* Makefile.am: Add pspp-mode.el to EXTRA_DIST.

[pspp] / src / algorithm.c

diff --git a/src/algorithm.c b/src/algorithm.c
index 3c1aed90e2be95ed75b8a9033aadd5b1cb5c47f2..ca427a0d49549acf11e8ce099ee1072a1793853d 100644 (file)
--- a/src/algorithm.c
+++ b/src/algorithm.c
@@ -14,8 +14,8 @@
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
-   02111-1307, USA. */
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301, USA. */
 
 /* Copyright (C) 2001 Free Software Foundation, Inc.
   
@@ -32,7 +32,7 @@
 
    You should have received a copy of the GNU General Public License along
    with this library; see the file COPYING.  If not, write to the Free
-   Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+   Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    USA.
 
    As a special exception, you may use this file as part of a free software
@@ -86,8 +86,8 @@
 
    You should have received a copy of the GNU Lesser General Public
    License along with the GNU C Library; if not, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
+   Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301 USA.  */
 
 #include <config.h>
 #include "algorithm.h"
@@ -393,6 +393,36 @@ remove_element (void *array, size_t count, size_t size,
   remove_range (array, count, size, idx, 1);
 }
 
+/* Moves an element in ARRAY, which consists of COUNT elements of
+   SIZE bytes each, from OLD_IDX to NEW_IDX, shifting around
+   other elements as needed.  Runs in O(abs(OLD_IDX - NEW_IDX))
+   time. */
+void
+move_element (void *array_, size_t count, size_t size,
+              size_t old_idx, size_t new_idx) 
+{
+  assert (array_ != NULL || count == 0);
+  assert (old_idx < count);
+  assert (new_idx < count);
+  
+  if (old_idx != new_idx) 
+    {
+      char *array = array_;
+      char *element = xmalloc (size);
+      char *new = array + new_idx * size;
+      char *old = array + old_idx * size;
+
+      memcpy (element, old, size);
+      if (new < old)
+        memmove (new + size, new, (old_idx - new_idx) * size);
+      else
+        memmove (old, old + size, (new_idx - old_idx) * size);
+      memcpy (new, element, size);
+
+      free (element);
+    }
+}
+
 /* A predicate and its auxiliary data. */
 struct pred_aux 
   {