--- Begin Message ---
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Subject: |
26.0.50; [PATCH] Make ucs-names a hash table |
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Date: |
Thu, 31 Aug 2017 01:04:15 -0400 |
Hi,
I seem to remember there having been complaints about ucs-names preview
being slow. I was curious about how much of that time was spent
assoc'ing every element of a roughly n = 42k element long alist, and so
tried making it a hash table instead. The result is a drastic speedup
of C-x 8 RET TAB, presumably this makes the operation O(n) vs O(n^2).
diff --git a/lisp/international/mule-cmds.el b/lisp/international/mule-cmds.el
index 338ca6a6e3..8c5fcf319b 100644
--- a/lisp/international/mule-cmds.el
+++ b/lisp/international/mule-cmds.el
@@ -2923,10 +2923,10 @@ nonascii-translation-table
(make-obsolete-variable 'nonascii-translation-table "do not use it." "23.1")
(defvar ucs-names nil
- "Alist of cached (CHAR-NAME . CHAR-CODE) pairs.")
+ "Hash table of cached (CHAR-NAME . CHAR-CODE) pairs.")
(defun ucs-names ()
- "Return alist of (CHAR-NAME . CHAR-CODE) pairs cached in `ucs-names'."
+ "Return hash table of (CHAR-NAME . CHAR-CODE) pairs cached in `ucs-names'."
(or ucs-names
(let ((ranges
'((#x0000 . #x33FF)
@@ -2954,7 +2954,7 @@ ucs-names
;; (#x20000 . #xDFFFF) CJK Ideograph Extension A, B, etc, unused
(#xE0000 . #xE01FF)))
(gc-cons-threshold 10000000)
- names)
+ (names (make-hash-table :size 42943 :test #'equal)))
(dolist (range ranges)
(let ((c (car range))
(end (cdr range)))
@@ -2965,27 +2965,28 @@ ucs-names
;; shadows a "new-name" but in practice every time an
;; `old-name' conflicts with a `new-name', the newer one has a
;; higher code, so it gets pushed later!
- (if new-name (push (cons new-name c) names))
- (if old-name (push (cons old-name c) names))
+ (if new-name (puthash new-name c names))
+ (if old-name (puthash old-name c names))
(setq c (1+ c))))))
;; Special case for "BELL" which is apparently the only char which
;; doesn't have a new name and whose old-name is shadowed by a newer
;; char with that name.
- (setq ucs-names `(("BELL (BEL)" . 7) ,@names)))))
+ (puthash "BELL (BEL)" ?\a names)
+ (setq ucs-names names))))
(defun mule--ucs-names-annotation (name)
;; FIXME: It would be much better to add this annotation before rather than
;; after the char name, so the annotations are aligned.
;; FIXME: The default behavior of displaying annotations in italics
;; doesn't work well here.
- (let ((char (assoc name ucs-names)))
- (when char (format " (%c)" (cdr char)))))
+ (let ((char (gethash name ucs-names)))
+ (when char (format " (%c)" char))))
(defun char-from-name (string &optional ignore-case)
"Return a character as a number from its Unicode name STRING.
If optional IGNORE-CASE is non-nil, ignore case in STRING.
Return nil if STRING does not name a character."
- (or (cdr (assoc-string string (ucs-names) ignore-case))
+ (or (gethash (if ignore-case (upcase string) string) (ucs-names))
(let ((minus (string-match-p "-[0-9A-F]+\\'" string)))
(when minus
;; Parse names like "VARIATION SELECTOR-17" and "CJK
--- End Message ---