

/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
 *                                                                  *
 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
 * by the Xiph.Org Foundation http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: code raw [Vorbis] packets into framed OggSquish stream and
           decode Ogg streams back into raw packets

 note: The CRC code is directly derived from public domain code by
 Ross Williams (ross@guest.adelaide.edu.au).  See docs/framing.html
 for details.

 ********************************************************************/


#include <gpac/internal/ogg.h>

#ifndef GPAC_DISABLE_OGG

#define BUFFER_INCREMENT 256

static u32 mask[]=
{	0x00000000,0x00000001,0x00000003,0x00000007,0x0000000f,
	0x0000001f,0x0000003f,0x0000007f,0x000000ff,0x000001ff,
	0x000003ff,0x000007ff,0x00000fff,0x00001fff,0x00003fff,
	0x00007fff,0x0000ffff,0x0001ffff,0x0003ffff,0x0007ffff,
	0x000fffff,0x001fffff,0x003fffff,0x007fffff,0x00ffffff,
	0x01ffffff,0x03ffffff,0x07ffffff,0x0fffffff,0x1fffffff,
	0x3fffffff,0x7fffffff,0xffffffff
};

static u32 mask8B[]=
{0x00,0x80,0xc0,0xe0,0xf0,0xf8,0xfc,0xfe,0xff};

void oggpack_writeinit(oggpack_buffer *b) {
	memset(b,0,sizeof(*b));
	b->ptr = b->buffer = (unsigned char *)gf_malloc(BUFFER_INCREMENT);
	b->buffer[0]='\0';
	b->storage=BUFFER_INCREMENT;
}

void oggpackB_writeinit(oggpack_buffer *b) {
	oggpack_writeinit(b);
}

void oggpack_writetrunc(oggpack_buffer *b,s32 bits) {
	s32 bytes=bits>>3;
	bits-=bytes*8;
	b->ptr=b->buffer+bytes;
	b->endbit=bits;
	b->endbyte=bytes;
	*b->ptr&=mask[bits];
}

void oggpackB_writetrunc(oggpack_buffer *b,s32 bits) {
	s32 bytes=bits>>3;
	bits-=bytes*8;
	b->ptr=b->buffer+bytes;
	b->endbit=bits;
	b->endbyte=bytes;
	*b->ptr&=mask8B[bits];
}

/* Takes only up to 32 bits. */
void oggpack_write(oggpack_buffer *b,u32 value,s32 bits) {
	if(b->endbyte+4>=b->storage) {
		b->buffer = (unsigned char *)gf_realloc(b->buffer,b->storage+BUFFER_INCREMENT);
		b->storage+=BUFFER_INCREMENT;
		b->ptr=b->buffer+b->endbyte;
	}

	value&=mask[bits];
	bits+=b->endbit;

	b->ptr[0]|=value<<b->endbit;

	if(bits>=8) {
		b->ptr[1]=value>>(8-b->endbit);
		if(bits>=16) {
			b->ptr[2]=value>>(16-b->endbit);
			if(bits>=24) {
				b->ptr[3]=value>>(24-b->endbit);
				if(bits>=32) {
					if(b->endbit)
						b->ptr[4]=value>>(32-b->endbit);
					else
						b->ptr[4]=0;
				}
			}
		}
	}

	b->endbyte+=bits/8;
	b->ptr+=bits/8;
	b->endbit=bits&7;
}

/* Takes only up to 32 bits. */
void oggpackB_write(oggpack_buffer *b,u32 value,s32 bits) {
	if(b->endbyte+4>=b->storage) {
		b->buffer = (unsigned char *)gf_realloc(b->buffer,b->storage+BUFFER_INCREMENT);
		b->storage+=BUFFER_INCREMENT;
		b->ptr=b->buffer+b->endbyte;
	}

	value=(value&mask[bits])<<(32-bits);
	bits+=b->endbit;

	b->ptr[0]|=value>>(24+b->endbit);

	if(bits>=8) {
		b->ptr[1]=value>>(16+b->endbit);
		if(bits>=16) {
			b->ptr[2]=value>>(8+b->endbit);
			if(bits>=24) {
				b->ptr[3]=value>>(b->endbit);
				if(bits>=32) {
					if(b->endbit)
						b->ptr[4]=value<<(8-b->endbit);
					else
						b->ptr[4]=0;
				}
			}
		}
	}

	b->endbyte+=bits/8;
	b->ptr+=bits/8;
	b->endbit=bits&7;
}

void oggpack_writealign(oggpack_buffer *b) {
	s32 bits=8-b->endbit;
	if(bits<8)
		oggpack_write(b,0,bits);
}

void oggpackB_writealign(oggpack_buffer *b) {
	s32 bits=8-b->endbit;
	if(bits<8)
		oggpackB_write(b,0,bits);
}

static void oggpack_writecopy_helper(oggpack_buffer *b,
                                     void *source,
                                     s32 bits,
                                     void (*w)(oggpack_buffer *,
                                             u32,
                                             s32),
                                     s32 msb) {
	unsigned char *ptr=(unsigned char *)source;

	s32 bytes=bits/8;
	bits-=bytes*8;

	if(b->endbit) {
		s32 i;
		/* unaligned copy.  Do it the hard way. */
		for(i=0; i<bytes; i++)
			w(b,(u32)(ptr[i]),8);
	} else {
		/* aligned block copy */
		if(b->endbyte+bytes+1>=b->storage) {
			b->storage=b->endbyte+bytes+BUFFER_INCREMENT;
			b->buffer = (unsigned char *)gf_realloc(b->buffer,b->storage);
			b->ptr=b->buffer+b->endbyte;
		}

		memmove(b->ptr,source,bytes);
		b->ptr+=bytes;
		b->buffer+=bytes;
		*b->ptr=0;

