Return-Path: <bremner@tethera.net>
X-Original-To: notmuch@notmuchmail.org
Delivered-To: notmuch@notmuchmail.org
Received: from localhost (localhost [127.0.0.1])
	by olra.theworths.org (Postfix) with ESMTP id 27627431FBF
	for <notmuch@notmuchmail.org>; Tue, 26 Nov 2013 05:08:04 -0800 (PST)
X-Virus-Scanned: Debian amavisd-new at olra.theworths.org
X-Spam-Flag: NO
X-Spam-Score: 0
X-Spam-Level: 
X-Spam-Status: No, score=0 tagged_above=-999 required=5 tests=[none]
	autolearn=disabled
Received: from olra.theworths.org ([127.0.0.1])
	by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024)
	with ESMTP id KfU3jAf6E6Ep for <notmuch@notmuchmail.org>;
	Tue, 26 Nov 2013 05:07:56 -0800 (PST)
Received: from yantan.tethera.net (yantan.tethera.net [199.188.72.155])
	(using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits))
	(No client certificate requested)
	by olra.theworths.org (Postfix) with ESMTPS id 33642431FB6
	for <notmuch@notmuchmail.org>; Tue, 26 Nov 2013 05:07:56 -0800 (PST)
Received: from remotemail by yantan.tethera.net with local (Exim 4.80)
	(envelope-from <bremner@tethera.net>)
	id 1VlIMq-0008Tq-Kw; Tue, 26 Nov 2013 09:07:52 -0400
Received: (nullmailer pid 31884 invoked by uid 1000); Tue, 26 Nov 2013
	13:07:48 -0000
From: david@tethera.net
To: notmuch@notmuchmail.org
Subject: [PATCH] util: detect byte order
Date: Tue, 26 Nov 2013 09:07:37 -0400
Message-Id: <1385471257-31835-1-git-send-email-david@tethera.net>
X-Mailer: git-send-email 1.8.4.2
In-Reply-To: <1385328583-24602-2-git-send-email-david@tethera.net>
References: <1385328583-24602-2-git-send-email-david@tethera.net>
X-BeenThere: notmuch@notmuchmail.org
X-Mailman-Version: 2.1.13
Precedence: list
List-Id: "Use and development of the notmuch mail system."
	<notmuch.notmuchmail.org>
List-Unsubscribe: <http://notmuchmail.org/mailman/options/notmuch>,
	<mailto:notmuch-request@notmuchmail.org?subject=unsubscribe>
List-Archive: <http://notmuchmail.org/pipermail/notmuch>
List-Post: <mailto:notmuch@notmuchmail.org>
List-Help: <mailto:notmuch-request@notmuchmail.org?subject=help>
List-Subscribe: <http://notmuchmail.org/mailman/listinfo/notmuch>,
	<mailto:notmuch-request@notmuchmail.org?subject=subscribe>
X-List-Received-Date: Tue, 26 Nov 2013 13:08:04 -0000

From: David Bremner <david@tethera.net>

Unfortunately old versions of GCC and clang do not provide byte order
macros, so we re-invent them.

If UTIL_BYTE_ORDER is not defined, we fall back to macros supported by
recent versions of GCC and clang
---

I pushed the series
id:1385328583-24602-1-git-send-email-david@tethera.net; unfortunately
that broke compilation on old versions of GCC, in particular on our
buildbot. Here is a proposed fix for the fix.

 configure          | 26 ++++++++++++++++++++++++--
 lib/libsha1.c      | 19 +++++--------------
 util/endian-util.h | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+), 16 deletions(-)
 create mode 100644 util/endian-util.h

diff --git a/configure b/configure
index 1a8e939..02d6396 100755
--- a/configure
+++ b/configure
@@ -441,6 +441,21 @@ else
 EOF
 fi
 
+printf "Checking byte order... "
+cat> _byteorder.c <<EOF
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+uint32_t test = 0x31323334;
+char buf[5];
+int main() { memcpy(buf, &test, 4); buf[4] = '\0'; printf("%s\n", buf); return 0; }
+EOF
+${CC} ${CFLAGS} _byteorder.c -o _byteorder > /dev/null 2>&1
+util_byte_order=$(./_byteorder)
+echo $util_byte_order
+
+#rm -f _byteorder _byteorder.c
+
 if [ $errors -gt 0 ]; then
     cat <<EOF
 
@@ -702,6 +717,9 @@ prefix = ${PREFIX}
 # LIBDIR_IN_LDCONFIG value below is still set correctly.
 libdir = ${LIBDIR:=\$(prefix)/lib}
 
+# byte order within a 32 bit word. 4321 = little, 1234 = big, 0 = guess
+UTIL_BYTE_ORDER = ${util_byte_order}
+
 # Whether libdir is in a path configured into ldconfig
 LIBDIR_IN_LDCONFIG = ${libdir_in_ldconfig}
 
