moved._root);
  impl::insert_node_before(moved._root, node._root);

  return moved;
}

PUGI__FN bool xml_node::remove_attribute(const char_t* name_) {
  return remove_attribute(attribute(name_));
}

PUGI__FN bool xml_node::remove_attribute(const xml_attribute& a) {
  if (!_root || !a._attr) return false;
  if (!impl::is_attribute_of(a._attr, _root)) return false;

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return false;

  impl::remove_attribute(a._attr, _root);
  impl::destroy_attribute(a._attr, alloc);

  return true;
}

PUGI__FN bool xml_node::remove_child(const char_t* name_) {
  return remove_child(child(name_));
}

PUGI__FN bool xml_node::remove_child(const xml_node& n) {
  if (!_root || !n._root || n._root->parent != _root) return false;

  impl::xml_allocator& alloc = impl::get_allocator(_root);
  if (!alloc.reserve()) return false;

  impl::remove_node(n._root);
  impl::destroy_node(n._root, alloc);

  return true;
}

PUGI__FN xml_parse_result xml_node::append_buffer(const void* contents,
                                                  size_t size,
                                                  unsigned int options,
                                                  xml_encoding encoding) {
  // append_buffer is only valid for elements/documents
  if (!impl::allow_insert_child(type(), node_element))
    return impl::make_parse_result(status_append_invalid_root);

  // get document node
  impl::xml_document_struct* doc = &impl::get_document(_root);

  // disable document_buffer_order optimization since in a document with
  // multiple buffers comparing buffer pointers does not make sense
  doc->header |= impl::xml_memory_page_contents_shared_mask;

  // get extra buffer element (we'll store the document fragment buffer there so
  // that we can deallocate it later)
  impl::xml_memory_page* page = 0;
  impl::xml_extra_buffer* extra = static_cast<impl::xml_extra_buffer*>(
      doc->allocate_memory(sizeof(impl::xml_extra_buffer), page));
  (void)page;

  if (!extra) return impl::make_parse_result(status_out_of_memory);

  // add extra buffer to the list
  extra->buffer = 0;
  extra->next = doc->extra_buffers;
  doc->extra_buffers = extra;

  // name of the root has to be NULL before parsing - otherwise closing node
  // mismatches will not be detected at the top level
  impl::name_null_sentry sentry(_root);

  return impl::load_buffer_impl(doc, _root, const_cast<void*>(contents), size,
                                options, encoding, false, false,
                                &extra->buffer);
}

PUGI__FN xml_node
xml_node::find_child_by_attribute(const char_t* name_, const char_t* attr_name,
                                  const char_t* attr_value) const {
  if (!_root) return xml_node();

  for (xml_node_struct* i = _root->first_child; i; i = i->next_sibling)
    if (i->name && impl::strequal(name_, i->name)) {
      for (xml_attribute_struct* a = i->first_attribute; a;
           a = a->next_attribute)
        if (a->name && impl::strequal(attr_name, a->name) &&
            impl::strequal(attr_value,
                           a->value ? a->value + 0 : PUGIXML_TEXT("")))
          return xml_node(i);
    }

  return xml_node();
}

PUGI__FN xml_node xml_node::find_child_by_attribute(
    const char_t* attr_name, const char_t* attr_value) const {
  if (!_root) return xml_node();

  for (xml_node_struct* i = _root->first_child; i; i = i->next_sibling)
    for (xml_attribute_struct* a = i->first_attribute; a; a = a->next_attribute)
      if (a->name && impl::strequal(attr_name, a->name) &&
          impl::strequal(attr_value,
                         a->value ? a->value + 0 : PUGIXML_TEXT("")))
        return xml_node(i);

  return xml_node();
}

#ifndef PUGIXML_NO_STL
PUGI__FN string_t xml_node::path(char_t delimiter) const {
  if (!_root) return string_t();

  size_t offset = 0;

  for (xml_node_struct* i = _root; i; i = i->parent) {
    offset += (i != _root);
    offset += i->name ? impl::strlength(i->name) : 0;
  }

  string_t result;
  result.resize(offset);

  for (xml_node_struct* j = _root; j; j = j->parent) {
    if (j != _root) result[--offset] = delimiter;

    if (j->name && *j->name) {
      size_t length = impl::strlength(j->name);

      offset -= length;
      memcpy(&result[offset], j->name, length * sizeof(char_t));
    }
  }

  assert(offset == 0);

  return result;
}
#endif

PUGI__FN xml_node xml_node::first_element_by_path(const char_t* path_,
                                                  char_t delimiter) const {
  xml_node found = *this;  // Current search context.

  if (!_root || !path_ || !path_[0]) return found;

  if (path_[0] == delimiter) {
    // Absolute path; e.g. '/foo/bar'
    found = found.root();
    ++path_;
  }

  const char_t* path_segment = path_;

  while (*path_segment == delimiter) ++path_segment;

  const char_t* path_segment_end = path_segment;

  while (*path_segment_end && *path_segment_end != delimiter)
    ++path_segment_end;

  if (path_segment == path_segment_end) return found;

  const char_t* next_segment = path_segment_end;

  while (*next_segment == delimiter) ++next_segment;

  if (*path_segment == '.' && path_segment + 1 == path_segment_end)
    return found.first_element_by_path(next_segment, delimiter);
  else if (*path_segment == '.' && *(path_segment + 1) == '.' &&
           path_segment + 2 == path_segment_end)
    return found.parent().first_element_by_path(next_segment, delimiter);
  else {
    for (xml_node_struct* j = found._root->first_child; j;
         j = j->next_sibling) {
      if (j->name && impl::strequalrange(j->name, path_segment,
                                         static_cast<size_t>(path_segment_end -
                                                             path_segment))) {
        xml_node subsearch =
            xml_node(j).first_element_by_path(next_segment, delimiter);

        if (subsearch) return subsearch;
      }
    }

    return xml_node();
  }
}

PUGI__FN bool xml_node::traverse(xml_tree_walker& walker) {
  walker._depth = -1;

  xml_node arg_begin = *this;
  if (!walker.begin(arg_begin)) return false;

  xml_node cur = first_child();

  if (cur) {
    ++walker._depth;

    do {
      xml_node arg_for_each = cur;
      if (!walker.for_each(arg_for_each)) return false;

      if (cur.first_child()) {
        ++walker._depth;
        cur = cur.first_child();
      } else if (cur.next_sibling())
        cur = cur.next_sibling();
      else {
        // Borland C++ workaround
        while (!cur.next_sibling() && cur != *this && !cur.parent().empty()) {
          --walker._depth;
          cur = cur.parent();
        }

        if (cur != *this) cur = cur.next_sibling();
      }
    } while (cur && cur != *this);
  }

  assert(walker._depth == -1);

  xml_node arg_end = *this;
  return walker.end(arg_end);
}

PUGI__FN size_t xml_node::hash_value() const {
  return static_cast<size_t>(reinterpret_cast<uintptr_t>(_root) /
                             sizeof(xml_node_struct));
}

PUGI__FN xml_node_struct* xml_node::internal_object() const { return _root; }

PUGI__FN void xml_node::print(xml_writer& writer, const char_t* indent,
                              unsigned int flags, xml_encoding encoding,
                              unsigned int depth) const {
  if (!_root) return;

  impl::xml_buffered_writer buffered_writer(writer, encoding);

  impl::node_output(buffered_writer, _root, indent, flags, depth);

  buffered_writer.flush();
}

#ifndef PUGIXML_NO_STL
PUGI__FN void xml_node::print(
    std::basic_ostream<char, std::char_traits<char> >& stream,
    const char_t* indent, unsigned int flags, xml_encoding encoding,
    unsigned int depth) const {
  xml_writer_stream writer(stream);

  print(writer, indent, flags, encoding, depth);
}

PUGI__FN void xml_node::print(
    std::basic_ostream<wchar_t, std::char_traits<wchar_t> >& stream,
    const char_t* indent, unsigned int flags, unsigned int depth) const {
  xml_writer_stream writer(stream);

  print(writer, indent, flags, encoding_wchar, depth);
}
#endif

PUGI__FN ptrdiff_t xml_node::offset_debug() const {
  if (!_root) return -1;

  impl::xml_document_struct& doc = impl::get_document(_root);

  // we can determine the offset reliably only if there is exactly once parse
  // buffer
  if (!doc.buffer || doc.extra_buffers) return -1;

  switch (type()) {
    case node_document:
      return 0;

    case node_element:
    case node_declaration:
    case node_pi:
      return _root->name &&
                     (_root->header &
                      impl::xml_memory_page_name_allocated_or_shared_mask) == 0
                 ? _root->name - doc.buffer
                 : -1;

    case node_pcdata:
    case node_cdata:
    case node_comment:
    case node_doctype:
      return _root->value &&
                     (_root->header &
                      impl::xml_memory_page_value_allocated_or_shared_mask) == 0
                 ? _root->value - doc.buffer
                 : -1;

    default:
      return -1;
  }
}

#ifdef __BORLANDC__
PUGI__FN bool operator&&(const xml_node& lhs, bool rhs) {
  return (bool)lhs && rhs;
}

PUGI__FN bool operator||(const xml_node& lhs, bool rhs) {
  return (bool)lhs || rhs;
}
#endif

PUGI__FN xml_text::xml_text(xml_node_struct* root) : _root(root) {}

PUGI__FN xml_node_struct* xml_text::_data() const {
  if (!_root || impl::is_text_node(_root)) return _root;

  // element nodes can have value if parse_embed_pcdata was used
  if (PUGI__NODETYPE(_root) == node_element && _root->value) return _root;

  for (xml_node_struct* node = _root->first_child; node;
       node = node->next_sibling)
    if (impl::is_text_node(node)) return node;

  return 0;
}

PUGI__FN xml_node_struct* xml_text::_data_new() {
  xml_node_struct* d = _data();
  if (d) return d;

  return xml_node(_root).append_child(node_pcdata).internal_object();
}

PUGI__FN xml_text::xml_text() : _root(0) {}

PUGI__FN static void unspecified_bool_xml_text(xml_text***) {}

PUGI__FN xml_text::operator xml_text::unspecified_bool_type() const {
  return _data() ? unspecified_bool_xml_text : 0;
}

PUGI__FN bool xml_text::operator!() const { return !_data(); }

PUGI__FN bool xml_text::empty() const { return _data() == 0; }

PUGI__FN const char_t* xml_text::get() const {
  xml_node_struct* d = _data();

  return (d && d->value) ? d->value + 0 : PUGIXML_TEXT("");
}

PUGI__FN const char_t* xml_text::as_string(const char_t* def) const {
  xml_node_struct* d = _data();

  return (d && d->value) ? d->value + 0 : def;
}

PUGI__FN int xml_text::as_int(int def) const {
  xml_node_struct* d = _data();

  return (d && d->value) ? impl::get_value_int(d->value) : def;
}

PUGI__FN unsigned int xml_text::as_uint(unsigned int def) const {
  xml_node_struct* d = _data();

  return (d && d->value) ? impl::get_value_uint(d->value) : def;
}

PUGI__FN double xml_text::as_double(double def) const {
  xml_node_struct* d = _data();

  return (d && d->value) ? impl::get_value_double(d->value) : def;
}

PUGI__FN float xml_text::as_float(float def) const {
  xml_node_struct* d = _data();

  return (d && d->value) ? impl::get_value_float(d->value) : def;
}

PUGI__FN bool xml_text::as_bool(bool def) const {
  xml_node_struct* d = _data();

  return (d && d->value) ? impl::get_value_bool(d->value) : def;
}

#ifdef PUGIXML_HAS_LONG_LONG
PUGI__FN long long xml_text::as_llong(long long def) const {
  xml_node_struct* d = _data();

  return (d && d->value) ? impl::get_value_llong(d->value) : def;
}

PUGI__FN unsigned long long xml_text::as_ullong(unsigned long long def) const {
  xml_node_struct* d = _data();

  return (d && d->value) ? impl::get_value_ullong(d->value) : def;
}
#endif

PUGI__FN bool xml_text::set(const char_t* rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::strcpy_insitu(dn->value, dn->header,
                                  impl::xml_memory_page_value_allocated_mask,
                                  rhs, impl::strlength(rhs))
            : false;
}

PUGI__FN bool xml_text::set(int rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::set_value_integer<unsigned int>(
                  dn->value, dn->header,
                  impl::xml_memory_page_value_allocated_mask, rhs, rhs < 0)
            : false;
}

PUGI__FN bool xml_text::set(unsigned int rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::set_value_integer<unsigned int>(
                  dn->value, dn->header,
                  impl::xml_memory_page_value_allocated_mask, rhs, false)
            : false;
}

PUGI__FN bool xml_text::set(long rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::set_value_integer<unsigned long>(
                  dn->value, dn->header,
                  impl::xml_memory_page_value_allocated_mask, rhs, rhs < 0)
            : false;
}

PUGI__FN bool xml_text::set(unsigned long rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::set_value_integer<unsigned long>(
                  dn->value, dn->header,
                  impl::xml_memory_page_value_allocated_mask, rhs, false)
            : false;
}

PUGI__FN bool xml_text::set(float rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::set_value_convert(
                  dn->value, dn->header,
                  impl::xml_memory_page_value_allocated_mask, rhs)
            : false;
}

PUGI__FN bool xml_text::set(double rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::set_value_convert(
                  dn->value, dn->header,
                  impl::xml_memory_page_value_allocated_mask, rhs)
            : false;
}

PUGI__FN bool xml_text::set(bool rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::set_value_bool(dn->value, dn->header,
                                   impl::xml_memory_page_value_allocated_mask,
                                   rhs)
            : false;
}

#ifdef PUGIXML_HAS_LONG_LONG
PUGI__FN bool xml_text::set(long long rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::set_value_integer<unsigned long long>(
                  dn->value, dn->header,
                  impl::xml_memory_page_value_allocated_mask, rhs, rhs < 0)
            : false;
}

PUGI__FN bool xml_text::set(unsigned long long rhs) {
  xml_node_struct* dn = _data_new();

  return dn ? impl::set_value_integer<unsigned long long>(
                  dn->value, dn->header,
                  impl::xml_memory_page_value_allocated_mask, rhs, false)
            : false;
}
#endif

PUGI__FN xml_text& xml_text::operator=(const char_t* rhs) {
  set(rhs);
  return *this;
}

PUGI__FN xml_text& xml_text::operator=(int rhs) {
  set(rhs);
  return *this;
}

PUGI__FN xml_text& xml_text::operator=(unsigned int rhs) {
  set(rhs);
  return *this;
}

PUGI__FN xml_text& xml_text::operator=(long rhs) {
  set(rhs);
  return *this;
}

PUGI__FN xml_text& xml_text::operator=(unsigned long rhs) {
  set(rhs);
  return *this;
}

PUGI__FN xml_text& xml_text::operator=(double rhs) {
  set(rhs);
  return *this;
}

PUGI__FN xml_text& xml_text::operator=(float rhs) {
  set(rhs);
  return *this;
}

PUGI__FN xml_text& xml_text::operator=(bool rhs) {
  set(rhs);
  return *this;
}

#ifdef PUGIXML_HAS_LONG_LONG
PUGI__FN xml_text& xml_text::operator=(long long rhs) {
  set(rhs);
  return *this;
}

PUGI__FN xml_text& xml_text::operator=(unsigned long long rhs) {
  set(rhs);
  return *this;
}
#endif

PUGI__FN xml_node xml_text::data() const { return xml_node(_data()); }

#ifdef __BORLANDC__
PUGI__FN bool operator&&(const xml_text& lhs, bool rhs) {
  return (bool)lhs && rhs;
}

PUGI__FN bool operator||(const xml_text& lhs, bool rhs) {
  return (bool)lhs || rhs;
}
#endif

PUGI__FN xml_node_iterator::xml_node_iterator() {}

PUGI__FN xml_node_iterator::xml_node_iterator(const xml_node& node)
    : _wrap(node), _parent(node.parent()) {}

PUGI__FN xml_node_iterator::xml_node_iterator(xml_node_struct* ref,
                                              xml_node_struct* parent)
    : _wrap(ref), _parent(parent) {}

PUGI__FN bool xml_node_iterator::operator==(
    const xml_node_iterator& rhs) const {
  return _wrap._root == rhs._wrap._root && _parent._root == rhs._parent._root;
}

PUGI__FN bool xml_node_iterator::operator!=(
    const xml_node_iterator& rhs) const {
  return _wrap._root != rhs._wrap._root || _parent._root != rhs._parent._root;
}

PUGI__FN xml_node& xml_node_iterator::operator*() const {
  assert(_wrap._root);
  return _wrap;
}

PUGI__FN xml_node* xml_node_iterator::operator->() const {
  assert(_wrap._root);
  return const_cast<xml_node*>(&_wrap);  // BCC5 workaround
}

PUGI__FN const xml_node_iterator& xml_node_iterator::operator++() {
  assert(_wrap._root);
  _wrap._root = _wrap._root->next_sibling;
  return *this;
}

PUGI__FN xml_node_iterator xml_node_iterator::operator++(int) {
  xml_node_iterator temp = *this;
  ++*this;
  return temp;
}

PUGI__FN const xml_node_iterator& xml_node_iterator::operator--() {
  _wrap = _wrap._root ? _wrap.previous_sibling() : _parent.last_child();
  return *this;
}

PUGI__FN xml_node_iterator xml_node_iterator::operator--(int) {
  xml_node_iterator temp = *this;
  --*this;
  return temp;
}

PUGI__FN xml_attribute_iterator::xml_attribute_iterator() {}

PUGI__FN xml_attribute_iterator::xml_attribute_iterator(
    const xml_attribute& attr, const xml_node& parent)
    : _wrap(attr), _parent(parent) {}

PUGI__FN xml_attribute_iterator::xml_attribute_iterator(
    xml_attribute_struct* ref, xml_node_struct* parent)
    : _wrap(ref), _parent(parent) {}

PUGI__FN bool xml_attribute_iterator::operator==(
    const xml_attribute_iterator& rhs) const {
  return _wrap._attr == rhs._wrap._attr && _parent._root == rhs._parent._root;
}

PUGI__FN bool xml_attribute_iterator::operator!=(
    const xml_attribute_iterator& rhs) const {
  return _wrap._attr != rhs._wrap._attr || _parent._root != rhs._parent._root;
}

PUGI__FN xml_attribute& xml_attribute_iterator::operator*() const {
  assert(_wrap._attr);
  return _wrap;
}

PUGI__FN xml_attribute* xml_attribute_iterator::operator->() const {
  assert(_wrap._attr);
  return const_cast<xml_attribute*>(&_wrap);  // BCC5 workaround
}

PUGI__FN const xml_attribute_iterator& xml_attribute_iterator::operator++() {
  assert(_wrap._attr);
  _wrap._attr = _wrap._attr->next_attribute;
  return *this;
}

PUGI__FN xml_attribute_iterator xml_attribute_iterator::operator++(int) {
  xml_attribute_iterator temp = *this;
  ++*this;
  return temp;
}

PUGI__FN const xml_attribute_iterator& xml_attribute_iterator::operator--() {
  _wrap = _wrap._attr ? _wrap.previous_attribute() : _parent.last_attribute();
  return *this;
}

PUGI__FN xml_attribute_iterator xml_attribute_iterator::operator--(int) {
  xml_attribute_iterator temp = *this;
  --*this;
  return temp;
}

PUGI__FN xml_named_node_iterator::xml_named_node_iterator() : _name(0) {}

PUGI__FN xml_named_node_iterator::xml_named_node_iterator(const xml_node& node,
                                                          const char_t* name)
    : _wrap(node), _parent(node.parent()), _name(name) {}

PUGI__FN xml_named_node_iterator::xml_named_node_iterator(
    xml_node_struct* ref, xml_node_struct* parent, const char_t* name)
    : _wrap(ref), _parent(parent), _name(name) {}

PUGI__FN bool xml_named_node_iterator::operator==(
    const xml_named_node_iterator& rhs) const {
  return _wrap._root == rhs._wrap._root && _parent._root == rhs._parent._root;
}

PUGI__FN bool xml_named_node_iterator::operator!=(
    const xml_named_node_iterator& rhs) const {
  return _wrap._root != rhs._wrap._root || _parent._root != rhs._parent._root;
}

PUGI__FN xml_node& xml_named_node_iterator::operator*() const {
  assert(_wrap._root);
  return _wrap;
}

PUGI__FN xml_node* xml_named_node_iterator::operator->() const {
  assert(_wrap._root);
  return const_cast<xml_node*>(&_wrap);  // BCC5 workaround
}

PUGI__FN const xml_named_node_iterator& xml_named_node_iterator::operator++() {
  assert(_wrap._root);
  _wrap = _wrap.next_sibling(_name);
  return *this;
}

PUGI__FN xml_named_node_iterator xml_named_node_iterator::operator++(int) {
  xml_named_node_iterator temp = *this;
  ++*this;
  return temp;
}

PUGI__FN const xml_named_node_iterator& xml_named_node_iterator::operator--() {
  if (_wrap._root)
    _wrap = _wrap.previous_sibling(_name);
  else {
    _wrap = _parent.last_child();

    if (!impl::strequal(_wrap.name(), _name))
      _wrap = _wrap.previous_sibling(_name);
  }

  return *this;
}

PUGI__FN xml_named_node_iterator xml_named_node_iterator::operator--(int) {
  xml_named_node_iterator temp = *this;
  --*this;
  return temp;
}

PUGI__FN xml_parse_result::xml_parse_result()
    : status(status_internal_error), offset(0), encoding(encoding_auto) {}

PUGI__FN xml_parse_result::operator bool() const { return status == status_ok; }

PUGI__FN const char* xml_parse_result::description() const {
  switch (status) {
    case status_ok:
      return "No error";

    case status_file_not_found:
      return "File was not found";
    case status_io_error:
      return "Error reading from file/stream";
    case status_out_of_memory:
      return "Could not allocate memory";
    case status_internal_error:
      return "Internal error occurred";

    case status_unrecognized_tag:
      return "Could not determine tag type";

    case status_bad_pi:
      return "Error parsing document declaration/processing instruction";
    case status_bad_comment:
      return "Error parsing comment";
    case status_bad_cdata:
      return "Error parsing CDATA section";
    case status_bad_doctype:
      return "Error parsing document type declaration";
    case status_bad_pcdata:
      return "Error parsing PCDATA section";
    case status_bad_start_element:
      return "Error parsing start element tag";
    case status_bad_attribute:
      return "Error parsing element attribute";
    case status_bad_end_element:
      return "Error parsing end element tag";
    case status_end_element_mismatch:
      return "Start-end tags mismatch";

    case status_append_invalid_root:
      return "Unable to append nodes: root is not an element or document";

    case status_no_document_element:
      return "No document element found";

    default:
      return "Unknown error";
  }
}

PUGI__FN xml_document::xml_document() : _buffer(0) { _create(); }

PUGI__FN xml_document::~xml_document() { _destroy(); }

PUGI__FN void xml_document::reset() {
  _destroy();
  _create();
}

PUGI__FN void xml_document::reset(const xml_document& proto) {
  reset();

  for (xml_node cur = proto.first_child(); cur; cur = cur.next_sibling())
    append_copy(cur);
}

