simple patch for `etags.el'

[Paul Pogonyshev]

This patch speeds building of tags table completion up several
times.

The best way to check: `M-x tags-reset-tags-tables', then kill
all `TAGS' buffers, then type `M-. TAB'.  Repeat for original
and patched versions.  If you test on a large tags table (e.g.
`emacs/src/TAGS'), the difference in speed will be obvious.

Paul

P.S. I assigned copyright to FSF.


2004-09-20  Paul Pogonyshev  <address@hidden>

        * progmodes/etags.el (etags-tags-completion-table): Report
        progress percentage only when it changes (speedup).


--- etags.el    28 Aug 2004 13:30:31 -0200      1.181
+++ etags.el    20 Sep 2004 16:44:09 -0200      
@@ -1230,6 +1230,7 @@ where they were found."
 (defun etags-tags-completion-table ()
   (let ((table (make-vector 511 0))
        (point-max (/ (float (point-max)) 100.0))
+       (next-notch 0)
        (msg-fmt (format 
                  "Making tags completion table for %s...%%d%%%%"
                  buffer-file-name)))
@@ -1253,7 +1254,14 @@ where they were found."
                           (buffer-substring (match-beginning 5) (match-end 5))
                         ;; No explicit tag name.  Best guess.
                         (buffer-substring (match-beginning 3) (match-end 3)))
-                 (message msg-fmt (/ (point) point-max)))
+                 ;; Only report progress percentage when it changes.
+                 ;; Otherwise, this function spends most of the time
+                 ;; somewhere in `(message ...)' form.
+                 (when (>= (point) next-notch)
+                   (let ((percentage (truncate (/ (point) point-max))))
+                     (message msg-fmt percentage)
+                     (setq next-notch (ceiling (* (1+ percentage)
+                                                  point-max))))))
                table)))
     table))