$Id$

This patch by Bartosz Zapalowski.

Already submitted upstream; see
<http://bugs.xfree86.org/show_bug.cgi?id=346>.

diff -ruN xc-old/programs/Xserver/hw/xfree86/input/mouse/mouse.c xc/programs/Xserver/hw/xfree86/input/mouse/mouse.c
--- xc-old/programs/Xserver/hw/xfree86/input/mouse/mouse.c	2004-10-21 06:27:45.939356000 +0000
+++ xc/programs/Xserver/hw/xfree86/input/mouse/mouse.c	2004-10-21 06:57:22.764238432 +0000
@@ -368,6 +368,45 @@
 }
 #endif
 
+static void
+MousePrepareShiftData(MouseDevPtr pMse)
+{
+    int wheels = 0;
+    int c, cs = 1, shifted = 0, s, ss, seen, mayshift = 0;
+    
+    if (!pMse->buttonsShiftData)
+       return;
+
+    wheels |= pMse->negativeZ | pMse->positiveZ
+           | pMse->negativeW | pMse->positiveW;
+   
+    for (c = 0; c < pMse->buttons; c++, cs = cs << 1)
+    {
+       if ((wheels & cs) == cs)
+           shifted++;
+       else if (shifted > 0)
+           mayshift++;
+
+       if (shifted == 0)
+           pMse->buttonsShiftData[c] = cs;
+       else {
+           ss = cs;
+           seen = 1;
+           for (s = c; s < pMse->buttons; s++, ss = ss << 1)
+           {
+               if ((wheels & ss) == ss)
+                   continue;
+               if (seen < (shifted + mayshift)) {
+                   seen++;
+                   continue;
+               }
+               pMse->buttonsShiftData[c] = ss;
+               break;
+           }
+       }
+    }
+}
+
 /* Process options common to all mouse types. */
 static void
 MouseCommonOptions(InputInfoPtr pInfo)
@@ -664,7 +703,11 @@
     if (origButtons != pMse->buttons)
 	buttons_from = X_CONFIG;
     xf86Msg(buttons_from, "%s: Buttons: %d\n", pInfo->name, pMse->buttons);
-    
+
+    pMse->buttonsShiftData = xcalloc(sizeof(int), pMse->buttons);
+
+    MousePrepareShiftData(pMse);
+
 }
 /*
  * map bits corresponding to lock buttons.
@@ -2185,6 +2228,23 @@
     }
 }
 
+static int
+MouseShiftButtons (MouseDevPtr pMse, int buttons)
+{
+    int i, s = 1;
+    int newbuttons = 0;
+    
+    if (!pMse->buttonsShiftData)
+       return buttons;
+
+    for (i = 0; i < pMse->buttons; i++, s = s << 1)  {
+       if (buttons & s)
+           newbuttons |= pMse->buttonsShiftData[i];
+    }
+  
+    return newbuttons;
+}
+
 static void
 MousePostEvent(InputInfoPtr pInfo, int buttons, int dx, int dy, int dz, int dw)
 {
@@ -2211,6 +2271,7 @@
 	}
 	break;
     default:	/* buttons */
+	buttons = MouseShiftButtons (pMse, buttons);
 	buttons &= ~(pMse->negativeZ | pMse->positiveZ
 		   | pMse->negativeW | pMse->positiveW);
 	if (dw < 0 || dz < -1)
diff -ruN xc-old/programs/Xserver/hw/xfree86/os-support/xf86OSmouse.h xc/programs/Xserver/hw/xfree86/os-support/xf86OSmouse.h
--- xc-old/programs/Xserver/hw/xfree86/os-support/xf86OSmouse.h	2004-07-24 17:35:39.000000000 +0000
+++ xc/programs/Xserver/hw/xfree86/os-support/xf86OSmouse.h	2004-10-21 06:58:47.382374520 +0000
@@ -269,6 +269,7 @@
     int			angleOffset;
     pointer		pDragLock;	/* drag lock area */
     int			xisbscale;	/* buffer size for 1 event */
+    int *		buttonsShiftData;
 } MouseDevRec, *MouseDevPtr;
 
 /* Z axis mapping */