PUGI__FN void xml_document::_create() {
  assert(!_root);

#ifdef PUGIXML_COMPACT
  const size_t page_offset = sizeof(uint32_t);
#else
  const size_t page_offset = 0;
#endif

  // initialize sentinel page
  PUGI__STATIC_ASSERT(sizeof(impl::xml_memory_page) +
                          sizeof(impl::xml_document_struct) + page_offset <=
                      sizeof(_memory));

  // prepare page structure
  impl::xml_memory_page* page = impl::xml_memory_page::construct(_memory);
  assert(page);

  page->busy_size = impl::xml_memory_page_size;

  // setup first page marker
#ifdef PUGIXML_COMPACT
  // round-trip through void* to avoid 'cast increases required alignment of
  // target type' warning
  page->compact_page_marker = reinterpret_cast<uint32_t*>(static_cast<void*>(
      reinterpret_cast<char*>(page) + sizeof(impl::xml_memory_page)));
  *page->compact_page_marker = sizeof(impl::xml_memory_page);
#endif

  // allocate new root
  _root = new (reinterpret_cast<char*>(page) + sizeof(impl::xml_memory_page) +
               page_offset) impl::xml_document_struct(page);
  _root->prev_sibling_c = _root;

  // setup sentinel page
  page->allocator = static_cast<impl::xml_document_struct*>(_root);

  // setup hash table pointer in allocator
#ifdef PUGIXML_COMPACT
  page->allocator->_hash =
      &static_cast<impl::xml_document_struct*>(_root)->hash;
#endif

  // verify the document allocation
  assert(reinterpret_cast<char*>(_root) + sizeof(impl::xml_document_struct) <=
         _memory + sizeof(_memory));
}

PUGI__FN void xml_document::_destroy() {
  assert(_root);

  // destroy static storage
  if (_buffer) {
    impl::xml_memory::deallocate(_buffer);
    _buffer = 0;
  }

  // destroy extra buffers (note: no need to destroy linked list nodes, they're
  // allocated using document allocator)
  for (impl::xml_extra_buffer* extra =
           static_cast<impl::xml_document_struct*>(_root)->extra_buffers;
       extra; extra = extra->next) {
    if (extra->buffer) impl::xml_memory::deallocate(extra->buffer);
  }

  // destroy dynamic storage, leave sentinel page (it's in static memory)
  impl::xml_memory_page* root_page = PUGI__GETPAGE(_root);
  assert(root_page && !root_page->prev);
  assert(reinterpret_cast<char*>(root_page) >= _memory &&
         reinterpret_cast<char*>(root_page) < _memory + sizeof(_memory));

  for (impl::xml_memory_page* page = root_page->next; page;) {
    impl::xml_memory_page* next = page->next;

    impl::xml_allocator::deallocate_page(page);

    page = next;
  }

#ifdef PUGIXML_COMPACT
  // destroy hash table
  static_cast<impl::xml_document_struct*>(_root)->hash.clear();
#endif

  _root = 0;
}

#ifndef PUGIXML_NO_STL
PUGI__FN xml_parse_result
xml_document::load(std::basic_istream<char, std::char_traits<char> >& stream,
                   unsigned int options, xml_encoding encoding) {
  reset();

  return impl::load_stream_impl(static_cast<impl::xml_document_struct*>(_root),
                                stream, options, encoding, &_buffer);
}

PUGI__FN xml_parse_result xml_document::load(
    std::basic_istream<wchar_t, std::char_traits<wchar_t> >& stream,
    unsigned int options) {
  reset();

  return impl::load_stream_impl(static_cast<impl::xml_document_struct*>(_root),
                                stream, options, encoding_wchar, &_buffer);
}
#endif

PUGI__FN xml_parse_result xml_document::load_string(const char_t* contents,
                                                    unsigned int options) {
  // Force native encoding (skip autodetection)
#ifdef PUGIXML_WCHAR_MODE
  xml_encoding encoding = encoding_wchar;
#else
  xml_encoding encoding = encoding_utf8;
#endif

  return load_buffer(contents, impl::strlength(contents) * sizeof(char_t),
                     options, encoding);
}

PUGI__FN xml_parse_result xml_document::load(const char_t* contents,
                                             unsigned int options) {
  return load_string(contents, options);
}

PUGI__FN xml_parse_result xml_document::load_file(const char* path_,
                                                  unsigned int options,
                                                  xml_encoding encoding) {
  reset();

  using impl::auto_deleter;  // MSVC7 workaround
  auto_deleter<FILE> file(fopen(path_, "rb"), impl::close_file);

  return impl::load_file_impl(static_cast<impl::xml_document_struct*>(_root),
                              file.data, options, encoding, &_buffer);
}

PUGI__FN xml_parse_result xml_document::load_file(const wchar_t* path_,
                                                  unsigned int options,
                                                  xml_encoding encoding) {
  reset();

  using impl::auto_deleter;  // MSVC7 workaround
  auto_deleter<FILE> file(impl::open_file_wide(path_, L"rb"), impl::close_file);

  return impl::load_file_impl(static_cast<impl::xml_document_struct*>(_root),
                              file.data, options, encoding, &_buffer);
}

PUGI__FN xml_parse_result xml_document::load_buffer(const void* contents,
                                                    size_t size,
                                                    unsigned int options,
                                                    xml_encoding encoding) {
  reset();

  return impl::load_buffer_impl(static_cast<impl::xml_document_struct*>(_root),
                                _root, const_cast<void*>(contents), size,
                                options, encoding, false, false, &_buffer);
}

PUGI__FN xml_parse_result xml_document::load_buffer_inplace(
    void* contents, size_t size, unsigned int options, xml_encoding encoding) {
  reset();

  return impl::load_buffer_impl(static_cast<impl::xml_document_struct*>(_root),
                                _root, contents, size, options, encoding, true,
                                false, &_buffer);
}

PUGI__FN xml_parse_result xml_document::load_buffer_inplace_own(
    void* contents, size_t size, unsigned int options, xml_encoding encoding) {
  reset();

  return impl::load_buffer_impl(static_cast<impl::xml_document_struct*>(_root),
                                _root, contents, size, options, encoding, true,
                                true, &_buffer);
}

PUGI__FN void xml_document::save(xml_writer& writer, const char_t* indent,
                                 unsigned int flags,
                                 xml_encoding encoding) const {
  impl::xml_buffered_writer buffered_writer(writer, encoding);

  if ((flags & format_write_bom) && encoding != encoding_latin1) {
    // BOM always represents the codepoint U+FEFF, so just write it in native
    // encoding
#ifdef PUGIXML_WCHAR_MODE
    unsigned int bom = 0xfeff;
    buffered_writer.write(static_cast<wchar_t>(bom));
#else
    buffered_writer.write('\xef', '\xbb', '\xbf');
#endif
  }

  if (!(flags & format_no_declaration) && !impl::has_declaration(_root)) {
    buffered_writer.write_string(PUGIXML_TEXT("<?xml version=\"1.0\""));
    if (encoding == encoding_latin1)
      buffered_writer.write_string(PUGIXML_TEXT(" encoding=\"ISO-8859-1\""));
    buffered_writer.write('?', '>');
    if (!(flags & format_raw)) buffered_writer.write('\n');
  }

  impl::node_output(buffered_writer, _root, indent, flags, 0);

  buffered_writer.flush();
}

#ifndef PUGIXML_NO_STL
PUGI__FN void xml_document::save(
    std::basic_ostream<char, std::char_traits<char> >& stream,
    const char_t* indent, unsigned int flags, xml_encoding encoding) const {
  xml_writer_stream writer(stream);

  save(writer, indent, flags, encoding);
}

PUGI__FN void xml_document::save(
    std::basic_ostream<wchar_t, std::char_traits<wchar_t> >& stream,
    const char_t* indent, unsigned int flags) const {
  xml_writer_stream writer(stream);

  save(writer, indent, flags, encoding_wchar);
}
#endif

PUGI__FN bool xml_document::save_file(const char* path_, const char_t* indent,
                                      unsigned int flags,
                                      xml_encoding encoding) const {
  using impl::auto_deleter;  // MSVC7 workaround
  auto_deleter<FILE> file(
      fopen(path_, (flags & format_save_file_text) ? "w" : "wb"),
      impl::close_file);

  return impl::save_file_impl(*this, file.data, indent, flags, encoding);
}

PUGI__FN bool xml_document::save_file(const wchar_t* path_,
                                      const char_t* indent, unsigned int flags,
                                      xml_encoding encoding) const {
  using impl::auto_deleter;  // MSVC7 workaround
  auto_deleter<FILE> file(
      impl::open_file_wide(path_,
                           (flags & format_save_file_text) ? L"w" : L"wb"),
      impl::close_file);

  return impl::save_file_impl(*this, file.data, indent, flags, encoding);
}

PUGI__FN xml_node xml_document::document_element() const {
  assert(_root);

  for (xml_node_struct* i = _root->first_child; i; i = i->next_sibling)
    if (PUGI__NODETYPE(i) == node_element) return xml_node(i);

  return xml_node();
}

#ifndef PUGIXML_NO_STL
PUGI__FN std::string PUGIXML_FUNCTION as_utf8(const wchar_t* str) {
  assert(str);

  return impl::as_utf8_impl(str, impl::strlength_wide(str));
}

PUGI__FN std::string PUGIXML_FUNCTION
as_utf8(const std::basic_string<wchar_t>& str) {
  return impl::as_utf8_impl(str.c_str(), str.size());
}

PUGI__FN std::basic_string<wchar_t> PUGIXML_FUNCTION as_wide(const char* str) {
  assert(str);

  return impl::as_wide_impl(str, strlen(str));
}

PUGI__FN std::basic_string<wchar_t> PUGIXML_FUNCTION
as_wide(const std::string& str) {
  return impl::as_wide_impl(str.c_str(), str.size());
}
#endif

PUGI__FN void PUGIXML_FUNCTION set_memory_management_functions(
    allocation_function allocate, deallocation_function deallocate) {
  impl::xml_memory::allocate = allocate;
  impl::xml_memory::deallocate = deallocate;
}

PUGI__FN allocation_function PUGIXML_FUNCTION get_memory_allocation_function() {
  return impl::xml_memory::allocate;
}

PUGI__FN deallocation_function PUGIXML_FUNCTION
get_memory_deallocation_function() {
  return impl::xml_memory::deallocate;
}
}  // namespace pugi

#if !defined(PUGIXML_NO_STL) && (defined(_MSC_VER) || defined(__ICC))
namespace std {
// Workarounds for (non-standard) iterator category detection for older versions
// (MSVC7/IC8 and earlier)
PUGI__FN std::bidirectional_iterator_tag _Iter_cat(
    const pugi::xml_node_iterator&) {
  return std::bidirectional_iterator_tag();
}

PUGI__FN std::bidirectional_iterator_tag _Iter_cat(
    const pugi::xml_attribute_iterator&) {
  return std::bidirectional_iterator_tag();
}

PUGI__FN std::bidirectional_iterator_tag _Iter_cat(
    const pugi::xml_named_node_iterator&) {
  return std::bidirectional_iterator_tag();
}
}  // namespace std
#endif

#if !defined(PUGIXML_NO_STL) && defined(__SUNPRO_CC)
namespace std {
// Workarounds for (non-standard) iterator category detection
PUGI__FN std::bidirectional_iterator_tag __iterator_category(
    const pugi::xml_node_iterator&) {
  return std::bidirectional_iterator_tag();
}

PUGI__FN std::bidirectional_iterator_tag __iterator_category(
    const pugi::xml_attribute_iterator&) {
  return std::bidirectional_iterator_tag();
}

PUGI__FN std::bidirectional_iterator_tag __iterator_category(
    const pugi::xml_named_node_iterator&) {
  return std::bidirectional_iterator_tag();
}
}  // namespace std
#endif

#ifndef PUGIXML_NO_XPATH
// STL replacements
PUGI__NS_BEGIN
struct equal_to {
  template <typename T>
  bool operator()(const T& lhs, const T& rhs) const {
    return lhs == rhs;
  }
};

struct not_equal_to {
  template <typename T>
  bool operator()(const T& lhs, const T& rhs) const {
    return lhs != rhs;
  }
};

struct less {
  template <typename T>
  bool operator()(const T& lhs, const T& rhs) const {
    return lhs < rhs;
  }
};

struct less_equal {
  template <typename T>
  bool operator()(const T& lhs, const T& rhs) const {
    return lhs <= rhs;
  }
};

template <typename T>
void swap(T& lhs, T& rhs) {
  T temp = lhs;
  lhs = rhs;
  rhs = temp;
}

template <typename I, typename Pred>
I min_element(I begin, I end, const Pred& pred) {
  I result = begin;

  for (I it = begin + 1; it != end; ++it)
    if (pred(*it, *result)) result = it;

  return result;
}

template <typename I>
void reverse(I begin, I end) {
  while (end - begin > 1) swap(*begin++, *--end);
}

template <typename I>
I unique(I begin, I end) {
  // fast skip head
  while (end - begin > 1 && *begin != *(begin + 1)) begin++;

  if (begin == end) return begin;

  // last written element
  I write = begin++;

  // merge unique elements
  while (begin != end) {
    if (*begin != *write)
      *++write = *begin++;
    else
      begin++;
  }

  // past-the-end (write points to live element)
  return write + 1;
}

template <typename I>
void copy_backwards(I begin, I end, I target) {
  while (begin != end) *--target = *--end;
}

template <typename I, typename Pred, typename T>
void insertion_sort(I begin, I end, const Pred& pred, T*) {
  assert(begin != end);

  for (I it = begin + 1; it != end; ++it) {
    T val = *it;

    if (pred(val, *begin)) {
      // move to front
      copy_backwards(begin, it, it + 1);
      *begin = val;
    } else {
      I hole = it;

      // move hole backwards
      while (pred(val, *(hole - 1))) {
        *hole = *(hole - 1);
        hole--;
      }

      // fill hole with element
      *hole = val;
    }
  }
}

// std variant for elements with ==
template <typename I, typename Pred>
void partition(I begin, I middle, I end, const Pred& pred, I* out_eqbeg,
               I* out_eqend) {
  I eqbeg = middle, eqend = middle + 1;

  // expand equal range
  while (eqbeg != begin && *(eqbeg - 1) == *eqbeg) --eqbeg;
  while (eqend != end && *eqend == *eqbeg) ++eqend;

  // process outer elements
  I ltend = eqbeg, gtbeg = eqend;

  for (;;) {
    // find the element from the right side that belongs to the left one
    for (; gtbeg != end; ++gtbeg)
      if (!pred(*eqbeg, *gtbeg)) {
        if (*gtbeg == *eqbeg)
          swap(*gtbeg, *eqend++);
        else
          break;
      }

    // find the element from the left side that belongs to the right one
    for (; ltend != begin; --ltend)
      if (!pred(*(ltend - 1), *eqbeg)) {
        if (*eqbeg == *(ltend - 1))
          swap(*(ltend - 1), *--eqbeg);
        else
          break;
      }

    // scanned all elements
    if (gtbeg == end && ltend == begin) {
      *out_eqbeg = eqbeg;
      *out_eqend = eqend;
      return;
    }

    // make room for elements by moving equal area
    if (gtbeg == end) {
      if (--ltend != --eqbeg) swap(*ltend, *eqbeg);
      swap(*eqbeg, *--eqend);
    } else if (ltend == begin) {
      if (eqend != gtbeg) swap(*eqbeg, *eqend);
      ++eqend;
      swap(*gtbeg++, *eqbeg++);
    } else
      swap(*gtbeg++, *--ltend);
  }
}

template <typename I, typename Pred>
void median3(I first, I middle, I last, const Pred& pred) {
  if (pred(*middle, *first)) swap(*middle, *first);
  if (pred(*last, *middle)) swap(*last, *middle);
  if (pred(*middle, *first)) swap(*middle, *first);
}

template <typename I, typename Pred>
void median(I first, I middle, I last, const Pred& pred) {
  if (last - first <= 40) {
    // median of three for small chunks
    median3(first, middle, last, pred);
  } else {
    // median of nine
    size_t step = (last - first + 1) / 8;

    median3(first, first + step, first + 2 * step, pred);
    median3(middle - step, middle, middle + step, pred);
    median3(last - 2 * step, last - step, last, pred);
    median3(first + step, middle, last - step, pred);
  }
}

template <typename I, typename Pred>
void sort(I begin, I end, const Pred& pred) {
  // sort large chunks
  while (end - begin > 32) {
    // find median element
    I middle = begin + (end - begin) / 2;
    median(begin, middle, end - 1, pred);

    // partition in three chunks (< = >)
    I eqbeg, eqend;
    partition(begin, middle, end, pred, &eqbeg, &eqend);

    // loop on larger half
    if (eqbeg - begin > end - eqend) {
      sort(eqend, end, pred);
      end = eqbeg;
    } else {
      sort(begin, eqbeg, pred);
      begin = eqend;
    }
  }

  // insertion sort small chunk
  if (begin != end) insertion_sort(begin, end, pred, &*begin);
}
PUGI__NS_END

// Allocator used for AST and evaluation stacks
PUGI__NS_BEGIN
static const size_t xpath_memory_page_size =
#ifdef PUGIXML_MEMORY_XPATH_PAGE_SIZE
    PUGIXML_MEMORY_XPATH_PAGE_SIZE
#else
    4096
#endif
    ;

static const uintptr_t xpath_memory_block_alignment = sizeof(double) >
                                                              sizeof(void*)
                                                          ? sizeof(double)
                                                          : sizeof(void*);

struct xpath_memory_block {
  xpath_memory_block* next;
  size_t capacity;

  union {
    char data[xpath_memory_page_size];
    double alignment;
  };
};

class xpath_allocator {
  xpath_memory_block* _root;
  size_t _root_size;

public:
#ifdef PUGIXML_NO_EXCEPTIONS
  jmp_buf* error_handler;
#endif

  xpath_allocator(xpath_memory_block* root, size_t root_size = 0)
      : _root(root), _root_size(root_size) {
#ifdef PUGIXML_NO_EXCEPTIONS
    error_handler = 0;
#endif
  }

  void* allocate_nothrow(size_t size) {
    // round size up to block alignment boundary
    size = (size + xpath_memory_block_alignment - 1) &
           ~(xpath_memory_block_alignment - 1);

    if (_root_size + size <= _root->capacity) {
      void* buf = &_root->data[0] + _root_size;
      _root_size += size;
      return buf;
    } else {
      // make sure we have at least 1/4th of the page free after allocation to
      // satisfy subsequent allocation requests
      size_t block_capacity_base = sizeof(_root->data);
      size_t block_capacity_req = size + block_capacity_base / 4;
      size_t block_capacity = (block_capacity_base > block_capacity_req)
                                  ? block_capacity_base
                                  : block_capacity_req;

      size_t block_size = block_capacity + offsetof(xpath_memory_block, data);

      xpath_memory_block* block =
          static_cast<xpath_memory_block*>(xml_memory::allocate(block_size));
      if (!block) return 0;

      block->next = _root;
      block->capacity = block_capacity;

      _root = block;
      _root_size = size;

      return block->data;
    }
  }

  void* allocate(size_t size) {
    void* result = allocate_nothrow(size);

    if (!result) {
#ifdef PUGIXML_NO_EXCEPTIONS
      assert(error_handler);
      longjmp(*error_handler, 1);
#else
      throw std::bad_alloc();
#endif
    }

    return result;
  }

  void* reallocate(void* ptr, size_t old_size, size_t new_size) {
    // round size up to block alignment boundary
    old_size = (old_size + xpath_memory_block_alignment - 1) &
               ~(xpath_memory_block_alignment - 1);
    new_size = (new_size + xpath_memory_block_alignment - 1) &
               ~(xpath_memory_block_alignment - 1);

    // we can only reallocate the last object
    assert(ptr == 0 ||
           static_cast<char*>(ptr) + old_size == &_root->data[0] + _root_size);

    // adjust root size so that we have not allocated the object at all
    bool only_object = (_root_size == old_size);

    if (ptr) _root_size -= old_size;

    // allocate a new version (this will obviously reuse the memory if possible)
    void* result = allocate(new_size);
    assert(result);

    // we have a new block
    if (result != ptr && ptr) {
      // copy old data
      assert(new_size >= old_size);
      memcpy(result, ptr, old_size);

      // free the previous page if it had no other objects
      if (only_object) {
        assert(_root->data == result);
        assert(_root->next);

        xpath_memory_block* next = _root->next->next;

        if (next) {
          // deallocate the whole page, unless it was the first one
          xml_memory::deallocate(_root->next);
          _root->next = next;
        }
      }
    }

    return result;
  }

  void revert(const xpath_allocator& state) {
    // free all new pages
    xpath_memory_block* cur = _root;

    while (cur != state._root) {
      xpath_memory_block* next = cur->next;

      xml_memory::deallocate(cur);

      cur = next;
    }

    // restore state
    _root = state._root;
    _root_size = state._root_size;
  }

  void release() {
    xpath_memory_block* cur = _root;
    assert(cur);

    while (cur->next) {
      xpath_memory_block* next = cur->next;

      xml_memory::deallocate(cur);

      cur = next;
    }
  }
};

struct xpath_allocator_capture {
  xpath_allocator_capture(xpath_allocator* alloc)
      : _target(alloc), _state(*alloc) {}

  ~xpath_allocator_capture() { _target->revert(_state); }

  xpath_allocator* _target;
  xpath_allocator _state;
};

struct xpath_stack {
  xpath_allocator* result;
  xpath_allocator* temp;
};

struct xpath_stack_data {
  xpath_memory_block blocks[2];
  xpath_allocator result;
  xpath_allocator temp;
  xpath_stack stack;

#ifdef PUGIXML_NO_EXCEPTIONS
  jmp_buf error_handler;
#endif

  xpath_stack_data() : result(blocks + 0), temp(blocks + 1) {
    blocks[0].next = blocks[1].next = 0;
    blocks[0].capacity = blocks[1].capacity = sizeof(blocks[0].data);

    stack.result = &result;
    stack.temp = &temp;

