mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-11 17:55:21 +00:00
71 lines
1.9 KiB
C
71 lines
1.9 KiB
C
/*
|
|
* 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
|
|
* leb128 handling implementations
|
|
*/
|
|
|
|
#ifndef AVCODEC_LEB_H
|
|
#define AVCODEC_LEB_H
|
|
|
|
#include "get_bits.h"
|
|
|
|
/**
|
|
* Read a unsigned integer coded as a variable number of up to eight
|
|
* little-endian bytes, where the MSB in a byte signals another byte
|
|
* must be read.
|
|
* All coded bits are read, but values > UINT_MAX are truncated.
|
|
*/
|
|
static inline unsigned get_leb(GetBitContext *s) {
|
|
int more, i = 0;
|
|
unsigned leb = 0;
|
|
|
|
do {
|
|
int byte = get_bits(s, 8);
|
|
unsigned bits = byte & 0x7f;
|
|
more = byte & 0x80;
|
|
if (i <= 4)
|
|
leb |= bits << (i * 7);
|
|
if (++i == 8)
|
|
break;
|
|
} while (more);
|
|
|
|
return leb;
|
|
}
|
|
|
|
/**
|
|
* Read a unsigned integer coded as a variable number of up to eight
|
|
* little-endian bytes, where the MSB in a byte signals another byte
|
|
* must be read.
|
|
*/
|
|
static inline int64_t get_leb128(GetBitContext *gb) {
|
|
int64_t ret = 0;
|
|
|
|
for (int i = 0; i < 8; i++) {
|
|
int byte = get_bits(gb, 8);
|
|
ret |= (int64_t)(byte & 0x7f) << (i * 7);
|
|
if (!(byte & 0x80))
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
#endif /* AVCODEC_LEB_H */
|