[PATCH 09/11] include: add version_compare helper function

[Peter Hutterer]

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 at who-t.net>
---
 Xi/xiqueryversion.c |    7 ++-----
 include/misc.h      |   18 ++++++++++++++++++
 randr/rrdispatch.c  |    8 ++++----
 xfixes/xfixes.c     |   12 ++++++------
 4 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/Xi/xiqueryversion.c b/Xi/xiqueryversion.c
index ae63297..1aaadb6 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) == 1)
     {
         major = stuff->major_version;
         minor = stuff->minor_version;
diff --git a/include/misc.h b/include/misc.h
index 803f5ba..604c893 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.
+ *
+ * @retval -1 if a is less than b
+ * @retval 0 if a is equal to b
+ * @retval 1 if a is greater than b
+ */
+static inline int
+version_compare(int a_major, int a_minor, int b_major, int b_minor)
+{
+    int a, b;
+
+    a = a_major * 1000 + a_minor;
+    b = b_major * 1000 + b_minor;
+
+    return (a == b) ? 0 : (a < b) ? -1 : 1;
+}
+
 /* some macros to help swap requests, replies, and events */
 
 #define LengthRestB(stuff) \
diff --git a/randr/rrdispatch.c b/randr/rrdispatch.c
index 2135504..579999d 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) == -1)
     {
 	rep.majorVersion = stuff->majorVersion;
 	rep.minorVersion = stuff->minorVersion;
diff --git a/xfixes/xfixes.c b/xfixes/xfixes.c
index e8c7bf1..8563b22 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) == -1)
+    {
 	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) {
-- 
1.7.4.4