telepathygabble/src/gheap.c
changeset 0 d0f3a028347a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/telepathygabble/src/gheap.c	Tue Feb 02 01:10:06 2010 +0200
@@ -0,0 +1,158 @@
+/*
+ * Header file for GHeap
+ *
+ * Copyright (C) 2006 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Olli Salli (Nokia-M/Helsinki) <olli.salli@nokia.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <glib.h>
+#include "gheap.h"
+
+#define DEFAULT_SIZE 64
+
+struct _GHeap
+{
+  GPtrArray *data;
+  GCompareFunc comparator;
+};
+
+
+GHeap *
+g_heap_new (GCompareFunc comparator)
+{
+  GHeap *ret = g_slice_new (GHeap);
+  g_assert (comparator != NULL);
+
+  ret->data = g_ptr_array_sized_new (DEFAULT_SIZE);
+  ret->comparator = comparator;
+
+  return ret;
+}
+
+void
+g_heap_destroy (GHeap * heap)
+{
+  g_return_if_fail (heap != NULL);
+
+  g_ptr_array_free (heap->data, TRUE);
+  g_slice_free (GHeap, heap);
+}
+
+void
+g_heap_clear (GHeap *heap)
+{
+  g_return_if_fail (heap != NULL);
+
+  g_ptr_array_free (heap->data, TRUE);
+  heap->data = g_ptr_array_sized_new (DEFAULT_SIZE);
+}
+
+#define HEAP_INDEX(heap, index) (g_ptr_array_index ((heap)->data, (index)-1))
+
+
+void
+g_heap_add (GHeap *heap, gpointer element)
+{
+  guint m;
+
+  g_return_if_fail (heap != NULL);
+
+  g_ptr_array_add (heap->data, element);
+  m = heap->data->len;
+  while (m != 1)
+    {
+      gpointer parent = HEAP_INDEX (heap, m / 2);
+
+      if (heap->comparator (element, parent) == -1)
+        {
+          HEAP_INDEX (heap, m / 2) = element;
+          HEAP_INDEX (heap, m) = parent;
+          m /= 2;
+        }
+      else
+        break;
+    }
+}
+
+
+gpointer
+g_heap_peek_first (GHeap *heap)
+{
+  g_return_val_if_fail (heap != NULL, NULL);
+
+  if (heap->data->len > 0)
+    return HEAP_INDEX (heap, 1);
+  else
+    return NULL;
+}
+
+
+gpointer
+g_heap_extract_first (GHeap * heap)
+{
+  gpointer ret;
+
+  g_return_val_if_fail (heap != NULL, NULL);
+
+  if (heap->data->len > 0)
+    {
+      guint m = heap->data->len;
+      guint i = 1, j;
+      ret = HEAP_INDEX (heap, 1);
+
+      HEAP_INDEX (heap, 1) = HEAP_INDEX (heap, m);
+
+      while (i * 2 <= m)
+        {
+          /* select the child which is supposed to come FIRST */
+          if ((i * 2 + 1 <= m)
+              && (heap->
+                  comparator (HEAP_INDEX (heap, i * 2),
+                              HEAP_INDEX (heap, i * 2 + 1)) == 1))
+            j = i * 2 + 1;
+          else
+            j = i * 2;
+
+          if (heap->comparator (HEAP_INDEX (heap, i), HEAP_INDEX (heap, j)) ==
+              1)
+            {
+              gpointer tmp = HEAP_INDEX (heap, i);
+              HEAP_INDEX (heap, i) = HEAP_INDEX (heap, j);
+              HEAP_INDEX (heap, j) = tmp;
+              i = j;
+            }
+          else
+            break;
+        }
+
+      g_ptr_array_remove_index (heap->data, m - 1);
+    }
+  else
+    ret = NULL;
+
+  return ret;
+}
+
+
+guint
+g_heap_size (GHeap *heap)
+{
+  g_return_val_if_fail (heap != NULL, 0);
+
+  return heap->data->len;
+}