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lavc/bitstream: templatize for BE/LE

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Allows using both BE and LE bitstream readers in the same file.
This commit is contained in:
Anton Khirnov 2021-01-28 13:23:23 +01:00
parent 8fe551eca0
commit 9177970bca
4 changed files with 609 additions and 448 deletions
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1
libavcodec/Makefile
View File

@ -1252,6 +1252,7 @@ SKIPHEADERS += %_tablegen.h \
aaccoder_trellis.h \ aaccoder_trellis.h \
aacenc_quantization.h \ aacenc_quantization.h \
aacenc_quantization_misc.h \ aacenc_quantization_misc.h \
bitstream_template.h \
$(ARCH)/vpx_arith.h \ $(ARCH)/vpx_arith.h \
SKIPHEADERS-$(CONFIG_AMF) += amfenc.h SKIPHEADERS-$(CONFIG_AMF) += amfenc.h

559
libavcodec/bitstream.h
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@ -23,6 +23,21 @@
* bitstream reader API header. * bitstream reader API header.
*/ */
/*
* Bit order (endianness) is controlled by #defining BITSTREAM_BE and/or
* BITSTREAM_LE before #including this header. The corresponding bitreading
* functions are provided as bits_*_be()/bits_*_le() respectively.
*
* If neither or only BITSTREAM_BE is defined, then the default (unsuffixed)
* bits_*() will resolve to the big-endian implementation. If only BITSTREAM_LE
* is defined, little-endian will be the default.
*
* If both are defined, then the default can be controlled by defining at most
* one of BITSTREAM_DEFAULT_LE/BE. When BITSTREAM_DEFAULT_* is not defined, no
* default is provided and you must always explicitly use the _be() or _le()
* variants.
*/
#ifndef AVCODEC_BITSTREAM_H #ifndef AVCODEC_BITSTREAM_H
#define AVCODEC_BITSTREAM_H #define AVCODEC_BITSTREAM_H
@ -42,461 +57,80 @@
#define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
#endif #endif
typedef struct BitstreamContext { // select the default endianness, if any
uint64_t bits; // stores bits read from the buffer #if defined(BITSTREAM_LE) && defined(BITSTREAM_BE)
const uint8_t *buffer, *buffer_end;
const uint8_t *ptr; // pointer to the position inside a buffer
unsigned bits_valid; // number of bits left in bits field
unsigned size_in_bits;
} BitstreamContext;
/** # if defined(BITSTREAM_DEFAULT_BE) && defined(BITSTREAM_DEFAULT_LE)
* @return # error "At most one of BITSTREAM_DEFAULT_BE/LE must be defined"
* - 0 on successful refill # elif defined(BITSTREAM_DEFAULT_BE)
* - a negative number when bitstream end is hit # define BITS_DEFAULT_BE
* # elif defined(BITSTREAM_DEFAULT_LE)
* Always succeeds when UNCHECKED_BITSTREAM_READER is enabled. # define BITS_DEFAULT_LE
*/ # endif
static inline int bits_priv_refill_64(BitstreamContext *bc)
{ #elif defined(BITSTREAM_LE)
#if !UNCHECKED_BITSTREAM_READER # define BITS_DEFAULT_LE
if (bc->ptr >= bc->buffer_end) #else // select BE if nothing is requested explicitly
return -1; # define BITS_DEFAULT_BE
# define BITSTREAM_WANT_BE
#endif #endif
#ifdef BITSTREAM_READER_LE #if defined(BITS_DEFAULT_LE)
bc->bits = AV_RL64(bc->ptr);
#else
bc->bits = AV_RB64(bc->ptr);
#endif
bc->ptr += 8;
bc->bits_valid = 64;
return 0; # define BitstreamContext BitstreamContextLE
} # define bits_init bits_init_le
