Rewrite QMap to use a RB tree

QMap used to use a skiplist in Qt 4.x, which has variable
sized nodes and we can thus not optimise using custom
allocators.

The rewrite now uses a red-black tree, and all allocations
and tree operations happen in the cpp file. This will allow
us to introduce custom allocation schemes in later versions
of Qt.

Added some more tests and a benchmark. Memory consumption
of the new QMap implementation is pretty much the same as before.
Performance of insertion and lookup has increased by 10-30%. iteration
is slower, but still extremely fast and should not matter compared
to the work usually done when iterating.

Change-Id: I8796c0e4b207d01111e2ead7ae55afb464dd88f5
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

4 files changed, 333 insertions, 4 deletions

diff --git a/tests/auto/corelib/tools/qmap/tst_qmap.cpp b/tests/auto/corelib/tools/qmap/tst_qmap.cpp
index 7d0ef7d7e4..ac75c0e5bd 100644
--- a/tests/auto/corelib/tools/qmap/tst_qmap.cpp
+++ b/tests/auto/corelib/tools/qmap/tst_qmap.cpp
@@ -41,10 +41,10 @@
 
 #define QT_STRICT_ITERATORS
 
+#include <qmap.h>
 #include <QtTest/QtTest>
 #include <QDebug>
 
-#include <qmap.h>
 
 class tst_QMap : public QObject
 {
@@ -74,6 +74,11 @@ private slots:
     void qmultimap_specific();
 
     void const_shared_null();
+
+    void equal_range();
+    void setSharable();
+
+    void insert();
 };
 
 typedef QMap<QString, QString> StringMap;
@@ -105,6 +110,11 @@ int MyClass::count = 0;
 
 typedef QMap<QString, MyClass> MyMap;
 
+QDebug operator << (QDebug d, const MyClass &c) {
+    d << c.str;
+    return d;
+}
+
 void tst_QMap::init()
 {
     MyClass::count = 0;
@@ -152,6 +162,7 @@ void tst_QMap::count()
         map.insert( "Paul", MyClass("Tvete 6") );
 
         QCOMPARE( map.count(), 9 );
+        QCOMPARE( map.count("Paul"), 1 );
 #ifndef Q_CC_SUN
         QCOMPARE( MyClass::count, 9 );
 #endif
@@ -519,6 +530,7 @@ void tst_QMap::find()
     for(i = 3; i < 10; ++i) {
         compareString = testString.arg(i);
         map1.insertMulti(4, compareString);
+        QCOMPARE(map1.count(4), i - 2);
     }
 
     QMap<int, QString>::const_iterator it=map1.constFind(4);
@@ -588,6 +600,33 @@ void tst_QMap::lowerUpperBound()
     QCOMPARE(map1.lowerBound(2).key(), 5);      // returns iterator to (5, "five")
     QCOMPARE(map1.lowerBound(10).key(), 10);     // returns iterator to (10, "ten")
     QVERIFY(map1.lowerBound(999) == map1.end());    // returns end()
+
+    map1.insert(3, "three");
+    map1.insert(7, "seven");
+    map1.insertMulti(7, "seven_2");
+
+    QCOMPARE(map1.upperBound(0).key(), 1);
+    QCOMPARE(map1.upperBound(1).key(), 3);
+    QCOMPARE(map1.upperBound(2).key(), 3);
+    QCOMPARE(map1.upperBound(3).key(), 5);
+    QCOMPARE(map1.upperBound(7).key(), 10);
+    QVERIFY(map1.upperBound(10) == map1.end());
+    QVERIFY(map1.upperBound(999) == map1.end());
+
+    QCOMPARE(map1.lowerBound(0).key(), 1);
+    QCOMPARE(map1.lowerBound(1).key(), 1);
+    QCOMPARE(map1.lowerBound(2).key(), 3);
+    QCOMPARE(map1.lowerBound(3).key(), 3);
+    QCOMPARE(map1.lowerBound(4).key(), 5);
+    QCOMPARE(map1.lowerBound(5).key(), 5);
+    QCOMPARE(map1.lowerBound(6).key(), 7);
+    QCOMPARE(map1.lowerBound(7).key(), 7);
+    QCOMPARE(map1.lowerBound(6).value(), QString("seven_2"));
+    QCOMPARE(map1.lowerBound(7).value(), QString("seven_2"));
+    QCOMPARE((++map1.lowerBound(6)).value(), QString("seven"));
+    QCOMPARE((++map1.lowerBound(7)).value(), QString("seven"));
+    QCOMPARE(map1.lowerBound(10).key(), 10);
+    QVERIFY(map1.lowerBound(999) == map1.end());
 }
 