	}
	if(bits) {
		if(msb)
			w(b,(u32)(ptr[bytes]>>(8-bits)),bits);
		else
			w(b,(u32)(ptr[bytes]),bits);
	}
}

void oggpack_writecopy(oggpack_buffer *b,void *source,s32 bits) {
	oggpack_writecopy_helper(b,source,bits,oggpack_write,0);
}

void oggpackB_writecopy(oggpack_buffer *b,void *source,s32 bits) {
	oggpack_writecopy_helper(b,source,bits,oggpackB_write,1);
}

void oggpack_reset(oggpack_buffer *b) {
	b->ptr=b->buffer;
	b->buffer[0]=0;
	b->endbit=b->endbyte=0;
}

void oggpackB_reset(oggpack_buffer *b) {
	oggpack_reset(b);
}

void oggpack_writeclear(oggpack_buffer *b) {
	gf_free(b->buffer);
	memset(b,0,sizeof(*b));
}

void oggpackB_writeclear(oggpack_buffer *b) {
	oggpack_writeclear(b);
}

void oggpack_readinit(oggpack_buffer *b,unsigned char *buf,s32 bytes) {
	memset(b,0,sizeof(*b));
	b->buffer=b->ptr=buf;
	b->storage=bytes;
}

void oggpackB_readinit(oggpack_buffer *b,unsigned char *buf,s32 bytes) {
	oggpack_readinit(b,buf,bytes);
}

/* Read in bits without advancing the bitptr; bits <= 32 */
s32 oggpack_look(oggpack_buffer *b,s32 bits) {
	u32 ret;
	u32 m=mask[bits];

	bits+=b->endbit;

	if(b->endbyte+4>=b->storage) {
		/* not the main path */
		if(b->endbyte*8+bits>b->storage*8)return(-1);
	}

	ret=b->ptr[0]>>b->endbit;
	if(bits>8) {
		ret|=b->ptr[1]<<(8-b->endbit);
		if(bits>16) {
			ret|=b->ptr[2]<<(16-b->endbit);
			if(bits>24) {
				ret|=b->ptr[3]<<(24-b->endbit);
				if(bits>32 && b->endbit)
					ret|=b->ptr[4]<<(32-b->endbit);
			}
		}
	}
	return(m&ret);
}

/* Read in bits without advancing the bitptr; bits <= 32 */
s32 oggpackB_look(oggpack_buffer *b,s32 bits) {
	u32 ret;
	s32 m=32-bits;

	bits+=b->endbit;

	if(b->endbyte+4>=b->storage) {
		/* not the main path */
		if(b->endbyte*8+bits>b->storage*8)return(-1);
	}

	ret=b->ptr[0]<<(24+b->endbit);
	if(bits>8) {
		ret|=b->ptr[1]<<(16+b->endbit);
		if(bits>16) {
			ret|=b->ptr[2]<<(8+b->endbit);
			if(bits>24) {
				ret|=b->ptr[3]<<(b->endbit);
				if(bits>32 && b->endbit)
					ret|=b->ptr[4]>>(8-b->endbit);
			}
		}
	}
	return (ret>>(m>>1))>>((m+1)>>1);
}

s32 oggpack_look1(oggpack_buffer *b) {
	if(b->endbyte>=b->storage)return(-1);
	return((b->ptr[0]>>b->endbit)&1);
}

s32 oggpackB_look1(oggpack_buffer *b) {
	if(b->endbyte>=b->storage)return(-1);
	return((b->ptr[0]>>(7-b->endbit))&1);
}

void oggpack_adv(oggpack_buffer *b,s32 bits) {
	bits+=b->endbit;
	b->ptr+=bits/8;
	b->endbyte+=bits/8;
	b->endbit=bits&7;
}

void oggpackB_adv(oggpack_buffer *b,s32 bits) {
	oggpack_adv(b,bits);
}

void oggpack_adv1(oggpack_buffer *b) {
	if(++(b->endbit)>7) {
		b->endbit=0;
		b->ptr++;
		b->endbyte++;
	}
}

void oggpackB_adv1(oggpack_buffer *b) {
	oggpack_adv1(b);
}

/* bits <= 32 */
s32 oggpack_read(oggpack_buffer *b,s32 bits) {
	u32 ret;
	u32 m=mask[bits];

	bits+=b->endbit;

	if(b->endbyte+4>=b->storage) {
		/* not the main path */
		ret=(u32) (-1);
		if(b->endbyte*8+bits>b->storage*8)goto overflow;
	}

	ret=b->ptr[0]>>b->endbit;
	if(bits>8) {
		ret|=b->ptr[1]<<(8-b->endbit);
		if(bits>16) {
			ret|=b->ptr[2]<<(16-b->endbit);
			if(bits>24) {
				ret|=b->ptr[3]<<(24-b->endbit);
				if(bits>32 && b->endbit) {
					ret|=b->ptr[4]<<(32-b->endbit);
				}
			}
		}
	}
	ret&=m;

overflow:

	b->ptr+=bits/8;
	b->endbyte+=bits/8;
	b->endbit=bits&7;
	return(ret);
}

/* bits <= 32 */
s32 oggpackB_read(oggpack_buffer *b,s32 bits) {
	u32 ret;
	s32 m=32-bits;

	bits+=b->endbit;

