FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/lagarithrac.c
Date: 2021-09-22 23:55:11
Exec Total Coverage
Lines: 16 16 100.0%
Branches: 4 4 100.0%

Line Branch Exec Source
1 /*
2 * Lagarith range decoder
3 * Copyright (c) 2009 Nathan Caldwell <saintdev (at) gmail.com>
4 * Copyright (c) 2009 David Conrad
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file
25 * Lagarith range decoder
26 * @author Nathan Caldwell
27 * @author David Conrad
28 */
29
30 #include "get_bits.h"
31 #include "lagarithrac.h"
32
33 126 void ff_lag_rac_init(lag_rac *l, GetBitContext *gb, int length)
34 {
35 int i, j, left;
36
37 /* According to reference decoder "1st byte is garbage",
38 * however, it gets skipped by the call to align_get_bits()
39 */
40 126 align_get_bits(gb);
41 126 left = get_bits_left(gb) >> 3;
42 126 l->bytestream_start =
43 126 l->bytestream = gb->buffer + get_bits_count(gb) / 8;
44 126 l->bytestream_end = l->bytestream_start + left;
45
46 126 l->range = 0x80;
47 126 l->low = *l->bytestream >> 1;
48 126 l->hash_shift = FFMAX(l->scale, 10) - 10;
49 126 l->overread = 0;
50
51
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129150 for (i = j = 0; i < 1024; i++) {
52 129024 unsigned r = i << l->hash_shift;
53
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161154 while (l->prob[j + 1] <= r)
54 32130 j++;
55 129024 l->range_hash[i] = j;
56 }
57 126 }
58