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1 | /* |
2 | * Copyright (C) 2013 Reimar Döffinger <Reimar.Doeffinger@gmx.de> | |
3 | * | |
4 | * This file is part of FFmpeg. | |
5 | * | |
6 | * FFmpeg is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
10 | * | |
11 | * FFmpeg is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with FFmpeg; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | */ | |
20 | ||
21 | #ifndef AVUTIL_HASH_H | |
22 | #define AVUTIL_HASH_H | |
23 | ||
24 | #include <stdint.h> | |
25 | ||
26 | struct AVHashContext; | |
27 | ||
28 | /** | |
29 | * Allocate a hash context for the algorithm specified by name. | |
30 | * | |
31 | * @return >= 0 for success, a negative error code for failure | |
32 | * @note The context is not initialized, you must call av_hash_init(). | |
33 | */ | |
34 | int av_hash_alloc(struct AVHashContext **ctx, const char *name); | |
35 | ||
36 | /** | |
37 | * Get the names of available hash algorithms. | |
38 | * | |
39 | * This function can be used to enumerate the algorithms. | |
40 | * | |
41 | * @param i index of the hash algorithm, starting from 0 | |
42 | * @return a pointer to a static string or NULL if i is out of range | |
43 | */ | |
44 | const char *av_hash_names(int i); | |
45 | ||
46 | /** | |
47 | * Get the name of the algorithm corresponding to the given hash context. | |
48 | */ | |
49 | const char *av_hash_get_name(const struct AVHashContext *ctx); | |
50 | ||
51 | /** | |
52 | * Maximum value that av_hash_get_size will currently return. | |
53 | * | |
54 | * You can use this if you absolutely want or need to use static allocation | |
55 | * and are fine with not supporting hashes newly added to libavutil without | |
56 | * recompilation. | |
57 | * Note that you still need to check against av_hash_get_size, adding new hashes | |
58 | * with larger sizes will not be considered an ABI change and should not cause | |
59 | * your code to overflow a buffer. | |
60 | */ | |
61 | #define AV_HASH_MAX_SIZE 64 | |
62 | ||
63 | /** | |
64 | * Get the size of the resulting hash value in bytes. | |
65 | * | |
66 | * The pointer passed to av_hash_final have space for at least this many bytes. | |
67 | */ | |
68 | int av_hash_get_size(const struct AVHashContext *ctx); | |
69 | ||
70 | /** | |
71 | * Initialize or reset a hash context. | |
72 | */ | |
73 | void av_hash_init(struct AVHashContext *ctx); | |
74 | ||
75 | /** | |
76 | * Update a hash context with additional data. | |
77 | */ | |
78 | void av_hash_update(struct AVHashContext *ctx, const uint8_t *src, int len); | |
79 | ||
80 | /** | |
81 | * Finalize a hash context and compute the actual hash value. | |
82 | */ | |
83 | void av_hash_final(struct AVHashContext *ctx, uint8_t *dst); | |
84 | ||
85 | /** | |
86 | * Finalize a hash context and compute the actual hash value. | |
87 | * If size is smaller than the hash size, the hash is truncated; | |
88 | * if size is larger, the buffer is padded with 0. | |
89 | */ | |
90 | void av_hash_final_bin(struct AVHashContext *ctx, uint8_t *dst, int size); | |
91 | ||
92 | /** | |
93 | * Finalize a hash context and compute the actual hash value as a hex string. | |
94 | * The string is always 0-terminated. | |
95 | * If size is smaller than 2 * hash_size + 1, the hex string is truncated. | |
96 | */ | |
97 | void av_hash_final_hex(struct AVHashContext *ctx, uint8_t *dst, int size); | |
98 | ||
99 | /** | |
100 | * Finalize a hash context and compute the actual hash value as a base64 string. | |
101 | * The string is always 0-terminated. | |
102 | * If size is smaller than AV_BASE64_SIZE(hash_size), the base64 string is | |
103 | * truncated. | |
104 | */ | |
105 | void av_hash_final_b64(struct AVHashContext *ctx, uint8_t *dst, int size); | |
106 | ||
107 | /** | |
108 | * Free hash context. | |
109 | */ | |
110 | void av_hash_freep(struct AVHashContext **ctx); | |
111 | ||
112 | #endif /* AVUTIL_HASH_H */ |