 void tst_QMap::mergeCompare()
@@ -846,10 +885,129 @@ void tst_QMap::const_shared_null()
     QMap<int, QString> map2;
     map2.setSharable(true);
     QVERIFY(!map2.isDetached());
+}
+
+void tst_QMap::equal_range()
+{
+    QMap<int, QString> map;
+
+    QPair<QMap<int, QString>::iterator, QMap<int, QString>::iterator> result = map.equal_range(0);
+    QCOMPARE(result.first, map.end());
+    QCOMPARE(result.second, map.end());
+
+    map.insert(1, "one");
+
+    result = map.equal_range(0);
+    QCOMPARE(result.first, map.find(1));
+    QCOMPARE(result.second, map.find(1));
 
-    QMap<int, QString> map3;
-    map3.setInsertInOrder(true);
-    map3.setInsertInOrder(false);
+    result = map.equal_range(1);
+    QCOMPARE(result.first, map.find(1));
+    QCOMPARE(result.second, map.end());
+
+    result = map.equal_range(2);
+    QCOMPARE(result.first, map.end());
+    QCOMPARE(result.second, map.end());
+
+    for (int i = -10; i < 10; i += 2)
+        map.insert(i, QString("%1").arg(i));
+
+    result = map.equal_range(0);
+    QCOMPARE(result.first, map.find(0));
+    QCOMPARE(result.second, map.find(1));
+
+    result = map.equal_range(1);
+    QCOMPARE(result.first, map.find(1));
+    QCOMPARE(result.second, map.find(2));
+
+    result = map.equal_range(2);
+    QCOMPARE(result.first, map.find(2));
+    QCOMPARE(result.second, map.find(4));
+
+    map.insertMulti(1, "another one");
+    result = map.equal_range(1);
+    QCOMPARE(result.first, map.find(1));
+    QCOMPARE(result.second, map.find(2));
+
+    QCOMPARE(map.count(1), 2);
+}
+
+template <class T>
+const T &const_(const T &t)
+{
+    return t;
+}
+
+void tst_QMap::setSharable()
+{
+    QMap<int, QString> map;
+
+    map.insert(1, "um");
+    map.insert(2, "dois");
+    map.insert(4, "quatro");
+    map.insert(5, "cinco");
+
+    map.setSharable(true);
+    QCOMPARE(map.size(), 4);
+    QCOMPARE(const_(map)[4], QString("quatro"));
+
+    {
+        QMap<int, QString> copy(map);
+
+        QVERIFY(!map.isDetached());
+        QVERIFY(copy.isSharedWith(map));
+    }
+
+    map.setSharable(false);
+    QVERIFY(map.isDetached());
+    QCOMPARE(map.size(), 4);
+    QCOMPARE(const_(map)[4], QString("quatro"));
+
+    {
+        QMap<int, QString> copy(map);
+
+        QVERIFY(map.isDetached());
+        QVERIFY(copy.isDetached());
+
+        QCOMPARE(copy.size(), 4);
+        QCOMPARE(const_(copy)[4], QString("quatro"));
+
+        QCOMPARE(map, copy);
+    }
+
+    map.setSharable(true);
+    QCOMPARE(map.size(), 4);
+    QCOMPARE(const_(map)[4], QString("quatro"));
+
+    {
+        QMap<int, QString> copy(map);
+
+        QVERIFY(!map.isDetached());
+        QVERIFY(copy.isSharedWith(map));
+    }
+}
+
+void tst_QMap::insert()
+{
+    QMap<QString, float> map;
+    map.insert("cs/key1", 1);
+    map.insert("cs/key2", 2);
+    map.insert("cs/key1", 3);
+    QCOMPARE(map.count(), 2);
+
+    QMap<int, int> intMap;
+    for (int i = 0; i < 1000; ++i) {
+        intMap.insert(i, i);
+    }
+
+    QCOMPARE(intMap.size(), 1000);
+
+    for (int i = 0; i < 1000; ++i) {
+        QCOMPARE(intMap.value(i), i);
+        intMap.insert(i, -1);
+        QCOMPARE(intMap.size(), 1000);
+        QCOMPARE(intMap.value(i), -1);
+    }
 }
 
