FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/snappy.c
Date: 2026-01-23 19:11:46
Exec Total Coverage
Lines: 70 90 77.8%
Functions: 8 9 88.9%
Branches: 22 36 61.1%
Line Branch Exec Source
1 /*
2 * Snappy 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 #include "bytestream.h"
23 #include "snappy.h"
24
25 enum {
26 SNAPPY_LITERAL,
27 SNAPPY_COPY_1,
28 SNAPPY_COPY_2,
29 SNAPPY_COPY_4,
30 };
31
32 100 static int64_t bytestream2_get_levarint(GetByteContext *gb)
33 {
34 100 uint64_t val = 0;
35 100 int shift = 0;
36 int tmp;
37
38 do {
39 206 tmp = bytestream2_get_byte(gb);
40
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 206 if (shift > 31 || ((tmp & 127LL) << shift) > INT_MAX)
41 ✗ return AVERROR_INVALIDDATA;
42 206 val |= (tmp & 127) << shift;
43 206 shift += 7;
44
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 206 } while (tmp & 128);
45
46 100 return val;
47 }
48
49 26644 static int snappy_literal(GetByteContext *gb, uint8_t *p, int size, int val)
50 {
51 26644 unsigned int len = 1;
52
53
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 26644 switch (val) {
54 ✗ case 63:
55 ✗ len += bytestream2_get_le32(gb);
56 ✗ break;
57 ✗ case 62:
58 ✗ len += bytestream2_get_le24(gb);
59 ✗ break;
60 65 case 61:
61 65 len += bytestream2_get_le16(gb);
62 65 break;
63 669 case 60:
64 669 len += bytestream2_get_byte(gb);
65 669 break;
66 25910 default: // val < 60
67 25910 len += val;
68 }
69
70
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 26644 if (size < len)
71 ✗ return AVERROR_INVALIDDATA;
72
73 26644 bytestream2_get_buffer(gb, p, len);
74
75 26644 return len;
76 }
77
78 33740 static int snappy_copy(uint8_t *start, uint8_t *p, int size,
79 unsigned int off, int len)
80 {
81 uint8_t *q;
82 int i;
83
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 33740 if (off > p - start || size < len)
84 ✗ return AVERROR_INVALIDDATA;
85
86 33740 q = p - off;
87
88
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 466071 for (i = 0; i < len; i++)
89 432331 p[i] = q[i];
90
91 33740 return len;
92 }
93
94 16119 static int snappy_copy1(GetByteContext *gb, uint8_t *start, uint8_t *p,
95 int size, int val)
96 {
97 16119 int len = 4 + (val & 0x7);
98 16119 unsigned int off = bytestream2_get_byte(gb) | (val & 0x38) << 5;
99
100 16119 return snappy_copy(start, p, size, off, len);
101 }
102
103 17621 static int snappy_copy2(GetByteContext *gb, uint8_t *start, uint8_t *p,
104 int size, int val)
105 {
106 17621 int len = 1 + val;
107 17621 unsigned int off = bytestream2_get_le16(gb);
108
109 17621 return snappy_copy(start, p, size, off, len);
110 }
111
112 ✗ static int snappy_copy4(GetByteContext *gb, uint8_t *start, uint8_t *p,
113 int size, int val)
114 {
115 ✗ int len = 1 + val;
116 ✗ unsigned int off = bytestream2_get_le32(gb);
117
118 ✗ return snappy_copy(start, p, size, off, len);
119 }
120
121 100 static int64_t decode_len(GetByteContext *gb)
122 {
123 100 int64_t len = bytestream2_get_levarint(gb);
124
125
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 100 if (len < 0 || len > UINT_MAX)
126 ✗ return AVERROR_INVALIDDATA;
127
128 100 return len;
129 }
130
131 50 int64_t ff_snappy_peek_uncompressed_length(GetByteContext *gb)
132 {
133 50 int pos = bytestream2_get_bytes_left(gb);
134 50 int64_t len = decode_len(gb);
135
136 50 bytestream2_seek(gb, -pos, SEEK_END);
137
138 50 return len;
139 }
140
141 50 int ff_snappy_uncompress(GetByteContext *gb, uint8_t *buf, int64_t *size)
142 {
143 50 int64_t len = decode_len(gb);
144 50 int ret = 0;
145 uint8_t *p;
146
147
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 50 if (len < 0)
148 ✗ return len;
149
150
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 50 if (len > *size)
151 ✗ return AVERROR_BUFFER_TOO_SMALL;
152
153 50 *size = len;
154 50 p = buf;
155
156
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 60434 while (bytestream2_get_bytes_left(gb) > 0) {
157 60384 uint8_t s = bytestream2_get_byte(gb);
158 60384 int val = s >> 2;
159
160
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 60384 switch (s & 0x03) {
161 26644 case SNAPPY_LITERAL:
162 26644 ret = snappy_literal(gb, p, len, val);
163 26644 break;
164 16119 case SNAPPY_COPY_1:
165 16119 ret = snappy_copy1(gb, buf, p, len, val);
166 16119 break;
167 17621 case SNAPPY_COPY_2:
168 17621 ret = snappy_copy2(gb, buf, p, len, val);
169 17621 break;
170 ✗ case SNAPPY_COPY_4:
171 ✗ ret = snappy_copy4(gb, buf, p, len, val);
172 ✗ break;
173 }
174
175
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 60384 if (ret < 0)
176 ✗ return ret;
177
178 60384 p += ret;
179 60384 len -= ret;
180 }
181
182 50 return 0;
183 }
184