[PATCH v2 01/21] Define new hash-size constants for allocating memory

From: brian m. carlson <sandals@crustytoothpaste.net>
Date: Mar 26, 2017, 16:01 UTC
Message-ID: <20170326160143.769630-2-sandals@crustytoothpaste.net>
In-Reply-To: <20170326160143.769630-1-sandals@crustytoothpaste.net>

Since we will want to transition to a new hash at some point in the future, and that hash may be larger in size than 160 bits, introduce two constants that can be used for allocating a sufficient amount of memory. They can be increased to reflect the largest supported hash size.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 cache.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/cache.h b/cache.h
index 2214d52f61..af4b2c78cf 100644
--- a/cache.h
+++ b/cache.h
@@ -66,8 +66,12 @@ unsigned long git_deflate_bound(git_zstream *, unsigned long);
 #define GIT_SHA1_RAWSZ 20
 #define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ)
 
+/* 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
+
 struct object_id {
-	unsigned char hash[GIT_SHA1_RAWSZ];
+	unsigned char hash[GIT_MAX_RAWSZ];
 };
 
 #if defined(DT_UNKNOWN) && !defined(NO_D_TYPE_IN_DIRENT)