/*
* copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav 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,
+ * Libav 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
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
- * @file libavcodec/get_bits.h
+ * @file
* bitstream reader API header.
*/
#define AVCODEC_GET_BITS_H
#include <stdint.h>
-#include <stdlib.h>
-#include <assert.h>
-#include "libavutil/bswap.h"
+
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/log.h"
#include "mathops.h"
+#include "vlc.h"
-#if defined(ALT_BITSTREAM_READER_LE) && !defined(ALT_BITSTREAM_READER)
-# define ALT_BITSTREAM_READER
-#endif
-
-#if !defined(LIBMPEG2_BITSTREAM_READER) && !defined(A32_BITSTREAM_READER) && !defined(ALT_BITSTREAM_READER)
-# if ARCH_ARM
-# define A32_BITSTREAM_READER
-# else
-# define ALT_BITSTREAM_READER
-//#define LIBMPEG2_BITSTREAM_READER
-//#define A32_BITSTREAM_READER
-# endif
-#endif
-
-extern const uint8_t ff_reverse[256];
-
-#if ARCH_X86
-// avoid +32 for shift optimization (gcc should do that ...)
-static inline int32_t NEG_SSR32( int32_t a, int8_t s){
- __asm__ ("sarl %1, %0\n\t"
- : "+r" (a)
- : "ic" ((uint8_t)(-s))
- );
- return a;
-}
-static inline uint32_t NEG_USR32(uint32_t a, int8_t s){
- __asm__ ("shrl %1, %0\n\t"
- : "+r" (a)
- : "ic" ((uint8_t)(-s))
- );
- return a;
-}
-#else
-# define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s)))
-# define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
+/*
+ * Safe bitstream reading:
+ * optionally, the get_bits API can check to ensure that we
+ * don't read past input buffer boundaries. This is protected
+ * with CONFIG_SAFE_BITSTREAM_READER at the global level, and
+ * then below that with UNCHECKED_BITSTREAM_READER at the per-
+ * decoder level. This means that decoders that check internally
+ * can "#define UNCHECKED_BITSTREAM_READER 1" to disable
+ * overread checks.
+ * Boundary checking causes a minor performance penalty so for
+ * applications that won't want/need this, it can be disabled
+ * globally using "#define CONFIG_SAFE_BITSTREAM_READER 0".
+ */
+#ifndef UNCHECKED_BITSTREAM_READER
+#define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
#endif
-/* bit input */
-/* buffer, buffer_end and size_in_bits must be present and used by every reader */
typedef struct GetBitContext {
const uint8_t *buffer, *buffer_end;
-#ifdef ALT_BITSTREAM_READER
int index;
-#elif defined LIBMPEG2_BITSTREAM_READER
- uint8_t *buffer_ptr;
- uint32_t cache;
- int bit_count;
-#elif defined A32_BITSTREAM_READER
- uint32_t *buffer_ptr;
- uint32_t cache0;
- uint32_t cache1;
- int bit_count;
-#endif
int size_in_bits;
+#if !UNCHECKED_BITSTREAM_READER
+ int size_in_bits_plus8;
+#endif
} GetBitContext;
-#define VLC_TYPE int16_t
-
-typedef struct VLC {
- int bits;
- VLC_TYPE (*table)[2]; ///< code, bits
- int table_size, table_allocated;
-} VLC;
-
-typedef struct RL_VLC_ELEM {
- int16_t level;
- int8_t len;
- uint8_t run;
-} RL_VLC_ELEM;
-
/* Bitstream reader API docs:
-name
- arbitrary name which is used as prefix for the internal variables
-
-gb
- getbitcontext
-
-OPEN_READER(name, gb)
- loads gb into local variables
-
-CLOSE_READER(name, gb)
- stores local vars in gb
-
-UPDATE_CACHE(name, gb)
- refills the internal cache from the bitstream
- after this call at least MIN_CACHE_BITS will be available,
-
-GET_CACHE(name, gb)
- will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
-
-SHOW_UBITS(name, gb, num)
- will return the next num bits
-
-SHOW_SBITS(name, gb, num)
- will return the next num bits and do sign extension
-
-SKIP_BITS(name, gb, num)
- will skip over the next num bits
- note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
-
-SKIP_CACHE(name, gb, num)
- will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
-
-SKIP_COUNTER(name, gb, num)
- will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
+ * name
+ * arbitrary name which is used as prefix for the internal variables
+ *
+ * gb
+ * getbitcontext
+ *
+ * OPEN_READER(name, gb)
+ * load gb into local variables
+ *
+ * CLOSE_READER(name, gb)
+ * store local vars in gb
+ *
+ * UPDATE_CACHE(name, gb)
+ * Refill the internal cache from the bitstream.