	if(b->endbyte+4>=b->storage) {
		/* not the main path */
		ret=(u32) (-1);
		if(b->endbyte*8+bits>b->storage*8)goto overflow;
	}

	ret=b->ptr[0]<<(24+b->endbit);
	if(bits>8) {
		ret|=b->ptr[1]<<(16+b->endbit);
		if(bits>16) {
			ret|=b->ptr[2]<<(8+b->endbit);
			if(bits>24) {
				ret|=b->ptr[3]<<(b->endbit);
				if(bits>32 && b->endbit)
					ret|=b->ptr[4]>>(8-b->endbit);
			}
		}
	}
	ret=(ret>>(m>>1))>>((m+1)>>1);

overflow:

	b->ptr+=bits/8;
	b->endbyte+=bits/8;
	b->endbit=bits&7;
	return(ret);
}

s32 oggpack_read1(oggpack_buffer *b) {
	u32 ret;

	if(b->endbyte>=b->storage) {
		/* not the main path */
		ret=(u32) (-1);
		goto overflow;
	}

	ret=(b->ptr[0]>>b->endbit)&1;

overflow:

	b->endbit++;
	if(b->endbit>7) {
		b->endbit=0;
		b->ptr++;
		b->endbyte++;
	}
	return(ret);
}

s32 oggpackB_read1(oggpack_buffer *b) {
	u32 ret;

	if(b->endbyte>=b->storage) {
		/* not the main path */
		ret=(u32) (-1);
		goto overflow;
	}

	ret=(b->ptr[0]>>(7-b->endbit))&1;

overflow:

	b->endbit++;
	if(b->endbit>7) {
		b->endbit=0;
		b->ptr++;
		b->endbyte++;
	}
	return(ret);
}

s32 oggpack_bytes(oggpack_buffer *b) {
	return(b->endbyte+(b->endbit+7)/8);
}

s32 oggpack_bits(oggpack_buffer *b) {
	return(b->endbyte*8+b->endbit);
}

s32 oggpackB_bytes(oggpack_buffer *b) {
	return oggpack_bytes(b);
}

s32 oggpackB_bits(oggpack_buffer *b) {
	return oggpack_bits(b);
}

unsigned char *oggpack_get_buffer(oggpack_buffer *b) {
	return(b->buffer);
}

unsigned char *oggpackB_get_buffer(oggpack_buffer *b) {
	return oggpack_get_buffer(b);
}


#undef BUFFER_INCREMENT

/* A complete description of Ogg framing exists in docs/framing.html */

s32 ogg_page_version(ogg_page *og) {
	return((s32)(og->header[4]));
}

s32 ogg_page_continued(ogg_page *og) {
	return((s32)(og->header[5]&0x01));
}

s32 ogg_page_bos(ogg_page *og) {
	return((s32)(og->header[5]&0x02));
}

s32 ogg_page_eos(ogg_page *og) {
	return((s32)(og->header[5]&0x04));
}

s64 ogg_page_granulepos(ogg_page *og) {
	unsigned char *page=og->header;
	s64 granulepos=page[13]&(0xff);
	granulepos= (granulepos<<8)|(page[12]&0xff);
	granulepos= (granulepos<<8)|(page[11]&0xff);
	granulepos= (granulepos<<8)|(page[10]&0xff);
	granulepos= (granulepos<<8)|(page[9]&0xff);
	granulepos= (granulepos<<8)|(page[8]&0xff);
	granulepos= (granulepos<<8)|(page[7]&0xff);
	granulepos= (granulepos<<8)|(page[6]&0xff);
	return(granulepos);
}

s32 ogg_page_serialno(ogg_page *og) {
	return(og->header[14] |
	       (og->header[15]<<8) |
	       (og->header[16]<<16) |
	       (og->header[17]<<24));
}

s32 ogg_page_pageno(ogg_page *og) {
	return(og->header[18] |
	       (og->header[19]<<8) |
	       (og->header[20]<<16) |
	       (og->header[21]<<24));
}



/* returns the number of packets that are completed on this page (if
   the leading packet is begun on a previous page, but ends on this
   page, it's counted */

/* NOTE:
If a page consists of a packet begun on a previous page, and a new
packet begun (but not completed) on this page, the return will be:
  ogg_page_packets(page)   ==1,
  ogg_page_continued(page) !=0

If a page happens to be a single packet that was begun on a
previous page, and spans to the next page (in the case of a three or
more page packet), the return will be:
  ogg_page_packets(page)   ==0,
  ogg_page_continued(page) !=0
*/

s32 ogg_page_packets(ogg_page *og) {
	s32 i,n=og->header[26],count=0;
	for(i=0; i<n; i++)
		if(og->header[27+i]<255)count++;
	return(count);
}


#if 0
/* helper to initialize lookup for direct-table CRC (illustrative; we
   use the static init below) */

static u32 _ogg_crc_entry(u32 index) {
	s32           i;
	u32 r;

	r = index << 24;
	for (i=0; i<8; i++)
		if (r & 0x80000000UL)
			r = (r << 1) ^ 0x04c11db7; /* The same as the ethernet generator
				    polynomial, although we use an
				    unreflected alg and an init/final
				    of 0, not 0xffffffff */
		else
			r<<=1;
	return (r & 0xffffffffUL);
}
#endif

