Merge branch 'rs/help-unknown-ref-does-not-return'
[git/git.git] / hash.h
CommitLineData
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
27dc04c5 18#if defined(SHA256_GCRYPT)
19#include "sha256/gcrypt.h"
4b4e2918 20#elif defined(SHA256_OPENSSL)
21#include <openssl/sha.h>
27dc04c5 22#else
13eeedb5 23#include "sha256/block/sha256.h"
27dc04c5 24#endif
13eeedb5 25
164e7163 26#ifndef platform_SHA_CTX
27/*
28 * platform's underlying implementation of SHA-1; could be OpenSSL,
b212c0ca 29 * blk_SHA, Apple CommonCrypto, etc... Note that the relevant
30 * SHA-1 header may have already defined platform_SHA_CTX for our
164e7163 31 * own implementations like block-sha1 and ppc-sha1, so we list
32 * the default for OpenSSL compatible SHA-1 implementations here.
33 */
34#define platform_SHA_CTX SHA_CTX
35#define platform_SHA1_Init SHA1_Init
36#define platform_SHA1_Update SHA1_Update
37#define platform_SHA1_Final SHA1_Final
38#endif
39
40#define git_SHA_CTX platform_SHA_CTX
41#define git_SHA1_Init platform_SHA1_Init
42#define git_SHA1_Update platform_SHA1_Update
43#define git_SHA1_Final platform_SHA1_Final
44
13eeedb5 45#ifndef platform_SHA256_CTX
46#define platform_SHA256_CTX SHA256_CTX
47#define platform_SHA256_Init SHA256_Init
48#define platform_SHA256_Update SHA256_Update
49#define platform_SHA256_Final SHA256_Final
50#endif
51
52#define git_SHA256_CTX platform_SHA256_CTX
53#define git_SHA256_Init platform_SHA256_Init
54#define git_SHA256_Update platform_SHA256_Update
55#define git_SHA256_Final platform_SHA256_Final
56
164e7163 57#ifdef SHA1_MAX_BLOCK_SIZE
58#include "compat/sha1-chunked.h"
59#undef git_SHA1_Update
60#define git_SHA1_Update git_SHA1_Update_Chunked
61#endif
62
f50e766b 63/*
64 * Note that these constants are suitable for indexing the hash_algos array and
65 * comparing against each other, but are otherwise arbitrary, so they should not
66 * be exposed to the user or serialized to disk. To know whether a
67 * git_hash_algo struct points to some usable hash function, test the format_id
68 * field for being non-zero. Use the name field for user-visible situations and
69 * the format_id field for fixed-length fields on disk.
70 */
71/* An unknown hash function. */
72#define GIT_HASH_UNKNOWN 0
73/* SHA-1 */
74#define GIT_HASH_SHA1 1
13eeedb5 75/* SHA-256 */
76#define GIT_HASH_SHA256 2
f50e766b 77/* Number of algorithms supported (including unknown). */
13eeedb5 78#define GIT_HASH_NALGOS (GIT_HASH_SHA256 + 1)
f50e766b 79
ac73cedf 80/* A suitably aligned type for stack allocations of hash contexts. */
81union git_hash_ctx {
82 git_SHA_CTX sha1;
13eeedb5 83 git_SHA256_CTX sha256;
ac73cedf 84};
85typedef union git_hash_ctx git_hash_ctx;
86
87typedef void (*git_hash_init_fn)(git_hash_ctx *ctx);
88typedef void (*git_hash_update_fn)(git_hash_ctx *ctx, const void *in, size_t len);
89typedef void (*git_hash_final_fn)(unsigned char *hash, git_hash_ctx *ctx);
f50e766b 90
91struct git_hash_algo {
92 /*
93 * The name of the algorithm, as appears in the config file and in
94 * messages.
95 */
96 const char *name;
97
98 /* A four-byte version identifier, used in pack indices. */
99 uint32_t format_id;
100
f50e766b 101 /* The length of the hash in binary. */
102 size_t rawsz;
103
104 /* The length of the hash in hex characters. */
105 size_t hexsz;
106
a2ce0a75 107 /* The block size of the hash. */
108 size_t blksz;
109
f50e766b 110 /* The hash initialization function. */
111 git_hash_init_fn init_fn;
112
113 /* The hash update function. */
114 git_hash_update_fn update_fn;
115
116 /* The hash finalization function. */
117 git_hash_final_fn final_fn;
118
119 /* The OID of the empty tree. */
120 const struct object_id *empty_tree;
121
122 /* The OID of the empty blob. */
123 const struct object_id *empty_blob;
124};
125extern const struct git_hash_algo hash_algos[GIT_HASH_NALGOS];
126
2f90b9d9 127/*
128 * Return a GIT_HASH_* constant based on the name. Returns GIT_HASH_UNKNOWN if
129 * the name doesn't match a known algorithm.
130 */
131int hash_algo_by_name(const char *name);
132/* Identical, except based on the format ID. */
133int hash_algo_by_id(uint32_t format_id);
95399788 134/* Identical, except based on the length. */
135int hash_algo_by_length(int len);
2f90b9d9 136/* Identical, except for a pointer to struct git_hash_algo. */
137static inline int hash_algo_by_ptr(const struct git_hash_algo *p)
138{
139 return p - hash_algos;
140}
141
c0566d78
JK
142/* The length in bytes and in hex digits of an object name (SHA-1 value). */
143#define GIT_SHA1_RAWSZ 20
144#define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ)
145/* The block size of SHA-1. */
146#define GIT_SHA1_BLKSZ 64
147
148/* The length in bytes and in hex digits of an object name (SHA-256 value). */
149#define GIT_SHA256_RAWSZ 32
150#define GIT_SHA256_HEXSZ (2 * GIT_SHA256_RAWSZ)
151/* The block size of SHA-256. */
152#define GIT_SHA256_BLKSZ 64
153
154/* The length in byte and in hex digits of the largest possible hash value. */
155#define GIT_MAX_RAWSZ GIT_SHA256_RAWSZ
156#define GIT_MAX_HEXSZ GIT_SHA256_HEXSZ
157/* The largest possible block size for any supported hash. */
158#define GIT_MAX_BLKSZ GIT_SHA256_BLKSZ
159
160struct object_id {
161 unsigned char hash[GIT_MAX_RAWSZ];
162};
163
164#define the_hash_algo the_repository->hash_algo
165
f18f816c 166#endif