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[PATCH] sha1dc: safeguard against outside definitions of BIGENDIAN

From
Johannes Schindelin <johannes.schindelin@gmx.de>
Date
Mar 24, 2017, 22:52 UTC
Message-ID
<856355e49e7a6016f5d1ef5f9785d94a455b5755.1490395862.git.johannes.schindelin@gmx.de>

In sha1dc/sha1.c, we #define BIGENDIAN under certain circumstances, and obviously leave the door open for scenarios where our conditions do not catch and that constant is #defined elsewhere.

However, we did not expect that anybody would possibly #define BIGENDIAN to 0, indicating that the current platform is *not* big endian.

This is not just a theoretical consideration: On Windows, the winsock2.h header file (which is used to allow Git to communicate via network) does indeed do this.

Let's test for that circumstance, too, and byte-swap as intended in that case.

This fixes a massive breakage on Windows where current `pu` (having switched on DC_SHA1 by default) breaks pretty much every single test case.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
Published-As: https://github.com/dscho/git/releases/tag/sha1dc-bigendian=0-v1
Fetch-It-Via: git fetch https://github.com/dscho/git sha1dc-bigendian=0-v1
	Obviously, this patch is based on `next`.
 sha1dc/sha1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sha1dc/sha1.c b/sha1dc/sha1.c
index 6dd0da36084..d99db4f2e1b 100644
--- a/sha1dc/sha1.c
+++ b/sha1dc/sha1.c
@@ -35,7 +35,7 @@
 
 #define sha1_mix(W, t)  (rotate_left(W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16], 1))
 
-#if defined(BIGENDIAN)
+#if defined(BIGENDIAN) && BIGENDIAN != 0
 	#define sha1_load(m, t, temp)  { temp = m[t]; }
 #else
 	#define sha1_load(m, t, temp)  { temp = m[t]; sha1_bswap32(temp); }

base-commit: c21884356fab0bc6bc5fa6abcadbda27a112a76c
-- 
2.12.1.windows.1
Next: Junio C Hamano
Message 1 of 5 in “sha1dc: safeguard against outside definitions of BIGENDIAN”
  1. sha1dc: safeguard against outside definitions of BIGENDIANJohannes Schindelin, Mar 24, 2017
  2. Junio C HamanoMar 25, 2017
  3. Junio C HamanoMar 25, 2017
  4. Johannes SchindelinMar 27, 2017
  5. Junio C HamanoMar 27, 2017

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