| /* | |
| * 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 |