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[thirdparty/git.git] / hash.h
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f18f816c 1#ifndef HASH_H
2#define HASH_H
3
f50e766b 4#include "git-compat-util.h"
5
f18f816c 6#if defined(SHA1_PPC)
7#include "ppc/sha1.h"
8#elif defined(SHA1_APPLE)
9#include <CommonCrypto/CommonDigest.h>
10#elif defined(SHA1_OPENSSL)
11#include <openssl/sha.h>
8325e43b 12#elif defined(SHA1_DC)
36f048c5 13#include "sha1dc_git.h"
f18f816c 14#else /* SHA1_BLK */
15#include "block-sha1/sha1.h"
16#endif
17
164e7163 18#ifndef platform_SHA_CTX
19/*
20 * platform's underlying implementation of SHA-1; could be OpenSSL,
b212c0ca 21 * blk_SHA, Apple CommonCrypto, etc... Note that the relevant
22 * SHA-1 header may have already defined platform_SHA_CTX for our
164e7163 23 * own implementations like block-sha1 and ppc-sha1, so we list
24 * the default for OpenSSL compatible SHA-1 implementations here.
25 */
26#define platform_SHA_CTX SHA_CTX
27#define platform_SHA1_Init SHA1_Init
28#define platform_SHA1_Update SHA1_Update
29#define platform_SHA1_Final SHA1_Final
30#endif
31
32#define git_SHA_CTX platform_SHA_CTX
33#define git_SHA1_Init platform_SHA1_Init
34#define git_SHA1_Update platform_SHA1_Update
35#define git_SHA1_Final platform_SHA1_Final
36
37#ifdef SHA1_MAX_BLOCK_SIZE
38#include "compat/sha1-chunked.h"
39#undef git_SHA1_Update
40#define git_SHA1_Update git_SHA1_Update_Chunked
41#endif
42
f50e766b 43/*
44 * Note that these constants are suitable for indexing the hash_algos array and
45 * comparing against each other, but are otherwise arbitrary, so they should not
46 * be exposed to the user or serialized to disk. To know whether a
47 * git_hash_algo struct points to some usable hash function, test the format_id
48 * field for being non-zero. Use the name field for user-visible situations and
49 * the format_id field for fixed-length fields on disk.
50 */
51/* An unknown hash function. */
52#define GIT_HASH_UNKNOWN 0
53/* SHA-1 */
54#define GIT_HASH_SHA1 1
55/* Number of algorithms supported (including unknown). */
56#define GIT_HASH_NALGOS (GIT_HASH_SHA1 + 1)
57
ac73cedf 58/* A suitably aligned type for stack allocations of hash contexts. */
59union git_hash_ctx {
60 git_SHA_CTX sha1;
61};
62typedef union git_hash_ctx git_hash_ctx;
63
64typedef void (*git_hash_init_fn)(git_hash_ctx *ctx);
65typedef void (*git_hash_update_fn)(git_hash_ctx *ctx, const void *in, size_t len);
66typedef void (*git_hash_final_fn)(unsigned char *hash, git_hash_ctx *ctx);
f50e766b 67
68struct git_hash_algo {
69 /*
70 * The name of the algorithm, as appears in the config file and in
71 * messages.
72 */
73 const char *name;
74
75 /* A four-byte version identifier, used in pack indices. */
76 uint32_t format_id;
77
f50e766b 78 /* The length of the hash in binary. */
79 size_t rawsz;
80
81 /* The length of the hash in hex characters. */
82 size_t hexsz;
83
84 /* The hash initialization function. */
85 git_hash_init_fn init_fn;
86
87 /* The hash update function. */
88 git_hash_update_fn update_fn;
89
90 /* The hash finalization function. */
91 git_hash_final_fn final_fn;
92
93 /* The OID of the empty tree. */
94 const struct object_id *empty_tree;
95
96 /* The OID of the empty blob. */
97 const struct object_id *empty_blob;
98};
99extern const struct git_hash_algo hash_algos[GIT_HASH_NALGOS];
100
f18f816c 101#endif