FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavutil/rc4.c
Date: 2024-02-16 17:37:06
Exec Total Coverage
Lines: 27 28 96.4%
Functions: 3 3 100.0%
Branches: 11 12 91.7%

Line Branch Exec Source
1 /*
2 * RC4 encryption/decryption/pseudo-random number generator
3 * Copyright (c) 2007 Reimar Doeffinger
4 *
5 * loosely based on LibTomCrypt by Tom St Denis
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 #include "error.h"
25 #include "macros.h"
26 #include "mem.h"
27 #include "rc4.h"
28
29 543 AVRC4 *av_rc4_alloc(void)
30 {
31 543 return av_mallocz(sizeof(struct AVRC4));
32 }
33
34 1086 int av_rc4_init(AVRC4 *r, const uint8_t *key, int key_bits, int decrypt) {
35 int i, j;
36 uint8_t y;
37 1086 uint8_t *state = r->state;
38 1086 int keylen = key_bits >> 3;
39
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1086 if (key_bits & 7)
40 return AVERROR(EINVAL);
41
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279102 for (i = 0; i < 256; i++)
42 278016 state[i] = i;
43 1086 y = 0;
44 // j is i % keylen
45
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279102 for (j = 0, i = 0; i < 256; i++, j++) {
46
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278016 if (j == keylen) j = 0;
47 278016 y += state[i] + key[j];
48 278016 FFSWAP(uint8_t, state[i], state[y]);
49 }
50 1086 r->x = 1;
51 1086 r->y = state[1];
52 1086 return 0;
53 }
54
55 1086 void av_rc4_crypt(AVRC4 *r, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt) {
56 1086 uint8_t x = r->x, y = r->y;
57 1086 uint8_t *state = r->state;
58
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403302 while (count-- > 0) {
59 402216 uint8_t sum = state[x] + state[y];
60 402216 FFSWAP(uint8_t, state[x], state[y]);
61
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402216 *dst++ = src ? *src++ ^ state[sum] : state[sum];
62 402216 x++;
63 402216 y += state[x];
64 }
65 1086 r->x = x; r->y = y;
66 1086 }
67