#ifdef PUGIXML_NO_EXCEPTIONS
    result.error_handler = temp.error_handler = &error_handler;
#endif
  }

  ~xpath_stack_data() {
    result.release();
    temp.release();
  }
};
PUGI__NS_END

// String class
PUGI__NS_BEGIN
class xpath_string {
  const char_t* _buffer;
  bool _uses_heap;
  size_t _length_heap;

  static char_t* duplicate_string(const char_t* string, size_t length,
                                  xpath_allocator* alloc) {
    char_t* result =
        static_cast<char_t*>(alloc->allocate((length + 1) * sizeof(char_t)));
    assert(result);

    memcpy(result, string, length * sizeof(char_t));
    result[length] = 0;

    return result;
  }

  xpath_string(const char_t* buffer, bool uses_heap_, size_t length_heap)
      : _buffer(buffer), _uses_heap(uses_heap_), _length_heap(length_heap) {}

public:
  static xpath_string from_const(const char_t* str) {
    return xpath_string(str, false, 0);
  }

  static xpath_string from_heap_preallocated(const char_t* begin,
                                             const char_t* end) {
    assert(begin <= end && *end == 0);

    return xpath_string(begin, true, static_cast<size_t>(end - begin));
  }

  static xpath_string from_heap(const char_t* begin, const char_t* end,
                                xpath_allocator* alloc) {
    assert(begin <= end);

    size_t length = static_cast<size_t>(end - begin);

    return length == 0 ? xpath_string()
                       : xpath_string(duplicate_string(begin, length, alloc),
                                      true, length);
  }

  xpath_string()
      : _buffer(PUGIXML_TEXT("")), _uses_heap(false), _length_heap(0) {}

  void append(const xpath_string& o, xpath_allocator* alloc) {
    // skip empty sources
    if (!*o._buffer) return;

    // fast append for constant empty target and constant source
    if (!*_buffer && !_uses_heap && !o._uses_heap) {
      _buffer = o._buffer;
    } else {
      // need to make heap copy
      size_t target_length = length();
      size_t source_length = o.length();
      size_t result_length = target_length + source_length;

      // allocate new buffer
      char_t* result = static_cast<char_t*>(
          alloc->reallocate(_uses_heap ? const_cast<char_t*>(_buffer) : 0,
                            (target_length + 1) * sizeof(char_t),
                            (result_length + 1) * sizeof(char_t)));
      assert(result);

      // append first string to the new buffer in case there was no reallocation
      if (!_uses_heap) memcpy(result, _buffer, target_length * sizeof(char_t));

      // append second string to the new buffer
      memcpy(result + target_length, o._buffer, source_length * sizeof(char_t));
      result[result_length] = 0;

      // finalize
      _buffer = result;
      _uses_heap = true;
      _length_heap = result_length;
    }
  }

  const char_t* c_str() const { return _buffer; }

  size_t length() const {
    return _uses_heap ? _length_heap : strlength(_buffer);
  }

  char_t* data(xpath_allocator* alloc) {
    // make private heap copy
    if (!_uses_heap) {
      size_t length_ = strlength(_buffer);

      _buffer = duplicate_string(_buffer, length_, alloc);
      _uses_heap = true;
      _length_heap = length_;
    }

    return const_cast<char_t*>(_buffer);
  }

  bool empty() const { return *_buffer == 0; }

  bool operator==(const xpath_string& o) const {
    return strequal(_buffer, o._buffer);
  }

  bool operator!=(const xpath_string& o) const {
    return !strequal(_buffer, o._buffer);
  }

  bool uses_heap() const { return _uses_heap; }
};
PUGI__NS_END

PUGI__NS_BEGIN
PUGI__FN bool starts_with(const char_t* string, const char_t* pattern) {
  while (*pattern && *string == *pattern) {
    string++;
    pattern++;
  }

  return *pattern == 0;
}

PUGI__FN const char_t* find_char(const char_t* s, char_t c) {
#ifdef PUGIXML_WCHAR_MODE
  return wcschr(s, c);
#else
  return strchr(s, c);
#endif
}

PUGI__FN const char_t* find_substring(const char_t* s, const char_t* p) {
#ifdef PUGIXML_WCHAR_MODE
  // MSVC6 wcsstr bug workaround (if s is empty it always returns 0)
  return (*p == 0) ? s : wcsstr(s, p);
#else
  return strstr(s, p);
#endif
}

// Converts symbol to lower case, if it is an ASCII one
PUGI__FN char_t tolower_ascii(char_t ch) {
  return static_cast<unsigned int>(ch - 'A') < 26
             ? static_cast<char_t>(ch | ' ')
             : ch;
}

PUGI__FN xpath_string string_value(const xpath_node& na,
                                   xpath_allocator* alloc) {
  if (na.attribute())
    return xpath_string::from_const(na.attribute().value());
  else {
    xml_node n = na.node();

    switch (n.type()) {
      case node_pcdata:
      case node_cdata:
      case node_comment:
      case node_pi:
        return xpath_string::from_const(n.value());

      case node_document:
      case node_element: {
        xpath_string result;

        // element nodes can have value if parse_embed_pcdata was used
        if (n.value()[0])
          result.append(xpath_string::from_const(n.value()), alloc);

        xml_node cur = n.first_child();

        while (cur && cur != n) {
          if (cur.type() == node_pcdata || cur.type() == node_cdata)
            result.append(xpath_string::from_const(cur.value()), alloc);

          if (cur.first_child())
            cur = cur.first_child();
          else if (cur.next_sibling())
            cur = cur.next_sibling();
          else {
            while (!cur.next_sibling() && cur != n) cur = cur.parent();

            if (cur != n) cur = cur.next_sibling();
          }
        }

        return result;
      }

      default:
        return xpath_string();
    }
  }
}

PUGI__FN bool node_is_before_sibling(xml_node_struct* ln, xml_node_struct* rn) {
  assert(ln->parent == rn->parent);

  // there is no common ancestor (the shared parent is null), nodes are from
  // different documents
  if (!ln->parent) return ln < rn;

  // determine sibling order
  xml_node_struct* ls = ln;
  xml_node_struct* rs = rn;

  while (ls && rs) {
    if (ls == rn) return true;
    if (rs == ln) return false;

    ls = ls->next_sibling;
    rs = rs->next_sibling;
  }

  // if rn sibling chain ended ln must be before rn
  return !rs;
}

PUGI__FN bool node_is_before(xml_node_struct* ln, xml_node_struct* rn) {
  // find common ancestor at the same depth, if any
  xml_node_struct* lp = ln;
  xml_node_struct* rp = rn;

  while (lp && rp && lp->parent != rp->parent) {
    lp = lp->parent;
    rp = rp->parent;
  }

  // parents are the same!
  if (lp && rp) return node_is_before_sibling(lp, rp);

  // nodes are at different depths, need to normalize heights
  bool left_higher = !lp;

  while (lp) {
    lp = lp->parent;
    ln = ln->parent;
  }

  while (rp) {
    rp = rp->parent;
    rn = rn->parent;
  }

  // one node is the ancestor of the other
  if (ln == rn) return left_higher;

  // find common ancestor... again
  while (ln->parent != rn->parent) {
    ln = ln->parent;
    rn = rn->parent;
  }

  return node_is_before_sibling(ln, rn);
}

PUGI__FN bool node_is_ancestor(xml_node_struct* parent, xml_node_struct* node) {
  while (node && node != parent) node = node->parent;

  return parent && node == parent;
}

PUGI__FN const void* document_buffer_order(const xpath_node& xnode) {
  xml_node_struct* node = xnode.node().internal_object();

  if (node) {
    if ((get_document(node).header & xml_memory_page_contents_shared_mask) ==
        0) {
      if (node->name &&
          (node->header &
           impl::xml_memory_page_name_allocated_or_shared_mask) == 0)
        return node->name;
      if (node->value &&
          (node->header &
           impl::xml_memory_page_value_allocated_or_shared_mask) == 0)
        return node->value;
    }

    return 0;
  }

  xml_attribute_struct* attr = xnode.attribute().internal_object();

  if (attr) {
    if ((get_document(attr).header & xml_memory_page_contents_shared_mask) ==
        0) {
      if ((attr->header &
           impl::xml_memory_page_name_allocated_or_shared_mask) == 0)
        return attr->name;
      if ((attr->header &
           impl::xml_memory_page_value_allocated_or_shared_mask) == 0)
        return attr->value;
    }

    return 0;
  }

  return 0;
}

struct document_order_comparator {
  bool operator()(const xpath_node& lhs, const xpath_node& rhs) const {
    // optimized document order based check
    const void* lo = document_buffer_order(lhs);
    const void* ro = document_buffer_order(rhs);

    if (lo && ro) return lo < ro;

    // slow comparison
    xml_node ln = lhs.node(), rn = rhs.node();

    // compare attributes
    if (lhs.attribute() && rhs.attribute()) {
      // shared parent
      if (lhs.parent() == rhs.parent()) {
        // determine sibling order
        for (xml_attribute a = lhs.attribute(); a; a = a.next_attribute())
          if (a == rhs.attribute()) return true;

        return false;
      }

      // compare attribute parents
      ln = lhs.parent();
      rn = rhs.parent();
    } else if (lhs.attribute()) {
      // attributes go after the parent element
      if (lhs.parent() == rhs.node()) return false;

      ln = lhs.parent();
    } else if (rhs.attribute()) {
      // attributes go after the parent element
      if (rhs.parent() == lhs.node()) return true;

      rn = rhs.parent();
    }

    if (ln == rn) return false;

    if (!ln || !rn) return ln < rn;

    return node_is_before(ln.internal_object(), rn.internal_object());
  }
};

struct duplicate_comparator {
  bool operator()(const xpath_node& lhs, const xpath_node& rhs) const {
    if (lhs.attribute())
      return rhs.attribute() ? lhs.attribute() < rhs.attribute() : true;
    else
      return rhs.attribute() ? false : lhs.node() < rhs.node();
  }
};

PUGI__FN double gen_nan() {
#if defined(__STDC_IEC_559__) ||                         \
    ((FLT_RADIX - 0 == 2) && (FLT_MAX_EXP - 0 == 128) && \
     (FLT_MANT_DIG - 0 == 24))
  PUGI__STATIC_ASSERT(sizeof(float) == sizeof(uint32_t));
  typedef uint32_t UI;  // BCC5 workaround
  union {
    float f;
    UI i;
  } u;
  u.i = 0x7fc00000;
  return u.f;
#else
  // fallback
  const volatile double zero = 0.0;
  return zero / zero;
#endif
}

PUGI__FN bool is_nan(double value) {
#if defined(PUGI__MSVC_CRT_VERSION) || defined(__BORLANDC__)
  return !!_isnan(value);
#elif defined(fpclassify) && defined(FP_NAN)
  return fpclassify(value) == FP_NAN;
#else
  // fallback
  const volatile double v = value;
  return v != v;
#endif
}

PUGI__FN const char_t* convert_number_to_string_special(double value) {
#if defined(PUGI__MSVC_CRT_VERSION) || defined(__BORLANDC__)
  if (_finite(value)) return (value == 0) ? PUGIXML_TEXT("0") : 0;
  if (_isnan(value)) return PUGIXML_TEXT("NaN");
  return value > 0 ? PUGIXML_TEXT("Infinity") : PUGIXML_TEXT("-Infinity");
#elif defined(fpclassify) && defined(FP_NAN) && defined(FP_INFINITE) && \
    defined(FP_ZERO)
  switch (fpclassify(value)) {
    case FP_NAN:
      return PUGIXML_TEXT("NaN");

    case FP_INFINITE:
      return value > 0 ? PUGIXML_TEXT("Infinity") : PUGIXML_TEXT("-Infinity");

    case FP_ZERO:
      return PUGIXML_TEXT("0");

    default:
      return 0;
  }
#else
  // fallback
  const volatile double v = value;

  if (v == 0) return PUGIXML_TEXT("0");
  if (v != v) return PUGIXML_TEXT("NaN");
  if (v * 2 == v)
    return value > 0 ? PUGIXML_TEXT("Infinity") : PUGIXML_TEXT("-Infinity");
  return 0;
#endif
}

PUGI__FN bool convert_number_to_boolean(double value) {
  return (value != 0 && !is_nan(value));
}

PUGI__FN void truncate_zeros(char* begin, char* end) {
  while (begin != end && end[-1] == '0') end--;

  *end = 0;
}

// gets mantissa digits in the form of 0.xxxxx with 0. implied and the exponent
#if defined(PUGI__MSVC_CRT_VERSION) && PUGI__MSVC_CRT_VERSION >= 1400 && \
    !defined(_WIN32_WCE)
PUGI__FN void convert_number_to_mantissa_exponent(double value, char* buffer,
                                                  size_t buffer_size,
                                                  char** out_mantissa,
                                                  int* out_exponent) {
  // get base values
  int sign, exponent;
  _ecvt_s(buffer, buffer_size, value, DBL_DIG + 1, &exponent, &sign);

  // truncate redundant zeros
  truncate_zeros(buffer, buffer + strlen(buffer));

  // fill results
  *out_mantissa = buffer;
  *out_exponent = exponent;
}
#else
PUGI__FN void convert_number_to_mantissa_exponent(double value, char* buffer,
                                                  size_t buffer_size,
                                                  char** out_mantissa,
                                                  int* out_exponent) {
  // get a scientific notation value with IEEE DBL_DIG decimals
  sprintf(buffer, "%.*e", DBL_DIG, value);
  assert(strlen(buffer) < buffer_size);
  (void)!buffer_size;

  // get the exponent (possibly negative)
  char* exponent_string = strchr(buffer, 'e');
  assert(exponent_string);

  int exponent = atoi(exponent_string + 1);

  // extract mantissa string: skip sign
  char* mantissa = buffer[0] == '-' ? buffer + 1 : buffer;
  assert(mantissa[0] != '0' && mantissa[1] == '.');

  // divide mantissa by 10 to eliminate integer part
  mantissa[1] = mantissa[0];
  mantissa++;
  exponent++;

  // remove extra mantissa digits and zero-terminate mantissa
  truncate_zeros(mantissa, exponent_string);

  // fill results
  *out_mantissa = mantissa;
  *out_exponent = exponent;
}
#endif

PUGI__FN xpath_string convert_number_to_string(double value,
                                               xpath_allocator* alloc) {
  // try special number conversion
  const char_t* special = convert_number_to_string_special(value);
  if (special) return xpath_string::from_const(special);

  // get mantissa + exponent form
  char mantissa_buffer[32];

  char* mantissa;
  int exponent;
  convert_number_to_mantissa_exponent(
      value, mantissa_buffer, sizeof(mantissa_buffer), &mantissa, &exponent);

  // allocate a buffer of suitable length for the number
  size_t result_size =
      strlen(mantissa_buffer) + (exponent > 0 ? exponent : -exponent) + 4;
  char_t* result =
      static_cast<char_t*>(alloc->allocate(sizeof(char_t) * result_size));
  assert(result);

  // make the number!
  char_t* s = result;

  // sign
  if (value < 0) *s++ = '-';

  // integer part
  if (exponent <= 0) {
    *s++ = '0';
  } else {
    while (exponent > 0) {
      assert(*mantissa == 0 ||
             static_cast<unsigned int>(static_cast<unsigned int>(*mantissa) -
                                       '0') <= 9);
      *s++ = *mantissa ? *mantissa++ : '0';
      exponent--;
    }
  }

  // fractional part
  if (*mantissa) {
    // decimal point
    *s++ = '.';

    // extra zeroes from negative exponent
    while (exponent < 0) {
      *s++ = '0';
      exponent++;
    }

    // extra mantissa digits
    while (*mantissa) {
      assert(static_cast<unsigned int>(*mantissa - '0') <= 9);
      *s++ = *mantissa++;
    }
  }

  // zero-terminate
  assert(s < result + result_size);
  *s = 0;

  return xpath_string::from_heap_preallocated(result, s);
}

PUGI__FN bool check_string_to_number_format(const char_t* string) {
  // parse leading whitespace
  while (PUGI__IS_CHARTYPE(*string, ct_space)) ++string;

  // parse sign
  if (*string == '-') ++string;

  if (!*string) return false;

  // if there is no integer part, there should be a decimal part with at least
  // one digit
  if (!PUGI__IS_CHARTYPEX(string[0], ctx_digit) &&
      (string[0] != '.' || !PUGI__IS_CHARTYPEX(string[1], ctx_digit)))
    return false;

  // parse integer part
  while (PUGI__IS_CHARTYPEX(*string, ctx_digit)) ++string;

  // parse decimal part
  if (*string == '.') {
    ++string;

    while (PUGI__IS_CHARTYPEX(*string, ctx_digit)) ++string;
  }

  // parse trailing whitespace
  while (PUGI__IS_CHARTYPE(*string, ct_space)) ++string;

  return *string == 0;
}

PUGI__FN double convert_string_to_number(const char_t* string) {
  // check string format
  if (!check_string_to_number_format(string)) return gen_nan();

    // parse string
#ifdef PUGIXML_WCHAR_MODE
  return wcstod(string, 0);
#else
  return strtod(string, 0);
#endif
}

PUGI__FN bool convert_string_to_number_scratch(char_t (&buffer)[32],
                                               const char_t* begin,
                                               const char_t* end,
                                               double* out_result) {
  size_t length = static_cast<size_t>(end - begin);
  char_t* scratch = buffer;

  if (length >= sizeof(buffer) / sizeof(buffer[0])) {
    // need to make dummy on-heap copy
    scratch = static_cast<char_t*>(
        xml_memory::allocate((length + 1) * sizeof(char_t)));
    if (!scratch) return false;
  }

  // copy string to zero-terminated buffer and perform conversion
  memcpy(scratch, begin, length * sizeof(char_t));
  scratch[length] = 0;

  *out_result = convert_string_to_number(scratch);

  // free dummy buffer
  if (scratch != buffer) xml_memory::deallocate(scratch);

  return true;
}

PUGI__FN double round_nearest(double value) { return floor(value + 0.5); }

PUGI__FN double round_nearest_nzero(double value) {
  // same as round_nearest, but returns -0 for [-0.5, -0]
  // ceil is used to differentiate between +0 and -0 (we return -0 for [-0.5,
  // -0] and +0 for +0)
  return (value >= -0.5 && value <= 0) ? ceil(value) : floor(value + 0.5);
}

PUGI__FN const char_t* qualified_name(const xpath_node& node) {
  return node.attribute() ? node.attribute().name() : node.node().name();
}

PUGI__FN const char_t* local_name(const xpath_node& node) {
  const char_t* name = qualified_name(node);
  const char_t* p = find_char(name, ':');

  return p ? p + 1 : name;
}

struct namespace_uri_predicate {
  const char_t* prefix;
  size_t prefix_length;

  namespace_uri_predicate(const char_t* name) {
    const char_t* pos = find_char(name, ':');

    prefix = pos ? name : 0;
    prefix_length = pos ? static_cast<size_t>(pos - name) : 0;
  }

  bool operator()(xml_attribute a) const {
    const char_t* name = a.name();

    if (!starts_with(name, PUGIXML_TEXT("xmlns"))) return false;

    return prefix ? name[5] == ':' &&
                        strequalrange(name + 6, prefix, prefix_length)
                  : name[5] == 0;
  }
};

PUGI__FN const char_t* namespace_uri(xml_node node) {
  namespace_uri_predicate pred = node.name();

  xml_node p = node;

  while (p) {
    xml_attribute a = p.find_attribute(pred);

    if (a) return a.value();

    p = p.parent();
  }

  return PUGIXML_TEXT("");
}

PUGI__FN const char_t* namespace_uri(xml_attribute attr, xml_node parent) {
  namespace_uri_predicate pred = attr.name();

  // Default namespace does not apply to attributes
  if (!pred.prefix) return PUGIXML_TEXT("");

  xml_node p = parent;

  while (p) {
    xml_attribute a = p.find_attribute(pred);

    if (a) return a.value();

    p = p.parent();
  }

  return PUGIXML_TEXT("");
}

PUGI__FN const char_t* namespace_uri(const xpath_node& node) {
  return node.attribute() ? namespace_uri(node.attribute(), node.parent())
                          : namespace_uri(node.node());
}

PUGI__FN char_t* normalize_space(char_t* buffer) {
  char_t* write = buffer;

  for (char_t* it = buffer; *it;) {
    char_t ch = *it++;

    if (PUGI__IS_CHARTYPE(ch, ct_space)) {
      // replace whitespace sequence with single space
      while (PUGI__IS_CHARTYPE(*it, ct_space)) it++;

      // avoid leading spaces
      if (write != buffer) *write++ = ' ';
    } else
      *write++ = ch;
  }

  // remove trailing space
  if (write != buffer && PUGI__IS_CHARTYPE(write[-1], ct_space)) write--;

  // zero-terminate
  *write = 0;

  return write;
}

PUGI__FN char_t* translate(char_t* buffer, const char_t* from, const char_t* to,
                           size_t to_length) {
  char_t* write = buffer;

  while (*buffer) {
    PUGI__DMC_VOLATILE char_t ch = *buffer++;

    const char_t* pos = find_char(from, ch);

    if (!pos)
      *write++ = ch;  // do not process
    else if (static_cast<size_t>(pos - from) < to_length)
      *write++ = to[pos - from];  // replace
  }

  // zero-terminate
  *write = 0;

  return write;
}

PUGI__FN unsigned char* translate_table_generate(xpath_allocator* alloc,
                                                 const char_t* from,
                                                 const char_t* to) {
  unsigned char table[128] = {0};

  while (*from) {
    unsigned int fc = static_cast<unsigned int>(*from);
    unsigned int tc = static_cast<unsigned int>(*to);

    if (fc >= 128 || tc >= 128) return 0;

    // code=128 means "skip character"
    if (!table[fc]) table[fc] = static_cast<unsigned char>(tc ? tc : 128);

    from++;
    if (tc) to++;
  }

  for (int i = 0; i < 128; ++i)
    if (!table[i]) table[i] = static_cast<unsigned char>(i);

  void* result = alloc->allocate_nothrow(sizeof(table));

  if (result) {
    memcpy(result, table, sizeof(table));
  }

  return static_cast<unsigned char*>(result);
}

PUGI__FN char_t* translate_table(char_t* buffer, const unsigned char* table) {
  char_t* write = buffer;

  while (*buffer) {
    char_t ch = *buffer++;
    unsigned int index = static_cast<unsigned int>(ch);

    if (index < 128) {
      unsigned char code = table[index];

