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| author | brian m. carlson <sandals@crustytoothpaste.net> | 2021-04-26 01:02:52 (GMT) |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2021-04-27 07:31:38 (GMT) |
| commit | ab795f0d77aec52496557eb69a5fc9e4f60ea1fd (patch) | |
| tree | 78a5e3451fac3e53b12364f4f8c5c854da318e84 /object-file.c | |
| parent | c3b4e4ee366b8de9802fa752d0a81be92e690e17 (diff) | |
| download | git-ab795f0d77aec52496557eb69a5fc9e4f60ea1fd.zip git-ab795f0d77aec52496557eb69a5fc9e4f60ea1fd.tar.gz git-ab795f0d77aec52496557eb69a5fc9e4f60ea1fd.tar.bz2 | |
hash: add a function to finalize object IDs
To avoid the penalty of having to branch in hash comparison functions,
we'll want to always compare the full hash member in a struct object_id,
which will require that SHA-1 object IDs be zero-padded. To do so, add
a function which finalizes a hash context and writes it into an object
ID that performs this padding.
Move the definition of struct object_id and the constant definitions
higher up so we they are available for us to use.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'object-file.c')
| -rw-r--r-- | object-file.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/object-file.c b/object-file.c index 624af40..ef1eb98 100644 --- a/object-file.c +++ b/object-file.c @@ -89,6 +89,12 @@ static void git_hash_sha1_final(unsigned char *hash, git_hash_ctx *ctx) git_SHA1_Final(hash, &ctx->sha1); } +static void git_hash_sha1_final_oid(struct object_id *oid, git_hash_ctx *ctx) +{ + git_SHA1_Final(oid->hash, &ctx->sha1); + memset(oid->hash + GIT_SHA1_RAWSZ, 0, GIT_MAX_RAWSZ - GIT_SHA1_RAWSZ); +} + static void git_hash_sha256_init(git_hash_ctx *ctx) { @@ -110,6 +116,16 @@ static void git_hash_sha256_final(unsigned char *hash, git_hash_ctx *ctx) git_SHA256_Final(hash, &ctx->sha256); } +static void git_hash_sha256_final_oid(struct object_id *oid, git_hash_ctx *ctx) +{ + git_SHA256_Final(oid->hash, &ctx->sha256); + /* + * This currently does nothing, so the compiler should optimize it out, + * but keep it in case we extend the hash size again. + */ + memset(oid->hash + GIT_SHA256_RAWSZ, 0, GIT_MAX_RAWSZ - GIT_SHA256_RAWSZ); +} + static void git_hash_unknown_init(git_hash_ctx *ctx) { BUG("trying to init unknown hash"); @@ -130,6 +146,12 @@ static void git_hash_unknown_final(unsigned char *hash, git_hash_ctx *ctx) BUG("trying to finalize unknown hash"); } +static void git_hash_unknown_final_oid(struct object_id *oid, git_hash_ctx *ctx) +{ + BUG("trying to finalize unknown hash"); +} + + const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = { { NULL, @@ -141,6 +163,7 @@ const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = { git_hash_unknown_clone, git_hash_unknown_update, git_hash_unknown_final, + git_hash_unknown_final_oid, NULL, NULL, }, @@ -155,6 +178,7 @@ const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = { git_hash_sha1_clone, git_hash_sha1_update, git_hash_sha1_final, + git_hash_sha1_final_oid, &empty_tree_oid, &empty_blob_oid, }, @@ -169,6 +193,7 @@ const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = { git_hash_sha256_clone, git_hash_sha256_update, git_hash_sha256_final, + git_hash_sha256_final_oid, &empty_tree_oid_sha256, &empty_blob_oid_sha256, } |