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#include "mpg123.h"
#include "common.h"
void backbits(struct bitstream_info *bitbuf,int number_of_bits)
{
bitbuf->bitindex -= number_of_bits;
bitbuf->wordpointer += (bitbuf->bitindex>>3);
bitbuf->bitindex &= 0x7;
}
int getbitoffset(struct bitstream_info *bitbuf)
{
return (-bitbuf->bitindex)&0x7;
}
int getbyte(struct bitstream_info *bitbuf)
{
#ifdef DEBUG_GETBITS
if(bitbuf->bitindex)
fprintf(stderr,"getbyte called unsynched!\n");
#endif
return *bitbuf->wordpointer++;
}
unsigned int getbits(struct bitstream_info *bitbuf,int number_of_bits)
{
unsigned long rval;
#ifdef DEBUG_GETBITS
fprintf(stderr,"g%d",number_of_bits);
#endif
if(!number_of_bits)
return 0;
#if 0
check_buffer_range(number_of_bits+bitbuf->bitindex);
#endif
{
rval = bitbuf->wordpointer[0];
rval <<= 8;
rval |= bitbuf->wordpointer[1];
rval <<= 8;
rval |= bitbuf->wordpointer[2];
rval <<= bitbuf->bitindex;
rval &= 0xffffff;
bitbuf->bitindex += number_of_bits;
rval >>= (24-number_of_bits);
bitbuf->wordpointer += (bitbuf->bitindex>>3);
bitbuf->bitindex &= 7;
}
#ifdef DEBUG_GETBITS
fprintf(stderr,":%x ",rval);
#endif
return rval;
}
unsigned int getbits_fast(struct bitstream_info *bitbuf,int number_of_bits)
{
unsigned int rval;
#ifdef DEBUG_GETBITS
fprintf(stderr,"g%d",number_of_bits);
#endif
#if 0
check_buffer_range(number_of_bits+bitbuf->bitindex);
#endif
rval = (unsigned char) (bitbuf->wordpointer[0] << bitbuf->bitindex);
rval |= ((unsigned int) bitbuf->wordpointer[1]<<bitbuf->bitindex)>>8;
rval <<= number_of_bits;
rval >>= 8;
bitbuf->bitindex += number_of_bits;
bitbuf->wordpointer += (bitbuf->bitindex>>3);
bitbuf->bitindex &= 7;
#ifdef DEBUG_GETBITS
fprintf(stderr,":%x ",rval);
#endif
return rval;
}
unsigned int get1bit(struct bitstream_info *bitbuf)
{
unsigned char rval;
#ifdef DEBUG_GETBITS
fprintf(stderr,"g%d",1);
#endif
#if 0
check_buffer_range(1+bitbuf->bitindex);
#endif
rval = *(bitbuf->wordpointer) << bitbuf->bitindex;
bitbuf->bitindex++;
bitbuf->wordpointer += (bitbuf->bitindex>>3);
bitbuf->bitindex &= 7;
#ifdef DEBUG_GETBITS
fprintf(stderr,":%d ",rval>>7);
#endif
return rval>>7;
}
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