67695617a1
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20883 a1c6a512-1295-4272-9138-f99709370657
322 lines
10 KiB
C
322 lines
10 KiB
C
/*
|
|
* Common bit i/o utils
|
|
* Copyright (c) 2000, 2001 Fabrice Bellard
|
|
* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file libavcodec/bitstream.c
|
|
* bitstream api.
|
|
*/
|
|
|
|
#include "avcodec.h"
|
|
#include "bitstream.h"
|
|
|
|
const uint8_t ff_log2_run[32]={
|
|
0, 0, 0, 0, 1, 1, 1, 1,
|
|
2, 2, 2, 2, 3, 3, 3, 3,
|
|
4, 4, 5, 5, 6, 6, 7, 7,
|
|
8, 9,10,11,12,13,14,15
|
|
};
|
|
|
|
/**
|
|
* Same as av_mallocz_static(), but does a realloc.
|
|
*
|
|
* @param[in] ptr The block of memory to reallocate.
|
|
* @param[in] size The requested size.
|
|
* @return Block of memory of requested size.
|
|
* @deprecated. Code which uses ff_realloc_static is broken/misdesigned
|
|
* and should correctly use static arrays
|
|
*/
|
|
attribute_deprecated av_alloc_size(2)
|
|
static void *ff_realloc_static(void *ptr, unsigned int size);
|
|
|
|
static void *ff_realloc_static(void *ptr, unsigned int size)
|
|
{
|
|
return av_realloc(ptr, size);
|
|
}
|
|
|
|
void align_put_bits(PutBitContext *s)
|
|
{
|
|
#ifdef ALT_BITSTREAM_WRITER
|
|
put_bits(s,( - s->index) & 7,0);
|
|
#else
|
|
put_bits(s,s->bit_left & 7,0);
|
|
#endif
|
|
}
|
|
|
|
void ff_put_string(PutBitContext * pbc, const char *s, int put_zero)
|
|
{
|
|
while(*s){
|
|
put_bits(pbc, 8, *s);
|
|
s++;
|
|
}
|
|
if(put_zero)
|
|
put_bits(pbc, 8, 0);
|
|
}
|
|
|
|
#if 0
|
|
void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
|
|
{
|
|
const uint16_t *srcw= (const uint16_t*)src;
|
|
int words= length>>4;
|
|
int bits= length&15;
|
|
int i;
|
|
|
|
if(length==0) return;
|
|
|
|
if(CONFIG_SMALL || words < 16 || put_bits_count(pb)&7){
|
|
for(i=0; i<words; i++) put_bits(pb, 16, AV_RB16(&srcw[i]));
|
|
}else{
|
|
for(i=0; put_bits_count(pb)&31; i++)
|
|
put_bits(pb, 8, src[i]);
|
|
flush_put_bits(pb);
|
|
memcpy(pbBufPtr(pb), src+i, 2*words-i);
|
|
skip_put_bytes(pb, 2*words-i);
|
|
}
|
|
|
|
put_bits(pb, bits, AV_RB16(&srcw[words])>>(16-bits));
|
|
}
|
|
#endif
|
|
|
|
/* VLC decoding */
|
|
|
|
//#define DEBUG_VLC
|
|
|
|
#define GET_DATA(v, table, i, wrap, size) \
|
|
{\
|
|
const uint8_t *ptr = (const uint8_t *)table + i * wrap;\
|
|
switch(size) {\
|
|
case 1:\
|
|
v = *(const uint8_t *)ptr;\
|
|
break;\
|
|
case 2:\
|
|
v = *(const uint16_t *)ptr;\
|
|
break;\
|
|
default:\
|
|
v = *(const uint32_t *)ptr;\
|
|
break;\
|
|
}\
|
|
}
|
|
|
|
|
|
static int alloc_table(VLC *vlc, int size, int use_static)
|
|
{
|
|
int index;
|
|
index = vlc->table_size;
|
|
vlc->table_size += size;
|
|
if (vlc->table_size > vlc->table_allocated) {
|
|
if(use_static>1)
|
|
abort(); //cant do anything, init_vlc() is used with too little memory
|
|
vlc->table_allocated += (1 << vlc->bits);
|
|
if(use_static)
|
|
vlc->table = ff_realloc_static(vlc->table,
|
|
sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
|
|
else
|
|
vlc->table = av_realloc(vlc->table,
|
|
sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
|
|
if (!vlc->table)
|
|
return -1;
|
|
}
|
|
return index;
|
|
}
|
|
|
|
static int build_table(VLC *vlc, int table_nb_bits,
|
|
int nb_codes,
|
|
const void *bits, int bits_wrap, int bits_size,
