/* 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; }