include: add version_compare helper function

Compare two version numbers in the major.minor form.
Switch the few users of manual version switching over to the new function.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Jamey Sharp <jamey@minilop.net>

6 files changed, 94 insertions, 16 deletions

diff --git a/Xi/xiqueryversion.c b/Xi/xiqueryversion.c
index ae63297da..f647f9872 100644
--- a/Xi/xiqueryversion.c
+++ b/Xi/xiqueryversion.c
@@ -58,7 +58,6 @@ ProcXIQueryVersion(ClientPtr client)
     xXIQueryVersionReply rep;
     XIClientPtr pXIClient;
     int major, minor;
-    unsigned int sversion, cversion;
 
     REQUEST(xXIQueryVersionReq);
     REQUEST_SIZE_MATCH(xXIQueryVersionReq);
@@ -72,10 +71,8 @@ ProcXIQueryVersion(ClientPtr client)
 
     pXIClient = dixLookupPrivate(&client->devPrivates, XIClientPrivateKey);
 
-    sversion = XIVersion.major_version * 1000 + XIVersion.minor_version;
-    cversion = stuff->major_version * 1000 + stuff->minor_version;
-
-    if (sversion > cversion)
+    if (version_compare(XIVersion.major_version, XIVersion.minor_version,
+                        stuff->major_version, stuff->minor_version) > 0)
     {
         major = stuff->major_version;
         minor = stuff->minor_version;
diff --git a/include/misc.h b/include/misc.h
index 803f5bade..bdcc8cc1e 100644
--- a/include/misc.h
+++ b/include/misc.h
@@ -223,6 +223,24 @@ pad_to_int32(const int bytes) {
 extern char**
 xstrtokenize(const char *str, const char* separators);
 
+/**
+ * Compare the two version numbers comprising of major.minor.
+ *
+ * @return A value less than 0 if a is less than b, 0 if a is equal to b,
+ * or a value greater than 0
+ */
+static inline int
+version_compare(uint16_t a_major, uint16_t a_minor,
+                uint16_t b_major, uint16_t b_minor)
+{
+    int a, b;
+
+    a = a_major << 16 | a_minor;
+    b = b_major << 16 | b_minor;
+
+    return (a - b);
+}
+
 /* some macros to help swap requests, replies, and events */
 
 #define LengthRestB(stuff) \
diff --git a/randr/rrdispatch.c b/randr/rrdispatch.c
index 213550475..d1c99c288 100644
--- a/randr/rrdispatch.c
+++ b/randr/rrdispatch.c
@@ -28,8 +28,8 @@ RRClientKnowsRates (ClientPtr	pClient)
 {
     rrClientPriv(pClient);
 
-    return (pRRClient->major_version > 1 ||
-	    (pRRClient->major_version == 1 && pRRClient->minor_version >= 1));
+    return version_compare(pRRClient->major_version, pRRClient->minor_version,
+                           1, 1) >= 0;
 }
 
 static int
@@ -47,8 +47,8 @@ ProcRRQueryVersion (ClientPtr client)
     rep.length = 0;
     rep.sequenceNumber = client->sequence;
 
-    if ((stuff->majorVersion * 1000 + stuff->minorVersion) <
-        (SERVER_RANDR_MAJOR_VERSION * 1000 + SERVER_RANDR_MINOR_VERSION))
+    if (version_compare(stuff->majorVersion, stuff->minorVersion,
+                        SERVER_RANDR_MAJOR_VERSION, SERVER_RANDR_MINOR_VERSION) < 0)
     {
 	rep.majorVersion = stuff->majorVersion;
 	rep.minorVersion = stuff->minorVersion;
diff --git a/test/Makefile.am b/test/Makefile.am
index fe9bc1f2e..b7ee070a1 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -1,7 +1,7 @@
 if ENABLE_UNIT_TESTS
 if HAVE_LD_WRAP
 SUBDIRS= . xi2
-noinst_PROGRAMS = xkb input xtest list
+noinst_PROGRAMS = xkb input xtest list misc
 check_LTLIBRARIES = libxservertest.la
 
 TESTS=$(noinst_PROGRAMS)
@@ -18,6 +18,7 @@ xkb_LDADD=$(TEST_LDADD)
 input_LDADD=$(TEST_LDADD)
 xtest_LDADD=$(TEST_LDADD)
 list_LDADD=$(TEST_LDADD)
+misc_LDADD=$(TEST_LDADD)
 
 libxservertest_la_LIBADD = \
             $(XSERVER_LIBS) \
diff --git a/test/misc.c b/test/misc.c
new file mode 100644
index 000000000..3d3b1a1e3
--- /dev/null
+++ b/test/misc.c
@@ -0,0 +1,62 @@
+/**
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a
+ *  copy of this software and associated documentation files (the "Software"),
+ *  to deal in the Software without restriction, including without limitation
+ *  the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ *  and/or sell copies of the Software, and to permit persons to whom the
+ *  Software is furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice (including the next
+ *  paragraph) shall be included in all copies or substantial portions of the
+ *  Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ *  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ *  DEALINGS IN THE SOFTWARE.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <stdint.h>
+#include "misc.h"
+
+static void dix_version_compare(void)
+{
+    int rc;
+
+    rc = version_compare(0, 0, 1, 0);
+    assert(rc < 0);
+    rc = version_compare(1, 0, 0, 0);
+    assert(rc > 0);
+    rc = version_compare(0, 0, 0, 0);
+    assert(rc == 0);
+    rc = version_compare(1, 0, 1, 0);
+    assert(rc == 0);
+    rc = version_compare(1, 0, 0, 9);
+    assert(rc > 0);
+    rc = version_compare(0, 9, 1, 0);
+    assert(rc < 0);
+    rc = version_compare(1, 0, 1, 9);
+    assert(rc < 0);
+    rc = version_compare(1, 9, 1, 0);
+    assert(rc > 0);
+    rc = version_compare(2, 0, 1, 9);
+    assert(rc > 0);
+    rc = version_compare(1, 9, 2, 0);
+    assert(rc < 0);
+}
+
+int main(int argc, char** argv)
+{
+    dix_version_compare();
+
+    return 0;
+}
diff --git a/xfixes/xfixes.c b/xfixes/xfixes.c
index e8c7bf161..54f0df341 100644
--- a/xfixes/xfixes.c
+++ b/xfixes/xfixes.c
@@ -72,17 +72,17 @@ ProcXFixesQueryVersion(ClientPtr client)
     rep.type = X_Reply;
     rep.length = 0;
     rep.sequenceNumber = client->sequence;
-    if (stuff->majorVersion < SERVER_XFIXES_MAJOR_VERSION) {
+
+    if (version_compare(stuff->majorVersion, stuff->minorVersion,
+                        SERVER_XFIXES_MAJOR_VERSION, SERVER_XFIXES_MAJOR_VERSION) < 0)
+    {
 	rep.majorVersion = stuff->majorVersion;
 	rep.minorVersion = stuff->minorVersion;
     } else {
 	rep.majorVersion = SERVER_XFIXES_MAJOR_VERSION;
-	if (stuff->majorVersion == SERVER_XFIXES_MAJOR_VERSION &&
-	    stuff->minorVersion < SERVER_XFIXES_MINOR_VERSION)
-	    rep.minorVersion = stuff->minorVersion;
-	else
-	    rep.minorVersion = SERVER_XFIXES_MINOR_VERSION;
+        rep.minorVersion = SERVER_XFIXES_MINOR_VERSION;
     }
+
     pXFixesClient->major_version = rep.majorVersion;
     pXFixesClient->minor_version = rep.minorVersion;
     if (client->swapped) {