      // code=128 means "skip character" (table size is 128 so 128 can be a
      // special value) this code skips these characters without extra branches
      *write = static_cast<char_t>(code);
      write += 1 - (code >> 7);
    } else {
      *write++ = ch;
    }
  }

  // zero-terminate
  *write = 0;

  return write;
}

inline bool is_xpath_attribute(const char_t* name) {
  return !(starts_with(name, PUGIXML_TEXT("xmlns")) &&
           (name[5] == 0 || name[5] == ':'));
}

struct xpath_variable_boolean : xpath_variable {
  xpath_variable_boolean() : xpath_variable(xpath_type_boolean), value(false) {}

  bool value;
  char_t name[1];
};

struct xpath_variable_number : xpath_variable {
  xpath_variable_number() : xpath_variable(xpath_type_number), value(0) {}

  double value;
  char_t name[1];
};

struct xpath_variable_string : xpath_variable {
  xpath_variable_string() : xpath_variable(xpath_type_string), value(0) {}

  ~xpath_variable_string() {
    if (value) xml_memory::deallocate(value);
  }

  char_t* value;
  char_t name[1];
};

struct xpath_variable_node_set : xpath_variable {
  xpath_variable_node_set() : xpath_variable(xpath_type_node_set) {}

  xpath_node_set value;
  char_t name[1];
};

static const xpath_node_set dummy_node_set;

PUGI__FN unsigned int hash_string(const char_t* str) {
  // Jenkins one-at-a-time hash
  // (http://en.wikipedia.org/wiki/Jenkins_hash_function#one-at-a-time)
  unsigned int result = 0;

  while (*str) {
    result += static_cast<unsigned int>(*str++);
    result += result << 10;
    result ^= result >> 6;
  }

  result += result << 3;
  result ^= result >> 11;
  result += result << 15;

  return result;
}

template <typename T>
PUGI__FN T* new_xpath_variable(const char_t* name) {
  size_t length = strlength(name);
  if (length == 0) return 0;  // empty variable names are invalid

  // $$ we can't use offsetof(T, name) because T is non-POD, so we just allocate
  // additional length characters
  void* memory = xml_memory::allocate(sizeof(T) + length * sizeof(char_t));
  if (!memory) return 0;

  T* result = new (memory) T();

  memcpy(result->name, name, (length + 1) * sizeof(char_t));

  return result;
}

PUGI__FN xpath_variable* new_xpath_variable(xpath_value_type type,
                                            const char_t* name) {
  switch (type) {
    case xpath_type_node_set:
      return new_xpath_variable<xpath_variable_node_set>(name);

    case xpath_type_number:
      return new_xpath_variable<xpath_variable_number>(name);

    case xpath_type_string:
      return new_xpath_variable<xpath_variable_string>(name);

    case xpath_type_boolean:
      return new_xpath_variable<xpath_variable_boolean>(name);

    default:
      return 0;
  }
}

template <typename T>
PUGI__FN void delete_xpath_variable(T* var) {
  var->~T();
  xml_memory::deallocate(var);
}

PUGI__FN void delete_xpath_variable(xpath_value_type type,
                                    xpath_variable* var) {
  switch (type) {
    case xpath_type_node_set:
      delete_xpath_variable(static_cast<xpath_variable_node_set*>(var));
      break;

    case xpath_type_number:
      delete_xpath_variable(static_cast<xpath_variable_number*>(var));
      break;

    case xpath_type_string:
      delete_xpath_variable(static_cast<xpath_variable_string*>(var));
      break;

    case xpath_type_boolean:
      delete_xpath_variable(static_cast<xpath_variable_boolean*>(var));
      break;

    default:
      assert(false && "Invalid variable type");
  }
}

PUGI__FN bool copy_xpath_variable(xpath_variable* lhs,
                                  const xpath_variable* rhs) {
  switch (rhs->type()) {
    case xpath_type_node_set:
      return lhs->set(static_cast<const xpath_variable_node_set*>(rhs)->value);

    case xpath_type_number:
      return lhs->set(static_cast<const xpath_variable_number*>(rhs)->value);

    case xpath_type_string:
      return lhs->set(static_cast<const xpath_variable_string*>(rhs)->value);

    case xpath_type_boolean:
      return lhs->set(static_cast<const xpath_variable_boolean*>(rhs)->value);

    default:
      assert(false && "Invalid variable type");
      return false;
  }
}

PUGI__FN bool get_variable_scratch(char_t (&buffer)[32],
                                   xpath_variable_set* set, const char_t* begin,
                                   const char_t* end,
                                   xpath_variable** out_result) {
  size_t length = static_cast<size_t>(end - begin);
  char_t* scratch = buffer;

  if (length >= sizeof(buffer) / sizeof(buffer[0])) {
    // need to make dummy on-heap copy
    scratch = static_cast<char_t*>(
        xml_memory::allocate((length + 1) * sizeof(char_t)));
    if (!scratch) return false;
  }

  // copy string to zero-terminated buffer and perform lookup
  memcpy(scratch, begin, length * sizeof(char_t));
  scratch[length] = 0;

  *out_result = set->get(scratch);

  // free dummy buffer
  if (scratch != buffer) xml_memory::deallocate(scratch);

  return true;
}
PUGI__NS_END

// Internal node set class
PUGI__NS_BEGIN
PUGI__FN xpath_node_set::type_t xpath_get_order(const xpath_node* begin,
                                                const xpath_node* end) {
  if (end - begin < 2) return xpath_node_set::type_sorted;

  document_order_comparator cmp;

  bool first = cmp(begin[0], begin[1]);

  for (const xpath_node* it = begin + 1; it + 1 < end; ++it)
    if (cmp(it[0], it[1]) != first) return xpath_node_set::type_unsorted;

  return first ? xpath_node_set::type_sorted
               : xpath_node_set::type_sorted_reverse;
}

PUGI__FN xpath_node_set::type_t xpath_sort(xpath_node* begin, xpath_node* end,
                                           xpath_node_set::type_t type,
                                           bool rev) {
  xpath_node_set::type_t order =
      rev ? xpath_node_set::type_sorted_reverse : xpath_node_set::type_sorted;

  if (type == xpath_node_set::type_unsorted) {
    xpath_node_set::type_t sorted = xpath_get_order(begin, end);

    if (sorted == xpath_node_set::type_unsorted) {
      sort(begin, end, document_order_comparator());

      type = xpath_node_set::type_sorted;
    } else
      type = sorted;
  }

  if (type != order) reverse(begin, end);

  return order;
}

PUGI__FN xpath_node xpath_first(const xpath_node* begin, const xpath_node* end,
                                xpath_node_set::type_t type) {
  if (begin == end) return xpath_node();

  switch (type) {
    case xpath_node_set::type_sorted:
      return *begin;

    case xpath_node_set::type_sorted_reverse:
      return *(end - 1);

    case xpath_node_set::type_unsorted:
      return *min_element(begin, end, document_order_comparator());

    default:
      assert(false && "Invalid node set type");
      return xpath_node();
  }
}

class xpath_node_set_raw {
  xpath_node_set::type_t _type;

  xpath_node* _begin;
  xpath_node* _end;
  xpath_node* _eos;

public:
  xpath_node_set_raw()
      : _type(xpath_node_set::type_unsorted), _begin(0), _end(0), _eos(0) {}

  xpath_node* begin() const { return _begin; }

  xpath_node* end() const { return _end; }

  bool empty() const { return _begin == _end; }

  size_t size() const { return static_cast<size_t>(_end - _begin); }

  xpath_node first() const { return xpath_first(_begin, _end, _type); }

  void push_back_grow(const xpath_node& node, xpath_allocator* alloc);

  void push_back(const xpath_node& node, xpath_allocator* alloc) {
    if (_end != _eos)
      *_end++ = node;
    else
      push_back_grow(node, alloc);
  }

  void append(const xpath_node* begin_, const xpath_node* end_,
              xpath_allocator* alloc) {
    if (begin_ == end_) return;

    size_t size_ = static_cast<size_t>(_end - _begin);
    size_t capacity = static_cast<size_t>(_eos - _begin);
    size_t count = static_cast<size_t>(end_ - begin_);

    if (size_ + count > capacity) {
      // reallocate the old array or allocate a new one
      xpath_node* data = static_cast<xpath_node*>(
          alloc->reallocate(_begin, capacity * sizeof(xpath_node),
                            (size_ + count) * sizeof(xpath_node)));
      assert(data);

      // finalize
      _begin = data;
      _end = data + size_;
      _eos = data + size_ + count;
    }

    memcpy(_end, begin_, count * sizeof(xpath_node));
    _end += count;
  }

  void sort_do() { _type = xpath_sort(_begin, _end, _type, false); }

  void truncate(xpath_node* pos) {
    assert(_begin <= pos && pos <= _end);

    _end = pos;
  }

  void remove_duplicates() {
    if (_type == xpath_node_set::type_unsorted)
      sort(_begin, _end, duplicate_comparator());

    _end = unique(_begin, _end);
  }

  xpath_node_set::type_t type() const { return _type; }

  void set_type(xpath_node_set::type_t value) { _type = value; }
};

PUGI__FN_NO_INLINE void xpath_node_set_raw::push_back_grow(
    const xpath_node& node, xpath_allocator* alloc) {
  size_t capacity = static_cast<size_t>(_eos - _begin);

  // get new capacity (1.5x rule)
  size_t new_capacity = capacity + capacity / 2 + 1;

  // reallocate the old array or allocate a new one
  xpath_node* data = static_cast<xpath_node*>(
      alloc->reallocate(_begin, capacity * sizeof(xpath_node),
                        new_capacity * sizeof(xpath_node)));
  assert(data);

  // finalize
  _begin = data;
  _end = data + capacity;
  _eos = data + new_capacity;

  // push
  *_end++ = node;
}
PUGI__NS_END

PUGI__NS_BEGIN
struct xpath_context {
  xpath_node n;
  size_t position, size;

  xpath_context(const xpath_node& n_, size_t position_, size_t size_)
      : n(n_), position(position_), size(size_) {}
};

enum lexeme_t {
  lex_none = 0,
  lex_equal,
  lex_not_equal,
  lex_less,
  lex_greater,
  lex_less_or_equal,
  lex_greater_or_equal,
  lex_plus,
  lex_minus,
  lex_multiply,
  lex_union,
  lex_var_ref,
  lex_open_brace,
  lex_close_brace,
  lex_quoted_string,
  lex_number,
  lex_slash,
  lex_double_slash,
  lex_open_square_brace,
  lex_close_square_brace,
  lex_string,
  lex_comma,
  lex_axis_attribute,
  lex_dot,
  lex_double_dot,
  lex_double_colon,
  lex_eof
};

struct xpath_lexer_string {
  const char_t* begin;
  const char_t* end;

  xpath_lexer_string() : begin(0), end(0) {}

  bool operator==(const char_t* other) const {
    size_t length = static_cast<size_t>(end - begin);

    return strequalrange(other, begin, length);
  }
};

class xpath_lexer {
  const char_t* _cur;
  const char_t* _cur_lexeme_pos;
  xpath_lexer_string _cur_lexeme_contents;

  lexeme_t _cur_lexeme;

public:
  explicit xpath_lexer(const char_t* query) : _cur(query) { next(); }

  const char_t* state() const { return _cur; }

  void next() {
    const char_t* cur = _cur;

    while (PUGI__IS_CHARTYPE(*cur, ct_space)) ++cur;

    // save lexeme position for error reporting
    _cur_lexeme_pos = cur;

    switch (*cur) {
      case 0:
        _cur_lexeme = lex_eof;
        break;

      case '>':
        if (*(cur + 1) == '=') {
          cur += 2;
          _cur_lexeme = lex_greater_or_equal;
        } else {
          cur += 1;
          _cur_lexeme = lex_greater;
        }
        break;

      case '<':
        if (*(cur + 1) == '=') {
          cur += 2;
          _cur_lexeme = lex_less_or_equal;
        } else {
          cur += 1;
          _cur_lexeme = lex_less;
        }
        break;

      case '!':
        if (*(cur + 1) == '=') {
          cur += 2;
          _cur_lexeme = lex_not_equal;
        } else {
          _cur_lexeme = lex_none;
        }
        break;

      case '=':
        cur += 1;
        _cur_lexeme = lex_equal;

        break;

      case '+':
        cur += 1;
        _cur_lexeme = lex_plus;

        break;

      case '-':
        cur += 1;
        _cur_lexeme = lex_minus;

        break;

      case '*':
        cur += 1;
        _cur_lexeme = lex_multiply;

        break;

      case '|':
        cur += 1;
        _cur_lexeme = lex_union;

        break;

      case '$':
        cur += 1;

        if (PUGI__IS_CHARTYPEX(*cur, ctx_start_symbol)) {
          _cur_lexeme_contents.begin = cur;

          while (PUGI__IS_CHARTYPEX(*cur, ctx_symbol)) cur++;

          if (cur[0] == ':' && PUGI__IS_CHARTYPEX(cur[1], ctx_symbol))  // qname
          {
            cur++;  // :

            while (PUGI__IS_CHARTYPEX(*cur, ctx_symbol)) cur++;
          }

          _cur_lexeme_contents.end = cur;

          _cur_lexeme = lex_var_ref;
        } else {
          _cur_lexeme = lex_none;
        }

        break;

      case '(':
        cur += 1;
        _cur_lexeme = lex_open_brace;

        break;

      case ')':
        cur += 1;
        _cur_lexeme = lex_close_brace;

        break;

      case '[':
        cur += 1;
        _cur_lexeme = lex_open_square_brace;

        break;

      case ']':
        cur += 1;
        _cur_lexeme = lex_close_square_brace;

        break;

      case ',':
        cur += 1;
        _cur_lexeme = lex_comma;

        break;

      case '/':
        if (*(cur + 1) == '/') {
          cur += 2;
          _cur_lexeme = lex_double_slash;
        } else {
          cur += 1;
          _cur_lexeme = lex_slash;
        }
        break;

      case '.':
        if (*(cur + 1) == '.') {
          cur += 2;
          _cur_lexeme = lex_double_dot;
        } else if (PUGI__IS_CHARTYPEX(*(cur + 1), ctx_digit)) {
          _cur_lexeme_contents.begin = cur;  // .

          ++cur;

          while (PUGI__IS_CHARTYPEX(*cur, ctx_digit)) cur++;

          _cur_lexeme_contents.end = cur;

          _cur_lexeme = lex_number;
        } else {
          cur += 1;
          _cur_lexeme = lex_dot;
        }
        break;

      case '@':
        cur += 1;
        _cur_lexeme = lex_axis_attribute;

        break;

      case '"':
      case '\'': {
        char_t terminator = *cur;

        ++cur;

        _cur_lexeme_contents.begin = cur;
        while (*cur && *cur != terminator) cur++;
        _cur_lexeme_contents.end = cur;

        if (!*cur)
          _cur_lexeme = lex_none;
        else {
          cur += 1;
          _cur_lexeme = lex_quoted_string;
        }

        break;
      }

      case ':':
        if (*(cur + 1) == ':') {
          cur += 2;
          _cur_lexeme = lex_double_colon;
        } else {
          _cur_lexeme = lex_none;
        }
        break;

      default:
        if (PUGI__IS_CHARTYPEX(*cur, ctx_digit)) {
          _cur_lexeme_contents.begin = cur;

          while (PUGI__IS_CHARTYPEX(*cur, ctx_digit)) cur++;

          if (*cur == '.') {
            cur++;

            while (PUGI__IS_CHARTYPEX(*cur, ctx_digit)) cur++;
          }

          _cur_lexeme_contents.end = cur;

          _cur_lexeme = lex_number;
        } else if (PUGI__IS_CHARTYPEX(*cur, ctx_start_symbol)) {
          _cur_lexeme_contents.begin = cur;

          while (PUGI__IS_CHARTYPEX(*cur, ctx_symbol)) cur++;

          if (cur[0] == ':') {
            if (cur[1] == '*')  // namespace test ncname:*
            {
              cur += 2;  // :*
            } else if (PUGI__IS_CHARTYPEX(cur[1],
                                          ctx_symbol))  // namespace test qname
            {
              cur++;  // :

              while (PUGI__IS_CHARTYPEX(*cur, ctx_symbol)) cur++;
            }
          }

          _cur_lexeme_contents.end = cur;

          _cur_lexeme = lex_string;
        } else {
          _cur_lexeme = lex_none;
        }
    }

    _cur = cur;
  }

  lexeme_t current() const { return _cur_lexeme; }

  const char_t* current_pos() const { return _cur_lexeme_pos; }

  const xpath_lexer_string& contents() const {
    assert(_cur_lexeme == lex_var_ref || _cur_lexeme == lex_number ||
           _cur_lexeme == lex_string || _cur_lexeme == lex_quoted_string);

    return _cur_lexeme_contents;
  }
};

enum ast_type_t {
  ast_unknown,
  ast_op_or,                // left or right
  ast_op_and,               // left and right
  ast_op_equal,             // left = right
  ast_op_not_equal,         // left != right
  ast_op_less,              // left < right
  ast_op_greater,           // left > right
  ast_op_less_or_equal,     // left <= right
  ast_op_greater_or_equal,  // left >= right
  ast_op_add,               // left + right
  ast_op_subtract,          // left - right
  ast_op_multiply,          // left * right
  ast_op_divide,            // left / right
  ast_op_mod,               // left % right
  ast_op_negate,            // left - right
  ast_op_union,             // left | right
  ast_predicate,        // apply predicate to set; next points to next predicate
  ast_filter,           // select * from left where right
  ast_string_constant,  // string constant
  ast_number_constant,  // number constant
  ast_variable,         // variable
  ast_func_last,        // last()
  ast_func_position,    // position()
  ast_func_count,       // count(left)
  ast_func_id,          // id(left)
  ast_func_local_name_0,       // local-name()
  ast_func_local_name_1,       // local-name(left)
  ast_func_namespace_uri_0,    // namespace-uri()
  ast_func_namespace_uri_1,    // namespace-uri(left)
  ast_func_name_0,             // name()
  ast_func_name_1,             // name(left)
  ast_func_string_0,           // string()
  ast_func_string_1,           // string(left)
  ast_func_concat,             // concat(left, right, siblings)
  ast_func_starts_with,        // starts_with(left, right)
  ast_func_contains,           // contains(left, right)
  ast_func_substring_before,   // substring-before(left, right)
  ast_func_substring_after,    // substring-after(left, right)
  ast_func_substring_2,        // substring(left, right)
  ast_func_substring_3,        // substring(left, right, third)
  ast_func_string_length_0,    // string-length()
  ast_func_string_length_1,    // string-length(left)
  ast_func_normalize_space_0,  // normalize-space()
  ast_func_normalize_space_1,  // normalize-space(left)
  ast_func_translate,          // translate(left, right, third)
  ast_func_boolean,            // boolean(left)
  ast_func_not,                // not(left)
  ast_func_true,               // true()
  ast_func_false,              // false()
  ast_func_lang,               // lang(left)
  ast_func_number_0,           // number()
  ast_func_number_1,           // number(left)
  ast_func_sum,                // sum(left)
  ast_func_floor,              // floor(left)
  ast_func_ceiling,            // ceiling(left)
  ast_func_round,              // round(left)
  ast_step,                    // process set left with step
  ast_step_root,               // select root node

  ast_opt_translate_table,   // translate(left, right, third) where right/third
                             // are constants
  ast_opt_compare_attribute  // @name = 'string'
};

enum axis_t {
  axis_ancestor,
  axis_ancestor_or_self,
  axis_attribute,
  axis_child,
  axis_descendant,
  axis_descendant_or_self,
  axis_following,
  axis_following_sibling,
  axis_namespace,
  axis_parent,
  axis_preceding,
  axis_preceding_sibling,
  axis_self
};

enum nodetest_t {
  nodetest_none,
  nodetest_name,
  nodetest_type_node,
  nodetest_type_comment,
  nodetest_type_pi,
  nodetest_type_text,
  nodetest_pi,
  nodetest_all,
  nodetest_all_in_namespace
};

enum predicate_t {
  predicate_default,
  predicate_posinv,
  predicate_constant,
  predicate_constant_one
};

enum nodeset_eval_t { nodeset_eval_all, nodeset_eval_any, nodeset_eval_first };

template <axis_t N>
struct axis_to_type {
  static const axis_t axis;
};

template <axis_t N>
const axis_t axis_to_type<N>::axis = N;

class xpath_ast_node {
private:
  // node type
  char _type;
  char _rettype;

  // for ast_step
  char _axis;

  // for ast_step/ast_predicate/ast_filter
  char _test;

