From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 23 Mar 2011 08:13:33 +0000 (-0700)
Subject: * chartab.c (sub_char_table_ref_and_range): Redo to avoid overflow
X-Git-Tag: emacs-pretest-24.0.90~104^2~275^2~460^2~15^2~4
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=6ae5284811ba17222b14424a5fd71005c14ae131;p=emacs.git

* chartab.c (sub_char_table_ref_and_range): Redo to avoid overflow

concerns.
---

diff --git a/src/ChangeLog b/src/ChangeLog
index 47d9dbe5aa2..b2686811875 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,8 @@
 2011-03-23  Paul Eggert  <eggert@cs.ucla.edu>
 
+	* chartab.c (sub_char_table_ref_and_range): Redo to avoid overflow
+	concerns.
+
 	* term.c (produce_glyphless_glyph): Remove unnecessary test.
 
 	* cm.c (calccost): Turn while-do into do-while, for clarity.
diff --git a/src/chartab.c b/src/chartab.c
index 85aa5932ac3..9a140eb8560 100644
--- a/src/chartab.c
+++ b/src/chartab.c
@@ -215,7 +215,7 @@ sub_char_table_ref_and_range (Lisp_Object table, int c, int *from, int *to, Lisp
   struct Lisp_Sub_Char_Table *tbl = XSUB_CHAR_TABLE (table);
   int depth = XINT (tbl->depth);
   int min_char = XINT (tbl->min_char);
-  int max_char = min_char + chartab_chars[depth - 1] - 1;
+  int char_offset_lim = chartab_chars[depth - 1];
   int chartab_idx = CHARTAB_IDX (c, depth, min_char), idx;
   Lisp_Object val;
 
@@ -244,8 +244,9 @@ sub_char_table_ref_and_range (Lisp_Object table, int c, int *from, int *to, Lisp
 	  break;
 	}
     }
-  while ((c = min_char + (chartab_idx + 1) * chartab_chars[depth]) <= max_char
-	 && *to >= c)
+
+  while ((c = (chartab_idx + 1) * chartab_chars[depth]) < char_offset_lim
+	 && (c += min_char) <= *to)
     {
       Lisp_Object this_val;