# define bits_init8 bits_init8_le
# define bits_tell bits_tell_le
# define bits_size bits_size_le
# define bits_left bits_left_le
# define bits_read_bit bits_read_bit_le
# define bits_read_nz bits_read_nz_le
# define bits_read bits_read_le
# define bits_read_63 bits_read_63_le
# define bits_read_64 bits_read_64_le
# define bits_read_signed bits_read_signed_le
# define bits_peek_nz bits_peek_nz_le
# define bits_peek bits_peek_le
# define bits_peek_signed bits_peek_signed_le
# define bits_skip bits_skip_le
# define bits_seek bits_seek_le
# define bits_align bits_align_le
# define bits_read_xbits bits_read_xbits_le
# define bits_decode012 bits_decode012_le
# define bits_decode210 bits_decode210_le
# define bits_apply_sign bits_apply_sign_le
# define bits_read_vlc bits_read_vlc_le
#elif defined(BITS_DEFAULT_BE)
# define BitstreamContext BitstreamContextBE
# define bits_init bits_init_be
# define bits_init8 bits_init8_be
# define bits_tell bits_tell_be
# define bits_size bits_size_be
# define bits_left bits_left_be
# define bits_read_bit bits_read_bit_be
# define bits_read_nz bits_read_nz_be
# define bits_read bits_read_be
# define bits_read_63 bits_read_63_be
# define bits_read_64 bits_read_64_be
# define bits_read_signed bits_read_signed_be
# define bits_peek_nz bits_peek_nz_be
# define bits_peek bits_peek_be
# define bits_peek_signed bits_peek_signed_be
# define bits_skip bits_skip_be
# define bits_seek bits_seek_be
# define bits_align bits_align_be
# define bits_read_xbits bits_read_xbits_be
# define bits_decode012 bits_decode012_be
# define bits_decode210 bits_decode210_be
# define bits_apply_sign bits_apply_sign_be
# define bits_read_vlc bits_read_vlc_be
/**
* @return
* - 0 on successful refill
* - a negative number when bitstream end is hit
*
* Always succeeds when UNCHECKED_BITSTREAM_READER is enabled.
*/
static inline int bits_priv_refill_32(BitstreamContext *bc)
{
#if !UNCHECKED_BITSTREAM_READER
if (bc->ptr >= bc->buffer_end)
return -1;
#endif #endif
#ifdef BITSTREAM_READER_LE #undef BITS_DEFAULT_LE
bc->bits |= (uint64_t)AV_RL32(bc->ptr) << bc->bits_valid; #undef BITS_DEFAULT_BE
#else
bc->bits |= (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_valid);
#endif
bc->ptr += 4;
bc->bits_valid += 32;
return 0;
}
/**
* Initialize BitstreamContext.
* @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 bits 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 bits_init(BitstreamContext *bc, const uint8_t *buffer,
unsigned int bit_size)
{
unsigned int buffer_size;
if (bit_size > INT_MAX - 7 || !buffer) {
bc->buffer = NULL;
bc->ptr = NULL;
bc->bits_valid = 0;
return AVERROR_INVALIDDATA;
}
buffer_size = (bit_size + 7) >> 3;
bc->buffer = buffer;
bc->buffer_end = buffer + buffer_size;
bc->ptr = bc->buffer;
bc->size_in_bits = bit_size;
bc->bits_valid = 0;
bc->bits = 0;
bits_priv_refill_64(bc);
return 0;
}
/**
* Initialize BitstreamContext.
* @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 bits 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
*/
static inline int bits_init8(BitstreamContext *bc, const uint8_t *buffer,
unsigned int byte_size)
{
if (byte_size > INT_MAX / 8)
return AVERROR_INVALIDDATA;
return bits_init(bc, buffer, byte_size * 8);
}
/**
* Return number of bits already read.
*/
static inline int bits_tell(const BitstreamContext *bc)
{
return (bc->ptr - bc->buffer) * 8 - bc->bits_valid;
}
/**
* Return buffer size in bits.