static u32 crc_lookup[256]= {
	0x00000000,0x04c11db7,0x09823b6e,0x0d4326d9,
	0x130476dc,0x17c56b6b,0x1a864db2,0x1e475005,
	0x2608edb8,0x22c9f00f,0x2f8ad6d6,0x2b4bcb61,
	0x350c9b64,0x31cd86d3,0x3c8ea00a,0x384fbdbd,
	0x4c11db70,0x48d0c6c7,0x4593e01e,0x4152fda9,
	0x5f15adac,0x5bd4b01b,0x569796c2,0x52568b75,
	0x6a1936c8,0x6ed82b7f,0x639b0da6,0x675a1011,
	0x791d4014,0x7ddc5da3,0x709f7b7a,0x745e66cd,
	0x9823b6e0,0x9ce2ab57,0x91a18d8e,0x95609039,
	0x8b27c03c,0x8fe6dd8b,0x82a5fb52,0x8664e6e5,
	0xbe2b5b58,0xbaea46ef,0xb7a96036,0xb3687d81,
	0xad2f2d84,0xa9ee3033,0xa4ad16ea,0xa06c0b5d,
	0xd4326d90,0xd0f37027,0xddb056fe,0xd9714b49,
	0xc7361b4c,0xc3f706fb,0xceb42022,0xca753d95,
	0xf23a8028,0xf6fb9d9f,0xfbb8bb46,0xff79a6f1,
	0xe13ef6f4,0xe5ffeb43,0xe8bccd9a,0xec7dd02d,
	0x34867077,0x30476dc0,0x3d044b19,0x39c556ae,
	0x278206ab,0x23431b1c,0x2e003dc5,0x2ac12072,
	0x128e9dcf,0x164f8078,0x1b0ca6a1,0x1fcdbb16,
	0x018aeb13,0x054bf6a4,0x0808d07d,0x0cc9cdca,
	0x7897ab07,0x7c56b6b0,0x71159069,0x75d48dde,
	0x6b93dddb,0x6f52c06c,0x6211e6b5,0x66d0fb02,
	0x5e9f46bf,0x5a5e5b08,0x571d7dd1,0x53dc6066,
	0x4d9b3063,0x495a2dd4,0x44190b0d,0x40d816ba,
	0xaca5c697,0xa864db20,0xa527fdf9,0xa1e6e04e,
	0xbfa1b04b,0xbb60adfc,0xb6238b25,0xb2e29692,
	0x8aad2b2f,0x8e6c3698,0x832f1041,0x87ee0df6,
	0x99a95df3,0x9d684044,0x902b669d,0x94ea7b2a,
	0xe0b41de7,0xe4750050,0xe9362689,0xedf73b3e,
	0xf3b06b3b,0xf771768c,0xfa325055,0xfef34de2,
	0xc6bcf05f,0xc27dede8,0xcf3ecb31,0xcbffd686,
	0xd5b88683,0xd1799b34,0xdc3abded,0xd8fba05a,
	0x690ce0ee,0x6dcdfd59,0x608edb80,0x644fc637,
	0x7a089632,0x7ec98b85,0x738aad5c,0x774bb0eb,
	0x4f040d56,0x4bc510e1,0x46863638,0x42472b8f,
	0x5c007b8a,0x58c1663d,0x558240e4,0x51435d53,
	0x251d3b9e,0x21dc2629,0x2c9f00f0,0x285e1d47,
	0x36194d42,0x32d850f5,0x3f9b762c,0x3b5a6b9b,
	0x0315d626,0x07d4cb91,0x0a97ed48,0x0e56f0ff,
	0x1011a0fa,0x14d0bd4d,0x19939b94,0x1d528623,
	0xf12f560e,0xf5ee4bb9,0xf8ad6d60,0xfc6c70d7,
	0xe22b20d2,0xe6ea3d65,0xeba91bbc,0xef68060b,
	0xd727bbb6,0xd3e6a601,0xdea580d8,0xda649d6f,
	0xc423cd6a,0xc0e2d0dd,0xcda1f604,0xc960ebb3,
	0xbd3e8d7e,0xb9ff90c9,0xb4bcb610,0xb07daba7,
	0xae3afba2,0xaafbe615,0xa7b8c0cc,0xa379dd7b,
	0x9b3660c6,0x9ff77d71,0x92b45ba8,0x9675461f,
	0x8832161a,0x8cf30bad,0x81b02d74,0x857130c3,
	0x5d8a9099,0x594b8d2e,0x5408abf7,0x50c9b640,
	0x4e8ee645,0x4a4ffbf2,0x470cdd2b,0x43cdc09c,
	0x7b827d21,0x7f436096,0x7200464f,0x76c15bf8,
	0x68860bfd,0x6c47164a,0x61043093,0x65c52d24,
	0x119b4be9,0x155a565e,0x18197087,0x1cd86d30,
	0x029f3d35,0x065e2082,0x0b1d065b,0x0fdc1bec,
	0x3793a651,0x3352bbe6,0x3e119d3f,0x3ad08088,
	0x2497d08d,0x2056cd3a,0x2d15ebe3,0x29d4f654,
	0xc5a92679,0xc1683bce,0xcc2b1d17,0xc8ea00a0,
	0xd6ad50a5,0xd26c4d12,0xdf2f6bcb,0xdbee767c,
	0xe3a1cbc1,0xe760d676,0xea23f0af,0xeee2ed18,
	0xf0a5bd1d,0xf464a0aa,0xf9278673,0xfde69bc4,
	0x89b8fd09,0x8d79e0be,0x803ac667,0x84fbdbd0,
	0x9abc8bd5,0x9e7d9662,0x933eb0bb,0x97ffad0c,
	0xafb010b1,0xab710d06,0xa6322bdf,0xa2f33668,
	0xbcb4666d,0xb8757bda,0xb5365d03,0xb1f740b4
};

