VLC 4.0.0-dev
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vlc_hash.h
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1/*****************************************************************************
2 * vlc_hash.h: Hash functions
3 *****************************************************************************
4 * Copyright © 2004-2020 VLC authors and VideoLAN
5 *
6 * Authors: Rémi Denis-Courmont
7 * Rafaël Carré
8 * Marvin Scholz
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU Lesser General Public License as published by
12 * the Free Software Foundation; either version 2.1 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public License
21 * along with this program; if not, write to the Free Software Foundation,
22 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
23 *****************************************************************************/
24
25#ifndef VLC_HASH_H
26# define VLC_HASH_H
27
28/**
29 * \defgroup vlc_hash Hash functions
30 * APIs for simple and frequently used hash algorithms in VLC
31 *
32 * Each hash algorithm has a context object which stores all data needed for the
33 * hash calculation, this context is not supposed to be modified directly by the
34 * called but only with the functions listed here.
35 *
36 * Supported hash algorithms:
37 * - \ref vlc_hash_md5 "MD5"
38 *
39 * @{
40 */
41
42/**
43 * \defgroup vlc_hash_utils Helper functions
44 * Functions commonly used together with hashing functions
45 * @{
46 */
47
48/**
49 * Finish hash computation and return hex representation
50 *
51 * Finishes the hash computation and provides the hash for the
52 * concatenation of all provided data in hex encoded format.
53 * The result is written to the buffer pointed to by output, which
54 * must be larger than twice the size of the hash output.
55 *
56 * \param[in,out] ctx Hash context to finish
57 * \param[out] output Output buffer to write the string to
58 */
59#ifndef __cplusplus
60#define vlc_hash_FinishHex(ctx, output) \
61 do { \
62 char out_tmp[_Generic((ctx), \
63 vlc_hash_md5_t *: VLC_HASH_MD5_DIGEST_SIZE)]; \
64 _Generic((ctx), \
65 vlc_hash_md5_t *: vlc_hash_md5_Finish) \
66 (ctx, out_tmp, sizeof(out_tmp)); \
67 vlc_hex_encode_binary(out_tmp, sizeof(out_tmp), output); \
68 } while (0)
69#endif
70
71/**
72 * @}
73 */
74
75/**
76 * \defgroup vlc_hash_md5 MD5 hashing
77 * APIs to hash data using the Message-Digest Algorithm 5 (MD5)
78 * @{
79 */
80
81/**
82 * MD5 hash context
83 */
84typedef struct vlc_hash_md5_ctx
86 struct md5_s {
87 uint32_t A, B, C, D; /* chaining variables */
88 uint32_t nblocks;
89 uint8_t buf[64];
90 int count;
91 } priv; /**< \internal Private */
94/**
95 * MD5 digest output size
96 */
97#define VLC_HASH_MD5_DIGEST_SIZE 16
99/**
100 * MD5 digest hex representation size
101 */
102#define VLC_HASH_MD5_DIGEST_HEX_SIZE 33 // 2 chars per byte + null
104/**
105 * Initialize MD5 context
106 *
107 * Initializes the given MD5 hash function context, if the context is
108 * already initialized, it is reset.
109 *
110 * \param[out] ctx MD5 hash context to init
111 */
113
114/**
115 * Update MD5 hash computation with new data
116 *
117 * Updates the context with provided data which is used for the hash
118 * calculation. Can be called repeatedly with new data. The final
119 * hash represents the hash for the concatenation of all data.
120 *
121 * \param[in,out] ctx MD5 hash context to update
122 * \param data Data to add
123 * \param size Size of the data to add
124 */
125VLC_API void vlc_hash_md5_Update(vlc_hash_md5_t *ctx, const void *data, size_t size);
126
127/**
128 * Finish MD5 hash computation
129 *
130 * Finishes the MD5 hash computation and provides the hash for the
131 * concatenation of all provided data by previous calls to \ref vlc_hash_md5_Update.
132 * The result is written to the buffer pointed to by output, which must be at
133 * least \ref VLC_HASH_MD5_DIGEST_SIZE big.
134 *
135 * \param[in,out] ctx MD5 hash context to finish
136 * \param[out] output Output buffer to write to
137 * \param size Output buffer size
138 */
139VLC_API void vlc_hash_md5_Finish(vlc_hash_md5_t *ctx, void *output, size_t size);
140
141/**
142 * @}
143 */
144
145/**
146 * @}
147 */
148
149#endif
#define VLC_API
Definition fourcc_gen.c:31
void vlc_hash_md5_Update(vlc_hash_md5_t *ctx, const void *data, size_t size)
Update MD5 hash computation with new data.
Definition md5.c:343
void vlc_hash_md5_Finish(vlc_hash_md5_t *ctx, void *output, size_t size)
Finish MD5 hash computation.
Definition md5.c:348
void vlc_hash_md5_Init(vlc_hash_md5_t *ctx)
Initialize MD5 context.
Definition md5.c:338
struct vlc_hash_md5_ctx vlc_hash_md5_t
MD5 hash context.
Definition vlc_hash.h:87
uint32_t A
Definition vlc_hash.h:88
int count
Definition vlc_hash.h:91
uint32_t nblocks
Definition vlc_hash.h:89
uint32_t B
Definition vlc_hash.h:88
uint8_t buf[64]
Definition vlc_hash.h:90
uint32_t C
Definition vlc_hash.h:88
uint32_t D
Definition vlc_hash.h:88
MD5 hash context.
Definition vlc_hash.h:86
struct vlc_hash_md5_ctx::md5_s priv
This file is a collection of common definitions and types.