[PATCH 01/20] Define new hash-size constants for allocating memory

From: "brian m. carlson" <sandals@crustytoothpaste.net>
To: git@vger.kernel.org
Cc: "Jeff King" <peff@peff.net>, "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Subject: [PATCH 01/20] Define new hash-size constants for allocating memory
Date: Sat, 18 Mar 2017 21:19:35 +0000	[thread overview]
Message-ID: <20170318211954.564030-2-sandals@crustytoothpaste.net> (raw)
In-Reply-To: <20170318211954.564030-1-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 9b2157f591..cb301d8d7d 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)