/* init the encode/decode logical stream state */

s32 ogg_stream_init(ogg_stream_state *os,s32 serialno) {
	if(os) {
		memset(os,0,sizeof(*os));
		os->body_storage=16*1024;
		os->body_data = (unsigned char *)gf_malloc(os->body_storage*sizeof(*os->body_data));

		os->lacing_storage=1024;
		os->lacing_vals=(s32 *)gf_malloc(os->lacing_storage*sizeof(*os->lacing_vals));
		os->granule_vals=(s64*)gf_malloc(os->lacing_storage*sizeof(*os->granule_vals));

		os->serialno=serialno;

		return(0);
	}
	return(-1);
}

/* _clear does not free os, only the non-flat storage within */
s32 ogg_stream_clear(ogg_stream_state *os) {
	if(os) {
		if(os->body_data)gf_free(os->body_data);
		if(os->lacing_vals)gf_free(os->lacing_vals);
		if(os->granule_vals)gf_free(os->granule_vals);

		memset(os,0,sizeof(*os));
	}
	return(0);
}

s32 ogg_stream_destroy(ogg_stream_state *os) {
	if(os) {
		ogg_stream_clear(os);
		gf_free(os);
	}
	return(0);
}

/* Helpers for ogg_stream_encode; this keeps the structure and
   what's happening fairly clear */

static void _os_body_expand(ogg_stream_state *os,s32 needed) {
	if(os->body_storage<=os->body_fill+needed) {
		os->body_storage+=(needed+1024);
		os->body_data = (unsigned char *)gf_realloc(os->body_data,os->body_storage*sizeof(*os->body_data));
	}
}

static void _os_lacing_expand(ogg_stream_state *os,s32 needed) {
	if(os->lacing_storage<=os->lacing_fill+needed) {
		os->lacing_storage+=(needed+32);
		os->lacing_vals=(s32*)gf_realloc(os->lacing_vals,os->lacing_storage*sizeof(*os->lacing_vals));
		os->granule_vals=(s64*)gf_realloc(os->granule_vals,os->lacing_storage*sizeof(*os->granule_vals));
	}
}

/* checksum the page */
/* Direct table CRC; note that this will be faster in the future if we
   perform the checksum silmultaneously with other copies */

void ogg_page_checksum_set(ogg_page *og) {
	if(og) {
		u32 crc_reg=0;
		s32 i;

		/* safety; needed for API behavior, but not framing code */
		og->header[22]=0;
		og->header[23]=0;
		og->header[24]=0;
		og->header[25]=0;

		for(i=0; i<og->header_len; i++)
			crc_reg=(crc_reg<<8)^crc_lookup[((crc_reg >> 24)&0xff)^og->header[i]];
		for(i=0; i<og->body_len; i++)
			crc_reg=(crc_reg<<8)^crc_lookup[((crc_reg >> 24)&0xff)^og->body[i]];

		og->header[22]=crc_reg&0xff;
		og->header[23]=(crc_reg>>8)&0xff;
		og->header[24]=(crc_reg>>16)&0xff;
		og->header[25]=(crc_reg>>24)&0xff;
	}
}

/* submit data to the internal buffer of the framing engine */
s32 ogg_stream_packetin(ogg_stream_state *os,ogg_packet *op) {
	s32 lacing_vals=op->bytes/255+1,i;

	if(os->body_returned) {
		/* advance packet data according to the body_returned pointer. We
		   had to keep it around to return a pointer into the buffer last
		   call */

		os->body_fill-=os->body_returned;
		if(os->body_fill)
			memmove(os->body_data,os->body_data+os->body_returned,
			        os->body_fill);
		os->body_returned=0;
	}

	/* make sure we have the buffer storage */
	_os_body_expand(os,op->bytes);
	_os_lacing_expand(os,lacing_vals);

	/* Copy in the submitted packet.  Yes, the copy is a waste; this is
	   the liability of overly clean abstraction for the time being.  It
	   will actually be fairly easy to eliminate the extra copy in the
	   future */

	memcpy(os->body_data+os->body_fill,op->packet,op->bytes);
	os->body_fill+=op->bytes;

	/* Store lacing vals for this packet */
	for(i=0; i<lacing_vals-1; i++) {
		os->lacing_vals[os->lacing_fill+i]=255;
		os->granule_vals[os->lacing_fill+i]=os->granulepos;
	}
	os->lacing_vals[os->lacing_fill+i]=(op->bytes)%255;
	os->granulepos=os->granule_vals[os->lacing_fill+i]=op->granulepos;

	/* flag the first segment as the beginning of the packet */
	os->lacing_vals[os->lacing_fill]|= 0x100;

	os->lacing_fill+=lacing_vals;

	/* for the sake of completeness */
	os->packetno++;

	if(op->e_o_s)os->e_o_s=1;

	return(0);
}

/* This will flush remaining packets into a page (returning nonzero),
   even if there is not enough data to trigger a flush normally
   (undersized page). If there are no packets or partial packets to
   flush, ogg_stream_flush returns 0.  Note that ogg_stream_flush will
   try to flush a normal sized page like ogg_stream_pageout; a call to
   ogg_stream_flush does not guarantee that all packets have flushed.
   Only a return value of 0 from ogg_stream_flush indicates all packet
   data is flushed into pages.