  // tree node structure
  xpath_ast_node* _left;
  xpath_ast_node* _right;
  xpath_ast_node* _next;

  union {
    // value for ast_string_constant
    const char_t* string;
    // value for ast_number_constant
    double number;
    // variable for ast_variable
    xpath_variable* variable;
    // node test for ast_step (node name/namespace/node type/pi target)
    const char_t* nodetest;
    // table for ast_opt_translate_table
    const unsigned char* table;
  } _data;

  xpath_ast_node(const xpath_ast_node&);
  xpath_ast_node& operator=(const xpath_ast_node&);

  template <class Comp>
  static bool compare_eq(xpath_ast_node* lhs, xpath_ast_node* rhs,
                         const xpath_context& c, const xpath_stack& stack,
                         const Comp& comp) {
    xpath_value_type lt = lhs->rettype(), rt = rhs->rettype();

    if (lt != xpath_type_node_set && rt != xpath_type_node_set) {
      if (lt == xpath_type_boolean || rt == xpath_type_boolean)
        return comp(lhs->eval_boolean(c, stack), rhs->eval_boolean(c, stack));
      else if (lt == xpath_type_number || rt == xpath_type_number)
        return comp(lhs->eval_number(c, stack), rhs->eval_number(c, stack));
      else if (lt == xpath_type_string || rt == xpath_type_string) {
        xpath_allocator_capture cr(stack.result);

        xpath_string ls = lhs->eval_string(c, stack);
        xpath_string rs = rhs->eval_string(c, stack);

        return comp(ls, rs);
      }
    } else if (lt == xpath_type_node_set && rt == xpath_type_node_set) {
      xpath_allocator_capture cr(stack.result);

      xpath_node_set_raw ls = lhs->eval_node_set(c, stack, nodeset_eval_all);
      xpath_node_set_raw rs = rhs->eval_node_set(c, stack, nodeset_eval_all);

      for (const xpath_node* li = ls.begin(); li != ls.end(); ++li)
        for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri) {
          xpath_allocator_capture cri(stack.result);

          if (comp(string_value(*li, stack.result),
                   string_value(*ri, stack.result)))
            return true;
        }

      return false;
    } else {
      if (lt == xpath_type_node_set) {
        swap(lhs, rhs);
        swap(lt, rt);
      }

      if (lt == xpath_type_boolean)
        return comp(lhs->eval_boolean(c, stack), rhs->eval_boolean(c, stack));
      else if (lt == xpath_type_number) {
        xpath_allocator_capture cr(stack.result);

        double l = lhs->eval_number(c, stack);
        xpath_node_set_raw rs = rhs->eval_node_set(c, stack, nodeset_eval_all);

        for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri) {
          xpath_allocator_capture cri(stack.result);

          if (comp(l, convert_string_to_number(
                          string_value(*ri, stack.result).c_str())))
            return true;
        }

        return false;
      } else if (lt == xpath_type_string) {
        xpath_allocator_capture cr(stack.result);

        xpath_string l = lhs->eval_string(c, stack);
        xpath_node_set_raw rs = rhs->eval_node_set(c, stack, nodeset_eval_all);

        for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri) {
          xpath_allocator_capture cri(stack.result);

          if (comp(l, string_value(*ri, stack.result))) return true;
        }

        return false;
      }
    }

    assert(false && "Wrong types");
    return false;
  }

  static bool eval_once(xpath_node_set::type_t type, nodeset_eval_t eval) {
    return type == xpath_node_set::type_sorted ? eval != nodeset_eval_all
                                               : eval == nodeset_eval_any;
  }

  template <class Comp>
  static bool compare_rel(xpath_ast_node* lhs, xpath_ast_node* rhs,
                          const xpath_context& c, const xpath_stack& stack,
                          const Comp& comp) {
    xpath_value_type lt = lhs->rettype(), rt = rhs->rettype();

    if (lt != xpath_type_node_set && rt != xpath_type_node_set)
      return comp(lhs->eval_number(c, stack), rhs->eval_number(c, stack));
    else if (lt == xpath_type_node_set && rt == xpath_type_node_set) {
      xpath_allocator_capture cr(stack.result);

      xpath_node_set_raw ls = lhs->eval_node_set(c, stack, nodeset_eval_all);
      xpath_node_set_raw rs = rhs->eval_node_set(c, stack, nodeset_eval_all);

      for (const xpath_node* li = ls.begin(); li != ls.end(); ++li) {
        xpath_allocator_capture cri(stack.result);

        double l =
            convert_string_to_number(string_value(*li, stack.result).c_str());

        for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri) {
          xpath_allocator_capture crii(stack.result);

          if (comp(l, convert_string_to_number(
                          string_value(*ri, stack.result).c_str())))
            return true;
        }
      }

      return false;
    } else if (lt != xpath_type_node_set && rt == xpath_type_node_set) {
      xpath_allocator_capture cr(stack.result);

      double l = lhs->eval_number(c, stack);
      xpath_node_set_raw rs = rhs->eval_node_set(c, stack, nodeset_eval_all);

      for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri) {
        xpath_allocator_capture cri(stack.result);

        if (comp(l, convert_string_to_number(
                        string_value(*ri, stack.result).c_str())))
          return true;
      }

      return false;
    } else if (lt == xpath_type_node_set && rt != xpath_type_node_set) {
      xpath_allocator_capture cr(stack.result);

      xpath_node_set_raw ls = lhs->eval_node_set(c, stack, nodeset_eval_all);
      double r = rhs->eval_number(c, stack);

      for (const xpath_node* li = ls.begin(); li != ls.end(); ++li) {
        xpath_allocator_capture cri(stack.result);

        if (comp(convert_string_to_number(
                     string_value(*li, stack.result).c_str()),
                 r))
          return true;
      }

      return false;
    } else {
      assert(false && "Wrong types");
      return false;
    }
  }

  static void apply_predicate_boolean(xpath_node_set_raw& ns, size_t first,
                                      xpath_ast_node* expr,
                                      const xpath_stack& stack, bool once) {
    assert(ns.size() >= first);
    assert(expr->rettype() != xpath_type_number);

    size_t i = 1;
    size_t size = ns.size() - first;

    xpath_node* last = ns.begin() + first;

    // remove_if... or well, sort of
    for (xpath_node* it = last; it != ns.end(); ++it, ++i) {
      xpath_context c(*it, i, size);

      if (expr->eval_boolean(c, stack)) {
        *last++ = *it;

        if (once) break;
      }
    }

    ns.truncate(last);
  }

  static void apply_predicate_number(xpath_node_set_raw& ns, size_t first,
                                     xpath_ast_node* expr,
                                     const xpath_stack& stack, bool once) {
    assert(ns.size() >= first);
    assert(expr->rettype() == xpath_type_number);

    size_t i = 1;
    size_t size = ns.size() - first;

    xpath_node* last = ns.begin() + first;

    // remove_if... or well, sort of
    for (xpath_node* it = last; it != ns.end(); ++it, ++i) {
      xpath_context c(*it, i, size);

      if (expr->eval_number(c, stack) == i) {
        *last++ = *it;

        if (once) break;
      }
    }

    ns.truncate(last);
  }

  static void apply_predicate_number_const(xpath_node_set_raw& ns, size_t first,
                                           xpath_ast_node* expr,
                                           const xpath_stack& stack) {
    assert(ns.size() >= first);
    assert(expr->rettype() == xpath_type_number);

    size_t size = ns.size() - first;

    xpath_node* last = ns.begin() + first;

    xpath_context c(xpath_node(), 1, size);

    double er = expr->eval_number(c, stack);

    if (er >= 1.0 && er <= size) {
      size_t eri = static_cast<size_t>(er);

      if (er == eri) {
        xpath_node r = last[eri - 1];

        *last++ = r;
      }
    }

    ns.truncate(last);
  }

  void apply_predicate(xpath_node_set_raw& ns, size_t first,
                       const xpath_stack& stack, bool once) {
    if (ns.size() == first) return;

    assert(_type == ast_filter || _type == ast_predicate);

    if (_test == predicate_constant || _test == predicate_constant_one)
      apply_predicate_number_const(ns, first, _right, stack);
    else if (_right->rettype() == xpath_type_number)
      apply_predicate_number(ns, first, _right, stack, once);
    else
      apply_predicate_boolean(ns, first, _right, stack, once);
  }

  void apply_predicates(xpath_node_set_raw& ns, size_t first,
                        const xpath_stack& stack, nodeset_eval_t eval) {
    if (ns.size() == first) return;

    bool last_once = eval_once(ns.type(), eval);

    for (xpath_ast_node* pred = _right; pred; pred = pred->_next)
      pred->apply_predicate(ns, first, stack, !pred->_next && last_once);
  }

  bool step_push(xpath_node_set_raw& ns, xml_attribute_struct* a,
                 xml_node_struct* parent, xpath_allocator* alloc) {
    assert(a);

    const char_t* name = a->name ? a->name + 0 : PUGIXML_TEXT("");

    switch (_test) {
      case nodetest_name:
        if (strequal(name, _data.nodetest) && is_xpath_attribute(name)) {
          ns.push_back(xpath_node(xml_attribute(a), xml_node(parent)), alloc);
          return true;
        }
        break;

      case nodetest_type_node:
      case nodetest_all:
        if (is_xpath_attribute(name)) {
          ns.push_back(xpath_node(xml_attribute(a), xml_node(parent)), alloc);
          return true;
        }
        break;

      case nodetest_all_in_namespace:
        if (starts_with(name, _data.nodetest) && is_xpath_attribute(name)) {
          ns.push_back(xpath_node(xml_attribute(a), xml_node(parent)), alloc);
          return true;
        }
        break;

      default:;
    }

    return false;
  }

  bool step_push(xpath_node_set_raw& ns, xml_node_struct* n,
                 xpath_allocator* alloc) {
    assert(n);

    xml_node_type type = PUGI__NODETYPE(n);

    switch (_test) {
      case nodetest_name:
        if (type == node_element && n->name &&
            strequal(n->name, _data.nodetest)) {
          ns.push_back(xml_node(n), alloc);
          return true;
        }
        break;

      case nodetest_type_node:
        ns.push_back(xml_node(n), alloc);
        return true;

      case nodetest_type_comment:
        if (type == node_comment) {
          ns.push_back(xml_node(n), alloc);
          return true;
        }
        break;

      case nodetest_type_text:
        if (type == node_pcdata || type == node_cdata) {
          ns.push_back(xml_node(n), alloc);
          return true;
        }
        break;

      case nodetest_type_pi:
        if (type == node_pi) {
          ns.push_back(xml_node(n), alloc);
          return true;
        }
        break;

      case nodetest_pi:
        if (type == node_pi && n->name && strequal(n->name, _data.nodetest)) {
          ns.push_back(xml_node(n), alloc);
          return true;
        }
        break;

      case nodetest_all:
        if (type == node_element) {
          ns.push_back(xml_node(n), alloc);
          return true;
        }
        break;

      case nodetest_all_in_namespace:
        if (type == node_element && n->name &&
            starts_with(n->name, _data.nodetest)) {
          ns.push_back(xml_node(n), alloc);
          return true;
        }
        break;

      default:
        assert(false && "Unknown axis");
    }

    return false;
  }

  template <class T>
  void step_fill(xpath_node_set_raw& ns, xml_node_struct* n,
                 xpath_allocator* alloc, bool once, T) {
    const axis_t axis = T::axis;

    switch (axis) {
      case axis_attribute: {
        for (xml_attribute_struct* a = n->first_attribute; a;
             a = a->next_attribute)
          if (step_push(ns, a, n, alloc) & once) return;

        break;
      }

      case axis_child: {
        for (xml_node_struct* c = n->first_child; c; c = c->next_sibling)
          if (step_push(ns, c, alloc) & once) return;

        break;
      }

      case axis_descendant:
      case axis_descendant_or_self: {
        if (axis == axis_descendant_or_self)
          if (step_push(ns, n, alloc) & once) return;

        xml_node_struct* cur = n->first_child;

        while (cur) {
          if (step_push(ns, cur, alloc) & once) return;

          if (cur->first_child)
            cur = cur->first_child;
          else {
            while (!cur->next_sibling) {
              cur = cur->parent;

              if (cur == n) return;
            }

            cur = cur->next_sibling;
          }
        }

        break;
      }

      case axis_following_sibling: {
        for (xml_node_struct* c = n->next_sibling; c; c = c->next_sibling)
          if (step_push(ns, c, alloc) & once) return;

        break;
      }

      case axis_preceding_sibling: {
        for (xml_node_struct* c = n->prev_sibling_c; c->next_sibling;
             c = c->prev_sibling_c)
          if (step_push(ns, c, alloc) & once) return;

        break;
      }

      case axis_following: {
        xml_node_struct* cur = n;

        // exit from this node so that we don't include descendants
        while (!cur->next_sibling) {
          cur = cur->parent;

          if (!cur) return;
        }

        cur = cur->next_sibling;

        while (cur) {
          if (step_push(ns, cur, alloc) & once) return;

          if (cur->first_child)
            cur = cur->first_child;
          else {
            while (!cur->next_sibling) {
              cur = cur->parent;

              if (!cur) return;
            }

            cur = cur->next_sibling;
          }
        }

        break;
      }

      case axis_preceding: {
        xml_node_struct* cur = n;

        // exit from this node so that we don't include descendants
        while (!cur->prev_sibling_c->next_sibling) {
          cur = cur->parent;

          if (!cur) return;
        }

        cur = cur->prev_sibling_c;

        while (cur) {
          if (cur->first_child)
            cur = cur->first_child->prev_sibling_c;
          else {
            // leaf node, can't be ancestor
            if (step_push(ns, cur, alloc) & once) return;

            while (!cur->prev_sibling_c->next_sibling) {
              cur = cur->parent;

              if (!cur) return;

              if (!node_is_ancestor(cur, n))
                if (step_push(ns, cur, alloc) & once) return;
            }

            cur = cur->prev_sibling_c;
          }
        }

        break;
      }

      case axis_ancestor:
      case axis_ancestor_or_self: {
        if (axis == axis_ancestor_or_self)
          if (step_push(ns, n, alloc) & once) return;

        xml_node_struct* cur = n->parent;

        while (cur) {
          if (step_push(ns, cur, alloc) & once) return;

          cur = cur->parent;
        }

        break;
      }

      case axis_self: {
        step_push(ns, n, alloc);

        break;
      }

      case axis_parent: {
        if (n->parent) step_push(ns, n->parent, alloc);

        break;
      }

      default:
        assert(false && "Unimplemented axis");
    }
  }

  template <class T>
  void step_fill(xpath_node_set_raw& ns, xml_attribute_struct* a,
                 xml_node_struct* p, xpath_allocator* alloc, bool once, T v) {
    const axis_t axis = T::axis;

    switch (axis) {
      case axis_ancestor:
      case axis_ancestor_or_self: {
        if (axis == axis_ancestor_or_self &&
            _test == nodetest_type_node)  // reject attributes based on
                                          // principal node type test
          if (step_push(ns, a, p, alloc) & once) return;

        xml_node_struct* cur = p;

        while (cur) {
          if (step_push(ns, cur, alloc) & once) return;

          cur = cur->parent;
        }

        break;
      }

      case axis_descendant_or_self:
      case axis_self: {
        if (_test == nodetest_type_node)  // reject attributes based on
                                          // principal node type test
          step_push(ns, a, p, alloc);

        break;
      }

      case axis_following: {
        xml_node_struct* cur = p;

        while (cur) {
          if (cur->first_child)
            cur = cur->first_child;
          else {
            while (!cur->next_sibling) {
              cur = cur->parent;

              if (!cur) return;
            }

            cur = cur->next_sibling;
          }

          if (step_push(ns, cur, alloc) & once) return;
        }

        break;
      }

      case axis_parent: {
        step_push(ns, p, alloc);

        break;
      }

      case axis_preceding: {
        // preceding:: axis does not include attribute nodes and attribute
        // ancestors (they are the same as parent's ancestors), so we can reuse
        // node preceding
        step_fill(ns, p, alloc, once, v);
        break;
      }

      default:
        assert(false && "Unimplemented axis");
    }
  }

  template <class T>
  void step_fill(xpath_node_set_raw& ns, const xpath_node& xn,
                 xpath_allocator* alloc, bool once, T v) {
    const axis_t axis = T::axis;
    const bool axis_has_attributes =
        (axis == axis_ancestor || axis == axis_ancestor_or_self ||
         axis == axis_descendant_or_self || axis == axis_following ||
         axis == axis_parent || axis == axis_preceding || axis == axis_self);

    if (xn.node())
      step_fill(ns, xn.node().internal_object(), alloc, once, v);
    else if (axis_has_attributes && xn.attribute() && xn.parent())
      step_fill(ns, xn.attribute().internal_object(),
                xn.parent().internal_object(), alloc, once, v);
  }

  template <class T>
  xpath_node_set_raw step_do(const xpath_context& c, const xpath_stack& stack,
                             nodeset_eval_t eval, T v) {
    const axis_t axis = T::axis;
    const bool axis_reverse =
        (axis == axis_ancestor || axis == axis_ancestor_or_self ||
         axis == axis_preceding || axis == axis_preceding_sibling);
    const xpath_node_set::type_t axis_type =
        axis_reverse ? xpath_node_set::type_sorted_reverse
                     : xpath_node_set::type_sorted;

    bool once =
        (axis == axis_attribute && _test == nodetest_name) ||
        (!_right && eval_once(axis_type, eval)) ||
        (_right && !_right->_next && _right->_test == predicate_constant_one);

    xpath_node_set_raw ns;
    ns.set_type(axis_type);

    if (_left) {
      xpath_node_set_raw s = _left->eval_node_set(c, stack, nodeset_eval_all);

      // self axis preserves the original order
      if (axis == axis_self) ns.set_type(s.type());

      for (const xpath_node* it = s.begin(); it != s.end(); ++it) {
        size_t size = ns.size();

        // in general, all axes generate elements in a particular order, but
        // there is no order guarantee if axis is applied to two nodes
        if (axis != axis_self && size != 0)
          ns.set_type(xpath_node_set::type_unsorted);

        step_fill(ns, *it, stack.result, once, v);
        if (_right) apply_predicates(ns, size, stack, eval);
      }
    } else {
      step_fill(ns, c.n, stack.result, once, v);
      if (_right) apply_predicates(ns, 0, stack, eval);
    }

    // child, attribute and self axes always generate unique set of nodes
    // for other axis, if the set stayed sorted, it stayed unique because the
    // traversal algorithms do not visit the same node twice
    if (axis != axis_child && axis != axis_attribute && axis != axis_self &&
        ns.type() == xpath_node_set::type_unsorted)
      ns.remove_duplicates();

    return ns;
  }

public:
  xpath_ast_node(ast_type_t type, xpath_value_type rettype_,
                 const char_t* value)
      : _type(static_cast<char>(type)),
        _rettype(static_cast<char>(rettype_)),
        _axis(0),
        _test(0),
        _left(0),
        _right(0),
        _next(0) {
    assert(type == ast_string_constant);
    _data.string = value;
  }

  xpath_ast_node(ast_type_t type, xpath_value_type rettype_, double value)
      : _type(static_cast<char>(type)),
        _rettype(static_cast<char>(rettype_)),
        _axis(0),
        _test(0),
        _left(0),
        _right(0),
        _next(0) {
    assert(type == ast_number_constant);
    _data.number = value;
  }

  xpath_ast_node(ast_type_t type, xpath_value_type rettype_,
                 xpath_variable* value)
      : _type(static_cast<char>(type)),
        _rettype(static_cast<char>(rettype_)),
        _axis(0),
        _test(0),
        _left(0),
        _right(0),
        _next(0) {
    assert(type == ast_variable);
    _data.variable = value;
  }

  xpath_ast_node(ast_type_t type, xpath_value_type rettype_,
                 xpath_ast_node* left = 0, xpath_ast_node* right = 0)
      : _type(static_cast<char>(type)),
        _rettype(static_cast<char>(rettype_)),
        _axis(0),
        _test(0),
        _left(left),
        _right(right),
        _next(0) {}

  xpath_ast_node(ast_type_t type, xpath_ast_node* left, axis_t axis,
                 nodetest_t test, const char_t* contents)
      : _type(static_cast<char>(type)),
        _rettype(xpath_type_node_set),
        _axis(static_cast<char>(axis)),
        _test(static_cast<char>(test)),
        _left(left),
        _right(0),
        _next(0) {
    assert(type == ast_step);
    _data.nodetest = contents;
  }

  xpath_ast_node(ast_type_t type, xpath_ast_node* left, xpath_ast_node* right,
                 predicate_t test)
      : _type(static_cast<char>(type)),
        _rettype(xpath_type_node_set),
        _axis(0),
        _test(static_cast<char>(test)),
        _left(left),
        _right(right),
        _next(0) {
    assert(type == ast_filter || type == ast_predicate);
  }

  void set_next(xpath_ast_node* value) { _next = value; }

  void set_right(xpath_ast_node* value) { _right = value; }

  bool eval_boolean(const xpath_context& c, const xpath_stack& stack) {
    switch (_type) {
      case ast_op_or:
        return _left->eval_boolean(c, stack) || _right->eval_boolean(c, stack);

      case ast_op_and:
        return _left->eval_boolean(c, stack) && _right->eval_boolean(c, stack);

      case ast_op_equal:
        return compare_eq(_left, _right, c, stack, equal_to());

      case ast_op_not_equal:
        return compare_eq(_left, _right, c, stack, not_equal_to());

      case ast_op_less:
        return compare_rel(_left, _right, c, stack, less());

      case ast_op_greater:
        return compare_rel(_right, _left, c, stack, less());

      case ast_op_less_or_equal:
        return compare_rel(_left, _right, c, stack, less_equal());

      case ast_op_greater_or_equal:
        return compare_rel(_right, _left, c, stack, less_equal());

      case ast_func_starts_with: {
        xpath_allocator_capture cr(stack.result);

        xpath_string lr = _left->eval_string(c, stack);
        xpath_string rr = _right->eval_string(c, stack);

        return starts_with(lr.c_str(), rr.c_str());
      }

      case ast_func_contains: {
        xpath_allocator_capture cr(stack.result);

        xpath_string lr = _left->eval_string(c, stack);
        xpath_string rr = _right->eval_string(c, stack);

        return find_substring(lr.c_str(), rr.c_str()) != 0;
      }

      case ast_func_boolean:
        return _left->eval_boolean(c, stack);

      case ast_func_not:
        return !_left->eval_boolean(c, stack);

      case ast_func_true:
        return true;

      case ast_func_false:
        return false;

      case ast_func_lang: {
        if (c.n.attribute()) return false;

        xpath_allocator_capture cr(stack.result);

        xpath_string lang = _left->eval_string(c, stack);

        for (xml_node n = c.n.node(); n; n = n.parent()) {
          xml_attribute a = n.attribute(PUGIXML_TEXT("xml:lang"));

          if (a) {
            const char_t* value = a.value();

