sha1-file: add a constant for hash block size

There is one place we need the hash algorithm block size: the HMAC code
for push certs.  Expose this constant in struct git_hash_algo and expose
values for SHA-1 and for the largest value of any hash.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/cache.h b/cache.h
index 85a8e7b..5d96972 100644
--- a/cache.h
+++ b/cache.h
@@ -45,10 +45,14 @@ unsigned long git_deflate_bound(git_zstream *, unsigned long);
 /* The length in bytes and in hex digits of an object name (SHA-1 value). */
 #define GIT_SHA1_RAWSZ 20
 #define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ)
+/* The block size of SHA-1. */
+#define GIT_SHA1_BLKSZ 64
 
 /* The length in byte and in hex digits of the largest possible hash value. */
 #define GIT_MAX_RAWSZ GIT_SHA1_RAWSZ
 #define GIT_MAX_HEXSZ GIT_SHA1_HEXSZ
+/* The largest possible block size for any supported hash. */
+#define GIT_MAX_BLKSZ GIT_SHA1_BLKSZ
 
 struct object_id {
 	unsigned char hash[GIT_MAX_RAWSZ];