ref: 3ba088193fc0e9b022957fb348cfdfe1d60daab7
dir: /libfaad/bits.c/
/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
**
** 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.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** The "appropriate copyright message" mentioned in section 2c of the GPLv2
** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
**
** $Id: bits.c,v 1.44 2007/11/01 12:33:29 menno Exp $
**/
#include "common.h"
#include "structs.h"
#include "bits.h"
/* initialize buffer, call once before first getbits or showbits */
void faad_initbits(bitfile *ld, const void *_buffer, const uint32_t buffer_size)
{
uint32_t tmp;
if (ld == NULL)
return;
// useless
//memset(ld, 0, sizeof(bitfile));
if (buffer_size == 0 || _buffer == NULL)
{
ld->error = 1;
return;
}
ld->buffer = _buffer;
ld->buffer_size = buffer_size;
ld->bytes_left = buffer_size;
if (ld->bytes_left >= 4)
{
tmp = getdword((uint32_t*)ld->buffer);
ld->bytes_left -= 4;
} else {
tmp = getdword_n((uint32_t*)ld->buffer, ld->bytes_left);
ld->bytes_left = 0;
}
ld->bufa = tmp;
if (ld->bytes_left >= 4)
{
tmp = getdword((uint32_t*)ld->buffer + 1);
ld->bytes_left -= 4;
} else {
tmp = getdword_n((uint32_t*)ld->buffer + 1, ld->bytes_left);
ld->bytes_left = 0;
}
ld->bufb = tmp;
ld->start = (uint32_t*)ld->buffer;
ld->tail = ((uint32_t*)ld->buffer + 2);
ld->bits_left = 32;
ld->error = 0;
}
void faad_endbits(bitfile *ld)
{
// void
}
uint32_t faad_get_processed_bits(bitfile *ld)
{
return (uint32_t)(8 * (4*(ld->tail - ld->start) - 4) - (ld->bits_left));
}
uint8_t faad_byte_align(bitfile *ld)
{
int remainder = (32 - ld->bits_left) & 0x7;
if (remainder)
{
faad_flushbits(ld, 8 - remainder);
return (uint8_t)(8 - remainder);
}
return 0;
}
void faad_flushbits_ex(bitfile *ld, uint32_t bits)
{
uint32_t tmp;
ld->bufa = ld->bufb;
if (ld->bytes_left >= 4)
{
tmp = getdword(ld->tail);
ld->bytes_left -= 4;
} else {
tmp = getdword_n(ld->tail, ld->bytes_left);
ld->bytes_left = 0;
}
ld->bufb = tmp;
ld->tail++;
ld->bits_left += (32 - bits);
//ld->bytes_left -= 4;
// if (ld->bytes_left == 0)
// ld->no_more_reading = 1;
// if (ld->bytes_left < 0)
// ld->error = 1;
}
/* rewind to beginning */
void faad_rewindbits(bitfile *ld)
{
uint32_t tmp;
ld->bytes_left = ld->buffer_size;
if (ld->bytes_left >= 4)
{
tmp = getdword((uint32_t*)&ld->start[0]);
ld->bytes_left -= 4;
} else {
tmp = getdword_n((uint32_t*)&ld->start[0], ld->bytes_left);
ld->bytes_left = 0;
}
ld->bufa = tmp;
if (ld->bytes_left >= 4)
{
tmp = getdword((uint32_t*)&ld->start[1]);
ld->bytes_left -= 4;
} else {
tmp = getdword_n((uint32_t*)&ld->start[1], ld->bytes_left);
ld->bytes_left = 0;
}
ld->bufb = tmp;
ld->bits_left = 32;
ld->tail = &ld->start[2];
}
/* reset to a certain point */
void faad_resetbits(bitfile *ld, int bits)
{
uint32_t tmp;
int words = bits >> 5;
int remainder = bits & 0x1F;
if (ld->buffer_size < words * 4)
ld->bytes_left = 0;
else
ld->bytes_left = ld->buffer_size - words*4;
if (ld->bytes_left >= 4)
{
tmp = getdword(&ld->start[words]);
ld->bytes_left -= 4;
} else {
tmp = getdword_n(&ld->start[words], ld->bytes_left);
ld->bytes_left = 0;
}
ld->bufa = tmp;
if (ld->bytes_left >= 4)
{
tmp = getdword(&ld->start[words+1]);
ld->bytes_left -= 4;
} else {
tmp = getdword_n(&ld->start[words+1], ld->bytes_left);
ld->bytes_left = 0;
}
ld->bufb = tmp;
ld->bits_left = 32 - remainder;
ld->tail = &ld->start[words+2];
/* recheck for reading too many bytes */
ld->error = 0;
// if (ld->bytes_left == 0)
// ld->no_more_reading = 1;
// if (ld->bytes_left < 0)
// ld->error = 1;
}
uint8_t *faad_getbitbuffer(bitfile *ld, uint32_t bits
DEBUGDEC)
{
int i;
unsigned int temp;
int bytes = bits >> 3;
int remainder = bits & 0x7;
uint8_t *buffer = (uint8_t*)faad_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 = faad_getbits(ld, remainder DEBUGVAR(print,var,dbg)) << (8-remainder);
buffer[bytes] = (uint8_t)temp;
}
return buffer;
}
#ifdef DRM
/* return the original data buffer */
void *faad_origbitbuffer(bitfile *ld)
{
return (void*)ld->start;
}
/* return the original data buffer size */
uint32_t faad_origbitbuffer_size(bitfile *ld)
{
return ld->buffer_size;
}
#endif
/* 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);
ld->bufa = tmp;
tmp = getdword((uint32_t*)buffer + index - 1);
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_left = ld->buffer_size;
ld->error = 0;
}
/* EOF */