 QTEST_APPLESS_MAIN(tst_QMap)
diff --git a/tests/benchmarks/corelib/tools/qmap/main.cpp b/tests/benchmarks/corelib/tools/qmap/main.cpp
new file mode 100644
index 0000000000..e68ea685a3
--- /dev/null
+++ b/tests/benchmarks/corelib/tools/qmap/main.cpp
@@ -0,0 +1,165 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QFile>
+#include <QMap>
+#include <QString>
+#include <QTest>
+#include <qdebug.h>
+
+
+class tst_QMap : public QObject
+{
+    Q_OBJECT
+
+private slots:
+    void insertion_int_int();
+    void insertion_int_string();
+    void insertion_string_int();
+
+    void lookup_int_int();
+    void lookup_int_string();
+    void lookup_string_int();
+
+    void iteration();
+};
+
+
+void tst_QMap::insertion_int_int()
+{
+    QMap<int, int> map;
+    QBENCHMARK {
+        for (int i = 0; i < 100000; ++i)
+            map.insert(i, i);
+    }
+}
+
+void tst_QMap::insertion_int_string()
+{
+    QMap<int, QString> map;
+    QString str("Hello World");
+    QBENCHMARK {
+        for (int i = 0; i < 100000; ++i)
+            map.insert(i, str);
+    }
+}
+
+void tst_QMap::insertion_string_int()
+{
+    QMap<QString, int> map;
+    QString str("Hello World");
+    QBENCHMARK {
+        for (int i = 1; i < 100000; ++i) {
+            str[0] = QChar(i);
+            map.insert(str, i);
+        }
+    }
+}
+
+
+void tst_QMap::lookup_int_int()
+{
+    QMap<int, int> map;
+    for (int i = 0; i < 100000; ++i)
+        map.insert(i, i);
+
+    int sum = 0;
+    QBENCHMARK {
+        for (int i = 0; i < 100000; ++i)
+             sum += map.value(i);
+    }
+}
+
+void tst_QMap::lookup_int_string()
+{
+    QMap<int, QString> map;
+    QString str("Hello World");
+    for (int i = 0; i < 100000; ++i)
+        map.insert(i, str);
+
+    QBENCHMARK {
+        for (int i = 0; i < 100000; ++i)
+             str += map.value(i);
+    }
+}
+
+void tst_QMap::lookup_string_int()
+{
+    QMap<QString, int> map;
+    QString str("Hello World");
+    for (int i = 1; i < 100000; ++i) {
+        str[0] = QChar(i);
+        map.insert(str, i);
+    }
+
+    int sum = 0;
+    QBENCHMARK {
+        for (int i = 1; i < 100000; ++i) {
+            str[0] = QChar(i);
+            sum += map.value(str);
+        }
+    }
+}
+
+// iteration speed doesn't depend on the type of the map.
+void tst_QMap::iteration()
+{
+    QMap<int, int> map;
+    for (int i = 0; i < 100000; ++i)
+        map.insert(i, i);
+
+    int j = 0;
+    QBENCHMARK {
+        for (int i = 0; i < 100; ++i) {
+            QMap<int, int>::const_iterator it = map.constBegin();
+            QMap<int, int>::const_iterator end = map.constEnd();
+            while (it != end) {
+                j += *it;
+                ++it;
+            }
+        }
+    }
+}
+
+
+QTEST_MAIN(tst_QMap)
+
+#include "main.moc"
diff --git a/tests/benchmarks/corelib/tools/qmap/qmap.pro b/tests/benchmarks/corelib/tools/qmap/qmap.pro
new file mode 100644
index 0000000000..6a0c8d62bd
--- /dev/null
+++ b/tests/benchmarks/corelib/tools/qmap/qmap.pro
@@ -0,0 +1,5 @@
+TARGET = tst_qmap
+QT = core testlib
+INCLUDEPATH += .
+SOURCES += main.cpp
+CONFIG += release
diff --git a/tests/benchmarks/corelib/tools/tools.pro b/tests/benchmarks/corelib/tools/tools.pro
index ea9059e759..7565b1a167 100644
--- a/tests/benchmarks/corelib/tools/tools.pro
+++ b/tests/benchmarks/corelib/tools/tools.pro
@@ -5,6 +5,7 @@ SUBDIRS = \
         qbytearray \
         qcontiguouscache \
         qlist \
+        qmap \
         qrect \
         qregexp \
         qstring \