+ * After this call at least MIN_CACHE_BITS will be available.
+ *
+ * GET_CACHE(name, gb)
+ * Will output the contents of the internal cache,
+ * next bit is MSB of 32 or 64 bits (FIXME 64 bits).
+ *
+ * SHOW_UBITS(name, gb, num)
+ * Will return the next num bits.
+ *
+ * SHOW_SBITS(name, gb, num)
+ * Will return the next num bits and do sign extension.
+ *
+ * SKIP_BITS(name, gb, num)
+ * Will skip over the next num bits.
+ * Note, this is equivalent to SKIP_CACHE; SKIP_COUNTER.
+ *
+ * SKIP_CACHE(name, gb, num)
+ * Will remove the next num bits from the cache (note SKIP_COUNTER
+ * MUST be called before UPDATE_CACHE / CLOSE_READER).
+ *
+ * SKIP_COUNTER(name, gb, num)
+ * Will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS).
+ *
+ * LAST_SKIP_BITS(name, gb, num)
+ * Like SKIP_BITS, to be used if next call is UPDATE_CACHE or CLOSE_READER.
+ *
+ * For examples see get_bits, show_bits, skip_bits, get_vlc.
+ */
-LAST_SKIP_CACHE(name, gb, num)
- will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
+#ifdef LONG_BITSTREAM_READER
+# define MIN_CACHE_BITS 32
+#else
+# define MIN_CACHE_BITS 25
+#endif
-LAST_SKIP_BITS(name, gb, num)
- is equivalent to LAST_SKIP_CACHE; SKIP_COUNTER
+#define OPEN_READER_NOSIZE(name, gb) \
+ unsigned int name ## _index = (gb)->index; \
+ unsigned int av_unused name ## _cache = 0
-for examples see get_bits, show_bits, skip_bits, get_vlc
-*/
+#if UNCHECKED_BITSTREAM_READER
+#define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb)
-#ifdef ALT_BITSTREAM_READER
-# define MIN_CACHE_BITS 25
+#define BITS_AVAILABLE(name, gb) 1
+#else
+#define OPEN_READER(name, gb) \
+ OPEN_READER_NOSIZE(name, gb); \
+ unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8
-# define OPEN_READER(name, gb)\
- int name##_index= (gb)->index;\
- int name##_cache= 0;\
+#define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8
+#endif
-# define CLOSE_READER(name, gb)\
- (gb)->index= name##_index;\
+#define CLOSE_READER(name, gb) (gb)->index = name ## _index
-# ifdef ALT_BITSTREAM_READER_LE
-# define UPDATE_CACHE(name, gb)\
- name##_cache= AV_RL32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
+#ifdef BITSTREAM_READER_LE
-# define SKIP_CACHE(name, gb, num)\
- name##_cache >>= (num);
+# ifdef LONG_BITSTREAM_READER
+# define UPDATE_CACHE(name, gb) name ## _cache = \
+ AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)
# else
-# define UPDATE_CACHE(name, gb)\
- name##_cache= AV_RB32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
-
-# define SKIP_CACHE(name, gb, num)\
- name##_cache <<= (num);
+# define UPDATE_CACHE(name, gb) name ## _cache = \
+ AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)
# endif
-// FIXME name?