|
|
const void *codes, int codes_wrap, int codes_size,
|
|
const void *symbols, int symbols_wrap, int symbols_size,
|
|
uint32_t code_prefix, int n_prefix, int flags)
|
|
{
|
|
int i, j, k, n, table_size, table_index, nb, n1, index, code_prefix2, symbol;
|
|
uint32_t code;
|
|
VLC_TYPE (*table)[2];
|
|
|
|
table_size = 1 << table_nb_bits;
|
|
table_index = alloc_table(vlc, table_size, flags & (INIT_VLC_USE_STATIC|INIT_VLC_USE_NEW_STATIC));
|
|
#ifdef DEBUG_VLC
|
|
av_log(NULL,AV_LOG_DEBUG,"new table index=%d size=%d code_prefix=%x n=%d\n",
|
|
table_index, table_size, code_prefix, n_prefix);
|
|
#endif
|
|
if (table_index < 0)
|
|
return -1;
|
|
table = &vlc->table[table_index];
|
|
|
|
for(i=0;i<table_size;i++) {
|
|
table[i][1] = 0; //bits
|
|
table[i][0] = -1; //codes
|
|
}
|
|
|
|
/* first pass: map codes and compute auxillary table sizes */
|
|
for(i=0;i<nb_codes;i++) {
|
|
GET_DATA(n, bits, i, bits_wrap, bits_size);
|
|
GET_DATA(code, codes, i, codes_wrap, codes_size);
|
|
/* we accept tables with holes */
|
|
if (n <= 0)
|
|
continue;
|
|
if (!symbols)
|
|
symbol = i;
|
|
else
|
|
GET_DATA(symbol, symbols, i, symbols_wrap, symbols_size);
|
|
#if defined(DEBUG_VLC) && 0
|
|
av_log(NULL,AV_LOG_DEBUG,"i=%d n=%d code=0x%x\n", i, n, code);
|
|
#endif
|
|
/* if code matches the prefix, it is in the table */
|
|
n -= n_prefix;
|
|
if(flags & INIT_VLC_LE)
|
|
code_prefix2= code & (n_prefix>=32 ? 0xffffffff : (1 << n_prefix)-1);
|
|
else
|
|
code_prefix2= code >> n;
|
|
if (n > 0 && code_prefix2 == code_prefix) {
|
|
if (n <= table_nb_bits) {
|
|
/* no need to add another table */
|
|
j = (code << (table_nb_bits - n)) & (table_size - 1);
|
|
nb = 1 << (table_nb_bits - n);
|
|
for(k=0;k<nb;k++) {
|
|
if(flags & INIT_VLC_LE)
|
|
j = (code >> n_prefix) + (k<<n);
|
|
#ifdef DEBUG_VLC
|
|
av_log(NULL, AV_LOG_DEBUG, "%4x: code=%d n=%d\n",
|
|
j, i, n);
|
|
#endif
|
|
if (table[j][1] /*bits*/ != 0) {
|
|
av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
|
|
return -1;
|
|
}
|
|
table[j][1] = n; //bits
|
|
table[j][0] = symbol;
|
|
j++;
|
|
}
|
|
} else {
|
|
n -= table_nb_bits;
|
|
j = (code >> ((flags & INIT_VLC_LE) ? n_prefix : n)) & ((1 << table_nb_bits) - 1);
|
|
#ifdef DEBUG_VLC
|
|
av_log(NULL,AV_LOG_DEBUG,"%4x: n=%d (subtable)\n",
|
|
j, n);
|
|
#endif
|
|
/* compute table size */
|
|
n1 = -table[j][1]; //bits
|
|
if (n > n1)
|
|
n1 = n;
|
|
table[j][1] = -n1; //bits
|
|
}
|
|
}
|
|
}
|
|
|
|
/* second pass : fill auxillary tables recursively */
|
|
for(i=0;i<table_size;i++) {
|
|
n = table[i][1]; //bits
|
|
if (n < 0) {
|
|
n = -n;
|
|
if (n > table_nb_bits) {
|
|
n = table_nb_bits;
|
|
table[i][1] = -n; //bits
|
|
}
|
|
index = build_table(vlc, n, nb_codes,
|
|
bits, bits_wrap, bits_size,
|
|
codes, codes_wrap, codes_size,
|
|
symbols, symbols_wrap, symbols_size,
|
|
(flags & INIT_VLC_LE) ? (code_prefix | (i << n_prefix)) : ((code_prefix << table_nb_bits) | i),
|
|
n_prefix + table_nb_bits, flags);
|
|
if (index < 0)
|
|
return -1;
|
|
/* note: realloc has been done, so reload tables */
|
|
table = &vlc->table[table_index];
|
|
table[i][0] = index; //code
|
|
}
|
|
}
|
|
return table_index;
|
|
}
|
|
|
|
|
|
/* Build VLC decoding tables suitable for use with get_vlc().
