From: Mattias Engdegård <mattiase@acm.org>
Date: Sat, 24 Aug 2024 13:00:32 +0000 (+0200)
Subject: Faster region-beginning and region-end for rectangle selections
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=457c61eb435e5698d1bdf9963d0f445f63d976c4;p=emacs.git

Faster region-beginning and region-end for rectangle selections

* lisp/rect.el (rectangle--region-beginning, rectangle--region-end):
Make these run in O(1), not linear, time and space.

(cherry picked from commit 3a8222e700304e4dff84fcdfa8ff2a4e48646c82)
---

diff --git a/lisp/rect.el b/lisp/rect.el
index 0212dedcb48..93007824679 100644
--- a/lisp/rect.el
+++ b/lisp/rect.el
@@ -766,7 +766,17 @@ Ignores `line-move-visual'."
    ((not rectangle-mark-mode)
     (funcall orig))
    (t
-    (apply #'min (mapcar #'car (region-bounds))))))
+    (save-excursion
+      (let* ((pt (point))
+             (mk (mark))
+             (start (min pt mk))
+             (end (max pt mk))
+             (cols (rectangle--pos-cols start end))
+             (startcol (car cols))
+             (endcol (cdr cols)))
+        (goto-char start)
+        (move-to-column (min startcol endcol))
+        (point))))))
 
 (defun rectangle--region-end (orig)
   "Like `region-end' but supports rectangular regions."
@@ -774,7 +784,17 @@ Ignores `line-move-visual'."
    ((not rectangle-mark-mode)
     (funcall orig))
    (t
-    (apply #'max (mapcar #'cdr (region-bounds))))))
+    (save-excursion
+      (let* ((pt (point))
+             (mk (mark))
+             (start (min pt mk))
+             (end (max pt mk))
+             (cols (rectangle--pos-cols start end))
+             (startcol (car cols))
+             (endcol (cdr cols)))
+        (goto-char end)
+        (move-to-column (max startcol endcol))
+        (point))))))
 
 (defun rectangle--extract-region (orig &optional delete)
   (cond