*/
static inline int bits_size(const BitstreamContext *bc)
{
return bc->size_in_bits;
}
/**
* Return the number of the bits left in a buffer.
*/
static inline int bits_left(const BitstreamContext *bc)
{
return (bc->buffer - bc->ptr) * 8 + bc->size_in_bits + bc->bits_valid;
}
static inline uint64_t bits_priv_val_show(BitstreamContext *bc, unsigned int n)
{
av_assert2(n > 0 && n <= 64);
#ifdef BITSTREAM_READER_LE
return bc->bits & (UINT64_MAX >> (64 - n));
#else
return bc->bits >> (64 - n);
#endif
}
static inline void bits_priv_skip_remaining(BitstreamContext *bc, unsigned int n)
{
#ifdef BITSTREAM_READER_LE
bc->bits >>= n;
#else
bc->bits <<= n;
#endif
bc->bits_valid -= n;
}
static inline uint64_t bits_priv_val_get(BitstreamContext *bc, unsigned int n)
{
uint64_t ret;
av_assert2(n > 0 && n < 64);
ret = bits_priv_val_show(bc, n);
bits_priv_skip_remaining(bc, n);
return ret;
}
/**
* Return one bit from the buffer.
*/
static inline unsigned int bits_read_bit(BitstreamContext *bc)
{
if (!bc->bits_valid && bits_priv_refill_64(bc) < 0)
return 0;
return bits_priv_val_get(bc, 1);
}
/**
* Return n bits from the buffer, n has to be in the 1-32 range.
* May be faster than bits_read() when n is not a compile-time constant and is
* known to be non-zero;
*/
static inline uint32_t bits_read_nz(BitstreamContext *bc, unsigned int n)
{
av_assert2(n > 0 && n <= 32);
if (n > bc->bits_valid) {
if (bits_priv_refill_32(bc) < 0)
bc->bits_valid = n;
}
return bits_priv_val_get(bc, n);
}
/**
* Return n bits from the buffer, n has to be in the 0-32 range.
*/
static inline uint32_t bits_read(BitstreamContext *bc, unsigned int n)
{
av_assert2(n <= 32);
if (!n)
return 0;
return bits_read_nz(bc, n);
}
/**
* Return n bits from the buffer, n has to be in the 0-63 range.
*/
static inline uint64_t bits_read_63(BitstreamContext *bc, unsigned int n)
{
uint64_t ret = 0;
unsigned left = 0;
av_assert2(n <= 63);
if (!n)
return 0;
if (n > bc->bits_valid) {
left = bc->bits_valid;
n -= left;
if (left)
ret = bits_priv_val_get(bc, left);
if (bits_priv_refill_64(bc) < 0)
bc->bits_valid = n;
}
#ifdef BITSTREAM_READER_LE
ret = bits_priv_val_get(bc, n) << left | ret;
#else
ret = bits_priv_val_get(bc, n) | ret << n;
#endif
return ret;
}
/**
* Return n bits from the buffer, n has to be in the 0-64 range.
*/
static inline uint64_t bits_read_64(BitstreamContext *bc, unsigned int n)
{
av_assert2(n <= 64);
if (n == 64) {
uint64_t ret = bits_read_63(bc, 63);
#ifdef BITSTREAM_READER_LE
return ret | ((uint64_t)bits_read_bit(bc) << 63);
#else
return (ret << 1) | (uint64_t)bits_read_bit(bc);
#endif
}
return bits_read_63(bc, n);
}
/**
* Return n bits from the buffer as a signed integer.
* n has to be in the 0-32 range.
*/
static inline int32_t bits_read_signed(BitstreamContext *bc, unsigned int n)
{
return sign_extend(bits_read(bc, n), n);
}
/**
* Return n bits from the buffer but do not change the buffer state.
