Don't assume that tab-width fits in int.

* character.h (sanitize_width): New inline function.
(SANE_TAB_WIDTH): New macro.
(ASCII_CHAR_WIDTH): Use it.
* indent.c (sane_tab_width): Remove.  All uses replaced by
SANE_TAB_WIDTH (current_buffer).
* xdisp.c (init_iterator): Use SANE_TAB_WIDTH.

4 files changed, 26 insertions, 20 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index c516a346a89..909bb052fea 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,13 @@
 2011-07-18  Paul Eggert  <eggert@cs.ucla.edu>
 
+        Don't assume that tab-width fits in int.
+        * character.h (sanitize_width): New inline function.
+        (SANE_TAB_WIDTH): New macro.
+        (ASCII_CHAR_WIDTH): Use it.
+        * indent.c (sane_tab_width): Remove.  All uses replaced by
+        SANE_TAB_WIDTH (current_buffer).
+        * xdisp.c (init_iterator): Use SANE_TAB_WIDTH.
+
         * fileio.c: Integer overflow issues with file modes.
         (Fset_file_modes, auto_save_1): Don't assume EMACS_INT fits in int.
 
diff --git a/src/character.h b/src/character.h
index 063b5147dc9..0c207113c1e 100644
--- a/src/character.h
+++ b/src/character.h
@@ -556,6 +556,16 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
   } while (0)
 
 
+/* Return a non-outlandish value for the tab width.  */
+
+#define SANE_TAB_WIDTH(buf) sanitize_width (XFASTINT (BVAR (buf, tab_width)))
+
+static inline int
+sanitize_width (EMACS_INT width)
+{
+  return 0 < width && width <= 1000 ? width : 8;
+}
+
 /* Return the width of ASCII character C.  The width is measured by
    how many columns C will occupy on the screen when displayed in the
    current buffer.  */
@@ -563,7 +573,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #define ASCII_CHAR_WIDTH(c)                                             \
   (c < 0x20                                                             \
    ? (c == '\t'                                                         \
-      ? XFASTINT (BVAR (current_buffer, tab_width))                             \
+      ? SANE_TAB_WIDTH (current_buffer)                                 \
       : (c == '\n' ? 0 : (NILP (BVAR (current_buffer, ctl_arrow)) ? 4 : 2)))    \
    : (c < 0x7f                                                          \
       ? 1                                                               \
diff --git a/src/indent.c b/src/indent.c
index aaeaaf591ef..d89c7a9de03 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -318,15 +318,6 @@ invalidate_current_column (void)
   last_known_column_point = 0;
 }
 
-/* Return a non-outlandish value for the tab width.  */
-
-static int
-sane_tab_width (void)
-{
-  EMACS_INT n = XFASTINT (BVAR (current_buffer, tab_width));
-  return 0 < n && n <= 1000 ? n : 8;
-}
-
 EMACS_INT
 current_column (void)
 {
@@ -335,7 +326,7 @@ current_column (void)
   register int tab_seen;
   EMACS_INT post_tab;
   register int c;
-  int tab_width = sane_tab_width ();
+  int tab_width = SANE_TAB_WIDTH (current_buffer);
   int ctl_arrow = !NILP (BVAR (current_buffer, ctl_arrow));
   register struct Lisp_Char_Table *dp = buffer_display_table ();
 
@@ -515,7 +506,7 @@ check_display_width (EMACS_INT pos, EMACS_INT col, EMACS_INT *endpos)
 static void
 scan_for_column (EMACS_INT *endpos, EMACS_INT *goalcol, EMACS_INT *prevcol)
 {
-  int tab_width = sane_tab_width ();
+  int tab_width = SANE_TAB_WIDTH (current_buffer);
   register int ctl_arrow = !NILP (BVAR (current_buffer, ctl_arrow));
   register struct Lisp_Char_Table *dp = buffer_display_table ();
   int multibyte = !NILP (BVAR (current_buffer, enable_multibyte_characters));
@@ -732,7 +723,7 @@ string_display_width (Lisp_Object string, Lisp_Object beg, Lisp_Object end)
   register int tab_seen;
   int post_tab;
   register int c;
-  int tab_width = sane_tab_width ();
+  int tab_width = SANE_TAB_WIDTH (current_buffer);
   int ctl_arrow = !NILP (current_buffer->ctl_arrow);
   register struct Lisp_Char_Table *dp = buffer_display_table ();
   int b, e;
@@ -808,7 +799,7 @@ The return value is COLUMN.  */)
 {
   EMACS_INT mincol;
   register EMACS_INT fromcol;
-  int tab_width = sane_tab_width ();
+  int tab_width = SANE_TAB_WIDTH (current_buffer);
 
   CHECK_NUMBER (column);
   if (NILP (minimum))
@@ -867,7 +858,7 @@ static EMACS_INT
 position_indentation (register int pos_byte)
 {
   register EMACS_INT column = 0;
-  int tab_width = sane_tab_width ();
+  int tab_width = SANE_TAB_WIDTH (current_buffer);
   register unsigned char *p;
   register unsigned char *stop;
   unsigned char *start;
@@ -1116,7 +1107,7 @@ compute_motion (EMACS_INT from, EMACS_INT fromvpos, EMACS_INT fromhpos, int did_
   register EMACS_INT pos;
   EMACS_INT pos_byte;
   register int c = 0;
-  int tab_width = sane_tab_width ();
+  int tab_width = SANE_TAB_WIDTH (current_buffer);
   register int ctl_arrow = !NILP (BVAR (current_buffer, ctl_arrow));
   register struct Lisp_Char_Table *dp = window_display_table (win);
   EMACS_INT selective
diff --git a/src/xdisp.c b/src/xdisp.c
index 4ea183ccc56..9d521ea7aaf 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2478,10 +2478,7 @@ init_iterator (struct it *it, struct window *w,
   else if (INTEGERP (w->redisplay_end_trigger))
     it->redisplay_end_trigger_charpos = XINT (w->redisplay_end_trigger);
 
-  /* Correct bogus values of tab_width.  */
-  it->tab_width = XINT (BVAR (current_buffer, tab_width));
-  if (it->tab_width <= 0 || it->tab_width > 1000)
-    it->tab_width = 8;
+  it->tab_width = SANE_TAB_WIDTH (current_buffer);
 
   /* Are lines in the display truncated?  */
   if (base_face_id != DEFAULT_FACE_ID