-# define SKIP_COUNTER(name, gb, num)\
- name##_index += (num);\
-
-# define SKIP_BITS(name, gb, num)\
- {\
- SKIP_CACHE(name, gb, num)\
- SKIP_COUNTER(name, gb, num)\
- }\
-
-# define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
-# define LAST_SKIP_CACHE(name, gb, num) ;
+# define SKIP_CACHE(name, gb, num) name ## _cache >>= (num)
-# ifdef ALT_BITSTREAM_READER_LE
-# define SHOW_UBITS(name, gb, num)\
- ((name##_cache) & (NEG_USR32(0xffffffff,num)))
+#else
-# define SHOW_SBITS(name, gb, num)\
- NEG_SSR32((name##_cache)<<(32-(num)), num)
+# ifdef LONG_BITSTREAM_READER
+# define UPDATE_CACHE(name, gb) name ## _cache = \
+ AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7))
# else
-# define SHOW_UBITS(name, gb, num)\
- NEG_USR32(name##_cache, num)
-
-# define SHOW_SBITS(name, gb, num)\
- NEG_SSR32(name##_cache, num)
+# define UPDATE_CACHE(name, gb) name ## _cache = \
+ AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7)
# endif
-# define GET_CACHE(name, gb)\
- ((uint32_t)name##_cache)
-
-static inline int get_bits_count(GetBitContext *s){
- return s->index;
-}
-
-static inline void skip_bits_long(GetBitContext *s, int n){
- s->index += n;
-}
-
-#elif defined LIBMPEG2_BITSTREAM_READER
-//libmpeg2 like reader
-
-# define MIN_CACHE_BITS 17
+# define SKIP_CACHE(name, gb, num) name ## _cache <<= (num)
-# define OPEN_READER(name, gb)\
- int name##_bit_count=(gb)->bit_count;\
- int name##_cache= (gb)->cache;\
- uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
-
-# define CLOSE_READER(name, gb)\
- (gb)->bit_count= name##_bit_count;\
- (gb)->cache= name##_cache;\
- (gb)->buffer_ptr= name##_buffer_ptr;\
-
-# define UPDATE_CACHE(name, gb)\
- if(name##_bit_count >= 0){\
- name##_cache+= AV_RB16(name##_buffer_ptr) << name##_bit_count; \
- name##_buffer_ptr+=2;\
- name##_bit_count-= 16;\
- }\
-
-# define SKIP_CACHE(name, gb, num)\
- name##_cache <<= (num);\
-
-# define SKIP_COUNTER(name, gb, num)\
- name##_bit_count += (num);\
-
-# define SKIP_BITS(name, gb, num)\
- {\
- SKIP_CACHE(name, gb, num)\
- SKIP_COUNTER(name, gb, num)\
- }\
-
-# define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
-# define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
-
-# define SHOW_UBITS(name, gb, num)\
- NEG_USR32(name##_cache, num)
-
-# define SHOW_SBITS(name, gb, num)\
- NEG_SSR32(name##_cache, num)
-
-# define GET_CACHE(name, gb)\
- ((uint32_t)name##_cache)
-
-static inline int get_bits_count(GetBitContext *s){
- return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
-}
-
-static inline void skip_bits_long(GetBitContext *s, int n){
- OPEN_READER(re, s)
- re_bit_count += n;
- re_buffer_ptr += 2*(re_bit_count>>4);
- re_bit_count &= 15;
- re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count);
- UPDATE_CACHE(re, s)
- CLOSE_READER(re, s)
-}
-
-#elif defined A32_BITSTREAM_READER
-
-# define MIN_CACHE_BITS 32
+#endif
-# define OPEN_READER(name, gb)\
- int name##_bit_count=(gb)->bit_count;\
- uint32_t name##_cache0= (gb)->cache0;\
- uint32_t name##_cache1= (gb)->cache1;\
- uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
-
-# define CLOSE_READER(name, gb)\
- (gb)->bit_count= name##_bit_count;\
- (gb)->cache0= name##_cache0;\
- (gb)->cache1= name##_cache1;\
- (gb)->buffer_ptr= name##_buffer_ptr;\
-
-# define UPDATE_CACHE(name, gb)\
- if(name##_bit_count > 0){\
- const uint32_t next= be2me_32( *name##_buffer_ptr );\
- name##_cache0 |= NEG_USR32(next,name##_bit_count);\
- name##_cache1 |= next<<name##_bit_count;\
