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lavc/get_bits: add a compat wrapper for the cached bitstream reader

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Use that instead of the merged version.
pull/388/head
Anton Khirnov 4 years ago
parent b6742259bf
commit fcd557a2c2
1 changed files with 62 additions and 247 deletions
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  1. 309
      libavcodec/get_bits.h

309
libavcodec/get_bits.h
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@ -1,6 +1,5 @@
/*
* Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
* Copyright (c) 2016 Alexandra Hájková
*
* This file is part of FFmpeg.
*
@ -58,12 +57,55 @@
#define CACHED_BITSTREAM_READER 0
#endif
typedef struct GetBitContext {
const uint8_t *buffer, *buffer_end;
#if CACHED_BITSTREAM_READER
uint64_t cache;
unsigned bits_left;
// we always want the LE implementation, to provide get_bits_le()
#define BITSTREAM_LE
#ifndef BITSTREAM_READER_LE
# define BITSTREAM_BE
# define BITSTREAM_DEFAULT_BE
#endif
#include "bitstream.h"
#undef BITSTREAM_LE
#undef BITSTREAM_BE
#undef BITSTREAM_DEFAULT_BE
typedef BitstreamContext GetBitContext;
#define get_bits_count bits_tell
#define get_bits_left bits_left
#define skip_bits_long bits_skip
#define skip_bits bits_skip
#define get_bits bits_read_nz
#define get_bitsz bits_read
#define get_bits_long bits_read
#define get_bits1 bits_read_bit
#define get_bits64 bits_read_64
#define get_xbits bits_read_xbits
#define get_sbits bits_read_signed
#define get_sbits_long bits_read_signed
#define show_bits bits_peek
#define show_bits_long bits_peek
#define init_get_bits bits_init
#define init_get_bits8 bits_init8
#define align_get_bits bits_align
#define get_vlc2 bits_read_vlc
#define init_get_bits8_le(s, buffer, byte_size) bits_init8_le((BitstreamContextLE*)s, buffer, byte_size)
#define get_bits_le(s, n) bits_read_le((BitstreamContextLE*)s, n)
#define show_bits1(s) bits_peek(s, 1)
#define skip_bits1(s) bits_skip(s, 1)
#define skip_1stop_8data_bits bits_skip_1stop_8data
#else // CACHED_BITSTREAM_READER
typedef struct GetBitContext {
const uint8_t *buffer, *buffer_end;
int index;
int size_in_bits;
int size_in_bits_plus8;
@ -120,16 +162,12 @@ static inline unsigned int show_bits(GetBitContext *s, int n);
* For examples see get_bits, show_bits, skip_bits, get_vlc.
*/
#if CACHED_BITSTREAM_READER
# define MIN_CACHE_BITS 64
#elif defined LONG_BITSTREAM_READER
#if defined LONG_BITSTREAM_READER
# define MIN_CACHE_BITS 32
#else
# define MIN_CACHE_BITS 25
#endif
#if !CACHED_BITSTREAM_READER
#define OPEN_READER_NOSIZE(name, gb) \
unsigned int name ## _index = (gb)->index; \
unsigned int av_unused name ## _cache
@ -214,73 +252,12 @@ static inline unsigned int show_bits(GetBitContext *s, int n);
#define GET_CACHE(name, gb) ((uint32_t) name ## _cache)
#endif
static inline int get_bits_count(const GetBitContext *s)
{
#if CACHED_BITSTREAM_READER
return s->index - s->bits_left;
#else
return s->index;
#endif
}
#if CACHED_BITSTREAM_READER
static inline void refill_32(GetBitContext *s, int is_le)
{
#if !UNCHECKED_BITSTREAM_READER
if (s->index >> 3 >= s->buffer_end - s->buffer)
return;
#endif
if (is_le)
s->cache = (uint64_t)AV_RL32(s->buffer + (s->index >> 3)) << s->bits_left | s->cache;
else
s->cache = s->cache | (uint64_t)AV_RB32(s->buffer + (s->index >> 3)) << (32 - s->bits_left);
s->index += 32;
s->bits_left += 32;
}
static inline void refill_64(GetBitContext *s, int is_le)
{
#if !UNCHECKED_BITSTREAM_READER
if (s->index >> 3 >= s->buffer_end - s->buffer)
return;
#endif
if (is_le)
s->cache = AV_RL64(s->buffer + (s->index >> 3));
else
s->cache = AV_RB64(s->buffer + (s->index >> 3));
s->index += 64;
s->bits_left = 64;
}
static inline uint64_t get_val(GetBitContext *s, unsigned n, int is_le)
{
uint64_t ret;
av_assert2(n>0 && n<=63);
if (is_le) {
ret = s->cache & ((UINT64_C(1) << n) - 1);
s->cache >>= n;
} else {
ret = s->cache >> (64 - n);
s->cache <<= n;
}
s->bits_left -= n;
return ret;
}
static inline unsigned show_val(const GetBitContext *s, unsigned n)
{
#ifdef BITSTREAM_READER_LE
return s->cache & ((UINT64_C(1) << n) - 1);
#else
return s->cache >> (64 - n);
#endif
}
#endif
/**
* Skips the specified number of bits.