            // strnicmp / strncasecmp is not portable
            for (const char_t* lit = lang.c_str(); *lit; ++lit) {
              if (tolower_ascii(*lit) != tolower_ascii(*value)) return false;
              ++value;
            }

            return *value == 0 || *value == '-';
          }
        }

        return false;
      }

      case ast_opt_compare_attribute: {
        const char_t* value = (_right->_type == ast_string_constant)
                                  ? _right->_data.string
                                  : _right->_data.variable->get_string();

        xml_attribute attr = c.n.node().attribute(_left->_data.nodetest);

        return attr && strequal(attr.value(), value) &&
               is_xpath_attribute(attr.name());
      }

      case ast_variable: {
        assert(_rettype == _data.variable->type());

        if (_rettype == xpath_type_boolean)
          return _data.variable->get_boolean();
      }
        // FALL THROUGH

      default: {
        switch (_rettype) {
          case xpath_type_number:
            return convert_number_to_boolean(eval_number(c, stack));

          case xpath_type_string: {
            xpath_allocator_capture cr(stack.result);

            return !eval_string(c, stack).empty();
          }

          case xpath_type_node_set: {
            xpath_allocator_capture cr(stack.result);

            return !eval_node_set(c, stack, nodeset_eval_any).empty();
          }

          default:
            assert(false && "Wrong expression for return type boolean");
            return false;
        }
      }
    }
  }

  double eval_number(const xpath_context& c, const xpath_stack& stack) {
    switch (_type) {
      case ast_op_add:
        return _left->eval_number(c, stack) + _right->eval_number(c, stack);

      case ast_op_subtract:
        return _left->eval_number(c, stack) - _right->eval_number(c, stack);

      case ast_op_multiply:
        return _left->eval_number(c, stack) * _right->eval_number(c, stack);

      case ast_op_divide:
        return _left->eval_number(c, stack) / _right->eval_number(c, stack);

      case ast_op_mod:
        return fmod(_left->eval_number(c, stack),
                    _right->eval_number(c, stack));

      case ast_op_negate:
        return -_left->eval_number(c, stack);

      case ast_number_constant:
        return _data.number;

      case ast_func_last:
        return static_cast<double>(c.size);

      case ast_func_position:
        return static_cast<double>(c.position);

      case ast_func_count: {
        xpath_allocator_capture cr(stack.result);

        return static_cast<double>(
            _left->eval_node_set(c, stack, nodeset_eval_all).size());
      }

      case ast_func_string_length_0: {
        xpath_allocator_capture cr(stack.result);

        return static_cast<double>(string_value(c.n, stack.result).length());
      }

      case ast_func_string_length_1: {
        xpath_allocator_capture cr(stack.result);

        return static_cast<double>(_left->eval_string(c, stack).length());
      }

      case ast_func_number_0: {
        xpath_allocator_capture cr(stack.result);

        return convert_string_to_number(
            string_value(c.n, stack.result).c_str());
      }

      case ast_func_number_1:
        return _left->eval_number(c, stack);

      case ast_func_sum: {
        xpath_allocator_capture cr(stack.result);

        double r = 0;

        xpath_node_set_raw ns =
            _left->eval_node_set(c, stack, nodeset_eval_all);

        for (const xpath_node* it = ns.begin(); it != ns.end(); ++it) {
          xpath_allocator_capture cri(stack.result);

          r +=
              convert_string_to_number(string_value(*it, stack.result).c_str());
        }

        return r;
      }

      case ast_func_floor: {
        double r = _left->eval_number(c, stack);

        return r == r ? floor(r) : r;
      }

      case ast_func_ceiling: {
        double r = _left->eval_number(c, stack);

        return r == r ? ceil(r) : r;
      }

      case ast_func_round:
        return round_nearest_nzero(_left->eval_number(c, stack));

      case ast_variable: {
        assert(_rettype == _data.variable->type());

        if (_rettype == xpath_type_number) return _data.variable->get_number();
      }
        // FALL THROUGH

      default: {
        switch (_rettype) {
          case xpath_type_boolean:
            return eval_boolean(c, stack) ? 1 : 0;

          case xpath_type_string: {
            xpath_allocator_capture cr(stack.result);

            return convert_string_to_number(eval_string(c, stack).c_str());
          }

          case xpath_type_node_set: {
            xpath_allocator_capture cr(stack.result);

            return convert_string_to_number(eval_string(c, stack).c_str());
          }

          default:
            assert(false && "Wrong expression for return type number");
            return 0;
        }
      }
    }
  }

  xpath_string eval_string_concat(const xpath_context& c,
                                  const xpath_stack& stack) {
    assert(_type == ast_func_concat);

    xpath_allocator_capture ct(stack.temp);

    // count the string number
    size_t count = 1;
    for (xpath_ast_node* nc = _right; nc; nc = nc->_next) count++;

    // gather all strings
    xpath_string static_buffer[4];
    xpath_string* buffer = static_buffer;

    // allocate on-heap for large concats
    if (count > sizeof(static_buffer) / sizeof(static_buffer[0])) {
      buffer = static_cast<xpath_string*>(
          stack.temp->allocate(count * sizeof(xpath_string)));
      assert(buffer);
    }

    // evaluate all strings to temporary stack
    xpath_stack swapped_stack = {stack.temp, stack.result};

    buffer[0] = _left->eval_string(c, swapped_stack);

    size_t pos = 1;
    for (xpath_ast_node* n = _right; n; n = n->_next, ++pos)
      buffer[pos] = n->eval_string(c, swapped_stack);
    assert(pos == count);

    // get total length
    size_t length = 0;
    for (size_t i = 0; i < count; ++i) length += buffer[i].length();

    // create final string
    char_t* result = static_cast<char_t*>(
        stack.result->allocate((length + 1) * sizeof(char_t)));
    assert(result);

    char_t* ri = result;

    for (size_t j = 0; j < count; ++j)
      for (const char_t* bi = buffer[j].c_str(); *bi; ++bi) *ri++ = *bi;

    *ri = 0;

    return xpath_string::from_heap_preallocated(result, ri);
  }

  xpath_string eval_string(const xpath_context& c, const xpath_stack& stack) {
    switch (_type) {
      case ast_string_constant:
        return xpath_string::from_const(_data.string);

      case ast_func_local_name_0: {
        xpath_node na = c.n;

        return xpath_string::from_const(local_name(na));
      }

      case ast_func_local_name_1: {
        xpath_allocator_capture cr(stack.result);

        xpath_node_set_raw ns =
            _left->eval_node_set(c, stack, nodeset_eval_first);
        xpath_node na = ns.first();

        return xpath_string::from_const(local_name(na));
      }

      case ast_func_name_0: {
        xpath_node na = c.n;

        return xpath_string::from_const(qualified_name(na));
      }

      case ast_func_name_1: {
        xpath_allocator_capture cr(stack.result);

        xpath_node_set_raw ns =
            _left->eval_node_set(c, stack, nodeset_eval_first);
        xpath_node na = ns.first();

        return xpath_string::from_const(qualified_name(na));
      }

      case ast_func_namespace_uri_0: {
        xpath_node na = c.n;

        return xpath_string::from_const(namespace_uri(na));
      }

      case ast_func_namespace_uri_1: {
        xpath_allocator_capture cr(stack.result);

        xpath_node_set_raw ns =
            _left->eval_node_set(c, stack, nodeset_eval_first);
        xpath_node na = ns.first();

        return xpath_string::from_const(namespace_uri(na));
      }

      case ast_func_string_0:
        return string_value(c.n, stack.result);

      case ast_func_string_1:
        return _left->eval_string(c, stack);

      case ast_func_concat:
        return eval_string_concat(c, stack);

      case ast_func_substring_before: {
        xpath_allocator_capture cr(stack.temp);

        xpath_stack swapped_stack = {stack.temp, stack.result};

        xpath_string s = _left->eval_string(c, swapped_stack);
        xpath_string p = _right->eval_string(c, swapped_stack);

        const char_t* pos = find_substring(s.c_str(), p.c_str());

        return pos ? xpath_string::from_heap(s.c_str(), pos, stack.result)
                   : xpath_string();
      }

      case ast_func_substring_after: {
        xpath_allocator_capture cr(stack.temp);

        xpath_stack swapped_stack = {stack.temp, stack.result};

        xpath_string s = _left->eval_string(c, swapped_stack);
        xpath_string p = _right->eval_string(c, swapped_stack);

        const char_t* pos = find_substring(s.c_str(), p.c_str());
        if (!pos) return xpath_string();

        const char_t* rbegin = pos + p.length();
        const char_t* rend = s.c_str() + s.length();

        return s.uses_heap()
                   ? xpath_string::from_heap(rbegin, rend, stack.result)
                   : xpath_string::from_const(rbegin);
      }

      case ast_func_substring_2: {
        xpath_allocator_capture cr(stack.temp);

        xpath_stack swapped_stack = {stack.temp, stack.result};

        xpath_string s = _left->eval_string(c, swapped_stack);
        size_t s_length = s.length();

        double first = round_nearest(_right->eval_number(c, stack));

        if (is_nan(first))
          return xpath_string();  // NaN
        else if (first >= s_length + 1)
          return xpath_string();

        size_t pos = first < 1 ? 1 : static_cast<size_t>(first);
        assert(1 <= pos && pos <= s_length + 1);

        const char_t* rbegin = s.c_str() + (pos - 1);
        const char_t* rend = s.c_str() + s.length();

        return s.uses_heap()
                   ? xpath_string::from_heap(rbegin, rend, stack.result)
                   : xpath_string::from_const(rbegin);
      }

      case ast_func_substring_3: {
        xpath_allocator_capture cr(stack.temp);

        xpath_stack swapped_stack = {stack.temp, stack.result};

        xpath_string s = _left->eval_string(c, swapped_stack);
        size_t s_length = s.length();

        double first = round_nearest(_right->eval_number(c, stack));
        double last =
            first + round_nearest(_right->_next->eval_number(c, stack));

        if (is_nan(first) || is_nan(last))
          return xpath_string();
        else if (first >= s_length + 1)
          return xpath_string();
        else if (first >= last)
          return xpath_string();
        else if (last < 1)
          return xpath_string();

        size_t pos = first < 1 ? 1 : static_cast<size_t>(first);
        size_t end =
            last >= s_length + 1 ? s_length + 1 : static_cast<size_t>(last);

        assert(1 <= pos && pos <= end && end <= s_length + 1);
        const char_t* rbegin = s.c_str() + (pos - 1);
        const char_t* rend = s.c_str() + (end - 1);

        return (end == s_length + 1 && !s.uses_heap())
                   ? xpath_string::from_const(rbegin)
                   : xpath_string::from_heap(rbegin, rend, stack.result);
      }

      case ast_func_normalize_space_0: {
        xpath_string s = string_value(c.n, stack.result);

        char_t* begin = s.data(stack.result);
        char_t* end = normalize_space(begin);

        return xpath_string::from_heap_preallocated(begin, end);
      }

      case ast_func_normalize_space_1: {
        xpath_string s = _left->eval_string(c, stack);

        char_t* begin = s.data(stack.result);
        char_t* end = normalize_space(begin);

        return xpath_string::from_heap_preallocated(begin, end);
      }

      case ast_func_translate: {
        xpath_allocator_capture cr(stack.temp);

        xpath_stack swapped_stack = {stack.temp, stack.result};

        xpath_string s = _left->eval_string(c, stack);
        xpath_string from = _right->eval_string(c, swapped_stack);
        xpath_string to = _right->_next->eval_string(c, swapped_stack);

        char_t* begin = s.data(stack.result);
        char_t* end = translate(begin, from.c_str(), to.c_str(), to.length());

        return xpath_string::from_heap_preallocated(begin, end);
      }

      case ast_opt_translate_table: {
        xpath_string s = _left->eval_string(c, stack);

        char_t* begin = s.data(stack.result);
        char_t* end = translate_table(begin, _data.table);

        return xpath_string::from_heap_preallocated(begin, end);
      }

      case ast_variable: {
        assert(_rettype == _data.variable->type());

        if (_rettype == xpath_type_string)
          return xpath_string::from_const(_data.variable->get_string());
      }
        // FALL THROUGH

      default: {
        switch (_rettype) {
          case xpath_type_boolean:
            return xpath_string::from_const(eval_boolean(c, stack)
                                                ? PUGIXML_TEXT("true")
                                                : PUGIXML_TEXT("false"));

          case xpath_type_number:
            return convert_number_to_string(eval_number(c, stack),
                                            stack.result);

          case xpath_type_node_set: {
            xpath_allocator_capture cr(stack.temp);

            xpath_stack swapped_stack = {stack.temp, stack.result};

            xpath_node_set_raw ns =
                eval_node_set(c, swapped_stack, nodeset_eval_first);
            return ns.empty() ? xpath_string()
                              : string_value(ns.first(), stack.result);
          }

          default:
            assert(false && "Wrong expression for return type string");
            return xpath_string();
        }
      }
    }
  }

  xpath_node_set_raw eval_node_set(const xpath_context& c,
                                   const xpath_stack& stack,
                                   nodeset_eval_t eval) {
    switch (_type) {
      case ast_op_union: {
        xpath_allocator_capture cr(stack.temp);

        xpath_stack swapped_stack = {stack.temp, stack.result};

        xpath_node_set_raw ls = _left->eval_node_set(c, swapped_stack, eval);
        xpath_node_set_raw rs = _right->eval_node_set(c, stack, eval);

        // we can optimize merging two sorted sets, but this is a very rare
        // operation, so don't bother
        rs.set_type(xpath_node_set::type_unsorted);

        rs.append(ls.begin(), ls.end(), stack.result);
        rs.remove_duplicates();

        return rs;
      }

      case ast_filter: {
        xpath_node_set_raw set = _left->eval_node_set(
            c, stack,
            _test == predicate_constant_one ? nodeset_eval_first
                                            : nodeset_eval_all);

        // either expression is a number or it contains position() call; sort by
        // document order
        if (_test != predicate_posinv) set.sort_do();

        bool once = eval_once(set.type(), eval);

        apply_predicate(set, 0, stack, once);

        return set;
      }

      case ast_func_id:
        return xpath_node_set_raw();

      case ast_step: {
        switch (_axis) {
          case axis_ancestor:
            return step_do(c, stack, eval, axis_to_type<axis_ancestor>());

          case axis_ancestor_or_self:
            return step_do(c, stack, eval,
                           axis_to_type<axis_ancestor_or_self>());

          case axis_attribute:
            return step_do(c, stack, eval, axis_to_type<axis_attribute>());

          case axis_child:
            return step_do(c, stack, eval, axis_to_type<axis_child>());

          case axis_descendant:
            return step_do(c, stack, eval, axis_to_type<axis_descendant>());

          case axis_descendant_or_self:
            return step_do(c, stack, eval,
                           axis_to_type<axis_descendant_or_self>());

          case axis_following:
            return step_do(c, stack, eval, axis_to_type<axis_following>());

          case axis_following_sibling:
            return step_do(c, stack, eval,
                           axis_to_type<axis_following_sibling>());

          case axis_namespace:
            // namespaced axis is not supported
            return xpath_node_set_raw();

          case axis_parent:
            return step_do(c, stack, eval, axis_to_type<axis_parent>());

          case axis_preceding:
            return step_do(c, stack, eval, axis_to_type<axis_preceding>());

          case axis_preceding_sibling:
            return step_do(c, stack, eval,
                           axis_to_type<axis_preceding_sibling>());

          case axis_self:
            return step_do(c, stack, eval, axis_to_type<axis_self>());

          default:
            assert(false && "Unknown axis");
            return xpath_node_set_raw();
        }
      }

      case ast_step_root: {
        assert(!_right);  // root step can't have any predicates

        xpath_node_set_raw ns;

        ns.set_type(xpath_node_set::type_sorted);

        if (c.n.node())
          ns.push_back(c.n.node().root(), stack.result);
        else if (c.n.attribute())
          ns.push_back(c.n.parent().root(), stack.result);

        return ns;
      }

      case ast_variable: {
        assert(_rettype == _data.variable->type());

        if (_rettype == xpath_type_node_set) {
          const xpath_node_set& s = _data.variable->get_node_set();

          xpath_node_set_raw ns;

          ns.set_type(s.type());
          ns.append(s.begin(), s.end(), stack.result);

          return ns;
        }
      }
        // FALL THROUGH

      default:
        assert(false && "Wrong expression for return type node set");
        return xpath_node_set_raw();
    }
  }

  void optimize(xpath_allocator* alloc) {
    if (_left) _left->optimize(alloc);

    if (_right) _right->optimize(alloc);

    if (_next) _next->optimize(alloc);

    optimize_self(alloc);
  }

  void optimize_self(xpath_allocator* alloc) {
    // Rewrite [position()=expr] with [expr]
    // Note that this step has to go before classification to recognize
    // [position()=1]
    if ((_type == ast_filter || _type == ast_predicate) &&
        _right->_type == ast_op_equal &&
        _right->_left->_type == ast_func_position &&
        _right->_right->_rettype == xpath_type_number) {
      _right = _right->_right;
    }

    // Classify filter/predicate ops to perform various optimizations during
    // evaluation
    if (_type == ast_filter || _type == ast_predicate) {
      assert(_test == predicate_default);

      if (_right->_type == ast_number_constant && _right->_data.number == 1.0)
        _test = predicate_constant_one;
      else if (_right->_rettype == xpath_type_number &&
               (_right->_type == ast_number_constant ||
                _right->_type == ast_variable ||
                _right->_type == ast_func_last))
        _test = predicate_constant;
      else if (_right->_rettype != xpath_type_number &&
               _right->is_posinv_expr())
        _test = predicate_posinv;
    }

    // Rewrite descendant-or-self::node()/child::foo with descendant::foo
    // The former is a full form of //foo, the latter is much faster since it
    // executes the node test immediately Do a similar kind of rewrite for
    // self/descendant/descendant-or-self axes Note that we only rewrite
    // positionally invariant steps (//foo[1] != /descendant::foo[1])
    if (_type == ast_step &&
        (_axis == axis_child || _axis == axis_self ||
         _axis == axis_descendant || _axis == axis_descendant_or_self) &&
        _left && _left->_type == ast_step &&
        _left->_axis == axis_descendant_or_self &&
        _left->_test == nodetest_type_node && !_left->_right &&
        is_posinv_step()) {
      if (_axis == axis_child || _axis == axis_descendant)
        _axis = axis_descendant;
      else
        _axis = axis_descendant_or_self;

      _left = _left->_left;
    }

    // Use optimized lookup table implementation for translate() with constant
    // arguments
    if (_type == ast_func_translate && _right->_type == ast_string_constant &&
        _right->_next->_type == ast_string_constant) {
      unsigned char* table = translate_table_generate(
          alloc, _right->_data.string, _right->_next->_data.string);

      if (table) {
        _type = ast_opt_translate_table;
        _data.table = table;
      }
    }

    // Use optimized path for @attr = 'value' or @attr = $value
    if (_type == ast_op_equal && _left->_type == ast_step &&
        _left->_axis == axis_attribute && _left->_test == nodetest_name &&
        !_left->_left && !_left->_right &&
        (_right->_type == ast_string_constant ||
         (_right->_type == ast_variable &&
          _right->_rettype == xpath_type_string))) {
      _type = ast_opt_compare_attribute;
    }
  }

  bool is_posinv_expr() const {
    switch (_type) {
      case ast_func_position:
      case ast_func_last:
        return false;

      case ast_string_constant:
      case ast_number_constant:
      case ast_variable:
        return true;

      case ast_step:
      case ast_step_root:
        return true;

      case ast_predicate:
      case ast_filter:
        return true;

      default:
        if (_left && !_left->is_posinv_expr()) return false;

        for (xpath_ast_node* n = _right; n; n = n->_next)
          if (!n->is_posinv_expr()) return false;

        return true;
    }
  }

  bool is_posinv_step() const {
    assert(_type == ast_step);

    for (xpath_ast_node* n = _right; n; n = n->_next) {
      assert(n->_type == ast_predicate);

      if (n->_test != predicate_posinv) return false;
    }

    return true;
  }

  xpath_value_type rettype() const {
    return static_cast<xpath_value_type>(_rettype);
  }
};

struct xpath_parser {
  xpath_allocator* _alloc;
  xpath_lexer _lexer;

  const char_t* _query;
  xpath_variable_set* _variables;

  xpath_parse_result* _result;

  char_t _scratch[32];

#ifdef PUGIXML_NO_EXCEPTIONS
  jmp_buf _error_handler;
#endif

  void throw_error(const char* message) {
    _result->error = message;
    _result->offset = _lexer.current_pos() - _query;

#ifdef PUGIXML_NO_EXCEPTIONS
    longjmp(_error_handler, 1);
#else
    throw xpath_exception(*_result);
#endif
  }

  void throw_error_oom() {
#ifdef PUGIXML_NO_EXCEPTIONS
    throw_error("Out of memory");
#else
    throw std::bad_alloc();
#endif
  }

  void* alloc_node() {
    void* result = _alloc->allocate_nothrow(sizeof(xpath_ast_node));

    if (!result) throw_error_oom();

    return result;
  }

  const char_t* alloc_string(const xpath_lexer_string& value) {
    if (value.begin) {
      size_t length = static_cast<size_t>(value.end - value.begin);

      char_t* c = static_cast<char_t*>(
          _alloc->allocate_nothrow((length + 1) * sizeof(char_t)));
      if (!c) throw_error_oom();
      assert(c);  // workaround for clang static analysis

      memcpy(c, value.begin, length * sizeof(char_t));
      c[length] = 0;

      return c;
    } else
      return 0;
  }

  xpath_ast_node* parse_function_helper(ast_type_t type0, ast_type_t type1,
                                        size_t argc, xpath_ast_node* args[2]) {
    assert(argc <= 1);

    if (argc == 1 && args[0]->rettype() != xpath_type_node_set)
      throw_error("Function has to be applied to node set");

    return new (alloc_node())
        xpath_ast_node(argc == 0 ? type0 : type1, xpath_type_string, args[0]);
  }

  xpath_ast_node* parse_function(const xpath_lexer_string& name, size_t argc,
                                 xpath_ast_node* args[2]) {
    switch (name.begin[0]) {
      case 'b':
        if (name == PUGIXML_TEXT("boolean") && argc == 1)
          return new (alloc_node())
              xpath_ast_node(ast_func_boolean, xpath_type_boolean, args[0]);

        break;

      case 'c':
        if (name == PUGIXML_TEXT("count") && argc == 1) {
          if (args[0]->rettype() != xpath_type_node_set)
            throw_error("Function has to be applied to node set");

          return new (alloc_node())
              xpath_ast_node(ast_func_count, xpath_type_number, args[0]);
        } else if (name == PUGIXML_TEXT("contains") && argc == 2)
          return new (alloc_node()) xpath_ast_node(
              ast_func_contains, xpath_type_boolean, args[0], args[1]);
        else if (name == PUGIXML_TEXT("concat") && argc >= 2)
          return new (alloc_node()) xpath_ast_node(
              ast_func_concat, xpath_type_string, args[0], args[1]);
        else if (name == PUGIXML_TEXT("ceiling") && argc == 1)
          return new (alloc_node())
              xpath_ast_node(ast_func_ceiling, xpath_type_number, args[0]);

        break;

      case 'f':
        if (name == PUGIXML_TEXT("false") && argc == 0)
          return new (alloc_node())
              xpath_ast_node(ast_func_false, xpath_type_boolean);
        else if (name == PUGIXML_TEXT("floor") && argc == 1)
          return new (alloc_node())
              xpath_ast_node(ast_func_floor, xpath_type_number, args[0]);

        break;

      case 'i':
        if (name == PUGIXML_TEXT("id") && argc == 1)
          return new (alloc_node())
              xpath_ast_node(ast_func_id, xpath_type_node_set, args[0]);

        break;

      case 'l':
        if (name == PUGIXML_TEXT("last") && argc == 0)
          return new (alloc_node())
              xpath_ast_node(ast_func_last, xpath_type_number);
        else if (name == PUGIXML_TEXT("lang") && argc == 1)
          return new (alloc_node())
              xpath_ast_node(ast_func_lang, xpath_type_boolean, args[0]);
        else if (name == PUGIXML_TEXT("local-name") && argc <= 1)
          return parse_function_helper(ast_func_local_name_0,
                                       ast_func_local_name_1, argc, args);

        break;