* n has to be in the 1-32 range. May
*/
static inline uint32_t bits_peek_nz(BitstreamContext *bc, unsigned int n)
{
av_assert2(n > 0 && n <= 32);
if (n > bc->bits_valid)
bits_priv_refill_32(bc);
return bits_priv_val_show(bc, n);
}
/**
* Return n bits from the buffer but do not change the buffer state.
* n has to be in the 0-32 range.
*/
static inline uint32_t bits_peek(BitstreamContext *bc, unsigned int n)
{
av_assert2(n <= 32);
if (!n)
return 0;
return bits_peek_nz(bc, n);
}
/**
* Return n bits from the buffer as a signed integer,
* do not change the buffer state.
* n has to be in the 0-32 range.
*/
static inline int bits_peek_signed(BitstreamContext *bc, unsigned int n)
{
return sign_extend(bits_peek(bc, n), n);
}
/**
* Skip n bits in the buffer.
*/
static inline void bits_skip(BitstreamContext *bc, unsigned int n)
{
if (n < bc->bits_valid)
bits_priv_skip_remaining(bc, n);
else {
n -= bc->bits_valid;
bc->bits = 0;
bc->bits_valid = 0;
if (n >= 64) {
unsigned int skip = n / 8;
n -= skip * 8;
bc->ptr += skip;
}
bits_priv_refill_64(bc);
if (n)
bits_priv_skip_remaining(bc, n);
}
}
/**
* Seek to the given bit position.
*/
static inline void bits_seek(BitstreamContext *bc, unsigned pos)
{
bc->ptr = bc->buffer;
bc->bits = 0;
bc->bits_valid = 0;
bits_skip(bc, pos);
}
/**
* Skip bits to a byte boundary.
*/
static inline const uint8_t *bits_align(BitstreamContext *bc)
{
unsigned int n = -bits_tell(bc) & 7;
if (n)
bits_skip(bc, n);
return bc->buffer + (bits_tell(bc) >> 3);
}
/**
* Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
* If MSB not set it is negative.
* @param n length in bits
*/
static inline int bits_read_xbits(BitstreamContext *bc, unsigned int n)
{
int32_t cache = bits_peek(bc, 32);
int sign = ~cache >> 31;
bits_priv_skip_remaining(bc, n);
return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
}
/**
* Return decoded truncated unary code for the values 0, 1, 2.
*/
static inline int bits_decode012(BitstreamContext *bc)
{
if (!bits_read_bit(bc))
return 0;
else
return bits_read_bit(bc) + 1;
}
/**
* Return decoded truncated unary code for the values 2, 1, 0.
*/
static inline int bits_decode210(BitstreamContext *bc)
{
if (bits_read_bit(bc))
return 0;
else
return 2 - bits_read_bit(bc);
}
/* Read sign bit and flip the sign of the provided value accordingly. */
static inline int bits_apply_sign(BitstreamContext *bc, int val)
{
int sign = bits_read_signed(bc, 1);
return (val ^ sign) - sign;
}
static inline int bits_skip_1stop_8data(BitstreamContext *s)
{
if (bits_left(s) <= 0)
return AVERROR_INVALIDDATA;
while (bits_read_bit(s)) {
bits_skip(s, 8);
if (bits_left(s) <= 0)
return AVERROR_INVALIDDATA;
}
return 0;
}
/**
* Return the LUT element for the given bitstream configuration.
*/
static inline int bits_priv_set_idx(BitstreamContext *bc, int code, int *n, int *nb_bits,
const VLCElem *table)
{
unsigned idx;
*nb_bits = -*n;
idx = bits_peek(bc, *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
* identical to nb_bits in init_vlc()
* @param max_depth is the number of times bits bits must be read to completely
* read the longest vlc code
* = (max_vlc_length + bits - 1) / bits
* 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.
