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/********************************************************************
* *
* 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: packing variable sized words into an octet stream
last mod: $Id$
********************************************************************/
/* We're 'LSb' endian; if we write a word but read individual bits,
then we'll read the lsb first */
#include <string.h>
#include <stdlib.h>
#include "ogg.h"
#define BUFFER_INCREMENT 256
static const unsigned long 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 const unsigned int 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=_ogg_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,long bits){
long 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,long bits){
long 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,unsigned long value,int bits){
if(b->endbyte+4>=b->storage){
b->buffer=_ogg_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]=(unsigned char)(value>>(8-b->endbit));
if(bits>=16){
b->ptr[2]=(unsigned char)(value>>(16-b->endbit));
if(bits>=24){
b->ptr[3]=(unsigned char)(value>>(24-b->endbit));
if(bits>=32){
if(b->endbit)
b->ptr[4]=(unsigned char)(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,unsigned long value,int bits){
if(b->endbyte+4>=b->storage){
b->buffer=_ogg_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]=(unsigned char)(value>>(16+b->endbit));
if(bits>=16){
b->ptr[2]=(unsigned char)(value>>(8+b->endbit));
if(bits>=24){
b->ptr[3]=(unsigned char)(value>>(b->endbit));
if(bits>=32){
if(b->endbit)
b->ptr[4]=(unsigned char)(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){
int bits=8-b->endbit;
if(bits<8)
oggpack_write(b,0,bits);
}
void oggpackB_writealign(oggpack_buffer *b){
int bits=8-b->endbit;
if(bits<8)
oggpackB_write(b,0,bits);
}
static void oggpack_writecopy_helper(oggpack_buffer *b,
void *source,
long bits,
void (*w)(oggpack_buffer *,
unsigned long,
int),
int msb){
unsigned char *ptr=(unsigned char *)source;
long bytes=bits/8;
bits-=bytes*8;
if(b->endbit){
int i;
/* unaligned copy. Do it the hard way. */
for(i=0;i<bytes;i++)
w(b,(unsigned long)(ptr[i]),8);
}else{
/* aligned block copy */
if(b->endbyte+bytes+1>=b->storage){
b->storage=b->endbyte+bytes+BUFFER_INCREMENT;
b->buffer=_ogg_realloc(b->buffer,b->storage);
b->ptr=b->buffer+b->endbyte;
}
memmove(b->ptr,source,bytes);
b->ptr+=bytes;
b->endbyte+=bytes;
*b->ptr=0;
}
if(bits){
if(msb)
w(b,(unsigned long)(ptr[bytes]>>(8-bits)),bits);
else
w(b,(unsigned long)(ptr[bytes]),bits);
}
}
void oggpack_writecopy(oggpack_buffer *b,void *source,long bits){
oggpack_writecopy_helper(b,source,bits,oggpack_write,0);
}
void oggpackB_writecopy(oggpack_buffer *b,void *source,long 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){
_ogg_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,int bytes){
memset(b,0,sizeof(*b));
b->buffer=b->ptr=buf;
b->storage=bytes;
}
void oggpackB_readinit(oggpack_buffer *b,unsigned char *buf,int bytes){
oggpack_readinit(b,buf,bytes);
}
/* Read in bits without advancing the bitptr; bits <= 32 */
long oggpack_look(oggpack_buffer *b,int bits){
unsigned long ret;
unsigned long 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 */
long oggpackB_look(oggpack_buffer *b,int bits){
unsigned long ret;
int 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&0xffffffff)>>(m>>1))>>((m+1)>>1);
}
long oggpack_look1(oggpack_buffer *b){
if(b->endbyte>=b->storage)return(-1);
return((b->ptr[0]>>b->endbit)&1);
}
long 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,int bits){
bits+=b->endbit;
b->ptr+=bits/8;
b->endbyte+=bits/8;
b->endbit=bits&7;
}
void oggpackB_adv(oggpack_buffer *b,int 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 */
long oggpack_read(oggpack_buffer *b,int bits){
long ret;
unsigned long m=mask[bits];
bits+=b->endbit;
if(b->endbyte+4>=b->storage){
/* not the main path */
ret=-1L;
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 */
long oggpackB_read(oggpack_buffer *b,int bits){
long ret;
long m=32-bits;
bits+=b->endbit;
if(b->endbyte+4>=b->storage){
/* not the main path */
ret=-1L;
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&0xffffffffUL)>>(m>>1))>>((m+1)>>1);
overflow:
b->ptr+=bits/8;
b->endbyte+=bits/8;
b->endbit=bits&7;
return(ret);
}
long oggpack_read1(oggpack_buffer *b){
long ret;
if(b->endbyte>=b->storage){
/* not the main path */
ret=-1L;
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);
}
long oggpackB_read1(oggpack_buffer *b){
long ret;
if(b->endbyte>=b->storage){
/* not the main path */
ret=-1L;
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);
}
long oggpack_bytes(oggpack_buffer *b){
return(b->endbyte+(b->endbit+7)/8);
}
long oggpack_bits(oggpack_buffer *b){
return(b->endbyte*8+b->endbit);
}
long oggpackB_bytes(oggpack_buffer *b){
return oggpack_bytes(b);
}
long 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
|