2014-06-26 Jerry DeLisle <jvdelisle@gcc.gnu.org>

	PR libgfortran/61499
	* io/list_read.c (eat_spaces): Use a 'for' loop instead of
	'while' loop to skip the loop if there are no bytes left in the
	string. Only seek if actual spaces can be skipped.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@212059 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index 7ae6d5f..26825ca 100644 (file)
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,10 @@
+2014-06-26  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
+
+       PR libgfortran/61499
+       * io/list_read.c (eat_spaces): Use a 'for' loop instead of
+       'while' loop to skip the loop if there are no bytes left in the
+       string. Only seek if actual spaces can be skipped.
+
 2014-06-25  Tobias Burnus  <burnus@net-b.de>
 
        * caf/single.c (assign_char4_from_char1, assign_char1_from_char4,

diff --git a/libgfortran/io/list_read.c b/libgfortran/io/list_read.c
index 3b04bd2..96db059 100644 (file)
--- a/libgfortran/io/list_read.c
+++ b/libgfortran/io/list_read.c
@@ -387,50 +387,39 @@ eat_spaces (st_parameter_dt *dtp)
   int c;
 
   /* If internal character array IO, peak ahead and seek past spaces.
-     This is an optimazation to eliminate numerous calls to
-     next character unique to character arrays with large character
-     lengths (PR38199). */
-  if (is_array_io (dtp))
+     This is an optimization unique to character arrays with large
+     character lengths (PR38199).  This code eliminates numerous calls
+     to next_character.  */
+  if (is_array_io (dtp) && (dtp->u.p.last_char == EOF - 1))
     {
       gfc_offset offset = stell (dtp->u.p.current_unit->s);
-      gfc_offset limit = offset + dtp->u.p.current_unit->bytes_left;
+      gfc_offset i;
 
       if (dtp->common.unit) /* kind=4 */
        {
-         gfc_char4_t cc;
-         limit *= (sizeof (gfc_char4_t));
-         do
+         for (i = 0; i < dtp->u.p.current_unit->bytes_left; i++)
            {
-             cc = dtp->internal_unit[offset];
-             offset += (sizeof (gfc_char4_t));
-             dtp->u.p.current_unit->bytes_left--;
+             if (dtp->internal_unit[offset + i * sizeof (gfc_char4_t)]
+                 != (gfc_char4_t)' ')
+               break;
            }
-         while (offset < limit && cc == (gfc_char4_t)' ');
-         /* Back up, seek ahead, and fall through to complete the
-            process so that END conditions are handled correctly.  */
-         dtp->u.p.current_unit->bytes_left++;
-
-         cc = dtp->internal_unit[offset];
-         if (cc != (gfc_char4_t)' ')
-           sseek (dtp->u.p.current_unit->s,
-                  offset-(sizeof (gfc_char4_t)), SEEK_SET);
        }
       else
        {
-         do
+         for (i = 0; i < dtp->u.p.current_unit->bytes_left; i++)
            {
-             c = dtp->internal_unit[offset++];
-             dtp->u.p.current_unit->bytes_left--;
+             if (dtp->internal_unit[offset + i] != ' ')
+               break;
            }
-         while (offset < limit && c == ' ');
-         /* Back up, seek ahead, and fall through to complete the
-            process so that END conditions are handled correctly.  */
-         dtp->u.p.current_unit->bytes_left++;
+       }
 
-         if (dtp->internal_unit[offset] != ' ')
-           sseek (dtp->u.p.current_unit->s, offset - 1, SEEK_SET);
+      if (i != 0)
+       {
+         sseek (dtp->u.p.current_unit->s, offset + i, SEEK_SET);
+         dtp->u.p.current_unit->bytes_left -= i;
        }
     }
+
   /* Now skip spaces, EOF and EOL are handled in next_char.  */
   do
     c = next_char (dtp);