libavcodec/bitstream.h - third_party/ffmpeg - Git at Google

 /*
  * 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
	/*
	* 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