| 0,0 → 1,134 |
|---|
| /* |
| getbits |
| |
| copyright ?-2006 by the mpg123 project - free software under the terms of the LGPL 2.1 |
| see COPYING and AUTHORS files in distribution or http://mpg123.de |
| initially written by Michael Hipp |
| */ |
| |
| #include "mpg123.h" |
| |
| #if 0 |
| static void check_buffer_range(int size) |
| { |
| int pos = (bsi.wordpointer-bsbuf) + (size>>3); |
| |
| if( pos >= fsizeold) { |
| fprintf(stderr,"Pointer out of range (%d,%d)!\n",pos,fsizeold); |
| } |
| } |
| #endif |
| |
| void backbits(int number_of_bits) |
| { |
| bsi.bitindex -= number_of_bits; |
| bsi.wordpointer += (bsi.bitindex>>3); |
| bsi.bitindex &= 0x7; |
| } |
| |
| int getbitoffset(void) |
| { |
| return (-bsi.bitindex)&0x7; |
| } |
| |
| int getbyte(void) |
| { |
| #ifdef DEBUG_GETBITS |
| if(bsi.bitindex) |
| fprintf(stderr,"getbyte called unsynched!\n"); |
| #endif |
| return *bsi.wordpointer++; |
| } |
| |
| unsigned int getbits(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+bsi.bitindex); |
| #endif |
| |
| { |
| rval = bsi.wordpointer[0]; |
| rval <<= 8; |
| rval |= bsi.wordpointer[1]; |
| rval <<= 8; |
| rval |= bsi.wordpointer[2]; |
| |
| rval <<= bsi.bitindex; |
| rval &= 0xffffff; |
| |
| bsi.bitindex += number_of_bits; |
| |
| rval >>= (24-number_of_bits); |
| |
| bsi.wordpointer += (bsi.bitindex>>3); |
| bsi.bitindex &= 7; |
| } |
| |
| #ifdef DEBUG_GETBITS |
| fprintf(stderr,":%x ",rval); |
| #endif |
| |
| return rval; |
| } |
| |
| unsigned int getbits_fast(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+bsi.bitindex); |
| #endif |
| |
| rval = (unsigned char) (bsi.wordpointer[0] << bsi.bitindex); |
| rval |= ((unsigned int) bsi.wordpointer[1]<<bsi.bitindex)>>8; |
| rval <<= number_of_bits; |
| rval >>= 8; |
| |
| bsi.bitindex += number_of_bits; |
| |
| bsi.wordpointer += (bsi.bitindex>>3); |
| bsi.bitindex &= 7; |
| |
| #ifdef DEBUG_GETBITS |
| fprintf(stderr,":%x ",rval); |
| #endif |
| return rval; |
| } |
| |
| unsigned int get1bit(void) |
| { |
| unsigned char rval; |
| |
| #ifdef DEBUG_GETBITS |
| fprintf(stderr,"g%d",1); |
| #endif |
| |
| #if 0 |
| check_buffer_range(1+bsi.bitindex); |
| #endif |
| |
| rval = *bsi.wordpointer << bsi.bitindex; |
| |
| bsi.bitindex++; |
| bsi.wordpointer += (bsi.bitindex>>3); |
| bsi.bitindex &= 7; |
| |
| #ifdef DEBUG_GETBITS |
| fprintf(stderr,":%d ",rval>>7); |
| #endif |
| |
| return rval>>7; |
| } |
| |