1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #define GOT_SHA1_STRING_ZERO "0000000000000000000000000000000000000000"
18 #define GOT_SHA256_STRING_ZERO "0000000000000000000000000000000000000000000000000000000000000000"
19 
20 #define GOT_HASH_DIGEST_MAXLEN SHA256_DIGEST_LENGTH
21 
22 int got_parse_xdigit(uint8_t *, const char *);
23 
24 char *got_sha1_digest_to_str(const uint8_t *, char *, size_t);
25 char *got_sha256_digest_to_str(const uint8_t *, char *, size_t);
26 
27 int got_parse_hash_digest(uint8_t *, const char *, enum got_hash_algorithm);
28 
29 /*
30  * Write the string representation fo an object ID in the given buffer.
31  * This buffer must be at least GOT_OBJECT_ID_HEX_MAXLEN bytes in size.
32  * The output depneds on the hash function used by the repository format.
33  */
34 char *got_object_id_hex(struct got_object_id *, char *, size_t);
35 
36 int got_parse_object_id(struct got_object_id *, const char *,
37     enum got_hash_algorithm);
38 
39 struct got_hash {
40 	SHA1_CTX		 sha1_ctx;
41 	SHA2_CTX		 sha256_ctx;
42 	enum got_hash_algorithm	 algo;
43 };
44 
45 /*
46  * These functions allow to compute and check hashes.
47  * The hash function used is specified during got_hash_init.
48  * Data can be added with got_hash_update and, once done, the checksum
49  * saved in a buffer long at least GOT_HASH_DIGEST_MAXLEN bytes with
50  * got_hash_final or in an got_object_id with got_hash_final_object_id.
51  */
52 void	got_hash_init(struct got_hash *, enum got_hash_algorithm);
53 void	got_hash_update(struct got_hash *, const void *, size_t);
54 void	got_hash_final(struct got_hash *, uint8_t *);
55 void	got_hash_final_object_id(struct got_hash *, struct got_object_id *);
56 
57 /*
58  * Compare two hash digest; similar to memcmp().
59  */
60 int	got_hash_cmp(enum got_hash_algorithm, uint8_t *, uint8_t *);