branch: externals/shift-number
commit 3362f2a373888e291982057d9be628f4de174510
Author: Campbell Barton <[email protected]>
Commit: Campbell Barton <[email protected]>
Replace only the contents of the number that changed
Reduce the amount of redundant data stored in undo.
---
shift-number.el | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 71 insertions(+), 10 deletions(-)
diff --git a/shift-number.el b/shift-number.el
index 97bc757e21..5755c5875f 100644
--- a/shift-number.el
+++ b/shift-number.el
@@ -47,6 +47,56 @@ The first parenthesized expression must match the number."
:type 'boolean
:group 'shift-number)
+(defun shift-number--replace-in-region (str beg end)
+ "Utility to replace region from BEG to END with STR.
+Return the region replaced."
+ (declare (important-return-value nil))
+
+ (let ((len (length str))
+ (i-beg nil)
+ (i-end nil)
+ (i-end-ofs nil))
+
+ ;; Check for skip end.
+ (let ((i 0))
+ (let ((len-test (min (- end beg) len)))
+ (while (< i len-test)
+ (let ((i-next (1+ i)))
+ (cond
+ ((eq (aref str (- len i-next)) (char-after (- end i-next)))
+ (setq i i-next))
+ (t ; Break.
+ (setq len-test i))))))
+ (unless (zerop i)
+ (setq i-end (- len i))
+ (setq len (- len i))
+ (setq end (- end i))
+ (setq i-end-ofs i)))
+
+ ;; Check for skip start.
+ (let ((i 0))
+ (let ((len-test (min (- end beg) len)))
+ (while (< i len-test)
+ (cond
+ ((eq (aref str i) (char-after (+ beg i)))
+ (setq i (1+ i)))
+ (t ; Break.
+ (setq len-test i)))))
+ (unless (zerop i)
+ (setq i-beg i)
+ (setq beg (+ beg i))))
+
+ (when (or i-beg i-end)
+ (setq str (substring str (or i-beg 0) (or i-end len))))
+
+ (goto-char beg)
+ (delete-region beg end)
+ (insert str)
+ (when i-end-ofs
+ ;; Leave the cursor where it would be if the end wasn't clipped.
+ (goto-char (+ (point) i-end-ofs)))
+ (cons beg (+ beg (length str)))))
+
(defun shift-number--in-regexp-p (regexp)
"Return non-nil, if point is inside REGEXP on the current line."
;; The code originates from `org-at-regexp-p'.
@@ -94,31 +144,42 @@ the current line and change it."
-1)
(t
1))))
+ (replace-bounds
+ (cons
+ (cond
+ ((eq sign -1)
+ (1- beg))
+ (t
+ beg))
+ end))
+
(old-num-str (buffer-substring-no-properties beg end))
(old-num (string-to-number old-num-str))
(new-num (+ old-num (* sign n)))
+
+ (new-num-sign-str "")
+ (new-num-leading-str "")
(new-num-str (number-to-string (abs new-num))))
- (delete-region
- (cond
- ((eq sign -1)
- (1- beg))
- (t
- beg))
- end)
;; Handle sign flipping & negative numbers.
(when (< new-num 0)
(setq sign (- sign)))
(when (eq sign -1)
- (insert "-"))
+ (setq new-num-sign-str "-"))
;; If there are leading zeros, preserve them keeping the same
;; length of the original number.
(when (string-match-p "\\`0" old-num-str)
(let ((len-diff (- (length old-num-str) (length new-num-str))))
(when (> len-diff 0)
- (insert (make-string len-diff ?0)))))
- (insert new-num-str)
+ (setq new-num-leading-str (make-string len-diff ?0)))))
+
+ ;; Prefer this over delete+insert so as to reduce the undo overhead
+ ;; when numbers are mostly the same.
+ (shift-number--replace-in-region
+ (concat new-num-sign-str new-num-leading-str new-num-str)
+ (car replace-bounds)
+ (cdr replace-bounds))
(cond
;; If the point was exactly at the end, keep it there.
