/* * 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 #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