* fns.c: Use much-faster test for byte-length change.

2 files changed, 6 insertions, 9 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index c47a6402e81..75b9327247c 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,6 +1,7 @@
 2011-06-18  Paul Eggert  <eggert@cs.ucla.edu>
 
         * fns.c (Ffillarray): Don't assume bool vector size fits in 'int'.
+        Use much-faster test for byte-length change.
 
         * alloc.c (Fmake_bool_vector): Avoid unnecessary multiplication.
 
diff --git a/src/fns.c b/src/fns.c
index 7b303ff3836..c308e06101f 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -23,6 +23,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <time.h>
 #include <setjmp.h>
 
+#include <intprops.h>
+
 #include "lisp.h"
 #include "commands.h"
 #include "character.h"
@@ -2167,17 +2169,11 @@ ARRAY is a vector, string, char-table, or bool-vector.  */)
           unsigned char str[MAX_MULTIBYTE_LENGTH];
           int len = CHAR_STRING (charval, str);
           EMACS_INT size_byte = SBYTES (array);
-          unsigned char *p1 = p, *endp = p + size_byte;
           int i;
 
-          if (size != size_byte)
-            while (p1 < endp)
-              {
-                int this_len = BYTES_BY_CHAR_HEAD (*p1);
-                if (len != this_len)
-                  error ("Attempt to change byte length of a string");
-                p1 += this_len;
-              }
+          if (INT_MULTIPLY_OVERFLOW (SCHARS (array), len)
+              || SCHARS (array) * len != size_byte)
+            error ("Attempt to change byte length of a string");
           for (i = 0; i < size_byte; i++)
             *p++ = str[i % len];
         }