// Copyright (c) 2016, the SDSL Project Authors.  All rights reserved.
// Please see the AUTHORS file for details.  Use of this source code is governed
// by a BSD license that can be found in the LICENSE file.
/*!\file lcp_bitcompressed.hpp
 * \brief lcp_bitcompressed.hpp contains a  bitcompressed LCP array.
 * \author Simon Gog
 */
#ifndef INCLUDED_SDSL_LCP_BITCOMPRESSED
#define INCLUDED_SDSL_LCP_BITCOMPRESSED

#include <sdsl/int_vector.hpp>
#include <sdsl/iterators.hpp>
#include <sdsl/lcp.hpp>

namespace sdsl
{

template <uint8_t t_width = 0>
class lcp_bitcompressed
{
  public:
    typedef typename int_vector<t_width>::value_type value_type;
    typedef typename int_vector<t_width>::size_type size_type;
    typedef random_access_const_iterator<lcp_bitcompressed> const_iterator;
    typedef const_iterator iterator;
    typedef const value_type const_reference;
    typedef const_reference reference;
    typedef const_reference * pointer;
    typedef const pointer const_pointer;
    typedef ptrdiff_t difference_type;

    typedef lcp_plain_tag lcp_category;
    typedef lcp_tag index_category;

    enum
    {
        fast_access = 1,
        text_order = 0,
        sa_order = 1
    };

    template <class Cst>
    using type = lcp_bitcompressed;

  private:
    int_vector<t_width> m_lcp;

  public:
    //! Default Constructor
    lcp_bitcompressed() {}
    lcp_bitcompressed(const lcp_bitcompressed &) = default;
    lcp_bitcompressed(lcp_bitcompressed &&) = default;
    lcp_bitcompressed & operator=(const lcp_bitcompressed &) = default;
    lcp_bitcompressed & operator=(lcp_bitcompressed &&) = default;

    //! Constructor taking a cache_config
    lcp_bitcompressed(cache_config & config)
    {
        std::string lcp_file = cache_file_name(conf::KEY_LCP, config);
        int_vector_buffer<> lcp_buf(lcp_file);
        m_lcp = int_vector<t_width>(lcp_buf.size(), 0, lcp_buf.width());
        for (size_type i = 0; i < m_lcp.size(); ++i) { m_lcp[i] = lcp_buf[i]; }
    }

    //! Number of elements in the instance.
    size_type size() const { return m_lcp.size(); }

    //! Returns the largest size that lcp_bitcompressed can ever have.
    static size_type max_size() { return int_vector<t_width>::max_size(); }

    //! Returns if the data structure is empty.
    bool empty() const { return m_lcp.empty(); }

    //! Returns a const_iterator to the first element.
    const_iterator begin() const { return const_iterator(this, 0); }

    //! Returns a const_iterator to the element after the last element.
    const_iterator end() const { return const_iterator(this, size()); }

    //! Access operator
    /*!\param i Index of the value. \f$ i \in [0..size()-1]\f$.
     */
    value_type operator[](size_type i) const { return m_lcp[i]; }

    template <typename archive_t>
    void CEREAL_SAVE_FUNCTION_NAME(archive_t & ar) const
    {
        ar(CEREAL_NVP(m_lcp));
    }

    template <typename archive_t>
    void CEREAL_LOAD_FUNCTION_NAME(archive_t & ar)
    {
        ar(CEREAL_NVP(m_lcp));
    }

    //! Serialize to a stream.
    size_type serialize(std::ostream & out, structure_tree_node * v = nullptr, std::string name = "") const
    {
        structure_tree_node * child = structure_tree::add_child(v, name, util::class_name(*this));
        size_type written_bytes = 0;
        written_bytes += m_lcp.serialize(out, child, "lcp");
        structure_tree::add_size(child, written_bytes);
        return written_bytes;
    }

    //! Equality operator.
    bool operator==(lcp_bitcompressed const & other) const noexcept { return (m_lcp == other.m_lcp); }

    //! Inequality operator.
    bool operator!=(lcp_bitcompressed const & other) const noexcept { return !(*this == other); }

    //! Load from a stream.
    void load(std::istream & in) { m_lcp.load(in); }
};

} // end namespace sdsl
#endif
