From: Eli Zaretskii <eliz@gnu.org>
Date: Wed, 22 Feb 2023 12:55:05 +0000 (+0200)
Subject: Avoid division by zero in get_narrowed_* functions
X-Git-Tag: emacs-29.0.90~355^2~6
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=ba91a76659b911f90914a61a2f2d5c0073a8890a;p=emacs.git

Avoid division by zero in get_narrowed_* functions

* src/xdisp.c (get_narrowed_width, get_narrowed_len): Return at
least 1 as the value.  (Bug#61704)
---

diff --git a/src/xdisp.c b/src/xdisp.c
index f5d54974b13..b64f1d35cbc 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -3498,18 +3498,18 @@ init_iterator (struct it *it, struct window *w,
 static int
 get_narrowed_width (struct window *w)
 {
-  int fact;
   /* In a character-only terminal, only one font size is used, so we
      can use a smaller factor.  */
-  fact = EQ (Fterminal_live_p (Qnil), Qt) ? 2 : 3;
-  return fact * window_body_width (w, WINDOW_BODY_IN_CANONICAL_CHARS);
+  int fact = EQ (Fterminal_live_p (Qnil), Qt) ? 2 : 3;
+  int width = window_body_width (w, WINDOW_BODY_IN_CANONICAL_CHARS);
+  return fact * max (1, width);
 }
 
 static int
 get_narrowed_len (struct window *w)
 {
-  return get_narrowed_width (w) *
-    window_body_height (w, WINDOW_BODY_IN_CANONICAL_CHARS);
+  int height = window_body_height (w, WINDOW_BODY_IN_CANONICAL_CHARS);
+  return get_narrowed_width (w) * max (1, height);
 }
 
 ptrdiff_t