*/
static inline int bits_read_vlc(BitstreamContext *bc, const VLCElem *table,
int bits, int max_depth)
{
int nb_bits;
unsigned idx = bits_peek(bc, bits);
int code = table[idx].sym;
int n = table[idx].len;
if (max_depth > 1 && n < 0) {
bits_priv_skip_remaining(bc, bits);
code = bits_priv_set_idx(bc, code, &n, &nb_bits, table);
if (max_depth > 2 && n < 0) {
bits_priv_skip_remaining(bc, nb_bits);
code = bits_priv_set_idx(bc, code, &n, &nb_bits, table);
}
}
bits_priv_skip_remaining(bc, n);
return code;
}
#define BITS_RL_VLC(level, run, bc, table, bits, max_depth) \ #define BITS_RL_VLC(level, run, bc, table, bits, max_depth) \
do { \ do { \
@ -527,3 +161,32 @@ static inline int bits_read_vlc(BitstreamContext *bc, const VLCElem *table,
} while (0) } while (0)
#endif /* AVCODEC_BITSTREAM_H */ #endif /* AVCODEC_BITSTREAM_H */
// the following is deliberately outside of the standard #include guards
#if defined(BITSTREAM_LE) && !defined(BITSTREAM_WANT_LE)
# define BITSTREAM_WANT_LE
#endif
#if defined(BITSTREAM_BE) && !defined(BITSTREAM_WANT_BE)
# define BITSTREAM_WANT_BE
#endif
#if defined(BITSTREAM_WANT_LE) && !defined(AVCODEC_BITSTREAM_LE)
#define AVCODEC_BITSTREAM_LE
#define BITSTREAM_TEMPLATE_LE
#include "bitstream_template.h"
#undef BITSTREAM_TEMPLATE_LE
#endif
#if defined(BITSTREAM_WANT_BE) && !defined(AVCODEC_BITSTREAM_BE)
#define AVCODEC_BITSTREAM_BE
#include "bitstream_template.h"
#endif
#undef BITSTREAM_WANT_LE
#undef BITSTREAM_WANT_BE

496
libavcodec/bitstream_template.h Normal file
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@ -0,0 +1,496 @@
/*
* Copyright (c) 2016 Alexandra Hájková
*
* 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
*/
#ifdef BITSTREAM_TEMPLATE_LE
# define BS_SUFFIX_LOWER _le
# define BS_SUFFIX_UPPER LE
#else
# define BS_SUFFIX_LOWER _be
# define BS_SUFFIX_UPPER BE
#endif
#define BS_JOIN(x, y, z) x ## y ## z
#define BS_JOIN3(x, y, z) BS_JOIN(x, y, z)
#define BS_FUNC(x) BS_JOIN3(bits_, x, BS_SUFFIX_LOWER)
#define BSCTX BS_JOIN3(Bitstream, Context, BS_SUFFIX_UPPER)
typedef struct BSCTX {
uint64_t bits; // stores bits read from the buffer
const uint8_t *buffer, *buffer_end;
const uint8_t *ptr; // pointer to the position inside a buffer
unsigned bits_valid; // number of bits left in bits field
unsigned size_in_bits;
} BSCTX;
/**
* @return
* - 0 on successful refill
* - a negative number when bitstream end is hit
*
* Always succeeds when UNCHECKED_BITSTREAM_READER is enabled.
*/
static inline int BS_FUNC(priv_refill_64)(BSCTX *bc)
{
#if !UNCHECKED_BITSTREAM_READER
if (bc->ptr >= bc->buffer_end)
return -1;
#endif
#ifdef BITSTREAM_TEMPLATE_LE
bc->bits = AV_RL64(bc->ptr);
#else
bc->bits = AV_RB64(bc->ptr);
#endif
bc->ptr += 8;
bc->bits_valid = 64;
return 0;
}
/**
* @return
* - 0 on successful refill
* - a negative number when bitstream end is hit
*
* Always succeeds when UNCHECKED_BITSTREAM_READER is enabled.
