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71 lines
1.9 KiB
71 lines
1.9 KiB
11 months ago
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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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* leb128 handling implementations
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*/
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#ifndef AVCODEC_LEB_H
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#define AVCODEC_LEB_H
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#include "get_bits.h"
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/**
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* Read a unsigned integer coded as a variable number of up to eight
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* little-endian bytes, where the MSB in a byte signals another byte
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* must be read.
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* All coded bits are read, but values > UINT_MAX are truncated.
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*/
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static inline unsigned get_leb(GetBitContext *s) {
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int more, i = 0;
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unsigned leb = 0;
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do {
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int byte = get_bits(s, 8);
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unsigned bits = byte & 0x7f;
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more = byte & 0x80;
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if (i <= 4)
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leb |= bits << (i * 7);
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if (++i == 8)
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break;
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} while (more);
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return leb;
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}
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/**
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* Read a unsigned integer coded as a variable number of up to eight
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* little-endian bytes, where the MSB in a byte signals another byte
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* must be read.
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*/
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static inline int64_t get_leb128(GetBitContext *gb) {
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int64_t ret = 0;
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for (int i = 0; i < 8; i++) {
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int byte = get_bits(gb, 8);
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ret |= (int64_t)(byte & 0x7f) << (i * 7);
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if (!(byte & 0x80))
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break;
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}
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return ret;
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}
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#endif /* AVCODEC_LEB_H */
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