      case 'n':
        if (name == PUGIXML_TEXT("name") && argc <= 1)
          return parse_function_helper(ast_func_name_0, ast_func_name_1, argc,
                                       args);
        else if (name == PUGIXML_TEXT("namespace-uri") && argc <= 1)
          return parse_function_helper(ast_func_namespace_uri_0,
                                       ast_func_namespace_uri_1, argc, args);
        else if (name == PUGIXML_TEXT("normalize-space") && argc <= 1)
          return new (alloc_node())
              xpath_ast_node(argc == 0 ? ast_func_normalize_space_0
                                       : ast_func_normalize_space_1,
                             xpath_type_string, args[0], args[1]);
        else if (name == PUGIXML_TEXT("not") && argc == 1)
          return new (alloc_node())
              xpath_ast_node(ast_func_not, xpath_type_boolean, args[0]);
        else if (name == PUGIXML_TEXT("number") && argc <= 1)
          return new (alloc_node())
              xpath_ast_node(argc == 0 ? ast_func_number_0 : ast_func_number_1,
                             xpath_type_number, args[0]);

        break;

      case 'p':
        if (name == PUGIXML_TEXT("position") && argc == 0)
          return new (alloc_node())
              xpath_ast_node(ast_func_position, xpath_type_number);

        break;

      case 'r':
        if (name == PUGIXML_TEXT("round") && argc == 1)
          return new (alloc_node())
              xpath_ast_node(ast_func_round, xpath_type_number, args[0]);

        break;

      case 's':
        if (name == PUGIXML_TEXT("string") && argc <= 1)
          return new (alloc_node())
              xpath_ast_node(argc == 0 ? ast_func_string_0 : ast_func_string_1,
                             xpath_type_string, args[0]);
        else if (name == PUGIXML_TEXT("string-length") && argc <= 1)
          return new (alloc_node()) xpath_ast_node(
              argc == 0 ? ast_func_string_length_0 : ast_func_string_length_1,
              xpath_type_number, args[0]);
        else if (name == PUGIXML_TEXT("starts-with") && argc == 2)
          return new (alloc_node()) xpath_ast_node(
              ast_func_starts_with, xpath_type_boolean, args[0], args[1]);
        else if (name == PUGIXML_TEXT("substring-before") && argc == 2)
          return new (alloc_node()) xpath_ast_node(
              ast_func_substring_before, xpath_type_string, args[0], args[1]);
        else if (name == PUGIXML_TEXT("substring-after") && argc == 2)
          return new (alloc_node()) xpath_ast_node(
              ast_func_substring_after, xpath_type_string, args[0], args[1]);
        else if (name == PUGIXML_TEXT("substring") && (argc == 2 || argc == 3))
          return new (alloc_node()) xpath_ast_node(
              argc == 2 ? ast_func_substring_2 : ast_func_substring_3,
              xpath_type_string, args[0], args[1]);
        else if (name == PUGIXML_TEXT("sum") && argc == 1) {
          if (args[0]->rettype() != xpath_type_node_set)
            throw_error("Function has to be applied to node set");
          return new (alloc_node())
              xpath_ast_node(ast_func_sum, xpath_type_number, args[0]);
        }

        break;

      case 't':
        if (name == PUGIXML_TEXT("translate") && argc == 3)
          return new (alloc_node()) xpath_ast_node(
              ast_func_translate, xpath_type_string, args[0], args[1]);
        else if (name == PUGIXML_TEXT("true") && argc == 0)
          return new (alloc_node())
              xpath_ast_node(ast_func_true, xpath_type_boolean);

        break;

      default:
        break;
    }

    throw_error("Unrecognized function or wrong parameter count");

    return 0;
  }

  axis_t parse_axis_name(const xpath_lexer_string& name, bool& specified) {
    specified = true;

    switch (name.begin[0]) {
      case 'a':
        if (name == PUGIXML_TEXT("ancestor"))
          return axis_ancestor;
        else if (name == PUGIXML_TEXT("ancestor-or-self"))
          return axis_ancestor_or_self;
        else if (name == PUGIXML_TEXT("attribute"))
          return axis_attribute;

        break;

      case 'c':
        if (name == PUGIXML_TEXT("child")) return axis_child;

        break;

      case 'd':
        if (name == PUGIXML_TEXT("descendant"))
          return axis_descendant;
        else if (name == PUGIXML_TEXT("descendant-or-self"))
          return axis_descendant_or_self;

        break;

      case 'f':
        if (name == PUGIXML_TEXT("following"))
          return axis_following;
        else if (name == PUGIXML_TEXT("following-sibling"))
          return axis_following_sibling;

        break;

      case 'n':
        if (name == PUGIXML_TEXT("namespace")) return axis_namespace;

        break;

      case 'p':
        if (name == PUGIXML_TEXT("parent"))
          return axis_parent;
        else if (name == PUGIXML_TEXT("preceding"))
          return axis_preceding;
        else if (name == PUGIXML_TEXT("preceding-sibling"))
          return axis_preceding_sibling;

        break;

      case 's':
        if (name == PUGIXML_TEXT("self")) return axis_self;

        break;

      default:
        break;
    }

    specified = false;
    return axis_child;
  }

  nodetest_t parse_node_test_type(const xpath_lexer_string& name) {
    switch (name.begin[0]) {
      case 'c':
        if (name == PUGIXML_TEXT("comment")) return nodetest_type_comment;

        break;

      case 'n':
        if (name == PUGIXML_TEXT("node")) return nodetest_type_node;

        break;

      case 'p':
        if (name == PUGIXML_TEXT("processing-instruction"))
          return nodetest_type_pi;

        break;

      case 't':
        if (name == PUGIXML_TEXT("text")) return nodetest_type_text;

        break;

      default:
        break;
    }

    return nodetest_none;
  }

  // PrimaryExpr ::= VariableReference | '(' Expr ')' | Literal | Number |
  // FunctionCall
  xpath_ast_node* parse_primary_expression() {
    switch (_lexer.current()) {
      case lex_var_ref: {
        xpath_lexer_string name = _lexer.contents();

        if (!_variables)
          throw_error("Unknown variable: variable set is not provided");

        xpath_variable* var = 0;
        if (!get_variable_scratch(_scratch, _variables, name.begin, name.end,
                                  &var))
          throw_error_oom();

        if (!var)
          throw_error(
              "Unknown variable: variable set does not contain the given name");

        _lexer.next();

        return new (alloc_node())
            xpath_ast_node(ast_variable, var->type(), var);
      }

      case lex_open_brace: {
        _lexer.next();

        xpath_ast_node* n = parse_expression();

        if (_lexer.current() != lex_close_brace)
          throw_error("Unmatched braces");

        _lexer.next();

        return n;
      }

      case lex_quoted_string: {
        const char_t* value = alloc_string(_lexer.contents());

        xpath_ast_node* n = new (alloc_node())
            xpath_ast_node(ast_string_constant, xpath_type_string, value);
        _lexer.next();

        return n;
      }

      case lex_number: {
        double value = 0;

        if (!convert_string_to_number_scratch(_scratch, _lexer.contents().begin,
                                              _lexer.contents().end, &value))
          throw_error_oom();

        xpath_ast_node* n = new (alloc_node())
            xpath_ast_node(ast_number_constant, xpath_type_number, value);
        _lexer.next();

        return n;
      }

      case lex_string: {
        xpath_ast_node* args[2] = {0};
        size_t argc = 0;

        xpath_lexer_string function = _lexer.contents();
        _lexer.next();

        xpath_ast_node* last_arg = 0;

        if (_lexer.current() != lex_open_brace)
          throw_error("Unrecognized function call");
        _lexer.next();

        if (_lexer.current() != lex_close_brace)
          args[argc++] = parse_expression();

        while (_lexer.current() != lex_close_brace) {
          if (_lexer.current() != lex_comma)
            throw_error("No comma between function arguments");
          _lexer.next();

          xpath_ast_node* n = parse_expression();

          if (argc < 2)
            args[argc] = n;
          else
            last_arg->set_next(n);

          argc++;
          last_arg = n;
        }

        _lexer.next();

        return parse_function(function, argc, args);
      }

      default:
        throw_error("Unrecognizable primary expression");

        return 0;
    }
  }

  // FilterExpr ::= PrimaryExpr | FilterExpr Predicate
  // Predicate ::= '[' PredicateExpr ']'
  // PredicateExpr ::= Expr
  xpath_ast_node* parse_filter_expression() {
    xpath_ast_node* n = parse_primary_expression();

    while (_lexer.current() == lex_open_square_brace) {
      _lexer.next();

      xpath_ast_node* expr = parse_expression();

      if (n->rettype() != xpath_type_node_set)
        throw_error("Predicate has to be applied to node set");

      n = new (alloc_node())
          xpath_ast_node(ast_filter, n, expr, predicate_default);

      if (_lexer.current() != lex_close_square_brace)
        throw_error("Unmatched square brace");

      _lexer.next();
    }

    return n;
  }

  // Step ::= AxisSpecifier NodeTest Predicate* | AbbreviatedStep
  // AxisSpecifier ::= AxisName '::' | '@'?
  // NodeTest ::= NameTest | NodeType '(' ')' | 'processing-instruction' '('
  // Literal ')' NameTest ::= '*' | NCName ':' '*' | QName AbbreviatedStep ::=
  // '.' | '..'
  xpath_ast_node* parse_step(xpath_ast_node* set) {
    if (set && set->rettype() != xpath_type_node_set)
      throw_error("Step has to be applied to node set");

    bool axis_specified = false;
    axis_t axis = axis_child;  // implied child axis

    if (_lexer.current() == lex_axis_attribute) {
      axis = axis_attribute;
      axis_specified = true;

      _lexer.next();
    } else if (_lexer.current() == lex_dot) {
      _lexer.next();

      return new (alloc_node())
          xpath_ast_node(ast_step, set, axis_self, nodetest_type_node, 0);
    } else if (_lexer.current() == lex_double_dot) {
      _lexer.next();

      return new (alloc_node())
          xpath_ast_node(ast_step, set, axis_parent, nodetest_type_node, 0);
    }

    nodetest_t nt_type = nodetest_none;
    xpath_lexer_string nt_name;

    if (_lexer.current() == lex_string) {
      // node name test
      nt_name = _lexer.contents();
      _lexer.next();

      // was it an axis name?
      if (_lexer.current() == lex_double_colon) {
        // parse axis name
        if (axis_specified) throw_error("Two axis specifiers in one step");

        axis = parse_axis_name(nt_name, axis_specified);

        if (!axis_specified) throw_error("Unknown axis");

        // read actual node test
        _lexer.next();

        if (_lexer.current() == lex_multiply) {
          nt_type = nodetest_all;
          nt_name = xpath_lexer_string();
          _lexer.next();
        } else if (_lexer.current() == lex_string) {
          nt_name = _lexer.contents();
          _lexer.next();
        } else
          throw_error("Unrecognized node test");
      }

      if (nt_type == nodetest_none) {
        // node type test or processing-instruction
        if (_lexer.current() == lex_open_brace) {
          _lexer.next();

          if (_lexer.current() == lex_close_brace) {
            _lexer.next();

            nt_type = parse_node_test_type(nt_name);

            if (nt_type == nodetest_none) throw_error("Unrecognized node type");

            nt_name = xpath_lexer_string();
          } else if (nt_name == PUGIXML_TEXT("processing-instruction")) {
            if (_lexer.current() != lex_quoted_string)
              throw_error(
                  "Only literals are allowed as arguments to "
                  "processing-instruction()");

            nt_type = nodetest_pi;
            nt_name = _lexer.contents();
            _lexer.next();

            if (_lexer.current() != lex_close_brace)
              throw_error("Unmatched brace near processing-instruction()");
            _lexer.next();
          } else {
            throw_error("Unmatched brace near node type test");
          }
        }
        // QName or NCName:*
        else {
          if (nt_name.end - nt_name.begin > 2 && nt_name.end[-2] == ':' &&
              nt_name.end[-1] == '*')  // NCName:*
          {
            nt_name.end--;  // erase *

            nt_type = nodetest_all_in_namespace;
          } else {
            nt_type = nodetest_name;
          }
        }
      }
    } else if (_lexer.current() == lex_multiply) {
      nt_type = nodetest_all;
      _lexer.next();
    } else {
      throw_error("Unrecognized node test");
    }

    const char_t* nt_name_copy = alloc_string(nt_name);
    xpath_ast_node* n = new (alloc_node())
        xpath_ast_node(ast_step, set, axis, nt_type, nt_name_copy);

    xpath_ast_node* last = 0;

    while (_lexer.current() == lex_open_square_brace) {
      _lexer.next();

      xpath_ast_node* expr = parse_expression();

      xpath_ast_node* pred = new (alloc_node())
          xpath_ast_node(ast_predicate, 0, expr, predicate_default);

      if (_lexer.current() != lex_close_square_brace)
        throw_error("Unmatched square brace");
      _lexer.next();

      if (last)
        last->set_next(pred);
      else
        n->set_right(pred);

      last = pred;
    }

    return n;
  }

  // RelativeLocationPath ::= Step | RelativeLocationPath '/' Step |
  // RelativeLocationPath '//' Step
  xpath_ast_node* parse_relative_location_path(xpath_ast_node* set) {
    xpath_ast_node* n = parse_step(set);

    while (_lexer.current() == lex_slash ||
           _lexer.current() == lex_double_slash) {
      lexeme_t l = _lexer.current();
      _lexer.next();

      if (l == lex_double_slash)
        n = new (alloc_node()) xpath_ast_node(
            ast_step, n, axis_descendant_or_self, nodetest_type_node, 0);

      n = parse_step(n);
    }

    return n;
  }

  // LocationPath ::= RelativeLocationPath | AbsoluteLocationPath
  // AbsoluteLocationPath ::= '/' RelativeLocationPath? | '//'
  // RelativeLocationPath
  xpath_ast_node* parse_location_path() {
    if (_lexer.current() == lex_slash) {
      _lexer.next();

      xpath_ast_node* n =
          new (alloc_node()) xpath_ast_node(ast_step_root, xpath_type_node_set);

      // relative location path can start from axis_attribute, dot, double_dot,
      // multiply and string lexemes; any other lexeme means standalone root
      // path
      lexeme_t l = _lexer.current();

      if (l == lex_string || l == lex_axis_attribute || l == lex_dot ||
          l == lex_double_dot || l == lex_multiply)
        return parse_relative_location_path(n);
      else
        return n;
    } else if (_lexer.current() == lex_double_slash) {
      _lexer.next();

      xpath_ast_node* n =
          new (alloc_node()) xpath_ast_node(ast_step_root, xpath_type_node_set);
      n = new (alloc_node()) xpath_ast_node(
          ast_step, n, axis_descendant_or_self, nodetest_type_node, 0);

      return parse_relative_location_path(n);
    }

    // else clause moved outside of if because of bogus warning 'control may
    // reach end of non-void function being inlined' in gcc 4.0.1
    return parse_relative_location_path(0);
  }

  // PathExpr ::= LocationPath
  //              | FilterExpr
  //              | FilterExpr '/' RelativeLocationPath
  //              | FilterExpr '//' RelativeLocationPath
  // UnionExpr ::= PathExpr | UnionExpr '|' PathExpr
  // UnaryExpr ::= UnionExpr | '-' UnaryExpr
  xpath_ast_node* parse_path_or_unary_expression() {
    // Clarification.
    // PathExpr begins with either LocationPath or FilterExpr.
    // FilterExpr begins with PrimaryExpr
    // PrimaryExpr begins with '$' in case of it being a variable reference,
    // '(' in case of it being an expression, string literal, number constant or
    // function call.

    if (_lexer.current() == lex_var_ref || _lexer.current() == lex_open_brace ||
        _lexer.current() == lex_quoted_string ||
        _lexer.current() == lex_number || _lexer.current() == lex_string) {
      if (_lexer.current() == lex_string) {
        // This is either a function call, or not - if not, we shall proceed
        // with location path
        const char_t* state = _lexer.state();

        while (PUGI__IS_CHARTYPE(*state, ct_space)) ++state;

        if (*state != '(') return parse_location_path();

        // This looks like a function call; however this still can be a
        // node-test. Check it.
        if (parse_node_test_type(_lexer.contents()) != nodetest_none)
          return parse_location_path();
      }

      xpath_ast_node* n = parse_filter_expression();

      if (_lexer.current() == lex_slash ||
          _lexer.current() == lex_double_slash) {
        lexeme_t l = _lexer.current();
        _lexer.next();

        if (l == lex_double_slash) {
          if (n->rettype() != xpath_type_node_set)
            throw_error("Step has to be applied to node set");

          n = new (alloc_node()) xpath_ast_node(
              ast_step, n, axis_descendant_or_self, nodetest_type_node, 0);
        }

        // select from location path
        return parse_relative_location_path(n);
      }

      return n;
    } else if (_lexer.current() == lex_minus) {
      _lexer.next();

      // precedence 7+ - only parses union expressions
      xpath_ast_node* expr =
          parse_expression_rec(parse_path_or_unary_expression(), 7);

      return new (alloc_node())
          xpath_ast_node(ast_op_negate, xpath_type_number, expr);
    } else {
      return parse_location_path();
    }
  }

  struct binary_op_t {
    ast_type_t asttype;
    xpath_value_type rettype;
    int precedence;

    binary_op_t()
        : asttype(ast_unknown), rettype(xpath_type_none), precedence(0) {}

    binary_op_t(ast_type_t asttype_, xpath_value_type rettype_, int precedence_)
        : asttype(asttype_), rettype(rettype_), precedence(precedence_) {}

    static binary_op_t parse(xpath_lexer& lexer) {
      switch (lexer.current()) {
        case lex_string:
          if (lexer.contents() == PUGIXML_TEXT("or"))
            return binary_op_t(ast_op_or, xpath_type_boolean, 1);
          else if (lexer.contents() == PUGIXML_TEXT("and"))
            return binary_op_t(ast_op_and, xpath_type_boolean, 2);
          else if (lexer.contents() == PUGIXML_TEXT("div"))
            return binary_op_t(ast_op_divide, xpath_type_number, 6);
          else if (lexer.contents() == PUGIXML_TEXT("mod"))
            return binary_op_t(ast_op_mod, xpath_type_number, 6);
          else
            return binary_op_t();

        case lex_equal:
          return binary_op_t(ast_op_equal, xpath_type_boolean, 3);

        case lex_not_equal:
          return binary_op_t(ast_op_not_equal, xpath_type_boolean, 3);

        case lex_less:
          return binary_op_t(ast_op_less, xpath_type_boolean, 4);

        case lex_greater:
          return binary_op_t(ast_op_greater, xpath_type_boolean, 4);

        case lex_less_or_equal:
          return binary_op_t(ast_op_less_or_equal, xpath_type_boolean, 4);

        case lex_greater_or_equal:
          return binary_op_t(ast_op_greater_or_equal, xpath_type_boolean, 4);

        case lex_plus:
          return binary_op_t(ast_op_add, xpath_type_number, 5);

        case lex_minus:
          return binary_op_t(ast_op_subtract, xpath_type_number, 5);

        case lex_multiply:
          return binary_op_t(ast_op_multiply, xpath_type_number, 6);

        case lex_union:
          return binary_op_t(ast_op_union, xpath_type_node_set, 7);

        default:
          return binary_op_t();
      }
    }
  };

  xpath_ast_node* parse_expression_rec(xpath_ast_node* lhs, int limit) {
    binary_op_t op = binary_op_t::parse(_lexer);

    while (op.asttype != ast_unknown && op.precedence >= limit) {
      _lexer.next();

      xpath_ast_node* rhs = parse_path_or_unary_expression();

      binary_op_t nextop = binary_op_t::parse(_lexer);

      while (nextop.asttype != ast_unknown &&
             nextop.precedence > op.precedence) {
        rhs = parse_expression_rec(rhs, nextop.precedence);

        nextop = binary_op_t::parse(_lexer);
      }

      if (op.asttype == ast_op_union &&
          (lhs->rettype() != xpath_type_node_set ||
           rhs->rettype() != xpath_type_node_set))
        throw_error("Union operator has to be applied to node sets");

      lhs = new (alloc_node()) xpath_ast_node(op.asttype, op.rettype, lhs, rhs);

      op = binary_op_t::parse(_lexer);
    }

    return lhs;
  }

  // Expr ::= OrExpr
  // OrExpr ::= AndExpr | OrExpr 'or' AndExpr
  // AndExpr ::= EqualityExpr | AndExpr 'and' EqualityExpr
  // EqualityExpr ::= RelationalExpr
  //                  | EqualityExpr '=' RelationalExpr
  //                  | EqualityExpr '!=' RelationalExpr
  // RelationalExpr ::= AdditiveExpr
  //                    | RelationalExpr '<' AdditiveExpr
  //                    | RelationalExpr '>' AdditiveExpr
  //                    | RelationalExpr '<=' AdditiveExpr
  //                    | RelationalExpr '>=' AdditiveExpr
  // AdditiveExpr ::= MultiplicativeExpr
  //                  | AdditiveExpr '+' MultiplicativeExpr
  //                  | AdditiveExpr '-' MultiplicativeExpr
  // MultiplicativeExpr ::= UnaryExpr
  //                        | MultiplicativeExpr '*' UnaryExpr
  //                        | MultiplicativeExpr 'div' UnaryExpr
  //                        | MultiplicativeExpr 'mod' UnaryExpr
  xpath_ast_node* parse_expression() {
    return parse_expression_rec(parse_path_or_unary_expression(), 0);
  }

  xpath_parser(const char_t* query, xpath_variable_set* variables,
               xpath_allocator* alloc, xpath_parse_result* result)
      : _alloc(alloc),
        _lexer(query),
        _query(query),
        _variables(variables),
        _result(result) {}

  xpath_ast_node* parse() {
    xpath_ast_node* result = parse_expression();

    // check if there are unparsed tokens left
    if (_lexer.current() != lex_eof) throw_error("Incorrect query");

    return result;
  }

  static xpath_ast_node* parse(const char_t* query,
                               xpath_variable_set* variables,
                               xpath_allocator* alloc,
                               xpath_parse_result* result) {
    xpath_parser parser(query, variables, alloc, result);

#ifdef PUGIXML_NO_EXCEPTIONS
    int error = setjmp(parser._error_handler);

    return (error == 0) ? parser.parse() : 0;
#else
    return parser.parse();
#endif
  }
};

struct xpath_query_impl {
  static xpath_query_impl* create() {
    void* memory = xml_memory::allocate(sizeof(xpath_query_impl));
    if (!memory) return 0;

    return new (memory) xpath_query_impl();
  }

  static void destroy(xpath_query_impl* impl) {
    // free all allocated pages
    impl->alloc.release();