   since ogg_stream_flush will flush the last page in a stream even if
   it's undersized, you almost certainly want to use ogg_stream_pageout
   (and *not* ogg_stream_flush) unless you specifically need to flush
   an page regardless of size in the middle of a stream. */

s32 ogg_stream_flush(ogg_stream_state *os,ogg_page *og) {
	s32 i;
	s32 vals=0;
	s32 maxvals=(os->lacing_fill>255?255:os->lacing_fill);
	s32 bytes=0;
	s32 acc=0;
	s64 granule_pos=os->granule_vals[0];

	if(maxvals==0)return(0);

	/* construct a page */
	/* decide how many segments to include */

	/* If this is the initial header case, the first page must only include
	   the initial header packet */
	if(os->b_o_s==0) { /* 'initial header page' case */
		granule_pos=0;
		for(vals=0; vals<maxvals; vals++) {
			if((os->lacing_vals[vals]&0x0ff)<255) {
				vals++;
				break;
			}
		}
	} else {
		for(vals=0; vals<maxvals; vals++) {
			if(acc>4096)break;
			acc+=os->lacing_vals[vals]&0x0ff;
			granule_pos=os->granule_vals[vals];
		}
	}

	/* construct the header in temp storage */
	memcpy(os->header,"OggS",4);

	/* stream structure version */
	os->header[4]=0x00;

	/* continued packet flag? */
	os->header[5]=0x00;
	if((os->lacing_vals[0]&0x100)==0)os->header[5]|=0x01;
	/* first page flag? */
	if(os->b_o_s==0)os->header[5]|=0x02;
	/* last page flag? */
	if(os->e_o_s && os->lacing_fill==vals)os->header[5]|=0x04;
	os->b_o_s=1;

	/* 64 bits of PCM position */
	for(i=6; i<14; i++) {
		os->header[i]=(u8) (granule_pos&0xff);
		granule_pos>>=8;
	}

	/* 32 bits of stream serial number */
	{
		s32 serialno=os->serialno;
		for(i=14; i<18; i++) {
			os->header[i]=(serialno&0xff);
			serialno>>=8;
		}
	}

	/* 32 bits of page counter (we have both counter and page header
	   because this val can roll over) */
	if(os->pageno==-1)os->pageno=0; /* because someone called
				     stream_reset; this would be a
				     strange thing to do in an
				     encode stream, but it has
				     plausible uses */
	{
		s32 pageno=os->pageno++;
		for(i=18; i<22; i++) {
			os->header[i]=(pageno&0xff);
			pageno>>=8;
		}
	}

	/* zero for computation; filled in later */
	os->header[22]=0;
	os->header[23]=0;
	os->header[24]=0;
	os->header[25]=0;

	/* segment table */
	os->header[26]=vals&0xff;
	for(i=0; i<vals; i++)
		bytes+=os->header[i+27]=(os->lacing_vals[i]&0xff);

	/* set pointers in the ogg_page struct */
	og->header=os->header;
	og->header_len=os->header_fill=vals+27;
	og->body=os->body_data+os->body_returned;
	og->body_len=bytes;

	/* advance the lacing data and set the body_returned pointer */

	os->lacing_fill-=vals;
	memmove(os->lacing_vals,os->lacing_vals+vals,os->lacing_fill*sizeof(*os->lacing_vals));
	memmove(os->granule_vals,os->granule_vals+vals,os->lacing_fill*sizeof(*os->granule_vals));
	os->body_returned+=bytes;

	/* calculate the checksum */

	ogg_page_checksum_set(og);

	/* done */
	return(1);
}


/* This constructs pages from buffered packet segments.  The pointers
returned are to static buffers; do not free. The returned buffers are
good only until the next call (using the same ogg_stream_state) */

s32 ogg_stream_pageout(ogg_stream_state *os, ogg_page *og) {

	if((os->e_o_s&&os->lacing_fill) ||          /* 'were done, now flush' case */
	        os->body_fill-os->body_returned > 4096 ||/* 'page nominal size' case */
	        os->lacing_fill>=255 ||                  /* 'segment table full' case */
	        (os->lacing_fill&&!os->b_o_s)) {         /* 'initial header page' case */

		return(ogg_stream_flush(os,og));
	}

	/* not enough data to construct a page and not end of stream */
	return(0);
}

s32 ogg_stream_eos(ogg_stream_state *os) {
	return os->e_o_s;
}

/* DECODING PRIMITIVES: packet streaming layer **********************/

/* This has two layers to place more of the multi-serialno and paging
   control in the application's hands.  First, we expose a data buffer
   using ogg_sync_buffer().  The app either copies into the
   buffer, or passes it directly to read(), etc.  We then call
   ogg_sync_wrote() to tell how many bytes we just added.

   Pages are returned (pointers into the buffer in ogg_sync_state)
   by ogg_sync_pageout().  The page is then submitted to
   ogg_stream_pagein() along with the appropriate
   ogg_stream_state* (ie, matching serialno).  We then get raw
   packets out calling ogg_stream_packetout() with a
   ogg_stream_state.  See the 'frame-prog.txt' docs for details and
   example code. */

/* initialize the struct to a known state */
s32 ogg_sync_init(ogg_sync_state *oy) {
	if(oy) {
		memset(oy,0,sizeof(*oy));
	}
	return(0);
}