- name##_buffer_ptr++;\
- name##_bit_count-= 32;\
- }\
-
-#if ARCH_X86
-# define SKIP_CACHE(name, gb, num)\
- __asm__(\
- "shldl %2, %1, %0 \n\t"\
- "shll %2, %1 \n\t"\
- : "+r" (name##_cache0), "+r" (name##_cache1)\
- : "Ic" ((uint8_t)(num))\
- );
+#if UNCHECKED_BITSTREAM_READER
+# define SKIP_COUNTER(name, gb, num) name ## _index += (num)
#else
-# define SKIP_CACHE(name, gb, num)\
- name##_cache0 <<= (num);\
- name##_cache0 |= NEG_USR32(name##_cache1,num);\
- name##_cache1 <<= (num);
+# define SKIP_COUNTER(name, gb, num) \
+ name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num))
#endif
-# define SKIP_COUNTER(name, gb, num)\
- name##_bit_count += (num);\
-
-# define SKIP_BITS(name, gb, num)\
- {\
- SKIP_CACHE(name, gb, num)\
- SKIP_COUNTER(name, gb, num)\
- }\
-
-# define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
-# define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
+#define SKIP_BITS(name, gb, num) \
+ do { \
+ SKIP_CACHE(name, gb, num); \
+ SKIP_COUNTER(name, gb, num); \
+ } while (0)
-# define SHOW_UBITS(name, gb, num)\
- NEG_USR32(name##_cache0, num)
+#define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
-# define SHOW_SBITS(name, gb, num)\
- NEG_SSR32(name##_cache0, num)
+#ifdef BITSTREAM_READER_LE
+# define SHOW_UBITS(name, gb, num) zero_extend(name ## _cache, num)
+# define SHOW_SBITS(name, gb, num) sign_extend(name ## _cache, num)
+#else
+# define SHOW_UBITS(name, gb, num) NEG_USR32(name ## _cache, num)
+# define SHOW_SBITS(name, gb, num) NEG_SSR32(name ## _cache, num)
+#endif
-# define GET_CACHE(name, gb)\
- (name##_cache0)
+#define GET_CACHE(name, gb) ((uint32_t) name ## _cache)
-static inline int get_bits_count(GetBitContext *s){
- return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
-}
-
-static inline void skip_bits_long(GetBitContext *s, int n){
- OPEN_READER(re, s)
- re_bit_count += n;
- re_buffer_ptr += re_bit_count>>5;
- re_bit_count &= 31;
- re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count;
- re_cache1 = 0;
- UPDATE_CACHE(re, s)
- CLOSE_READER(re, s)
+static inline int get_bits_count(const GetBitContext *s)
+{
+ return s->index;
}
+static inline void skip_bits_long(GetBitContext *s, int n)
+{
+#if UNCHECKED_BITSTREAM_READER
+ s->index += n;
+#else
+ s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index);
#endif
+}
/**
- * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
+ * Read MPEG-1 dc-style VLC (sign bit + mantisse with no MSB).
* if MSB not set it is negative
* @param n length in bits
- * @author BERO
*/
-static inline int get_xbits(GetBitContext *s, int n){
+static inline int get_xbits(GetBitContext *s, int n)
+{
register int sign;
register int32_t cache;
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
- cache = GET_CACHE(re,s);
- sign=(~cache)>>31;
- LAST_SKIP_BITS(re, s, n)
- CLOSE_READER(re, s)
+ OPEN_READER(re, s);
+ UPDATE_CACHE(re, s);
+ cache = GET_CACHE(re, s);
+ sign = ~cache >> 31;
+ LAST_SKIP_BITS(re, s, n);
+ CLOSE_READER(re, s);
return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
}
-static inline int get_sbits(GetBitContext *s, int n){
+static inline int get_sbits(GetBitContext *s, int n)
+{
register int tmp;
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
- tmp= SHOW_SBITS(re, s, n);
- LAST_SKIP_BITS(re, s, n)
- CLOSE_READER(re, s)
+ OPEN_READER(re, s);
+ UPDATE_CACHE(re, s);
+ tmp = SHOW_SBITS(re, s, n);
+ LAST_SKIP_BITS(re, s, n);
+ CLOSE_READER(re, s);
return tmp;
}
/**
- * reads 1-17 bits.
- * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
+ * Read 1-25 bits.
*/
-static inline unsigned int get_bits(GetBitContext *s, int n){
+static inline unsigned int get_bits(GetBitContext *s, int n)
+{
register int tmp;
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
- tmp= SHOW_UBITS(re, s, n);
- LAST_SKIP_BITS(re, s, n)
- CLOSE_READER(re, s)
+ OPEN_READER(re, s);
+ UPDATE_CACHE(re, s);
+ tmp = SHOW_UBITS(re, s, n);
+ LAST_SKIP_BITS(re, s, n);
+ CLOSE_READER(re, s);
return tmp;
}
/**
- * shows 1-17 bits.
- * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
+ * Read 0-25 bits.
+ */
+static av_always_inline int get_bitsz(GetBitContext *s, int n)
+{
+ return n ? get_bits(s, n) : 0;
+}
+
+/**
+ * Show 1-25 bits.
*/
-static inline unsigned int show_bits(GetBitContext *s, int n){
+static inline unsigned int show_bits(GetBitContext *s, int n)
+{
register int tmp;
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
- tmp= SHOW_UBITS(re, s, n);
-// CLOSE_READER(re, s)
+ OPEN_READER_NOSIZE(re, s);
+ UPDATE_CACHE(re, s);
+ tmp = SHOW_UBITS(re, s, n);
return tmp;
}
-static inline void skip_bits(GetBitContext *s, int n){
- //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
- LAST_SKIP_BITS(re, s, n)
- CLOSE_READER(re, s)
+static inline void skip_bits(GetBitContext *s, int n)
+{
+ OPEN_READER(re, s);
+ UPDATE_CACHE(re, s);
+ LAST_SKIP_BITS(re, s, n);
+ CLOSE_READER(re, s);
}
-static inline unsigned int get_bits1(GetBitContext *s){
-#ifdef ALT_BITSTREAM_READER
- int index= s->index;
- uint8_t result= s->buffer[ index>>3 ];
-#ifdef ALT_BITSTREAM_READER_LE
- result>>= (index&0x07);
- result&= 1;
+static inline unsigned int get_bits1(GetBitContext *s)
+{
+ unsigned int index = s->index;
+ uint8_t result = s->buffer[index >> 3];
+#ifdef BITSTREAM_READER_LE
+ result >>= index & 7;
+ result &= 1;
#else
- result<<= (index&0x07);
- result>>= 8 - 1;
+ result <<= index & 7;
+ result >>= 8 - 1;
+#endif
+#if !UNCHECKED_BITSTREAM_READER
+ if (s->index < s->size_in_bits_plus8)
#endif
- index++;
- s->index= index;
+ index++;
+ s->index = index;
return result;
-#else
- return get_bits(s, 1);
-#endif
}
-static inline unsigned int show_bits1(GetBitContext *s){
+static inline unsigned int show_bits1(GetBitContext *s)
+{
return show_bits(s, 1);
}
-static inline void skip_bits1(GetBitContext *s){
+static inline void skip_bits1(GetBitContext *s)
+{
skip_bits(s, 1);
}
/**
- * reads 0-32 bits.
+ * Read 0-32 bits.
*/
-static inline unsigned int get_bits_long(GetBitContext *s, int n){
- if(n<=17) return get_bits(s, n);
- else{
-#ifdef ALT_BITSTREAM_READER_LE
- int ret= get_bits(s, 16);
- return ret | (get_bits(s, n-16) << 16);
+static inline unsigned int get_bits_long(GetBitContext *s, int n)
+{
+ if (n <= MIN_CACHE_BITS) {
+ return get_bits(s, n);
+ } else {
+#ifdef BITSTREAM_READER_LE
+ int ret = get_bits(s, 16);
+ return ret | (get_bits(s, n - 16) << 16);
#else
- int ret= get_bits(s, 16) << (n-16);
- return ret | get_bits(s, n-16);
+ int ret = get_bits(s, 16) << (n - 16);
+ return ret | get_bits(s, n - 16);
+#endif
+ }
+}
+
+/*
+ * Read 0-64 bits.