    // free allocator memory (with the first page)
    xml_memory::deallocate(impl);
  }

  xpath_query_impl() : root(0), alloc(&block) {
    block.next = 0;
    block.capacity = sizeof(block.data);
  }

  xpath_ast_node* root;
  xpath_allocator alloc;
  xpath_memory_block block;
};

PUGI__FN xpath_string evaluate_string_impl(xpath_query_impl* impl,
                                           const xpath_node& n,
                                           xpath_stack_data& sd) {
  if (!impl) return xpath_string();

#ifdef PUGIXML_NO_EXCEPTIONS
  if (setjmp(sd.error_handler)) return xpath_string();
#endif

  xpath_context c(n, 1, 1);

  return impl->root->eval_string(c, sd.stack);
}

PUGI__FN impl::xpath_ast_node* evaluate_node_set_prepare(
    xpath_query_impl* impl) {
  if (!impl) return 0;

  if (impl->root->rettype() != xpath_type_node_set) {
#ifdef PUGIXML_NO_EXCEPTIONS
    return 0;
#else
    xpath_parse_result res;
    res.error = "Expression does not evaluate to node set";

    throw xpath_exception(res);
#endif
  }

  return impl->root;
}
PUGI__NS_END

namespace pugi {
#ifndef PUGIXML_NO_EXCEPTIONS
PUGI__FN xpath_exception::xpath_exception(const xpath_parse_result& result_)
    : _result(result_) {
  assert(_result.error);
}

PUGI__FN const char* xpath_exception::what() const throw() {
  return _result.error;
}

PUGI__FN const xpath_parse_result& xpath_exception::result() const {
  return _result;
}
#endif

PUGI__FN xpath_node::xpath_node() {}

PUGI__FN xpath_node::xpath_node(const xml_node& node_) : _node(node_) {}

PUGI__FN xpath_node::xpath_node(const xml_attribute& attribute_,
                                const xml_node& parent_)
    : _node(attribute_ ? parent_ : xml_node()), _attribute(attribute_) {}

PUGI__FN xml_node xpath_node::node() const {
  return _attribute ? xml_node() : _node;
}

PUGI__FN xml_attribute xpath_node::attribute() const { return _attribute; }

PUGI__FN xml_node xpath_node::parent() const {
  return _attribute ? _node : _node.parent();
}

PUGI__FN static void unspecified_bool_xpath_node(xpath_node***) {}

PUGI__FN xpath_node::operator xpath_node::unspecified_bool_type() const {
  return (_node || _attribute) ? unspecified_bool_xpath_node : 0;
}

PUGI__FN bool xpath_node::operator!() const { return !(_node || _attribute); }

PUGI__FN bool xpath_node::operator==(const xpath_node& n) const {
  return _node == n._node && _attribute == n._attribute;
}

PUGI__FN bool xpath_node::operator!=(const xpath_node& n) const {
  return _node != n._node || _attribute != n._attribute;
}

#ifdef __BORLANDC__
PUGI__FN bool operator&&(const xpath_node& lhs, bool rhs) {
  return (bool)lhs && rhs;
}

PUGI__FN bool operator||(const xpath_node& lhs, bool rhs) {
  return (bool)lhs || rhs;
}
#endif

PUGI__FN void xpath_node_set::_assign(const_iterator begin_,
                                      const_iterator end_, type_t type_) {
  assert(begin_ <= end_);

  size_t size_ = static_cast<size_t>(end_ - begin_);

  if (size_ <= 1) {
    // deallocate old buffer
    if (_begin != &_storage) impl::xml_memory::deallocate(_begin);

    // use internal buffer
    if (begin_ != end_) _storage = *begin_;

    _begin = &_storage;
    _end = &_storage + size_;
    _type = type_;
  } else {
    // make heap copy
    xpath_node* storage = static_cast<xpath_node*>(
        impl::xml_memory::allocate(size_ * sizeof(xpath_node)));

    if (!storage) {
#ifdef PUGIXML_NO_EXCEPTIONS
      return;
#else
      throw std::bad_alloc();
#endif
    }

    memcpy(storage, begin_, size_ * sizeof(xpath_node));

    // deallocate old buffer
    if (_begin != &_storage) impl::xml_memory::deallocate(_begin);

    // finalize
    _begin = storage;
    _end = storage + size_;
    _type = type_;
  }
}

#ifdef PUGIXML_HAS_MOVE
PUGI__FN void xpath_node_set::_move(xpath_node_set& rhs) {
  _type = rhs._type;
  _storage = rhs._storage;
  _begin = (rhs._begin == &rhs._storage) ? &_storage : rhs._begin;
  _end = _begin + (rhs._end - rhs._begin);

  rhs._type = type_unsorted;
  rhs._begin = &rhs._storage;
  rhs._end = rhs._begin;
}
#endif

PUGI__FN xpath_node_set::xpath_node_set()
    : _type(type_unsorted), _begin(&_storage), _end(&_storage) {}

PUGI__FN xpath_node_set::xpath_node_set(const_iterator begin_,
                                        const_iterator end_, type_t type_)
    : _type(type_unsorted), _begin(&_storage), _end(&_storage) {
  _assign(begin_, end_, type_);
}

PUGI__FN xpath_node_set::~xpath_node_set() {
  if (_begin != &_storage) impl::xml_memory::deallocate(_begin);
}

PUGI__FN xpath_node_set::xpath_node_set(const xpath_node_set& ns)
    : _type(type_unsorted), _begin(&_storage), _end(&_storage) {
  _assign(ns._begin, ns._end, ns._type);
}

PUGI__FN xpath_node_set& xpath_node_set::operator=(const xpath_node_set& ns) {
  if (this == &ns) return *this;

  _assign(ns._begin, ns._end, ns._type);

  return *this;
}

#ifdef PUGIXML_HAS_MOVE
PUGI__FN xpath_node_set::xpath_node_set(xpath_node_set&& rhs)
    : _type(type_unsorted), _begin(&_storage), _end(&_storage) {
  _move(rhs);
}

PUGI__FN xpath_node_set& xpath_node_set::operator=(xpath_node_set&& rhs) {
  if (this == &rhs) return *this;

  if (_begin != &_storage) impl::xml_memory::deallocate(_begin);

  _move(rhs);

  return *this;
}
#endif

PUGI__FN xpath_node_set::type_t xpath_node_set::type() const { return _type; }

PUGI__FN size_t xpath_node_set::size() const { return _end - _begin; }

PUGI__FN bool xpath_node_set::empty() const { return _begin == _end; }

PUGI__FN const xpath_node& xpath_node_set::operator[](size_t index) const {
  assert(index < size());
  return _begin[index];
}

PUGI__FN xpath_node_set::const_iterator xpath_node_set::begin() const {
  return _begin;
}

PUGI__FN xpath_node_set::const_iterator xpath_node_set::end() const {
  return _end;
}

PUGI__FN void xpath_node_set::sort(bool reverse) {
  _type = impl::xpath_sort(_begin, _end, _type, reverse);
}

PUGI__FN xpath_node xpath_node_set::first() const {
  return impl::xpath_first(_begin, _end, _type);
}

PUGI__FN xpath_parse_result::xpath_parse_result()
    : error("Internal error"), offset(0) {}

PUGI__FN xpath_parse_result::operator bool() const { return error == 0; }

PUGI__FN const char* xpath_parse_result::description() const {
  return error ? error : "No error";
}

PUGI__FN xpath_variable::xpath_variable(xpath_value_type type_)
    : _type(type_), _next(0) {}

PUGI__FN const char_t* xpath_variable::name() const {
  switch (_type) {
    case xpath_type_node_set:
      return static_cast<const impl::xpath_variable_node_set*>(this)->name;

    case xpath_type_number:
      return static_cast<const impl::xpath_variable_number*>(this)->name;

    case xpath_type_string:
      return static_cast<const impl::xpath_variable_string*>(this)->name;

    case xpath_type_boolean:
      return static_cast<const impl::xpath_variable_boolean*>(this)->name;

    default:
      assert(false && "Invalid variable type");
      return 0;
  }
}

PUGI__FN xpath_value_type xpath_variable::type() const { return _type; }

PUGI__FN bool xpath_variable::get_boolean() const {
  return (_type == xpath_type_boolean)
             ? static_cast<const impl::xpath_variable_boolean*>(this)->value
             : false;
}

PUGI__FN double xpath_variable::get_number() const {
  return (_type == xpath_type_number)
             ? static_cast<const impl::xpath_variable_number*>(this)->value
             : impl::gen_nan();
}

PUGI__FN const char_t* xpath_variable::get_string() const {
  const char_t* value =
      (_type == xpath_type_string)
          ? static_cast<const impl::xpath_variable_string*>(this)->value
          : 0;
  return value ? value : PUGIXML_TEXT("");
}

PUGI__FN const xpath_node_set& xpath_variable::get_node_set() const {
  return (_type == xpath_type_node_set)
             ? static_cast<const impl::xpath_variable_node_set*>(this)->value
             : impl::dummy_node_set;
}

PUGI__FN bool xpath_variable::set(bool value) {
  if (_type != xpath_type_boolean) return false;

  static_cast<impl::xpath_variable_boolean*>(this)->value = value;
  return true;
}

PUGI__FN bool xpath_variable::set(double value) {
  if (_type != xpath_type_number) return false;

  static_cast<impl::xpath_variable_number*>(this)->value = value;
  return true;
}

PUGI__FN bool xpath_variable::set(const char_t* value) {
  if (_type != xpath_type_string) return false;

  impl::xpath_variable_string* var =
      static_cast<impl::xpath_variable_string*>(this);

  // duplicate string
  size_t size = (impl::strlength(value) + 1) * sizeof(char_t);

  char_t* copy = static_cast<char_t*>(impl::xml_memory::allocate(size));
  if (!copy) return false;

  memcpy(copy, value, size);

  // replace old string
  if (var->value) impl::xml_memory::deallocate(var->value);
  var->value = copy;

  return true;
}

PUGI__FN bool xpath_variable::set(const xpath_node_set& value) {
  if (_type != xpath_type_node_set) return false;

  static_cast<impl::xpath_variable_node_set*>(this)->value = value;
  return true;
}

PUGI__FN xpath_variable_set::xpath_variable_set() {
  for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i) _data[i] = 0;
}

PUGI__FN xpath_variable_set::~xpath_variable_set() {
  for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i)
    _destroy(_data[i]);
}

PUGI__FN xpath_variable_set::xpath_variable_set(const xpath_variable_set& rhs) {
  for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i) _data[i] = 0;

  _assign(rhs);
}

PUGI__FN xpath_variable_set& xpath_variable_set::operator=(
    const xpath_variable_set& rhs) {
  if (this == &rhs) return *this;

  _assign(rhs);

  return *this;
}

#ifdef PUGIXML_HAS_MOVE
PUGI__FN xpath_variable_set::xpath_variable_set(xpath_variable_set&& rhs) {
  for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i) {
    _data[i] = rhs._data[i];
    rhs._data[i] = 0;
  }
}

PUGI__FN xpath_variable_set& xpath_variable_set::operator=(
    xpath_variable_set&& rhs) {
  for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i) {
    _destroy(_data[i]);

    _data[i] = rhs._data[i];
    rhs._data[i] = 0;
  }

  return *this;
}
#endif

PUGI__FN void xpath_variable_set::_assign(const xpath_variable_set& rhs) {
  xpath_variable_set temp;

  for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i)
    if (rhs._data[i] && !_clone(rhs._data[i], &temp._data[i])) return;

  _swap(temp);
}

PUGI__FN void xpath_variable_set::_swap(xpath_variable_set& rhs) {
  for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i) {
    xpath_variable* chain = _data[i];

    _data[i] = rhs._data[i];
    rhs._data[i] = chain;
  }
}

PUGI__FN xpath_variable* xpath_variable_set::_find(const char_t* name) const {
  const size_t hash_size = sizeof(_data) / sizeof(_data[0]);
  size_t hash = impl::hash_string(name) % hash_size;

  // look for existing variable
  for (xpath_variable* var = _data[hash]; var; var = var->_next)
    if (impl::strequal(var->name(), name)) return var;

  return 0;
}

PUGI__FN bool xpath_variable_set::_clone(xpath_variable* var,
                                         xpath_variable** out_result) {
  xpath_variable* last = 0;

  while (var) {
    // allocate storage for new variable
    xpath_variable* nvar = impl::new_xpath_variable(var->_type, var->name());
    if (!nvar) return false;

    // link the variable to the result immediately to handle failures gracefully
    if (last)
      last->_next = nvar;
    else
      *out_result = nvar;

    last = nvar;

    // copy the value; this can fail due to out-of-memory conditions
    if (!impl::copy_xpath_variable(nvar, var)) return false;

    var = var->_next;
  }

  return true;
}

PUGI__FN void xpath_variable_set::_destroy(xpath_variable* var) {
  while (var) {
    xpath_variable* next = var->_next;

    impl::delete_xpath_variable(var->_type, var);

    var = next;
  }
}

PUGI__FN xpath_variable* xpath_variable_set::add(const char_t* name,
                                                 xpath_value_type type) {
  const size_t hash_size = sizeof(_data) / sizeof(_data[0]);
  size_t hash = impl::hash_string(name) % hash_size;

  // look for existing variable
  for (xpath_variable* var = _data[hash]; var; var = var->_next)
    if (impl::strequal(var->name(), name)) return var->type() == type ? var : 0;

  // add new variable
  xpath_variable* result = impl::new_xpath_variable(type, name);

  if (result) {
    result->_next = _data[hash];

    _data[hash] = result;
  }

  return result;
}

PUGI__FN bool xpath_variable_set::set(const char_t* name, bool value) {
  xpath_variable* var = add(name, xpath_type_boolean);
  return var ? var->set(value) : false;
}

PUGI__FN bool xpath_variable_set::set(const char_t* name, double value) {
  xpath_variable* var = add(name, xpath_type_number);
  return var ? var->set(value) : false;
}

PUGI__FN bool xpath_variable_set::set(const char_t* name, const char_t* value) {
  xpath_variable* var = add(name, xpath_type_string);
  return var ? var->set(value) : false;
}

PUGI__FN bool xpath_variable_set::set(const char_t* name,
                                      const xpath_node_set& value) {
  xpath_variable* var = add(name, xpath_type_node_set);
  return var ? var->set(value) : false;
}

PUGI__FN xpath_variable* xpath_variable_set::get(const char_t* name) {
  return _find(name);
}

PUGI__FN const xpath_variable* xpath_variable_set::get(
    const char_t* name) const {
  return _find(name);
}

PUGI__FN xpath_query::xpath_query(const char_t* query,
                                  xpath_variable_set* variables)
    : _impl(0) {
  impl::xpath_query_impl* qimpl = impl::xpath_query_impl::create();

  if (!qimpl) {
#ifdef PUGIXML_NO_EXCEPTIONS
    _result.error = "Out of memory";
#else
    throw std::bad_alloc();
#endif
  } else {
    using impl::auto_deleter;  // MSVC7 workaround
    auto_deleter<impl::xpath_query_impl> impl(qimpl,
                                              impl::xpath_query_impl::destroy);

    qimpl->root =
        impl::xpath_parser::parse(query, variables, &qimpl->alloc, &_result);

    if (qimpl->root) {
      qimpl->root->optimize(&qimpl->alloc);

      _impl = impl.release();
      _result.error = 0;
    }
  }
}

PUGI__FN xpath_query::xpath_query() : _impl(0) {}

PUGI__FN xpath_query::~xpath_query() {
  if (_impl)
    impl::xpath_query_impl::destroy(
        static_cast<impl::xpath_query_impl*>(_impl));
}

#ifdef PUGIXML_HAS_MOVE
PUGI__FN xpath_query::xpath_query(xpath_query&& rhs) {
  _impl = rhs._impl;
  _result = rhs._result;
  rhs._impl = 0;
  rhs._result = xpath_parse_result();
}

PUGI__FN xpath_query& xpath_query::operator=(xpath_query&& rhs) {
  if (this == &rhs) return *this;

  if (_impl)
    impl::xpath_query_impl::destroy(
        static_cast<impl::xpath_query_impl*>(_impl));

  _impl = rhs._impl;
  _result = rhs._result;
  rhs._impl = 0;
  rhs._result = xpath_parse_result();

  return *this;
}
#endif

PUGI__FN xpath_value_type xpath_query::return_type() const {
  if (!_impl) return xpath_type_none;

  return static_cast<impl::xpath_query_impl*>(_impl)->root->rettype();
}

PUGI__FN bool xpath_query::evaluate_boolean(const xpath_node& n) const {
  if (!_impl) return false;

  impl::xpath_context c(n, 1, 1);
  impl::xpath_stack_data sd;

#ifdef PUGIXML_NO_EXCEPTIONS
  if (setjmp(sd.error_handler)) return false;
#endif

  return static_cast<impl::xpath_query_impl*>(_impl)->root->eval_boolean(
      c, sd.stack);
}

PUGI__FN double xpath_query::evaluate_number(const xpath_node& n) const {
  if (!_impl) return impl::gen_nan();

  impl::xpath_context c(n, 1, 1);
  impl::xpath_stack_data sd;

#ifdef PUGIXML_NO_EXCEPTIONS
  if (setjmp(sd.error_handler)) return impl::gen_nan();
#endif

  return static_cast<impl::xpath_query_impl*>(_impl)->root->eval_number(
      c, sd.stack);
}

#ifndef PUGIXML_NO_STL
PUGI__FN string_t xpath_query::evaluate_string(const xpath_node& n) const {
  impl::xpath_stack_data sd;

  impl::xpath_string r = impl::evaluate_string_impl(
      static_cast<impl::xpath_query_impl*>(_impl), n, sd);

  return string_t(r.c_str(), r.length());
}
#endif

PUGI__FN size_t xpath_query::evaluate_string(char_t* buffer, size_t capacity,
                                             const xpath_node& n) const {
  impl::xpath_stack_data sd;

  impl::xpath_string r = impl::evaluate_string_impl(
      static_cast<impl::xpath_query_impl*>(_impl), n, sd);

  size_t full_size = r.length() + 1;

  if (capacity > 0) {
    size_t size = (full_size < capacity) ? full_size : capacity;
    assert(size > 0);

    memcpy(buffer, r.c_str(), (size - 1) * sizeof(char_t));
    buffer[size - 1] = 0;
  }

  return full_size;
}

PUGI__FN xpath_node_set
xpath_query::evaluate_node_set(const xpath_node& n) const {
  impl::xpath_ast_node* root = impl::evaluate_node_set_prepare(
      static_cast<impl::xpath_query_impl*>(_impl));
  if (!root) return xpath_node_set();

  impl::xpath_context c(n, 1, 1);
  impl::xpath_stack_data sd;

#ifdef PUGIXML_NO_EXCEPTIONS
  if (setjmp(sd.error_handler)) return xpath_node_set();
#endif

  impl::xpath_node_set_raw r =
      root->eval_node_set(c, sd.stack, impl::nodeset_eval_all);

  return xpath_node_set(r.begin(), r.end(), r.type());
}

PUGI__FN xpath_node xpath_query::evaluate_node(const xpath_node& n) const {
  impl::xpath_ast_node* root = impl::evaluate_node_set_prepare(
      static_cast<impl::xpath_query_impl*>(_impl));
  if (!root) return xpath_node();

  impl::xpath_context c(n, 1, 1);
  impl::xpath_stack_data sd;

#ifdef PUGIXML_NO_EXCEPTIONS
  if (setjmp(sd.error_handler)) return xpath_node();
#endif

  impl::xpath_node_set_raw r =
      root->eval_node_set(c, sd.stack, impl::nodeset_eval_first);

  return r.first();
}

PUGI__FN const xpath_parse_result& xpath_query::result() const {
  return _result;
}

PUGI__FN static void unspecified_bool_xpath_query(xpath_query***) {}

PUGI__FN xpath_query::operator xpath_query::unspecified_bool_type() const {
  return _impl ? unspecified_bool_xpath_query : 0;
}

PUGI__FN bool xpath_query::operator!() const { return !_impl; }

PUGI__FN xpath_node xml_node::select_node(const char_t* query,
                                          xpath_variable_set* variables) const {
  xpath_query q(query, variables);
  return select_node(q);
}

PUGI__FN xpath_node xml_node::select_node(const xpath_query& query) const {
  return query.evaluate_node(*this);
}

PUGI__FN xpath_node_set xml_node::select_nodes(
    const char_t* query, xpath_variable_set* variables) const {
  xpath_query q(query, variables);
  return select_nodes(q);
}

PUGI__FN xpath_node_set xml_node::select_nodes(const xpath_query& query) const {
  return query.evaluate_node_set(*this);
}

PUGI__FN xpath_node xml_node::select_single_node(
    const char_t* query, xpath_variable_set* variables) const {
  xpath_query q(query, variables);
  return select_single_node(q);
}

PUGI__FN xpath_node
xml_node::select_single_node(const xpath_query& query) const {
  return query.evaluate_node(*this);
}
}  // namespace pugi

#endif

#ifdef __BORLANDC__
#pragma option pop
#endif

// Intel C++ does not properly keep warning state for function templates,
// so popping warning state at the end of translation unit leads to warnings in
// the middle.
#if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
#pragma warning(pop)
#endif

// Undefine all local macros (makes sure we're not leaking macros in header-only
// mode)
#undef PUGI__NO_INLINE
#undef PUGI__UNLIKELY
#undef PUGI__STATIC_ASSERT
#undef PUGI__DMC_VOLATILE
#undef PUGI__MSVC_CRT_VERSION
#undef PUGI__NS_BEGIN
#undef PUGI__NS_END
#undef PUGI__FN
#undef PUGI__FN_NO_INLINE
#undef PUGI__GETHEADER_IMPL
#undef PUGI__GETPAGE_IMPL
#undef PUGI__GETPAGE
#undef PUGI__NODETYPE
#undef PUGI__IS_CHARTYPE_IMPL
#undef PUGI__IS_CHARTYPE
#undef PUGI__IS_CHARTYPEX
#undef PUGI__ENDSWITH
#undef PUGI__SKIPWS
#undef PUGI__OPTSET
#undef PUGI__PUSHNODE
#undef PUGI__POPNODE
#undef PUGI__SCANFOR
#undef PUGI__SCANWHILE
#undef PUGI__SCANWHILE_UNROLL
#undef PUGI__ENDSEG
#undef PUGI__THROW_ERROR
#undef PUGI__CHECK_ERROR

#endif

/**
 * Copyright (c) 2006-2016 Arseny Kapoulkine
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