* @param n the number of bits to skip,
@ -290,28 +267,12 @@ static inline unsigned show_val(const GetBitContext *s, unsigned n)
*/
static inline void skip_bits_long(GetBitContext *s, int n)
{
#if CACHED_BITSTREAM_READER
skip_bits(s, n);
#else
#if UNCHECKED_BITSTREAM_READER
s->index += n;
#else
s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index);
#endif
#endif
}
#if CACHED_BITSTREAM_READER
static inline void skip_remaining(GetBitContext *s, unsigned n)
{
#ifdef BITSTREAM_READER_LE
s->cache >>= n;
#else
s->cache <<= n;
#endif
s->bits_left -= n;
}
#endif
/**
* Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
@ -320,13 +281,6 @@ static inline void skip_remaining(GetBitContext *s, unsigned n)
*/
static inline int get_xbits(GetBitContext *s, int n)
{
#if CACHED_BITSTREAM_READER
int32_t cache = show_bits(s, 32);
int sign = ~cache >> 31;
skip_remaining(s, n);
return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
#else
register int sign;
register int32_t cache;
OPEN_READER(re, s);
@ -337,10 +291,8 @@ static inline int get_xbits(GetBitContext *s, int n)
LAST_SKIP_BITS(re, s, n);
CLOSE_READER(re, s);
return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
#endif
}
#if !CACHED_BITSTREAM_READER
static inline int get_xbits_le(GetBitContext *s, int n)
{
register int sign;
@ -354,22 +306,16 @@ static inline int get_xbits_le(GetBitContext *s, int n)
CLOSE_READER(re, s);
return (zero_extend(sign ^ cache, n) ^ sign) - sign;
}
#endif
static inline int get_sbits(GetBitContext *s, int n)
{
register int tmp;
#if CACHED_BITSTREAM_READER
av_assert2(n>0 && n<=25);
tmp = sign_extend(get_bits(s, n), n);
#else
OPEN_READER(re, s);
av_assert2(n>0 && n<=25);
UPDATE_CACHE(re, s);
tmp = SHOW_SBITS(re, s, n);
LAST_SKIP_BITS(re, s, n);
CLOSE_READER(re, s);
#endif
return tmp;
}
@ -379,32 +325,12 @@ static inline int get_sbits(GetBitContext *s, int n)
static inline unsigned int get_bits(GetBitContext *s, int n)
{
register unsigned int tmp;
#if CACHED_BITSTREAM_READER
av_assert2(n>0 && n<=32);
if (n > s->bits_left) {
#ifdef BITSTREAM_READER_LE
refill_32(s, 1);
#else
refill_32(s, 0);
#endif
if (s->bits_left < 32)
s->bits_left = n;
}
#ifdef BITSTREAM_READER_LE
tmp = get_val(s, n, 1);
#else
tmp = get_val(s, n, 0);
#endif
#else
OPEN_READER(re, s);
av_assert2(n>0 && n<=25);
UPDATE_CACHE(re, s);
tmp = SHOW_UBITS(re, s, n);
LAST_SKIP_BITS(re, s, n);
CLOSE_READER(re, s);
#endif
av_assert2(tmp < UINT64_C(1) << n);
return tmp;
}
@ -419,16 +345,6 @@ static av_always_inline int get_bitsz(GetBitContext *s, int n)
static inline unsigned int get_bits_le(GetBitContext *s, int n)
{
#if CACHED_BITSTREAM_READER
av_assert2(n>0 && n<=32);
if (n > s->bits_left) {
refill_32(s, 1);
if (s->bits_left < 32)
s->bits_left = n;
}
return get_val(s, n, 1);
#else
register int tmp;
OPEN_READER(re, s);
av_assert2(n>0 && n<=25);
@ -437,7 +353,6 @@ static inline unsigned int get_bits_le(GetBitContext *s, int n)
LAST_SKIP_BITS(re, s, n);
CLOSE_READER(re, s);
return tmp;
#endif
}
/**
@ -446,71 +361,22 @@ static inline unsigned int get_bits_le(GetBitContext *s, int n)
static inline unsigned int show_bits(GetBitContext *s, int n)
{
register unsigned int tmp;
#if CACHED_BITSTREAM_READER
if (n > s->bits_left)
#ifdef BITSTREAM_READER_LE
refill_32(s, 1);
#else
refill_32(s, 0);
#endif
tmp = show_val(s, n);
#else
OPEN_READER_NOSIZE(re, s);
av_assert2(n>0 && n<=25);
UPDATE_CACHE(re, s);
tmp = SHOW_UBITS(re, s, n);
#endif
return tmp;
}
static inline void skip_bits(GetBitContext *s, int n)
{
#if CACHED_BITSTREAM_READER
if (n < s->bits_left)
skip_remaining(s, n);
else {
n -= s->bits_left;
s->cache = 0;
s->bits_left = 0;
if (n >= 64) {
unsigned skip = (n / 8) * 8;
n -= skip;
s->index += skip;
}
#ifdef BITSTREAM_READER_LE
refill_64(s, 1);
#else
refill_64(s, 0);
#endif
if (n)
skip_remaining(s, n);
}
#else
OPEN_READER(re, s);
LAST_SKIP_BITS(re, s, n);