@@ -807,7 +825,9 @@ CONFIGURE_CFLAGS = -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS)      \\
 		   -DHAVE_STRSEP=\$(HAVE_STRSEP)                         \\
 		   -DSTD_GETPWUID=\$(STD_GETPWUID)                       \\
 		   -DSTD_ASCTIME=\$(STD_ASCTIME)                         \\
-		   -DHAVE_XAPIAN_COMPACT=\$(HAVE_XAPIAN_COMPACT)
+		   -DHAVE_XAPIAN_COMPACT=\$(HAVE_XAPIAN_COMPACT)	 \\
+		   -DUTIL_BYTE_ORDER=\$(UTIL_BYTE_ORDER)
+
 CONFIGURE_CXXFLAGS = -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS)    \\
 		     \$(TALLOC_CFLAGS) -DHAVE_VALGRIND=\$(HAVE_VALGRIND) \\
 		     \$(VALGRIND_CFLAGS) \$(XAPIAN_CXXFLAGS)             \\
@@ -815,6 +835,8 @@ CONFIGURE_CXXFLAGS = -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS)    \\
 		     -DHAVE_STRSEP=\$(HAVE_STRSEP)                       \\
 		     -DSTD_GETPWUID=\$(STD_GETPWUID)                     \\
 		     -DSTD_ASCTIME=\$(STD_ASCTIME)                       \\
-		     -DHAVE_XAPIAN_COMPACT=\$(HAVE_XAPIAN_COMPACT)
+		     -DHAVE_XAPIAN_COMPACT=\$(HAVE_XAPIAN_COMPACT)       \\
+		     -DUTIL_BYTE_ORDER=\$(UTIL_BYTE_ORDER)
+
 CONFIGURE_LDFLAGS =  \$(GMIME_LDFLAGS) \$(TALLOC_LDFLAGS) \$(XAPIAN_LDFLAGS)
 EOF
diff --git a/lib/libsha1.c b/lib/libsha1.c
index 87c7c52..3566ed7 100644
--- a/lib/libsha1.c
+++ b/lib/libsha1.c
@@ -34,7 +34,7 @@
 */
 
 #include <string.h>     /* for memcpy() etc.        */
-
+#include "endian-util.h"
 #include "libsha1.h"
 
 #if defined(__cplusplus)
@@ -49,20 +49,11 @@ extern "C"
 
 #define bswap_32(x) ((rotr32((x), 24) & 0x00ff00ff) | (rotr32((x), 8) & 0xff00ff00))
 
-/* The macros __BYTE_ORDER__ and __ORDER_*_ENDIAN__ are GNU C
- * extensions. They are also supported by clang as of v3.2 */
-
-#ifdef __BYTE_ORDER__
-#  if (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
-#    define bsw_32(p,n) \
-       { int _i = (n); while(_i--) ((uint32_t*)p)[_i] = bswap_32(((uint32_t*)p)[_i]); }
-#  elif (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
-#    define bsw_32(p,n)
-#  else
-#    error "unknown byte order"
-#  endif
+#if (UTIL_BYTE_ORDER == UTIL_ORDER_LITTLE_ENDIAN)
+#  define bsw_32(p,n) \
+     { int _i = (n); while(_i--) ((uint32_t*)p)[_i] = bswap_32(((uint32_t*)p)[_i]); }
 #else
-#    error "macro __BYTE_ORDER__ is not defined"
+#  define bsw_32(p,n)
 #endif
 
 #define SHA1_MASK   (SHA1_BLOCK_SIZE - 1)
diff --git a/util/endian-util.h b/util/endian-util.h
new file mode 100644
index 0000000..cbecf66
--- /dev/null
+++ b/util/endian-util.h
@@ -0,0 +1,39 @@
+/* this file mimics the macros present in recent GCC and CLANG */
+
+#ifndef _ENDIAN_UTIL_H
+#define _ENDIAN_UTIL_H
+
+/* This are prefixed with UTIL to avoid collisions
+ *
+ * You can use something like the following to define UTIL_BYTE_ORDER
+ * in a configure script.
+ */
+#if 0
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+uint32_t test = 0x31323334;
+char buf[5];
+int main() { memcpy(buf, &test, 4); buf[4] = '\0'; printf("%s\n", buf); return 0; }
+#endif
+
+#define UTIL_ORDER_LITTLE_ENDIAN 4321
+#define UTIL_ORDER_BIG_ENDIAN    1234
+
+
+#if !defined(UTIL_BYTE_ORDER) || ((UTIL_BYTE_ORDER != UTIL_ORDER_LITTLE_ENDIAN) && \
+				   (UTIL_BYTE_ORDER != UTIL_ORDER_LITTLE_ENDIAN))
+#ifdef __BYTE_ORDER__
+#  if (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
+#    define UTIL_BYTE_ORDER UTIL_ORDER_LITTLE_ENDIAN
+#  elif (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+#    define UTIL_BYTE_ORDER UTIL_ORDER_BIG_ENDIAN
+#  else
+#    error "Unsupported __BYTE_ORDER__"
+#  endif
+#else
+#  error "UTIL_BYTE_ORDER not correctly defined and __BYTE_ORDER__ not defined."
+#endif
+#endif
+
+#endif
-- 
1.8.4.2