/* clear non-flat storage within */
s32 ogg_sync_clear(ogg_sync_state *oy) {
	if(oy) {
		if(oy->data)gf_free(oy->data);
		ogg_sync_init(oy);
	}
	return(0);
}

s32 ogg_sync_destroy(ogg_sync_state *oy) {
	if(oy) {
		ogg_sync_clear(oy);
		gf_free(oy);
	}
	return(0);
}

char *ogg_sync_buffer(ogg_sync_state *oy, s32 size) {

	/* first, clear out any space that has been previously returned */
	if(oy->returned) {
		oy->fill-=oy->returned;
		if(oy->fill>0)
			memmove(oy->data,oy->data+oy->returned,oy->fill);
		oy->returned=0;
	}

	if(size>oy->storage-oy->fill) {
		/* We need to extend the internal buffer */
		s32 newsize=size+oy->fill+4096; /* an extra page to be nice */

		if(oy->data)
			oy->data = (unsigned char *)gf_realloc(oy->data,newsize);
		else
			oy->data = (unsigned char *)gf_malloc(newsize);
		oy->storage=newsize;
	}

	/* expose a segment at least as large as requested at the fill mark */
	return((char *)oy->data+oy->fill);
}

s32 ogg_sync_wrote(ogg_sync_state *oy, s32 bytes) {
	if(oy->fill+bytes>oy->storage)return(-1);
	oy->fill+=bytes;
	return(0);
}

/* sync the stream.  This is meant to be useful for finding page
   boundaries.

   return values for this:
  -n) skipped n bytes
   0) page not ready; more data (no bytes skipped)
   n) page synced at current location; page length n bytes

*/

s32 ogg_sync_pageseek(ogg_sync_state *oy,ogg_page *og) {
	unsigned char *page=oy->data+oy->returned;
	unsigned char *next;
	s32 bytes=oy->fill-oy->returned;

	if(oy->headerbytes==0) {
		s32 headerbytes,i;
		if(bytes<27)return(0); /* not enough for a header */

		/* verify capture pattern */
		if(memcmp(page,"OggS",4))goto sync_fail;

		headerbytes=page[26]+27;
		if(bytes<headerbytes)return(0); /* not enough for header + seg table */

		/* count up body length in the segment table */

		for(i=0; i<page[26]; i++)
			oy->bodybytes+=page[27+i];
		oy->headerbytes=headerbytes;
	}

	if(oy->bodybytes+oy->headerbytes>bytes)return(0);

	/* The whole test page is buffered.  Verify the checksum */
	{
		/* Grab the checksum bytes, set the header field to zero */
		char chksum[4];
		ogg_page log;

		memcpy(chksum,page+22,4);
		memset(page+22,0,4);

		/* set up a temp page struct and recompute the checksum */
		log.header=page;
		log.header_len=oy->headerbytes;
		log.body=page+oy->headerbytes;
		log.body_len=oy->bodybytes;
		ogg_page_checksum_set(&log);

		/* Compare */
		if(memcmp(chksum,page+22,4)) {
			/* D'oh.  Mismatch! Corrupt page (or miscapture and not a page
			at all) */
			/* replace the computed checksum with the one actually read in */
			memcpy(page+22,chksum,4);

			/* Bad checksum. Lose sync */
			goto sync_fail;
		}
	}

	/* yes, have a whole page all ready to go */
	{
		unsigned char *page=oy->data+oy->returned;
		s32 bytes;

		if(og) {
			og->header=page;
			og->header_len=oy->headerbytes;
			og->body=page+oy->headerbytes;
			og->body_len=oy->bodybytes;
		}

		oy->unsynced=0;
		oy->returned+=(bytes=oy->headerbytes+oy->bodybytes);
		oy->headerbytes=0;
		oy->bodybytes=0;
		return(bytes);
	}

sync_fail:

	oy->headerbytes=0;
	oy->bodybytes=0;

	/* search for possible capture */
	next = (unsigned char *)memchr(page+1,'O',bytes-1);
	if(!next)
		next=oy->data+oy->fill;

	oy->returned = (s32) (next-oy->data);
	return (s32) (-(next-page));
}

/* sync the stream and get a page.  Keep trying until we find a page.
   Supress 'sync errors' after reporting the first.

   return values:
   -1) recapture (hole in data)
    0) need more data
    1) page returned

   Returns pointers into buffered data; invalidated by next call to
   _stream, _clear, _init, or _buffer */

s32 ogg_sync_pageout(ogg_sync_state *oy, ogg_page *og) {

	/* all we need to do is verify a page at the head of the stream
	   buffer.  If it doesn't verify, we look for the next potential
	   frame */

	while(1) {
		s32 ret=ogg_sync_pageseek(oy,og);
		if(ret>0) {
			/* have a page */
			return(1);
		}
		if(ret==0) {
			/* need more data */
			return(0);
		}

		/* head did not start a synced page... skipped some bytes */
		if(!oy->unsynced) {
			oy->unsynced=1;
			return(-1);
		}

		/* loop. keep looking */

	}
}

/* add the incoming page to the stream state; we decompose the page
   into packet segments here as well. */

s32 ogg_stream_pagein(ogg_stream_state *os, ogg_page *og) {
	unsigned char *header=og->header;
	unsigned char *body=og->body;
	s32           bodysize=og->body_len;
	s32            segptr=0;

	s32 version=ogg_page_version(og);
	s32 continued=ogg_page_continued(og);
	s32 bos=ogg_page_bos(og);
	s32 eos=ogg_page_eos(og);
	s64 granulepos=ogg_page_granulepos(og);
	s32 serialno=ogg_page_serialno(og);
	s32 pageno=ogg_page_pageno(og);
	s32 segments=header[26];

	/* clean up 'returned data' */
	{
		s32 lr=os->lacing_returned;
		s32 br=os->body_returned;

