ref: 802ecda1ad2bac9c50a4e9e0398ca8255d0d329f
dir: /libfaad/bits.h/
/* ** FAAD - Freeware Advanced Audio Decoder ** Copyright (C) 2002 M. Bakker ** ** This program is free software; you can redistribute it and/or modify ** it under the terms of the GNU General Public License as published by ** the Free Software Foundation; either version 2 of the License, or ** (at your option) any later version. ** ** This program is distributed in the hope that it will be useful, ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ** GNU General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program; if not, write to the Free Software ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ** ** $Id: bits.h,v 1.7 2002/08/07 08:14:31 menno Exp $ **/ #ifndef __BITS_H__ #define __BITS_H__ #ifdef __cplusplus extern "C" { #endif #include "analysis.h" #ifdef ANALYSIS #include <stdio.h> #endif #define BYTE_NUMBIT 8 #define bit2byte(a) ((a+7)/BYTE_NUMBIT) typedef struct _bitfile { /* bit input */ uint32_t bufa; uint32_t bufb; uint32_t pos; uint32_t *tail; uint32_t *start; } bitfile; #if defined(_WIN32) #define BSWAP(a) __asm mov eax,a __asm bswap eax __asm mov a, eax #elif defined(LINUX) || defined(DJGPP) #define BSWAP(a) __asm__ ( "bswapl %0\n" : "=r" (a) : "0" (a) ) #else #define BSWAP(a) \ ((a) = ( ((a)&0xff)<<24) | (((a)&0xff00)<<8) | (((a)>>8)&0xff00) | (((a)>>24)&0xff)) #endif void faad_initbits(bitfile *ld, void *buffer); uint8_t faad_byte_align(bitfile *ld); uint32_t faad_get_processed_bits(bitfile *ld); uint8_t *faad_getbitbuffer(bitfile *ld, uint16_t bits DEBUGDEC); static INLINE uint32_t faad_showbits(bitfile *ld, uint8_t bits) { int32_t nbit = (bits + ld->pos) - 32; if (nbit > 0) { return ((ld->bufa & (0xffffffff >> ld->pos)) << nbit) | (ld->bufb >> (32 - nbit)); } else { return (ld->bufa & (0xffffffff >> ld->pos)) >> (32 - ld->pos - bits); } } static INLINE void faad_flushbits(bitfile *ld, uint8_t bits) { ld->pos += bits; if (ld->pos >= 32) { uint32_t tmp; ld->bufa = ld->bufb; tmp = *(uint32_t*)ld->tail; #ifndef ARCH_IS_BIG_ENDIAN BSWAP(tmp); #endif ld->bufb = tmp; ld->tail++; ld->pos -= 32; } } /* return next n bits (right adjusted) */ static INLINE uint32_t faad_getbits(bitfile *ld, uint8_t n DEBUGDEC) { uint32_t ret; if (n == 0) return 0; ret = faad_showbits(ld, n); faad_flushbits(ld, n); #ifdef ANALYSIS if (print) fprintf(stdout, "%4d %2d bits, val: %4d, variable: %d %s\n", dbg_count++, n, ret, var, dbg); #endif return ret; } static INLINE uint8_t faad_get1bit(bitfile *ld DEBUGDEC) { return (uint8_t)faad_getbits(ld, 1 DEBUGVAR(print,var,dbg)); } #ifdef __cplusplus } #endif #endif