ref: 323eccb93a870117de76b97aace1958f61e36139
dir: /libfaad/bits.c/
/* ** 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.c,v 1.21 2003/02/24 15:02:25 menno Exp $ **/ #include "common.h" #include "structs.h" #include <stdlib.h> #include <string.h> #include "bits.h" /* initialize buffer, call once before first getbits or showbits */ void faad_initbits(bitfile *ld, void *_buffer, uint32_t buffer_size) { uint32_t tmp; ld->buffer = malloc((buffer_size+12)*sizeof(uint8_t)); memset(ld->buffer, 0, (buffer_size+12)*sizeof(uint8_t)); memcpy(ld->buffer, _buffer, buffer_size*sizeof(uint8_t)); ld->buffer_size = buffer_size; tmp = getdword((uint32_t*)ld->buffer); #ifndef ARCH_IS_BIG_ENDIAN BSWAP(tmp); #endif ld->bufa = tmp; tmp = getdword((uint32_t*)ld->buffer + 1); #ifndef ARCH_IS_BIG_ENDIAN BSWAP(tmp); #endif ld->bufb = tmp; ld->start = (uint32_t*)ld->buffer; ld->tail = ((uint32_t*)ld->buffer + 2); ld->bits_left = 32; ld->bytes_used = 0; ld->no_more_reading = 0; ld->error = 0; } void faad_endbits(bitfile *ld) { if (ld) if (ld->buffer) free(ld->buffer); } uint32_t faad_get_processed_bits(bitfile *ld) { return 8 * (4*(ld->tail - ld->start) - 4) - (ld->bits_left); } uint8_t faad_byte_align(bitfile *ld) { uint8_t remainder = (uint8_t)((32 - ld->bits_left) % 8); if (remainder) { faad_flushbits(ld, 8 - remainder); return (8 - remainder); } return 0; } /* rewind to beginning */ void faad_rewindbits(bitfile *ld) { uint32_t tmp; tmp = ld->start[0]; #ifndef ARCH_IS_BIG_ENDIAN BSWAP(tmp); #endif ld->bufa = tmp; tmp = ld->start[1]; #ifndef ARCH_IS_BIG_ENDIAN BSWAP(tmp); #endif ld->bufb = tmp; ld->bits_left = 32; ld->tail = &ld->start[2]; ld->bytes_used = 0; ld->no_more_reading = 0; } uint8_t *faad_getbitbuffer(bitfile *ld, uint32_t bits DEBUGDEC) { uint16_t i; uint8_t temp; uint16_t bytes = (uint16_t)bits / 8; uint8_t remainder = (uint8_t)bits % 8; uint8_t *buffer = (uint8_t*)malloc((bytes+1)*sizeof(uint8_t)); for (i = 0; i < bytes; i++) { buffer[i] = (uint8_t)faad_getbits(ld, 8 DEBUGVAR(print,var,dbg)); } if (remainder) { temp = (uint8_t)faad_getbits(ld, remainder DEBUGVAR(print,var,dbg)) << (8-remainder); buffer[bytes] = temp; } return buffer; } /* reversed bit reading routines, used for RVLC and HCR */ void faad_initbits_rev(bitfile *ld, void *buffer, uint32_t bits_in_buffer) { uint32_t tmp; int32_t index; ld->buffer_size = bit2byte(bits_in_buffer); index = (bits_in_buffer+31)/32 - 1; ld->start = (uint32_t*)buffer + index - 2; tmp = getdword((uint32_t*)buffer + index); #ifndef ARCH_IS_BIG_ENDIAN BSWAP(tmp); #endif ld->bufa = tmp; tmp = getdword((uint32_t*)buffer + index - 1); #ifndef ARCH_IS_BIG_ENDIAN BSWAP(tmp); #endif ld->bufb = tmp; ld->tail = (uint32_t*)buffer + index; ld->bits_left = bits_in_buffer % 32; if (ld->bits_left == 0) ld->bits_left = 32; ld->bytes_used = 0; ld->no_more_reading = 0; ld->error = 0; }