*/
static inline int BS_FUNC(priv_refill_32)(BSCTX *bc)
{
#if !UNCHECKED_BITSTREAM_READER
if (bc->ptr >= bc->buffer_end)
return -1;
#endif
#ifdef BITSTREAM_TEMPLATE_LE
bc->bits |= (uint64_t)AV_RL32(bc->ptr) << bc->bits_valid;
#else
bc->bits |= (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_valid);
#endif
bc->ptr += 4;
bc->bits_valid += 32;
return 0;
}
/**
* Initialize BitstreamContext.
* @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 bits 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 BS_FUNC(init)(BSCTX *bc, const uint8_t *buffer,
unsigned int bit_size)
{
unsigned int buffer_size;
if (bit_size > INT_MAX - 7 || !buffer) {
bc->buffer = NULL;
bc->ptr = NULL;
bc->bits_valid = 0;
return AVERROR_INVALIDDATA;
}
buffer_size = (bit_size + 7) >> 3;
bc->buffer = buffer;
bc->buffer_end = buffer + buffer_size;
bc->ptr = bc->buffer;
bc->size_in_bits = bit_size;
bc->bits_valid = 0;
bc->bits = 0;
BS_FUNC(priv_refill_64)(bc);
return 0;
}
/**
* Initialize BitstreamContext.
* @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 bits 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
*/
static inline int BS_FUNC(init8)(BSCTX *bc, const uint8_t *buffer,
unsigned int byte_size)
{
if (byte_size > INT_MAX / 8)
return AVERROR_INVALIDDATA;
return BS_FUNC(init)(bc, buffer, byte_size * 8);
}
/**
* Return number of bits already read.
*/
static inline int BS_FUNC(tell)(const BSCTX *bc)
{
return (bc->ptr - bc->buffer) * 8 - bc->bits_valid;
}
/**
* Return buffer size in bits.
*/
static inline int BS_FUNC(size)(const BSCTX *bc)
{
return bc->size_in_bits;
}
/**
* Return the number of the bits left in a buffer.
*/
static inline int BS_FUNC(left)(const BSCTX *bc)
{
return (bc->buffer - bc->ptr) * 8 + bc->size_in_bits + bc->bits_valid;
}
static inline uint64_t BS_FUNC(priv_val_show)(BSCTX *bc, unsigned int n)
{
av_assert2(n > 0 && n <= 64);
#ifdef BITSTREAM_TEMPLATE_LE
return bc->bits & (UINT64_MAX >> (64 - n));
#else
return bc->bits >> (64 - n);
#endif
}
static inline void BS_FUNC(priv_skip_remaining)(BSCTX *bc, unsigned int n)
{
#ifdef BITSTREAM_TEMPLATE_LE
bc->bits >>= n;
#else
bc->bits <<= n;
#endif
bc->bits_valid -= n;
}
static inline uint64_t BS_FUNC(priv_val_get)(BSCTX *bc, unsigned int n)
{
uint64_t ret;
av_assert2(n > 0 && n < 64);
ret = BS_FUNC(priv_val_show)(bc, n);
BS_FUNC(priv_skip_remaining)(bc, n);
return ret;
}
/**
* Return one bit from the buffer.
*/
static inline unsigned int BS_FUNC(read_bit)(BSCTX *bc)
{
if (!bc->bits_valid && BS_FUNC(priv_refill_64)(bc) < 0)
return 0;
return BS_FUNC(priv_val_get)(bc, 1);
}
/**
* Return n bits from the buffer, n has to be in the 1-32 range.
* May be faster than bits_read() when n is not a compile-time constant and is
* known to be non-zero;
*/
static inline uint32_t BS_FUNC(read_nz)(BSCTX *bc, unsigned int n)
{
av_assert2(n > 0 && n <= 32);
if (n > bc->bits_valid) {
if (BS_FUNC(priv_refill_32)(bc) < 0)
bc->bits_valid = n;
}
return BS_FUNC(priv_val_get)(bc, n);
}
/**
* Return n bits from the buffer, n has to be in the 0-32 range.
