| 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 */ |