Fix bug #16576 with PRINTCHARFUN that conses output a lot.

 src/print.c (print_object): Use FETCH_STRING_CHAR_ADVANCE, not
 STRING_CHAR_AND_LENGTH, so that if the string is relocated by GC,
 we still use correct addresses.

2 files changed, 9 insertions, 12 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 04f5f0d6bbe..33ffc40d8c1 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2014-01-29  Eli Zaretskii  <eliz@gnu.org>
+
+        * print.c (print_object): Use FETCH_STRING_CHAR_ADVANCE, not
+        STRING_CHAR_AND_LENGTH, so that if the string is relocated by GC,
+        we still use correct addresses.  (Bug#16576)
+
 2014-01-27  K. Handa  <handa@gnu.org>
 
         Fix bug#16286 by the different way than revno:116158 to preserve
diff --git a/src/print.c b/src/print.c
index 586c0615776..71fa30da93e 100644
--- a/src/print.c
+++ b/src/print.c
@@ -1389,9 +1389,8 @@ print_object (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag)
         print_string (obj, printcharfun);
       else
         {
-          register ptrdiff_t i_byte;
+          register ptrdiff_t i, i_byte;
           struct gcpro gcpro1;
-          unsigned char *str;
           ptrdiff_t size_byte;
           /* 1 means we must ensure that the next character we output
              cannot be taken as part of a hex character escape.  */
@@ -1410,23 +1409,15 @@ print_object (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag)
             }
 
           PRINTCHAR ('\"');
-          str = SDATA (obj);
           size_byte = SBYTES (obj);
 
-          for (i_byte = 0; i_byte < size_byte;)
+          for (i = 0, i_byte = 0; i_byte < size_byte;)
             {
               /* Here, we must convert each multi-byte form to the
                  corresponding character code before handing it to PRINTCHAR.  */
-              int len;
               int c;
 
-              if (multibyte)
-                {
-                  c = STRING_CHAR_AND_LENGTH (str + i_byte, len);
-                  i_byte += len;
-                }
-              else
-                c = str[i_byte++];
+              FETCH_STRING_CHAR_ADVANCE (c, obj, i, i_byte);
 
               QUIT;