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/*
* 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
#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
#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
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