*/
static inline uint32_t BS_FUNC(read)(BSCTX *bc, unsigned int n)
{
av_assert2(n <= 32);
if (!n)
return 0;
return BS_FUNC(read_nz)(bc, n);
}
/**
* Return n bits from the buffer, n has to be in the 0-63 range.
*/
static inline uint64_t BS_FUNC(read_63)(BSCTX *bc, unsigned int n)
{
uint64_t ret = 0;
unsigned left = 0;
av_assert2(n <= 63);
if (!n)
return 0;
if (n > bc->bits_valid) {
left = bc->bits_valid;
n -= left;
if (left)
ret = BS_FUNC(priv_val_get)(bc, left);
if (BS_FUNC(priv_refill_64)(bc) < 0)
bc->bits_valid = n;
}
#ifdef BITSTREAM_TEMPLATE_LE
ret = BS_FUNC(priv_val_get)(bc, n) << left | ret;
#else
ret = BS_FUNC(priv_val_get)(bc, n) | ret << n;
#endif
return ret;
}
/**
* Return n bits from the buffer, n has to be in the 0-64 range.
*/
static inline uint64_t BS_FUNC(read_64)(BSCTX *bc, unsigned int n)
{
av_assert2(n <= 64);
if (n == 64) {
uint64_t ret = BS_FUNC(read_63)(bc, 63);
#ifdef BITSTREAM_TEMPLATE_LE
return ret | ((uint64_t)BS_FUNC(read_bit)(bc) << 63);
#else
return (ret << 1) | (uint64_t)BS_FUNC(read_bit)(bc);
#endif
}
return BS_FUNC(read_63)(bc, n);
}
/**
* Return n bits from the buffer as a signed integer.
* n has to be in the 0-32 range.
*/
static inline int32_t BS_FUNC(read_signed)(BSCTX *bc, unsigned int n)
{
return sign_extend(BS_FUNC(read)(bc, n), n);
}
/**
* Return n bits from the buffer but do not change the buffer state.
* n has to be in the 1-32 range. May
*/
static inline uint32_t BS_FUNC(peek_nz)(BSCTX *bc, unsigned int n)
{
av_assert2(n > 0 && n <= 32);
if (n > bc->bits_valid)
BS_FUNC(priv_refill_32)(bc);
return BS_FUNC(priv_val_show)(bc, n);
}
/**
* Return n bits from the buffer but do not change the buffer state.
* n has to be in the 0-32 range.
*/
static inline uint32_t BS_FUNC(peek)(BSCTX *bc, unsigned int n)
{
av_assert2(n <= 32);
if (!n)
return 0;
return BS_FUNC(peek_nz)(bc, n);
}
/**
* Return n bits from the buffer as a signed integer,
* do not change the buffer state.
* n has to be in the 0-32 range.
*/
static inline int BS_FUNC(peek_signed)(BSCTX *bc, unsigned int n)
{
return sign_extend(BS_FUNC(peek)(bc, n), n);
}
/**
* Skip n bits in the buffer.
*/
static inline void BS_FUNC(skip)(BSCTX *bc, unsigned int n)
{
if (n < bc->bits_valid)
BS_FUNC(priv_skip_remaining)(bc, n);
else {
n -= bc->bits_valid;
bc->bits = 0;
bc->bits_valid = 0;
if (n >= 64) {
unsigned int skip = n / 8;
n -= skip * 8;
bc->ptr += skip;
}
BS_FUNC(priv_refill_64)(bc);
if (n)
BS_FUNC(priv_skip_remaining)(bc, n);
}
}
/**
* Seek to the given bit position.
*/
static inline void BS_FUNC(seek)(BSCTX *bc, unsigned pos)
{
bc->ptr = bc->buffer;
bc->bits = 0;
bc->bits_valid = 0;
BS_FUNC(skip)(bc, pos);
}
/**
* Skip bits to a byte boundary.
