diff options
| -rw-r--r-- | hash.h | 57 | ||||
| -rw-r--r-- | sha1_file.c | 58 |
2 files changed, 115 insertions, 0 deletions
@@ -1,6 +1,8 @@ #ifndef HASH_H #define HASH_H +#include "git-compat-util.h" + #if defined(SHA1_PPC) #include "ppc/sha1.h" #elif defined(SHA1_APPLE) @@ -13,4 +15,59 @@ #include "block-sha1/sha1.h" #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 +/* Number of algorithms supported (including unknown). */ +#define GIT_HASH_NALGOS (GIT_HASH_SHA1 + 1) + +typedef void (*git_hash_init_fn)(void *ctx); +typedef void (*git_hash_update_fn)(void *ctx, const void *in, size_t len); +typedef void (*git_hash_final_fn)(unsigned char *hash, void *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 size of a hash context (e.g. git_SHA_CTX). */ + size_t ctxsz; + + /* The length of the hash in binary. */ + size_t rawsz; + + /* The length of the hash in hex characters. */ + size_t hexsz; + + /* 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]; + #endif diff --git a/sha1_file.c b/sha1_file.c index d708981376..a04389be71 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -39,6 +39,64 @@ const struct object_id empty_blob_oid = { EMPTY_BLOB_SHA1_BIN_LITERAL }; +static void git_hash_sha1_init(void *ctx) +{ + git_SHA1_Init((git_SHA_CTX *)ctx); +} + +static void git_hash_sha1_update(void *ctx, const void *data, size_t len) +{ + git_SHA1_Update((git_SHA_CTX *)ctx, data, len); +} + +static void git_hash_sha1_final(unsigned char *hash, void *ctx) +{ + git_SHA1_Final(hash, (git_SHA_CTX *)ctx); +} + +static void git_hash_unknown_init(void *ctx) +{ + die("trying to init unknown hash"); +} + +static void git_hash_unknown_update(void *ctx, const void *data, size_t len) +{ + die("trying to update unknown hash"); +} + +static void git_hash_unknown_final(unsigned char *hash, void *ctx) +{ + die("trying to finalize unknown hash"); +} + +const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = { + { + NULL, + 0x00000000, + 0, + 0, + 0, + git_hash_unknown_init, + git_hash_unknown_update, + git_hash_unknown_final, + NULL, + NULL, + }, + { + "sha-1", + /* "sha1", big-endian */ + 0x73686131, + sizeof(git_SHA_CTX), + GIT_SHA1_RAWSZ, + GIT_SHA1_HEXSZ, + git_hash_sha1_init, + git_hash_sha1_update, + git_hash_sha1_final, + &empty_tree_oid, + &empty_blob_oid, + }, +}; + /* * This is meant to hold a *small* number of objects that you would * want read_sha1_file() to be able to return, but yet you do not want |