FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/lzf.c
Date: 2021-09-23 20:34:37
Exec Total Coverage
Lines: 24 35 68.6%
Branches: 9 16 56.2%

Line Branch Exec Source
1 /*
2 * lzf decompression algorithm
3 * Copyright (c) 2015 Luca Barbato
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * lzf decompression
25 *
26 * LZF is a fast compression/decompression algorithm that takes very little
27 * code space and working memory, ideal for real-time and block compression.
28 *
29 * https://en.wikibooks.org/wiki/Data_Compression/Dictionary_compression#LZF
30 */
31
32 #include "libavutil/mem.h"
33
34 #include "bytestream.h"
35 #include "lzf.h"
36
37 #define LZF_LITERAL_MAX (1 << 5)
38 #define LZF_LONG_BACKREF 7 + 2
39
40 4 int ff_lzf_uncompress(GetByteContext *gb, uint8_t **buf, int64_t *size)
41 {
42 4 int ret = 0;
43 4 uint8_t *p = *buf;
44 4 int64_t len = 0;
45
46
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85160 while (bytestream2_get_bytes_left(gb) > 2) {
47 85156 uint8_t s = bytestream2_get_byte(gb);
48
49
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85156 if (s < LZF_LITERAL_MAX) {
50 18284 s++;
51
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18284 if (s > *size - len) {
52 *size += s + *size /2;
53 ret = av_reallocp(buf, *size);
54 if (ret < 0)
55 return ret;
56 p = *buf + len;
57 }
58
59 18284 bytestream2_get_buffer(gb, p, s);
60 18284 p += s;
61 18284 len += s;
62 } else {
63 66872 int l = 2 + (s >> 5);
64 66872 int off = ((s & 0x1f) << 8) + 1;
65
66
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66872 if (l == LZF_LONG_BACKREF)
67 39906 l += bytestream2_get_byte(gb);
68
69 66872 off += bytestream2_get_byte(gb);
70
71
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66872 if (off > len)
72 return AVERROR_INVALIDDATA;
73
74
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66872 if (l > *size - len) {
75 *size += l + *size / 2;
76 ret = av_reallocp(buf, *size);
77 if (ret < 0)
78 return ret;
79 p = *buf + len;
80 }
81
82 66872 av_memcpy_backptr(p, off, l);
83
84 66872 p += l;
85 66872 len += l;
86 }
87 }
88
89 4 *size = len;
90
91 4 return 0;
92 }
93