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70 lines
1.9 KiB
70 lines
1.9 KiB
/* |
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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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