1 files changed, 91 insertions, 0 deletions
diff --git a/info/gc.c b/info/gc.c
new file mode 100644
index 0000000..e883e4b
--- /dev/null
+++ b/info/gc.c
@@ -0,0 +1,91 @@
+/* gc.c -- Functions to remember and garbage collect unused node contents.
+   $Id: gc.c,v 1.7 2008/06/11 09:55:42 gray Exp $
+
+   Copyright (C) 1993, 2004, 2007, 2008 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+   Written by Brian Fox (bfox@ai.mit.edu). */
+
+#include "info.h"
+
+/* Array of pointers to the contents of gc-able nodes.  A pointer on this
+   list can be garbage collected when no info window contains a node whose
+   contents member match the pointer. */
+static char **gcable_pointers = NULL;
+static int gcable_pointers_index = 0;
+static int gcable_pointers_slots = 0;
+
+/* Add POINTER to the list of garbage collectible pointers.  A pointer
+   is not actually garbage collected until no info window contains a node
+   whose contents member is equal to the pointer. */
+void
+add_gcable_pointer (char *pointer)
+{
+  gc_pointers ();
+  add_pointer_to_array (pointer, gcable_pointers_index, gcable_pointers,
+			gcable_pointers_slots, 10, char *);
+}
+
+/* Grovel the list of info windows and gc-able pointers finding those
+   node->contents which are collectible, and free them. */
+void
+gc_pointers (void)
+{
+  register int i, j, k;
+  INFO_WINDOW *iw;
+  char **new = NULL;
+  int new_index = 0;
+  int new_slots = 0;
+
+  if (!info_windows || !gcable_pointers_index)
+    return;
+
+  for (i = 0; (iw = info_windows[i]); i++)
+    {
+      for (j = 0; j < iw->nodes_index; j++)
+	{
+	  NODE *node = iw->nodes[j];
+
+	  /* If this node->contents appears in our list of gcable_pointers,
+	     it is not gc-able, so save it. */
+	  for (k = 0; k < gcable_pointers_index; k++)
+	    if (gcable_pointers[k] == node->contents)
+	      {
+		add_pointer_to_array
+		  (node->contents, new_index, new, new_slots, 10, char *);
+		break;
+	      }
+	}
+    }
+
+  /* We have gathered all of the pointers which need to be saved.  Free any
+     of the original pointers which do not appear in the new list. */
+  for (i = 0; i < gcable_pointers_index; i++)
+    {
+      for (j = 0; j < new_index; j++)
+	if (gcable_pointers[i] == new[j])
+	  break;
+
+      /* If we got all the way through the new list, then the old pointer
+	 can be garbage collected. */
+      if (new && !new[j])
+	free (gcable_pointers[i]);
+    }
+
+  free (gcable_pointers);
+  gcable_pointers = new;
+  gcable_pointers_slots = new_slots;
+  gcable_pointers_index = new_index;
+}