mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-28 20:53:54 +02:00
199 lines
7.0 KiB
C
199 lines
7.0 KiB
C
/*
|
|
* 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
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* 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
|
|
#define AVCODEC_BITSTREAM_H
|
|
|
|
#include <stdint.h>
|
|
|
|
#include "config.h"
|
|
|
|
#include "libavutil/avassert.h"
|
|
#include "libavutil/common.h"
|
|
#include "libavutil/intreadwrite.h"
|
|
#include "libavutil/log.h"
|
|
|
|
#include "mathops.h"
|
|
#include "vlc.h"
|
|
|
|
#ifndef UNCHECKED_BITSTREAM_READER
|
|
#define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
|
|
#endif
|
|
|
|
// select the default endianness, if any
|
|
#if defined(BITSTREAM_LE) && defined(BITSTREAM_BE)
|
|
|
|
# if defined(BITSTREAM_DEFAULT_BE) && defined(BITSTREAM_DEFAULT_LE)
|
|
# error "At most one of BITSTREAM_DEFAULT_BE/LE must be defined"
|
|
# elif defined(BITSTREAM_DEFAULT_BE)
|
|
# define BITS_DEFAULT_BE
|
|
# elif defined(BITSTREAM_DEFAULT_LE)
|
|
# define BITS_DEFAULT_LE
|
|
# endif
|
|
|
|
#elif defined(BITSTREAM_LE)
|
|
# define BITS_DEFAULT_LE
|
|
#else // select BE if nothing is requested explicitly
|
|
# define BITS_DEFAULT_BE
|
|
# define BITSTREAM_WANT_BE
|
|
#endif
|
|
|
|
#if defined(BITS_DEFAULT_LE)
|
|
|
|
# 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_read_signed_nz bits_read_signed_nz_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_peek_signed_nz bits_peek_signed_nz_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
|
|
# define bits_read_vlc_multi bits_read_vlc_multi_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_read_signed_nz bits_read_signed_nz_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_peek_signed_nz bits_peek_signed_nz_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
|
|
# define bits_read_vlc_multi bits_read_vlc_multi_be
|
|
|
|
#endif
|
|
|
|
#undef BITS_DEFAULT_LE
|
|
#undef BITS_DEFAULT_BE
|
|
|
|
#define BITS_RL_VLC(level, run, bc, table, bits, max_depth) \
|
|
do { \
|
|
int n, nb_bits; \
|
|
unsigned int index = bits_peek(bc, bits); \
|
|
level = table[index].level; \
|
|
n = table[index].len; \
|
|
\
|
|
if (max_depth > 1 && n < 0) { \
|
|
bits_skip(bc, bits); \
|
|
\
|
|
nb_bits = -n; \
|
|
\
|
|
index = bits_peek(bc, nb_bits) + level; \
|
|
level = table[index].level; \
|
|
n = table[index].len; \
|
|
if (max_depth > 2 && n < 0) { \
|
|
bits_skip(bc, nb_bits); \
|
|
nb_bits = -n; \
|
|
\
|
|
index = bits_peek(bc, nb_bits) + level; \
|
|
level = table[index].level; \
|
|
n = table[index].len; \
|
|
} \
|
|
} \
|
|
run = table[index].run; \
|
|
bits_skip(bc, n); \
|
|
} while (0)
|
|
|
|
#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
|