bug#16800: 24.3; flyspell works slow on very short words at the end of big file

[Agustin Martin <agustin.martin@hispalinux.es>]

On Mon, Feb 24, 2014 at 08:03:17PM +0400, Aleksey Cherepanov wrote:
> I played with different (maybe wrong) implementations of
> flyspell-word-search-backward and measured time against t.txt
> (produced by the one-liner). All implementations are attached.

[ ... Tons of extensive and impressive debugging ... ]

> We could avoid capturing at all. And it works faster as shown by 4
> last functions.

Hi, 

Thanks a lot for the extensive debugging and for all the suggestions. I
have been playing with something based in your last function, but trying
to get something more compact, see below current status


;; -----------------------------------                         
(defun my-test-concat-up-goto-notcap-nobob-bobp-if (word bound &optional ignore-case)
  (save-excursion
    (let* ((r '())
           (inhibit-point-motion-hooks t)
           (flyspell-not-casechars (flyspell-get-not-casechars))
           (word-re (concat
                     flyspell-not-casechars
                     (regexp-quote word)
                     flyspell-not-casechars))
           p)
      (while
          (and (not r)
               (setq p (if (re-search-backward word-re bound t)
                           (progn (forward-char) (point))
                         ;; Check if word is at bob
                         (goto-char (point-min))
                         (search-forward word (length word) t))))
        (let ((lw (flyspell-get-word)))
          (if (and (consp lw)
                   (if ignore-case
                       (string-equal (downcase (car lw)) (downcase word))
                     (string-equal (car lw) word)))
              (setq r p)
            (goto-char p))))
      r)))
;; -----------------------------------                         

I did some efficiency test and it seemed similar to those of your efficient
functions. Need to check further for corner cases, bugs, etc ...

Big thanks!

-- 
Agustin