+ */
+static inline uint64_t get_bits64(GetBitContext *s, int n)
+{
+ if (n <= 32) {
+ return get_bits_long(s, n);
+ } else {
+#ifdef BITSTREAM_READER_LE
+ uint64_t ret = get_bits_long(s, 32);
+ return ret | (uint64_t) get_bits_long(s, n - 32) << 32;
+#else
+ uint64_t ret = (uint64_t) get_bits_long(s, n - 32) << 32;
+ return ret | get_bits_long(s, 32);
#endif
}
}
/**
- * reads 0-32 bits as a signed integer.
+ * Read 0-32 bits as a signed integer.
*/
-static inline int get_sbits_long(GetBitContext *s, int n) {
+static inline int get_sbits_long(GetBitContext *s, int n)
+{
return sign_extend(get_bits_long(s, n), n);
}
/**
- * shows 0-32 bits.
+ * Show 0-32 bits.
*/
-static inline unsigned int show_bits_long(GetBitContext *s, int n){
- if(n<=17) return show_bits(s, n);
- else{
- GetBitContext gb= *s;
+static inline unsigned int show_bits_long(GetBitContext *s, int n)
+{
+ if (n <= MIN_CACHE_BITS) {
+ return show_bits(s, n);
+ } else {
+ GetBitContext gb = *s;
return get_bits_long(&gb, n);
}
}
-static inline int check_marker(GetBitContext *s, const char *msg)
-{
- int bit= get_bits1(s);
- if(!bit)
- av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
-
- return bit;
-}
-
/**
- * init GetBitContext.
- * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
- * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
+ * Initialize GetBitContext.
+ * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
+ * larger than the actual read bits because some optimized bitstream
+ * readers read 32 or 64 bit at once and could read over the end
* @param bit_size the size of the buffer in bits
- *
- * While GetBitContext stores the buffer size, for performance reasons you are
- * responsible for checking for the buffer end yourself (take advantage of the padding)!
+ * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
*/
-static inline void init_get_bits(GetBitContext *s,
- const uint8_t *buffer, int bit_size)
+static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
+ int bit_size)
{
- int buffer_size= (bit_size+7)>>3;
- if(buffer_size < 0 || bit_size < 0) {
- buffer_size = bit_size = 0;
- buffer = NULL;
+ int buffer_size;
+ int ret = 0;
+
+ if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
+ bit_size = 0;
+ buffer = NULL;
+ ret = AVERROR_INVALIDDATA;
}
- s->buffer= buffer;
- s->size_in_bits= bit_size;
- s->buffer_end= buffer + buffer_size;
-#ifdef ALT_BITSTREAM_READER
- s->index=0;
-#elif defined LIBMPEG2_BITSTREAM_READER
- s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));
- s->bit_count = 16 + 8*((intptr_t)buffer&1);
- skip_bits_long(s, 0);
-#elif defined A32_BITSTREAM_READER
- s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3));
- s->bit_count = 32 + 8*((intptr_t)buffer&3);
- skip_bits_long(s, 0);
-#endif
-}
+ buffer_size = (bit_size + 7) >> 3;
-static inline void align_get_bits(GetBitContext *s)
-{
- int n= (-get_bits_count(s)) & 7;
- if(n) skip_bits(s, n);
-}
+ s->buffer = buffer;
+ s->size_in_bits = bit_size;
+#if !UNCHECKED_BITSTREAM_READER
+ s->size_in_bits_plus8 = bit_size + 8;
+#endif
+ s->buffer_end = buffer + buffer_size;
+ s->index = 0;
-#define init_vlc(vlc, nb_bits, nb_codes,\
- bits, bits_wrap, bits_size,\
- codes, codes_wrap, codes_size,\
- flags)\
- init_vlc_sparse(vlc, nb_bits, nb_codes,\
- bits, bits_wrap, bits_size,\
- codes, codes_wrap, codes_size,\
- NULL, 0, 0, flags)
-
-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);
-#define INIT_VLC_USE_STATIC 1 ///< VERY strongly deprecated and forbidden
-#define INIT_VLC_LE 2
-#define INIT_VLC_USE_NEW_STATIC 4
-void free_vlc(VLC *vlc);
-
-#define INIT_VLC_STATIC(vlc, bits, a,b,c,d,e,f,g, static_size)\
-{\
- static VLC_TYPE table[static_size][2];\
- (vlc)->table= table;\
- (vlc)->table_allocated= static_size;\
- init_vlc(vlc, bits, a,b,c,d,e,f,g, INIT_VLC_USE_NEW_STATIC);\
+ return ret;
}
-
/**
- *
- * if the vlc code is invalid and max_depth=1 than no bits will be removed
- * if the vlc code is invalid and max_depth>1 than the number of bits removed
- * is undefined
+ * Initialize GetBitContext.
+ * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
+ * larger than the actual read bits because some optimized bitstream
+ * readers read 32 or 64 bit at once and could read over the end
+ * @param byte_size the size of the buffer in bytes
+ * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
*/
-#define GET_VLC(code, name, gb, table, bits, max_depth)\
-{\
- int n, index, nb_bits;\
-\
- index= SHOW_UBITS(name, gb, bits);\
- code = table[index][0];\
- n = table[index][1];\
-\
- if(max_depth > 1 && n < 0){\
- LAST_SKIP_BITS(name, gb, bits)\
- UPDATE_CACHE(name, gb)\
-\
- nb_bits = -n;\
-\
- index= SHOW_UBITS(name, gb, nb_bits) + code;\
- code = table[index][0];\
- n = table[index][1];\
- if(max_depth > 2 && n < 0){\
- LAST_SKIP_BITS(name, gb, nb_bits)\
- UPDATE_CACHE(name, gb)\
-\
- nb_bits = -n;\
-\
- index= SHOW_UBITS(name, gb, nb_bits) + code;\
- code = table[index][0];\
- n = table[index][1];\
- }\
- }\
- SKIP_BITS(name, gb, n)\
+static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer,
+ int byte_size)
+{
+ if (byte_size > INT_MAX / 8)
+ return AVERROR_INVALIDDATA;
+ return init_get_bits(s, buffer, byte_size * 8);
}
-#define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
-{\
- int n, index, nb_bits;\
-\
- index= SHOW_UBITS(name, gb, bits);\
- level = table[index].level;\
- n = table[index].len;\
-\
- if(max_depth > 1 && n < 0){\
- SKIP_BITS(name, gb, bits)\
- if(need_update){\
- UPDATE_CACHE(name, gb)\
- }\
-\
- nb_bits = -n;\
-\
- index= SHOW_UBITS(name, gb, nb_bits) + level;\
- level = table[index].level;\
- n = table[index].len;\
- }\
- run= table[index].run;\
- SKIP_BITS(name, gb, n)\
+static inline const uint8_t *align_get_bits(GetBitContext *s)
+{
+ int n = -get_bits_count(s) & 7;
+ if (n)
+ skip_bits(s, n);
+ return s->buffer + (s->index >> 3);
}
+/**
+ * If the vlc code is invalid and max_depth=1, then no bits will be removed.
+ * If the vlc code is invalid and max_depth>1, then the number of bits removed
+ * is undefined.
