path: root/hash.h
diff options
authorbrian m. carlson <>2018-10-22 02:43:32 (GMT)
committerJunio C Hamano <>2018-10-22 03:59:08 (GMT)
commit2f90b9d9b4ba1f8e79318853301e8ef19ca02681 (patch)
tree76cc6f9d74fcc6153e9e2717f75194649ed6db4e /hash.h
parent1ccf07cbb762b44746c49634e1c6fb945c9977df (diff)
sha1-file: provide functions to look up hash algorithms
There are several ways we might refer to a hash algorithm: by name, such as in the config file; by format ID, such as in a pack; or internally, by a pointer to the hash_algos array. Provide functions to look up hash algorithms based on these various forms and return the internal constant used for them. If conversion to another form is necessary, this internal constant can be used to look up the proper data in the hash_algos array. Signed-off-by: brian m. carlson <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'hash.h')
1 files changed, 13 insertions, 0 deletions
diff --git a/hash.h b/hash.h
index 7c8238b..80881ee 100644
--- a/hash.h
+++ b/hash.h
@@ -98,4 +98,17 @@ struct git_hash_algo {
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;