(xterm-mouse-truncate-wrap): New function.

(xterm-mouse-event): Use it.

1 files changed, 18 insertions, 2 deletions

diff --git a/lisp/xt-mouse.el b/lisp/xt-mouse.el
index 8ae79903d51..a4779053937 100644
--- a/lisp/xt-mouse.el
+++ b/lisp/xt-mouse.el
@@ -122,6 +122,22 @@
         (+ c #x8000000 128)
       c)))
 
+(defun xterm-mouse-truncate-wrap (f)
+  "Truncate with wrap-around."
+  (condition-case nil
+      ;; First try the built-in truncate, in case there's no overflow.
+      (truncate f)
+    ;; In case of overflow, do wraparound by hand.
+    (range-error
+     ;; In our case, we wrap around every 3 days or so, so if we assume
+     ;; a maximum of 65536 wraparounds, we're safe for a couple years.
+     ;; Using a power of 2 makes rounding errors less likely.
+     (let* ((maxwrap (* 65536 2048))
+            (dbig (truncate (/ f maxwrap)))
+            (fdiff (- f (* 1.0 maxwrap dbig))))
+       (+ (truncate fdiff) (* maxwrap dbig))))))
+
+
 (defun xterm-mouse-event ()
   "Convert XTerm mouse event to Emacs mouse event."
   (let* ((type (- (xterm-mouse-event-read) #o40))
@@ -129,7 +145,7 @@
 	 (y (- (xterm-mouse-event-read) #o40 1))
 	 ;; Emulate timestamp information.  This is accurate enough
 	 ;; for default value of mouse-1-click-follows-link (450msec).
-	 (timestamp (truncate
+	 (timestamp (xterm-mouse-truncate-wrap
 		     (* 1000
 			(- (float-time)
 			   (or xt-mouse-epoch
@@ -206,5 +222,5 @@ down the SHIFT key while pressing the mouse button."
 
 (provide 'xt-mouse)
 
-;;; arch-tag: 84962d4e-fae9-4c13-a9d7-ef4925a4ac03
+;; arch-tag: 84962d4e-fae9-4c13-a9d7-ef4925a4ac03
 ;;; xt-mouse.el ends here