Extract sorting-algorithm from KFileItemModel into custom class

1 files changed, 70 insertions, 0 deletions

diff --git a/src/kitemviews/kfileitemmodelsortalgorithm_p.h b/src/kitemviews/kfileitemmodelsortalgorithm_p.h
new file mode 100644
index 000000000..3a596dff5
--- /dev/null
+++ b/src/kitemviews/kfileitemmodelsortalgorithm_p.h
@@ -0,0 +1,70 @@
+/***************************************************************************
+ *   Copyright (C) 2012 by Peter Penz <[email protected]>             *
+ *                                                                         *
+ *   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 2 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, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
+ ***************************************************************************/
+
+#ifndef KFILEITEMMODELSORTALGORITHM_H
+#define KFILEITEMMODELSORTALGORITHM_H
+
+#include <libdolphin_export.h>
+
+#include <kitemviews/kfileitemmodel.h>
+
+/**
+ * @brief Sort algorithm for sorting items of KFileItemModel.
+ *
+ * Sorts the items by using KFileItemModel::lessThan() as comparison criteria.
+ * The merge sort algorithm is used to assure a worst-case
+ * of O(n * log(n)) and to keep the number of comparisons low.
+ *
+ * The implementation is based on qStableSortHelper() from qalgorithms.h
+ * Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+ * The sorting implementations of qAlgorithms could not be used as they
+ * don't support having a member-function as comparison criteria.
+ */
+class LIBDOLPHINPRIVATE_EXPORT KFileItemModelSortAlgorithm
+{
+public:
+    static void sort(KFileItemModel* model,
+                     QList<KFileItemModel::ItemData*>::iterator begin,
+                     QList<KFileItemModel::ItemData*>::iterator end);
+
+private:
+    static void merge(KFileItemModel* model,
+                      QList<KFileItemModel::ItemData*>::iterator begin,
+                      QList<KFileItemModel::ItemData*>::iterator pivot,
+                      QList<KFileItemModel::ItemData*>::iterator end);
+
+    static QList<KFileItemModel::ItemData*>::iterator
+                lowerBound(KFileItemModel* model,
+                           QList<KFileItemModel::ItemData*>::iterator begin,
+                           QList<KFileItemModel::ItemData*>::iterator end,
+                           const KFileItemModel::ItemData* value);
+
+    static QList<KFileItemModel::ItemData*>::iterator
+                upperBound(KFileItemModel* model,
+                           QList<KFileItemModel::ItemData*>::iterator begin,
+                           QList<KFileItemModel::ItemData*>::iterator end,
+                           const KFileItemModel::ItemData* value);
+
+    static void reverse(QList<KFileItemModel::ItemData*>::iterator begin,
+                        QList<KFileItemModel::ItemData*>::iterator end);
+};
+
+#endif
+
+