		/* body data */
		if(br) {
			os->body_fill-=br;
			if(os->body_fill)
				memmove(os->body_data,os->body_data+br,os->body_fill);
			os->body_returned=0;
		}

		if(lr) {
			/* segment table */
			if(os->lacing_fill-lr) {
				memmove(os->lacing_vals,os->lacing_vals+lr,
				        (os->lacing_fill-lr)*sizeof(*os->lacing_vals));
				memmove(os->granule_vals,os->granule_vals+lr,
				        (os->lacing_fill-lr)*sizeof(*os->granule_vals));
			}
			os->lacing_fill-=lr;
			os->lacing_packet-=lr;
			os->lacing_returned=0;
		}
	}

	/* check the serial number */
	if(serialno!=os->serialno)return(-1);
	if(version>0)return(-1);

	_os_lacing_expand(os,segments+1);

	/* are we in sequence? */
	if(pageno!=os->pageno) {
		s32 i;

		/* unroll previous partial packet (if any) */
		for(i=os->lacing_packet; i<os->lacing_fill; i++)
			os->body_fill-=os->lacing_vals[i]&0xff;
		os->lacing_fill=os->lacing_packet;

		/* make a note of dropped data in segment table */
		if(os->pageno!=-1) {
			os->lacing_vals[os->lacing_fill++]=0x400;
			os->lacing_packet++;
		}

		/* are we a 'continued packet' page?  If so, we'll need to skip
		   some segments */
		if(continued) {
			bos=0;
			for(; segptr<segments; segptr++) {
				s32 val=header[27+segptr];
				body+=val;
				bodysize-=val;
				if(val<255) {
					segptr++;
					break;
				}
			}
		}
	}

	if(bodysize) {
		_os_body_expand(os,bodysize);
		memcpy(os->body_data+os->body_fill,body,bodysize);
		os->body_fill+=bodysize;
	}

	{
		s32 saved=-1;
		while(segptr<segments) {
			s32 val=header[27+segptr];
			os->lacing_vals[os->lacing_fill]=val;
			os->granule_vals[os->lacing_fill]=-1;

			if(bos) {
				os->lacing_vals[os->lacing_fill]|=0x100;
				bos=0;
			}

			if(val<255)saved=os->lacing_fill;

			os->lacing_fill++;
			segptr++;

			if(val<255)os->lacing_packet=os->lacing_fill;
		}

		/* set the granulepos on the last granuleval of the last full packet */
		if(saved!=-1) {
			os->granule_vals[saved]=granulepos;
		}

	}

	if(eos) {
		os->e_o_s=1;
		if(os->lacing_fill>0)
			os->lacing_vals[os->lacing_fill-1]|=0x200;
	}

	os->pageno=pageno+1;

	return(0);
}

/* clear things to an initial state.  Good to call, eg, before seeking */
s32 ogg_sync_reset(ogg_sync_state *oy) {
	oy->fill=0;
	oy->returned=0;
	oy->unsynced=0;
	oy->headerbytes=0;
	oy->bodybytes=0;
	return(0);
}

s32 ogg_stream_reset(ogg_stream_state *os) {
	os->body_fill=0;
	os->body_returned=0;

	os->lacing_fill=0;
	os->lacing_packet=0;
	os->lacing_returned=0;

	os->header_fill=0;

	os->e_o_s=0;
	os->b_o_s=0;
	os->pageno=-1;
	os->packetno=0;
	os->granulepos=0;

	return(0);
}

s32 ogg_stream_reset_serialno(ogg_stream_state *os,s32 serialno) {
	ogg_stream_reset(os);
	os->serialno=serialno;
	return(0);
}

static s32 _packetout(ogg_stream_state *os,ogg_packet *op,s32 adv) {

	/* The last part of decode. We have the stream broken into packet
	   segments.  Now we need to group them into packets (or return the
	   out of sync markers) */

	s32 ptr=os->lacing_returned;

	if(os->lacing_packet<=ptr)return(0);

	if(os->lacing_vals[ptr]&0x400) {
		/* we need to tell the codec there's a gap; it might need to
		   handle previous packet dependencies. */
		os->lacing_returned++;
		os->packetno++;
		return(-1);
	}

	if(!op && !adv)return(1); /* just using peek as an inexpensive way
                               to ask if there's a whole packet
                               waiting */

	/* Gather the whole packet. We'll have no holes or a partial packet */
	{
		s32 size=os->lacing_vals[ptr]&0xff;
		s32 bytes=size;
		s32 eos=os->lacing_vals[ptr]&0x200; /* last packet of the stream? */
		s32 bos=os->lacing_vals[ptr]&0x100; /* first packet of the stream? */

		while(size==255) {
			s32 val=os->lacing_vals[++ptr];
			size=val&0xff;
			if(val&0x200)eos=0x200;
			bytes+=size;
		}

		if(op) {
			op->e_o_s=eos;
			op->b_o_s=bos;
			op->packet=os->body_data+os->body_returned;
			op->packetno=os->packetno;
			op->granulepos=os->granule_vals[ptr];
			op->bytes=bytes;
		}

		if(adv) {
			os->body_returned+=bytes;
			os->lacing_returned=ptr+1;
			os->packetno++;
		}
	}
	return(1);
}

s32 ogg_stream_packetout(ogg_stream_state *os,ogg_packet *op) {
	return _packetout(os,op,1);
}

s32 ogg_stream_packetpeek(ogg_stream_state *os,ogg_packet *op) {
	return _packetout(os,op,0);
}

void ogg_packet_clear(ogg_packet *op) {
	gf_free(op->packet);
	memset(op, 0, sizeof(*op));
}

#endif /*GPAC_DISABLE_OGG*/
