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200 lines
7.1 KiB
200 lines
7.1 KiB
/* |
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* Copyright (c) 2016 Alexandra Hájková |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/** |
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* @file |
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* bitstream reader API header. |
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*/ |
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/* |
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* Bit order (endianness) is controlled by #defining BITSTREAM_BE and/or |
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* BITSTREAM_LE before #including this header. The corresponding bitreading |
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* functions are provided as bits_*_be()/bits_*_le() respectively. |
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* |
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* If neither or only BITSTREAM_BE is defined, then the default (unsuffixed) |
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* bits_*() will resolve to the big-endian implementation. If only BITSTREAM_LE |
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* is defined, little-endian will be the default. |
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* |
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* If both are defined, then the default can be controlled by defining at most |
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* one of BITSTREAM_DEFAULT_LE/BE. When BITSTREAM_DEFAULT_* is not defined, no |
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* default is provided and you must always explicitly use the _be() or _le() |
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* variants. |
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*/ |
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#ifndef AVCODEC_BITSTREAM_H |
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#define AVCODEC_BITSTREAM_H |
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#include <stdint.h> |
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#include "config.h" |
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#include "libavutil/avassert.h" |
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#include "libavutil/common.h" |
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#include "libavutil/intreadwrite.h" |
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#include "libavutil/log.h" |
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#include "mathops.h" |
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#include "vlc.h" |
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#ifndef UNCHECKED_BITSTREAM_READER |
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#define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER |
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#endif |
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// select the default endianness, if any |
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#if defined(BITSTREAM_LE) && defined(BITSTREAM_BE) |
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# if defined(BITSTREAM_DEFAULT_BE) && defined(BITSTREAM_DEFAULT_LE) |
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# error "At most one of BITSTREAM_DEFAULT_BE/LE must be defined" |
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# elif defined(BITSTREAM_DEFAULT_BE) |
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# define BITS_DEFAULT_BE |
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# elif defined(BITSTREAM_DEFAULT_LE) |
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# define BITS_DEFAULT_LE |
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# endif |
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#elif defined(BITSTREAM_LE) |
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# define BITS_DEFAULT_LE |
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#else // select BE if nothing is requested explicitly |
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# define BITS_DEFAULT_BE |
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# define BITSTREAM_WANT_BE |
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#endif |
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#if defined(BITS_DEFAULT_LE) |
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# define BitstreamContext BitstreamContextLE |
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# define bits_init bits_init_le |
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# define bits_init8 bits_init8_le |
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# define bits_tell bits_tell_le |
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# define bits_size bits_size_le |
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# define bits_left bits_left_le |
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# define bits_read_bit bits_read_bit_le |
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# define bits_read_nz bits_read_nz_le |
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# define bits_read bits_read_le |
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# define bits_read_63 bits_read_63_le |
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# define bits_read_64 bits_read_64_le |
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# define bits_read_signed bits_read_signed_le |
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# define bits_read_signed_nz bits_read_signed_nz_le |
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# define bits_peek_nz bits_peek_nz_le |
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# define bits_peek bits_peek_le |
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# define bits_peek_signed bits_peek_signed_le |
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# define bits_peek_signed_nz bits_peek_signed_nz_le |
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# define bits_skip bits_skip_le |
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# define bits_seek bits_seek_le |
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# define bits_align bits_align_le |
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# define bits_read_xbits bits_read_xbits_le |
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# define bits_decode012 bits_decode012_le |
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# define bits_decode210 bits_decode210_le |
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# define bits_apply_sign bits_apply_sign_le |
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# define bits_read_vlc bits_read_vlc_le |
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# define bits_read_vlc_multi bits_read_vlc_multi_le |
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# define bits_read_leb bits_read_leb_le |
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#elif defined(BITS_DEFAULT_BE) |
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# define BitstreamContext BitstreamContextBE |
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# define bits_init bits_init_be |
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# define bits_init8 bits_init8_be |
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# define bits_tell bits_tell_be |
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# define bits_size bits_size_be |
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# define bits_left bits_left_be |
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# define bits_read_bit bits_read_bit_be |
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# define bits_read_nz bits_read_nz_be |
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# define bits_read bits_read_be |
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# define bits_read_63 bits_read_63_be |
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# define bits_read_64 bits_read_64_be |
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# define bits_read_signed bits_read_signed_be |
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# define bits_read_signed_nz bits_read_signed_nz_be |
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# define bits_peek_nz bits_peek_nz_be |
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# define bits_peek bits_peek_be |
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# define bits_peek_signed bits_peek_signed_be |
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# define bits_peek_signed_nz bits_peek_signed_nz_be |
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# define bits_skip bits_skip_be |
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# define bits_seek bits_seek_be |
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# define bits_align bits_align_be |
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# define bits_read_xbits bits_read_xbits_be |
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# define bits_decode012 bits_decode012_be |
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# define bits_decode210 bits_decode210_be |
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# define bits_apply_sign bits_apply_sign_be |
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# define bits_read_vlc bits_read_vlc_be |
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# define bits_read_vlc_multi bits_read_vlc_multi_be |
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# define bits_read_leb bits_read_leb_be |
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#endif |
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#undef BITS_DEFAULT_LE |
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#undef BITS_DEFAULT_BE |
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#define BITS_RL_VLC(level, run, bc, table, bits, max_depth) \ |
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do { \ |
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int n, nb_bits; \ |
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unsigned int index = bits_peek(bc, bits); \ |
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level = table[index].level; \ |
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n = table[index].len; \ |
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\ |
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if (max_depth > 1 && n < 0) { \ |
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bits_skip(bc, bits); \ |
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\ |
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nb_bits = -n; \ |
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\ |
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index = bits_peek(bc, nb_bits) + level; \ |
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level = table[index].level; \ |
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n = table[index].len; \ |
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if (max_depth > 2 && n < 0) { \ |
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bits_skip(bc, nb_bits); \ |
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nb_bits = -n; \ |
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\ |
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index = bits_peek(bc, nb_bits) + level; \ |
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level = table[index].level; \ |
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n = table[index].len; \ |
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} \ |
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} \ |
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run = table[index].run; \ |
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bits_skip(bc, n); \ |
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} while (0) |
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#endif /* AVCODEC_BITSTREAM_H */ |
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// the following is deliberately outside of the standard #include guards |
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#if defined(BITSTREAM_LE) && !defined(BITSTREAM_WANT_LE) |
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# define BITSTREAM_WANT_LE |
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#endif |
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#if defined(BITSTREAM_BE) && !defined(BITSTREAM_WANT_BE) |
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# define BITSTREAM_WANT_BE |
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#endif |
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#if defined(BITSTREAM_WANT_LE) && !defined(AVCODEC_BITSTREAM_LE) |
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#define AVCODEC_BITSTREAM_LE |
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#define BITSTREAM_TEMPLATE_LE |
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#include "bitstream_template.h" |
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#undef BITSTREAM_TEMPLATE_LE |
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#endif |
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#if defined(BITSTREAM_WANT_BE) && !defined(AVCODEC_BITSTREAM_BE) |
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#define AVCODEC_BITSTREAM_BE |
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#include "bitstream_template.h" |
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#endif |
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#undef BITSTREAM_WANT_LE |
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#undef BITSTREAM_WANT_BE
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