From 282fb5fc9f9d01c4d933a6eb6bee6ae9f0d512c7 Mon Sep 17 00:00:00 2001
From: Owen Taylor <otaylor@src.gnome.org>
Date: Thu, 13 Jan 2000 04:12:07 +0000
Subject: Initial revision

---
 pango/reorder-items.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 pango/reorder-items.c

(limited to 'pango/reorder-items.c')

diff --git a/pango/reorder-items.c b/pango/reorder-items.c
new file mode 100644
index 00000000..bbe415b7
--- /dev/null
+++ b/pango/reorder-items.c
@@ -0,0 +1,104 @@
+/* Pango
+ * reorder-items.c:
+ *
+ * Copyright (C) 1999 Red Hat Software
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <pango.h>
+
+static GList *reorder_items_recurse (GList *items, int n_items);
+
+/**
+ * pango_reorder_items:
+ * @logical_items:  a GList of #PangoItem in logical order.
+ *
+ * From a list of items in logical order and the associated
+ * directional levels, produce a list in visual order.
+ * The original list is unmodified.
+ *
+ * Returns a GList of PangoItem structures in visual order.
+ */
+GList *
+pango_reorder_items (GList *logical_items)
+{
+  return reorder_items_recurse (logical_items, g_list_length (logical_items));
+}
+
+static GList *
+reorder_items_recurse (GList *items, int n_items)
+{
+  GList *tmp_list, *level_start_node;
+  int i, level_start_i;
+  int min_level = G_MAXINT;
+  GList *result = NULL;
+
+  if (n_items == 0)
+    return NULL;
+
+  tmp_list = items;
+  for (i=0; i<n_items; i++)
+    {
+      PangoItem *item = tmp_list->data;
+
+      min_level = MIN (min_level, item->analysis.level);
+
+      tmp_list = tmp_list->next;
+    }
+
+  level_start_i = 0;
+  level_start_node = items;
+  tmp_list = items;
+  for (i=0; i<n_items; i++)
+    {
+      PangoItem *item = tmp_list->data;
+
+      if (item->analysis.level == min_level)
+	{
+	  if (min_level % 2)
+	    {
+	      if (i > level_start_i)
+		result = g_list_concat (reorder_items_recurse (level_start_node, i - level_start_i), result);
+	      result = g_list_prepend (result, item);
+	    }
+	  else
+	    {
+	      if (i > level_start_i)
+		result = g_list_concat (result, reorder_items_recurse (level_start_node, i - level_start_i));
+	      result = g_list_append (result, item);
+	    }
+
+	  level_start_i = i + 1;
+	  level_start_node = tmp_list->next;
+	}
+
+      tmp_list = tmp_list->next;
+    }
+  
+  if (min_level % 2)
+    {
+      if (i > level_start_i)
+	result = g_list_concat (reorder_items_recurse (level_start_node, i - level_start_i), result);
+    }
+  else
+    {
+      if (i > level_start_i)
+	result = g_list_concat (result, reorder_items_recurse (level_start_node, i - level_start_i));
+    }
+
+  return result;
+}
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