diff options
Diffstat (limited to 'hash.h')
| -rw-r--r-- | hash.h | 126 |
1 files changed, 126 insertions, 0 deletions
@@ -1,14 +1,140 @@ #ifndef HASH_H #define HASH_H +#include "git-compat-util.h" + #if defined(SHA1_PPC) #include "ppc/sha1.h" #elif defined(SHA1_APPLE) #include <CommonCrypto/CommonDigest.h> #elif defined(SHA1_OPENSSL) #include <openssl/sha.h> +#elif defined(SHA1_DC) +#include "sha1dc_git.h" #else /* SHA1_BLK */ #include "block-sha1/sha1.h" #endif +#if defined(SHA256_GCRYPT) +#include "sha256/gcrypt.h" +#elif defined(SHA256_OPENSSL) +#include <openssl/sha.h> +#else +#include "sha256/block/sha256.h" +#endif + +#ifndef platform_SHA_CTX +/* + * platform's underlying implementation of SHA-1; could be OpenSSL, + * blk_SHA, Apple CommonCrypto, etc... Note that the relevant + * SHA-1 header may have already defined platform_SHA_CTX for our + * own implementations like block-sha1 and ppc-sha1, so we list + * the default for OpenSSL compatible SHA-1 implementations here. + */ +#define platform_SHA_CTX SHA_CTX +#define platform_SHA1_Init SHA1_Init +#define platform_SHA1_Update SHA1_Update +#define platform_SHA1_Final SHA1_Final +#endif + +#define git_SHA_CTX platform_SHA_CTX +#define git_SHA1_Init platform_SHA1_Init +#define git_SHA1_Update platform_SHA1_Update +#define git_SHA1_Final platform_SHA1_Final + +#ifndef platform_SHA256_CTX +#define platform_SHA256_CTX SHA256_CTX +#define platform_SHA256_Init SHA256_Init +#define platform_SHA256_Update SHA256_Update +#define platform_SHA256_Final SHA256_Final +#endif + +#define git_SHA256_CTX platform_SHA256_CTX +#define git_SHA256_Init platform_SHA256_Init +#define git_SHA256_Update platform_SHA256_Update +#define git_SHA256_Final platform_SHA256_Final + +#ifdef SHA1_MAX_BLOCK_SIZE +#include "compat/sha1-chunked.h" +#undef git_SHA1_Update +#define git_SHA1_Update git_SHA1_Update_Chunked +#endif + +/* + * Note that these constants are suitable for indexing the hash_algos array and + * comparing against each other, but are otherwise arbitrary, so they should not + * be exposed to the user or serialized to disk. To know whether a + * git_hash_algo struct points to some usable hash function, test the format_id + * field for being non-zero. Use the name field for user-visible situations and + * the format_id field for fixed-length fields on disk. + */ +/* An unknown hash function. */ +#define GIT_HASH_UNKNOWN 0 +/* SHA-1 */ +#define GIT_HASH_SHA1 1 +/* SHA-256 */ +#define GIT_HASH_SHA256 2 +/* Number of algorithms supported (including unknown). */ +#define GIT_HASH_NALGOS (GIT_HASH_SHA256 + 1) + +/* A suitably aligned type for stack allocations of hash contexts. */ +union git_hash_ctx { + git_SHA_CTX sha1; + git_SHA256_CTX sha256; +}; +typedef union git_hash_ctx git_hash_ctx; + +typedef void (*git_hash_init_fn)(git_hash_ctx *ctx); +typedef void (*git_hash_update_fn)(git_hash_ctx *ctx, const void *in, size_t len); +typedef void (*git_hash_final_fn)(unsigned char *hash, git_hash_ctx *ctx); + +struct git_hash_algo { + /* + * The name of the algorithm, as appears in the config file and in + * messages. + */ + const char *name; + + /* A four-byte version identifier, used in pack indices. */ + uint32_t format_id; + + /* The length of the hash in binary. */ + size_t rawsz; + + /* The length of the hash in hex characters. */ + size_t hexsz; + + /* The block size of the hash. */ + size_t blksz; + + /* The hash initialization function. */ + git_hash_init_fn init_fn; + + /* The hash update function. */ + git_hash_update_fn update_fn; + + /* The hash finalization function. */ + git_hash_final_fn final_fn; + + /* The OID of the empty tree. */ + const struct object_id *empty_tree; + + /* The OID of the empty blob. */ + const struct object_id *empty_blob; +}; +extern const struct git_hash_algo hash_algos[GIT_HASH_NALGOS]; + +/* + * Return a GIT_HASH_* constant based on the name. Returns GIT_HASH_UNKNOWN if + * the name doesn't match a known algorithm. + */ +int hash_algo_by_name(const char *name); +/* Identical, except based on the format ID. */ +int hash_algo_by_id(uint32_t format_id); +/* Identical, except for a pointer to struct git_hash_algo. */ +static inline int hash_algo_by_ptr(const struct git_hash_algo *p) +{ + return p - hash_algos; +} + #endif |