CLOSE_READER(re, s);
#endif
}
static inline unsigned int get_bits1(GetBitContext *s)
{
#if CACHED_BITSTREAM_READER
if (!s->bits_left)
#ifdef BITSTREAM_READER_LE
refill_64(s, 1);
#else
refill_64(s, 0);
#endif
#ifdef BITSTREAM_READER_LE
return get_val(s, 1, 1);
#else
return get_val(s, 1, 0);
#endif
#else
unsigned int index = s->index;
uint8_t result = s->buffer[index >> 3];
#ifdef BITSTREAM_READER_LE
@ -527,7 +393,6 @@ static inline unsigned int get_bits1(GetBitContext *s)
s->index = index;
return result;
#endif
}
static inline unsigned int show_bits1(GetBitContext *s)
@ -548,10 +413,6 @@ static inline unsigned int get_bits_long(GetBitContext *s, int n)
av_assert2(n>=0 && n<=32);
if (!n) {
return 0;
#if CACHED_BITSTREAM_READER
}
return get_bits(s, n);
#else
} else if (n <= MIN_CACHE_BITS) {
return get_bits(s, n);
} else {
@ -563,7 +424,6 @@ static inline unsigned int get_bits_long(GetBitContext *s, int n)
return ret | get_bits(s, n - 16);
#endif
}
#endif
}
/**
@ -621,8 +481,17 @@ static inline unsigned int show_bits_long(GetBitContext *s, int n)
}
}
static inline int init_get_bits_xe(GetBitContext *s, const uint8_t *buffer,
int bit_size, int is_le)
/**
* 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
* @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
*/
static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
int bit_size)
{
int buffer_size;
int ret = 0;
@ -641,33 +510,9 @@ static inline int init_get_bits_xe(GetBitContext *s, const uint8_t *buffer,
s->buffer_end = buffer + buffer_size;
s->index = 0;
#if CACHED_BITSTREAM_READER
s->cache = 0;
s->bits_left = 0;
refill_64(s, is_le);
#endif
return ret;
}
/**
* 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
* @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
*/
static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
int bit_size)
{
#ifdef BITSTREAM_READER_LE
return init_get_bits_xe(s, buffer, bit_size, 1);
#else
return init_get_bits_xe(s, buffer, bit_size, 0);
#endif
}
/**
* Initialize GetBitContext.
* @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
@ -689,7 +534,7 @@ static inline int init_get_bits8_le(GetBitContext *s, const uint8_t *buffer,
{
if (byte_size > INT_MAX / 8 || byte_size < 0)
byte_size = -1;
return init_get_bits_xe(s, buffer, byte_size * 8, 1);
return init_get_bits(s, buffer, byte_size * 8);
}
static inline const uint8_t *align_get_bits(GetBitContext *s)
@ -774,19 +619,6 @@ static inline const uint8_t *align_get_bits(GetBitContext *s)
SKIP_BITS(name, gb, n); \
} while (0)
/* Return the LUT element for the given bitstream configuration. */
static inline int set_idx(GetBitContext *s, int code, int *n, int *nb_bits,
const VLCElem *table)
{
unsigned idx;
*nb_bits = -*n;
idx = show_bits(s, *nb_bits) + code;
*n = table[idx].len;
return table[idx].sym;
}
/**
* Parse a vlc code.
* @param bits is the number of bits which will be read at once, must be
@ -799,24 +631,6 @@ static inline int set_idx(GetBitContext *s, int code, int *n, int *nb_bits,
static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table,
int bits, int max_depth)
{
#if CACHED_BITSTREAM_READER
int nb_bits;
unsigned idx = show_bits(s, bits);
int code = table[idx].sym;
int n = table[idx].len;
if (max_depth > 1 && n < 0) {
skip_remaining(s, bits);
code = set_idx(s, code, &n, &nb_bits, table);
if (max_depth > 2 && n < 0) {
skip_remaining(s, nb_bits);
code = set_idx(s, code, &n, &nb_bits, table);
}
}
skip_remaining(s, n);
return code;
#else
int code;
OPEN_READER(re, s);
@ -827,7 +641,6 @@ static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table,
CLOSE_READER(re, s);
return code;
#endif
}
static inline int decode012(GetBitContext *gb)
@ -867,4 +680,6 @@ static inline int skip_1stop_8data_bits(GetBitContext *gb)
return 0;
}
#endif // CACHED_BITSTREAM_READER
#endif /* AVCODEC_GET_BITS_H */

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