*/
static inline const uint8_t *BS_FUNC(align)(BSCTX *bc)
{
unsigned int n = -BS_FUNC(tell)(bc) & 7;
if (n)
BS_FUNC(skip)(bc, n);
return bc->buffer + (BS_FUNC(tell)(bc) >> 3);
}
/**
* Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
* If MSB not set it is negative.
* @param n length in bits
*/
static inline int BS_FUNC(read_xbits)(BSCTX *bc, unsigned int n)
{
int32_t cache = BS_FUNC(peek)(bc, 32);
int sign = ~cache >> 31;
BS_FUNC(priv_skip_remaining)(bc, n);
return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
}
/**
* Return decoded truncated unary code for the values 0, 1, 2.
*/
static inline int BS_FUNC(decode012)(BSCTX *bc)
{
if (!BS_FUNC(read_bit)(bc))
return 0;
else
return BS_FUNC(read_bit)(bc) + 1;
}
/**
* Return decoded truncated unary code for the values 2, 1, 0.
*/
static inline int BS_FUNC(decode210)(BSCTX *bc)
{
if (BS_FUNC(read_bit)(bc))
return 0;
else
return 2 - BS_FUNC(read_bit)(bc);
}
/* Read sign bit and flip the sign of the provided value accordingly. */
static inline int BS_FUNC(apply_sign)(BSCTX *bc, int val)
{
int sign = BS_FUNC(read_signed)(bc, 1);
return (val ^ sign) - sign;
}
static inline int BS_FUNC(skip_1stop_8data)(BSCTX *s)
{
if (BS_FUNC(left)(s) <= 0)
return AVERROR_INVALIDDATA;
while (BS_FUNC(read_bit)(s)) {
BS_FUNC(skip)(s, 8);
if (BS_FUNC(left)(s) <= 0)
return AVERROR_INVALIDDATA;
}
return 0;
}
/**
* Return the LUT element for the given bitstream configuration.
*/
static inline int BS_FUNC(priv_set_idx)(BSCTX *bc, int code, int *n,
int *nb_bits, const VLCElem *table)
{
unsigned idx;
*nb_bits = -*n;
idx = BS_FUNC(peek)(bc, *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
* identical to nb_bits in init_vlc()
* @param max_depth is the number of times bits bits must be read to completely
* read the longest vlc code
* = (max_vlc_length + bits - 1) / bits
* 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.
*/
static inline int BS_FUNC(read_vlc)(BSCTX *bc, const VLCElem *table,
int bits, int max_depth)
{
int nb_bits;
unsigned idx = BS_FUNC(peek)(bc, bits);
int code = table[idx].sym;
int n = table[idx].len;
if (max_depth > 1 && n < 0) {
BS_FUNC(priv_skip_remaining)(bc, bits);
code = BS_FUNC(priv_set_idx)(bc, code, &n, &nb_bits, table);
if (max_depth > 2 && n < 0) {
BS_FUNC(priv_skip_remaining)(bc, nb_bits);
code = BS_FUNC(priv_set_idx)(bc, code, &n, &nb_bits, table);
}
}
BS_FUNC(priv_skip_remaining)(bc, n);
return code;
}
#undef BSCTX
#undef BS_FUNC
#undef BS_JOIN3
#undef BS_JOIN
#undef BS_SUFFIX_UPPER
#undef BS_SUFFIX_LOWER

1
tests/ref/fate/source
View File

@ -21,6 +21,7 @@ Headers without standard inclusion guards:
compat/djgpp/math.h compat/djgpp/math.h
compat/float/float.h compat/float/float.h
compat/float/limits.h compat/float/limits.h
libavcodec/bitstream_template.h
tools/decode_simple.h tools/decode_simple.h
Use of av_clip() where av_clip_uintp2() could be used: Use of av_clip() where av_clip_uintp2() could be used:
Use of av_clip() where av_clip_intp2() could be used: Use of av_clip() where av_clip_intp2() could be used: