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FFmpeg/libavcodec/golomb.h
Justin Ruggles 4795362660 golomb: check remaining bits during unary decoding in get_ur_golomb_jpegls() 
Fixes infinite loop in FLAC decoding in case of a truncated bitstream due to
the safe bitstream reader returning 0's at the end.

Fixes Bug 310.

CC:libav-stable@libav.org
2012-06-12 14:33:39 -04:00

547 lines
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/*
* exp golomb vlc stuff
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
* Copyright (c) 2004 Alex Beregszaszi
*
* 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
* @brief
* exp golomb vlc stuff
* @author Michael Niedermayer <michaelni@gmx.at> and Alex Beregszaszi
*/
#ifndef AVCODEC_GOLOMB_H
#define AVCODEC_GOLOMB_H
#include <stdint.h>
#include "get_bits.h"
#include "put_bits.h"
#define INVALID_VLC 0x80000000
extern const uint8_t ff_golomb_vlc_len[512];
extern const uint8_t ff_ue_golomb_vlc_code[512];
extern const int8_t ff_se_golomb_vlc_code[512];
extern const uint8_t ff_ue_golomb_len[256];
extern const uint8_t ff_interleaved_golomb_vlc_len[256];
extern const uint8_t ff_interleaved_ue_golomb_vlc_code[256];
extern const int8_t ff_interleaved_se_golomb_vlc_code[256];
extern const uint8_t ff_interleaved_dirac_golomb_vlc_code[256];
/**
* read unsigned exp golomb code.
*/
static inline int get_ue_golomb(GetBitContext *gb){
unsigned int buf;
int log;
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf=GET_CACHE(re, gb);
if(buf >= (1<<27)){
buf >>= 32 - 9;
LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
return ff_ue_golomb_vlc_code[buf];
}else{
log= 2*av_log2(buf) - 31;
buf>>= log;
buf--;
LAST_SKIP_BITS(re, gb, 32 - log);
CLOSE_READER(re, gb);
return buf;
}
}
/**
* Read an unsigned Exp-Golomb code in the range 0 to UINT32_MAX-1.
*/
static inline unsigned get_ue_golomb_long(GetBitContext *gb)
{
unsigned buf, log;
buf = show_bits_long(gb, 32);
log = 31 - av_log2(buf);
skip_bits_long(gb, log);
return get_bits_long(gb, log + 1) - 1;
}
/**
* read unsigned exp golomb code, constraint to a max of 31.
* the return value is undefined if the stored value exceeds 31.
*/
static inline int get_ue_golomb_31(GetBitContext *gb){
unsigned int buf;
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf=GET_CACHE(re, gb);
buf >>= 32 - 9;
LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
return ff_ue_golomb_vlc_code[buf];
}
static inline int svq3_get_ue_golomb(GetBitContext *gb){
uint32_t buf;
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf=GET_CACHE(re, gb);
if(buf&0xAA800000){
buf >>= 32 - 8;
LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
return ff_interleaved_ue_golomb_vlc_code[buf];
}else{
int ret = 1;
do {
buf >>= 32 - 8;
LAST_SKIP_BITS(re, gb, FFMIN(ff_interleaved_golomb_vlc_len[buf], 8));
if (ff_interleaved_golomb_vlc_len[buf] != 9){
ret <<= (ff_interleaved_golomb_vlc_len[buf] - 1) >> 1;
ret |= ff_interleaved_dirac_golomb_vlc_code[buf];
break;
}
ret = (ret << 4) | ff_interleaved_dirac_golomb_vlc_code[buf];
UPDATE_CACHE(re, gb);
buf = GET_CACHE(re, gb);
} while (ret<0x8000000U && HAVE_BITS_REMAINING(re, gb));
CLOSE_READER(re, gb);
return ret - 1;
}
}
/**
* read unsigned truncated exp golomb code.
*/
static inline int get_te0_golomb(GetBitContext *gb, int range){
av_assert2(range >= 1);
if(range==1) return 0;
else if(range==2) return get_bits1(gb)^1;
else return get_ue_golomb(gb);
}
/**
* read unsigned truncated exp golomb code.
*/
static inline int get_te_golomb(GetBitContext *gb, int range){
av_assert2(range >= 1);
if(range==2) return get_bits1(gb)^1;
else return get_ue_golomb(gb);
}
/**
* read signed exp golomb code.
*/
static inline int get_se_golomb(GetBitContext *gb){
unsigned int buf;
int log;
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf=GET_CACHE(re, gb);
if(buf >= (1<<27)){
buf >>= 32 - 9;
LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
return ff_se_golomb_vlc_code[buf];
}else{
log= 2*av_log2(buf) - 31;
buf>>= log;
LAST_SKIP_BITS(re, gb, 32 - log);
CLOSE_READER(re, gb);
if(buf&1) buf= -(buf>>1);
else buf= (buf>>1);
return buf;
}
}
static inline int svq3_get_se_golomb(GetBitContext *gb){
unsigned int buf;
int log;
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf=GET_CACHE(re, gb);
if(buf&0xAA800000){
buf >>= 32 - 8;
LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
CLOSE_READER(re, gb);
return ff_interleaved_se_golomb_vlc_code[buf];
}else{
LAST_SKIP_BITS(re, gb, 8);
UPDATE_CACHE(re, gb);
buf |= 1 | (GET_CACHE(re, gb) >> 8);
if((buf & 0xAAAAAAAA) == 0)
return INVALID_VLC;
for(log=31; (buf & 0x80000000) == 0; log--){
buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
}
LAST_SKIP_BITS(re, gb, 63 - 2*log - 8);
CLOSE_READER(re, gb);
return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
}
}
static inline int dirac_get_se_golomb(GetBitContext *gb){
uint32_t buf;
uint32_t ret;
ret = svq3_get_ue_golomb(gb);
if (ret) {
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf = SHOW_SBITS(re, gb, 1);
LAST_SKIP_BITS(re, gb, 1);
ret = (ret ^ buf) - buf;
CLOSE_READER(re, gb);
}
return ret;
}
/**
* read unsigned golomb rice code (ffv1).
*/
static inline int get_ur_golomb(GetBitContext *gb, int k, int limit, int esc_len){
unsigned int buf;
int log;
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf=GET_CACHE(re, gb);
log= av_log2(buf);
if(log > 31-limit){
buf >>= log - k;
buf += (30-log)<<k;
LAST_SKIP_BITS(re, gb, 32 + k - log);
CLOSE_READER(re, gb);
return buf;
}else{
LAST_SKIP_BITS(re, gb, limit);
UPDATE_CACHE(re, gb);
buf = SHOW_UBITS(re, gb, esc_len);
LAST_SKIP_BITS(re, gb, esc_len);
CLOSE_READER(re, gb);
return buf + limit - 1;
}
}
/**
* read unsigned golomb rice code (jpegls).
*/
static inline int get_ur_golomb_jpegls(GetBitContext *gb, int k, int limit, int esc_len){
unsigned int buf;
int log;
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
buf=GET_CACHE(re, gb);
log= av_log2(buf);
if(log - k >= 32-MIN_CACHE_BITS+(MIN_CACHE_BITS==32) && 32-log < limit){
buf >>= log - k;
buf += (30-log)<<k;
LAST_SKIP_BITS(re, gb, 32 + k - log);
CLOSE_READER(re, gb);
return buf;
}else{
int i;
for (i = 0; i < limit && SHOW_UBITS(re, gb, 1) == 0; i++) {
if (gb->size_in_bits <= re_index)
return -1;
LAST_SKIP_BITS(re, gb, 1);
UPDATE_CACHE(re, gb);
}
SKIP_BITS(re, gb, 1);
if(i < limit - 1){
if(k){
buf = SHOW_UBITS(re, gb, k);
LAST_SKIP_BITS(re, gb, k);
}else{
buf=0;
}
CLOSE_READER(re, gb);
return buf + (i<<k);
}else if(i == limit - 1){
buf = SHOW_UBITS(re, gb, esc_len);
LAST_SKIP_BITS(re, gb, esc_len);
CLOSE_READER(re, gb);
return buf + 1;
}else
return -1;
}
}
/**
* read signed golomb rice code (ffv1).
*/
static inline int get_sr_golomb(GetBitContext *gb, int k, int limit, int esc_len){
int v= get_ur_golomb(gb, k, limit, esc_len);
v++;
if (v&1) return v>>1;
else return -(v>>1);
// return (v>>1) ^ -(v&1);
}
/**
* read signed golomb rice code (flac).
*/
static inline int get_sr_golomb_flac(GetBitContext *gb, int k, int limit, int esc_len){
int v= get_ur_golomb_jpegls(gb, k, limit, esc_len);
return (v>>1) ^ -(v&1);
}
/**
* read unsigned golomb rice code (shorten).
*/
static inline unsigned int get_ur_golomb_shorten(GetBitContext *gb, int k){
return get_ur_golomb_jpegls(gb, k, INT_MAX, 0);
}
/**
* read signed golomb rice code (shorten).
*/
static inline int get_sr_golomb_shorten(GetBitContext* gb, int k)
{
int uvar = get_ur_golomb_jpegls(gb, k + 1, INT_MAX, 0);
if (uvar & 1)
return ~(uvar >> 1);
else
return uvar >> 1;
}
#ifdef TRACE
static inline int get_ue(GetBitContext *s, char *file, const char *func, int line){
int show= show_bits(s, 24);
int pos= get_bits_count(s);
int i= get_ue_golomb(s);
int len= get_bits_count(s) - pos;
int bits= show>>(24-len);
print_bin(bits, len);
av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d ue @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
return i;
}
static inline int get_se(GetBitContext *s, char *file, const char *func, int line){
int show= show_bits(s, 24);
int pos= get_bits_count(s);
int i= get_se_golomb(s);
int len= get_bits_count(s) - pos;
int bits= show>>(24-len);
print_bin(bits, len);
av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d se @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
return i;
}
static inline int get_te(GetBitContext *s, int r, char *file, const char *func, int line){
int show= show_bits(s, 24);
int pos= get_bits_count(s);
int i= get_te0_golomb(s, r);
int len= get_bits_count(s) - pos;
int bits= show>>(24-len);
print_bin(bits, len);
av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d te @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
return i;
}
#define get_ue_golomb(a) get_ue(a, __FILE__, __PRETTY_FUNCTION__, __LINE__)
#define get_se_golomb(a) get_se(a, __FILE__, __PRETTY_FUNCTION__, __LINE__)
#define get_te_golomb(a, r) get_te(a, r, __FILE__, __PRETTY_FUNCTION__, __LINE__)
#define get_te0_golomb(a, r) get_te(a, r, __FILE__, __PRETTY_FUNCTION__, __LINE__)
#endif
/**
* write unsigned exp golomb code.
*/
static inline void set_ue_golomb(PutBitContext *pb, int i){
int e;
av_assert2(i>=0);
#if 0
if(i=0){
put_bits(pb, 1, 1);
return;
}
#endif
if(i<256)
put_bits(pb, ff_ue_golomb_len[i], i+1);
else{
e= av_log2(i+1);
put_bits(pb, 2*e+1, i+1);
}
}
/**
* write truncated unsigned exp golomb code.
*/
static inline void set_te_golomb(PutBitContext *pb, int i, int range){
av_assert2(range >= 1);
av_assert2(i<=range);
if(range==2) put_bits(pb, 1, i^1);
else set_ue_golomb(pb, i);
}
/**
* write signed exp golomb code. 16 bits at most.
*/
static inline void set_se_golomb(PutBitContext *pb, int i){
// if (i>32767 || i<-32767)
// av_log(NULL,AV_LOG_ERROR,"value out of range %d\n", i);
#if 0
if(i<=0) i= -2*i;
else i= 2*i-1;
#elif 1
i= 2*i-1;
if(i<0) i^= -1; //FIXME check if gcc does the right thing
#else
i= 2*i-1;
i^= (i>>31);
#endif
set_ue_golomb(pb, i);
}
/**
* write unsigned golomb rice code (ffv1).
*/
static inline void set_ur_golomb(PutBitContext *pb, int i, int k, int limit, int esc_len){
int e;
av_assert2(i>=0);
e= i>>k;
if(e<limit){
put_bits(pb, e + k + 1, (1<<k) + (i&((1<<k)-1)));
}else{
put_bits(pb, limit + esc_len, i - limit + 1);
}
}
/**
* write unsigned golomb rice code (jpegls).
*/
static inline void set_ur_golomb_jpegls(PutBitContext *pb, int i, int k, int limit, int esc_len){
int e;
av_assert2(i>=0);
e= (i>>k) + 1;
if(e<limit){
while(e > 31) {
put_bits(pb, 31, 0);
e -= 31;
}
put_bits(pb, e, 1);
if(k)
put_sbits(pb, k, i);
}else{
while(limit > 31) {
put_bits(pb, 31, 0);
limit -= 31;
}
put_bits(pb, limit , 1);
put_bits(pb, esc_len, i - 1);
}
}
/**
* write signed golomb rice code (ffv1).
*/
static inline void set_sr_golomb(PutBitContext *pb, int i, int k, int limit, int esc_len){
int v;
v = -2*i-1;
v ^= (v>>31);
set_ur_golomb(pb, v, k, limit, esc_len);
}
/**
* write signed golomb rice code (flac).
*/
static inline void set_sr_golomb_flac(PutBitContext *pb, int i, int k, int limit, int esc_len){
int v;
v = -2*i-1;
v ^= (v>>31);
set_ur_golomb_jpegls(pb, v, k, limit, esc_len);
}
#endif /* AVCODEC_GOLOMB_H */
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