|
|
|
|
'nb_bits' set thee decoding table size (2^nb_bits) entries. The
|
|
bigger it is, the faster is the decoding. But it should not be too
|
|
big to save memory and L1 cache. '9' is a good compromise.
|
|
|
|
'nb_codes' : number of vlcs codes
|
|
|
|
'bits' : table which gives the size (in bits) of each vlc code.
|
|
|
|
'codes' : table which gives the bit pattern of of each vlc code.
|
|
|
|
'symbols' : table which gives the values to be returned from get_vlc().
|
|
|
|
'xxx_wrap' : give the number of bytes between each entry of the
|
|
'bits' or 'codes' tables.
|
|
|
|
'xxx_size' : gives the number of bytes of each entry of the 'bits'
|
|
or 'codes' tables.
|
|
|
|
'wrap' and 'size' allows to use any memory configuration and types
|
|
(byte/word/long) to store the 'bits', 'codes', and 'symbols' tables.
|
|
|
|
'use_static' should be set to 1 for tables, which should be freed
|
|
with av_free_static(), 0 if free_vlc() will be used.
|
|
*/
|
|
int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
|
|
const void *bits, int bits_wrap, int bits_size,
|
|
const void *codes, int codes_wrap, int codes_size,
|
|
const void *symbols, int symbols_wrap, int symbols_size,
|
|
int flags)
|
|
{
|
|
vlc->bits = nb_bits;
|
|
if(flags & INIT_VLC_USE_NEW_STATIC){
|
|
if(vlc->table_size && vlc->table_size == vlc->table_allocated){
|
|
return 0;
|
|
}else if(vlc->table_size){
|
|
abort(); // fatal error, we are called on a partially initialized table
|
|
}
|
|
}else if(!(flags & INIT_VLC_USE_STATIC)) {
|
|
vlc->table = NULL;
|
|
vlc->table_allocated = 0;
|
|
vlc->table_size = 0;
|
|
} else {
|
|
/* Static tables are initially always NULL, return
|
|
if vlc->table != NULL to avoid double allocation */
|
|
if(vlc->table)
|
|
return 0;
|
|
}
|
|
|
|
#ifdef DEBUG_VLC
|
|
av_log(NULL,AV_LOG_DEBUG,"build table nb_codes=%d\n", nb_codes);
|
|
#endif
|
|
|
|
if (build_table(vlc, nb_bits, nb_codes,
|
|
bits, bits_wrap, bits_size,
|
|
codes, codes_wrap, codes_size,
|
|
symbols, symbols_wrap, symbols_size,
|
|
0, 0, flags) < 0) {
|
|
av_freep(&vlc->table);
|
|
return -1;
|
|
}
|
|
if((flags & INIT_VLC_USE_NEW_STATIC) && vlc->table_size != vlc->table_allocated)
|
|
av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated);
|
|
return 0;
|
|
}
|
|
|
|
|
|
void free_vlc(VLC *vlc)
|
|
{
|
|
av_freep(&vlc->table);
|
|
}
|
|
|