+ */
+#define GET_VLC(code, name, gb, table, bits, max_depth) \
+ do { \
+ int n, nb_bits; \
+ unsigned int index; \
+ \
+ index = SHOW_UBITS(name, gb, bits); \
+ code = table[index][0]; \
+ n = table[index][1]; \
+ \
+ if (max_depth > 1 && n < 0) { \
+ LAST_SKIP_BITS(name, gb, bits); \
+ UPDATE_CACHE(name, gb); \
+ \
+ nb_bits = -n; \
+ \
+ index = SHOW_UBITS(name, gb, nb_bits) + code; \
+ code = table[index][0]; \
+ n = table[index][1]; \
+ if (max_depth > 2 && n < 0) { \
+ LAST_SKIP_BITS(name, gb, nb_bits); \
+ UPDATE_CACHE(name, gb); \
+ \
+ nb_bits = -n; \
+ \
+ index = SHOW_UBITS(name, gb, nb_bits) + code; \
+ code = table[index][0]; \
+ n = table[index][1]; \
+ } \
+ } \
+ SKIP_BITS(name, gb, n); \
+ } while (0)
+
+#define GET_RL_VLC(level, run, name, gb, table, bits, \
+ max_depth, need_update) \
+ do { \
+ int n, nb_bits; \
+ unsigned int index; \
+ \
+ index = SHOW_UBITS(name, gb, bits); \
+ level = table[index].level; \
+ n = table[index].len; \
+ \
+ if (max_depth > 1 && n < 0) { \
+ SKIP_BITS(name, gb, bits); \
+ if (need_update) { \
+ UPDATE_CACHE(name, gb); \
+ } \
+ \
+ nb_bits = -n; \
+ \
+ index = SHOW_UBITS(name, gb, nb_bits) + level; \
+ level = table[index].level; \
+ n = table[index].len; \
+ if (max_depth > 2 && n < 0) { \
+ LAST_SKIP_BITS(name, gb, nb_bits); \
+ if (need_update) { \
+ UPDATE_CACHE(name, gb); \
+ } \
+ nb_bits = -n; \
+ \
+ index = SHOW_UBITS(name, gb, nb_bits) + level; \
+ level = table[index].level; \
+ n = table[index].len; \
+ } \
+ } \
+ run = table[index].run; \
+ SKIP_BITS(name, gb, n); \
+ } while (0)
/**
- * parses a vlc code, faster then get_vlc()
+ * Parse a vlc code.
* @param bits is the number of bits which will be read at once, must be
* identical to nb_bits in init_vlc()
* @param max_depth is the number of times bits bits must be read to completely
* = (max_vlc_length + bits - 1) / bits
*/
static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
- int bits, int max_depth)
+ int bits, int max_depth)
{
int code;
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
-
- GET_VLC(code, re, s, table, bits, max_depth)
-
- CLOSE_READER(re, s)
- return code;
-}
-
-//#define TRACE
-
-#ifdef TRACE
-static inline void print_bin(int bits, int n){
- int i;
-
- for(i=n-1; i>=0; i--){
- av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
- }
- for(i=n; i<24; i++)
- av_log(NULL, AV_LOG_DEBUG, " ");
-}
-
-static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
- int r= get_bits(s, n);
+ OPEN_READER(re, s);
+ UPDATE_CACHE(re, s);
- print_bin(r, n);
- av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d bit @%5d in %s %s:%d\n", r, n, r, get_bits_count(s)-n, file, func, line);
- return r;
-}
-static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
- int show= show_bits(s, 24);
- int pos= get_bits_count(s);
- int r= get_vlc2(s, table, bits, max_depth);
- int len= get_bits_count(s) - pos;
- int bits2= show>>(24-len);
+ GET_VLC(code, re, s, table, bits, max_depth);
- print_bin(bits2, len);
+ CLOSE_READER(re, s);
- av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
- return r;
-}
-static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
- int show= show_bits(s, n);
- int r= get_xbits(s, n);
-
- print_bin(show, n);
- av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d xbt @%5d in %s %s:%d\n", show, n, r, get_bits_count(s)-n, file, func, line);
- return r;
+ return code;
}
-#define get_bits(s, n) get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-#define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-#define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-#define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-
-#define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__)
-
-#else //TRACE
-#define tprintf(p, ...) {}
-#endif
-
-static inline int decode012(GetBitContext *gb){
+static inline int decode012(GetBitContext *gb)
+{
int n;
n = get_bits1(gb);
if (n == 0)
return get_bits1(gb) + 1;
}
-static inline int decode210(GetBitContext *gb){
+static inline int decode210(GetBitContext *gb)
+{
if (get_bits1(gb))
return 0;
else
return 2 - get_bits1(gb);
}
+static inline int get_bits_left(GetBitContext *gb)
+{
+ return gb->size_in_bits - get_bits_count(gb);
+}
+
#endif /* AVCODEC_GET_BITS_H */