5 files changed, 88 insertions, 55 deletions
diff --git a/tests/benchmarks/corelib/tools/qhash/qhash_string.cpp b/tests/benchmarks/corelib/tools/qhash/main.cpp
index 874a0c543a..6f3228d0eb 100644
--- a/tests/benchmarks/corelib/tools/qhash/qhash_string.cpp
+++ b/tests/benchmarks/corelib/tools/qhash/main.cpp
@@ -1,8 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
-** All rights reserved.
-** Contact: Nokia Corporation (qt-info@nokia.com)
+** Contact: http://www.qt-project.org/
 **
 ** This file is part of the test suite of the Qt Toolkit.
 **
@@ -35,38 +34,12 @@
 **
 **
 **
+**
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
 
-/*
-
-////////////////////////////////////////////////////////////////////
-
-This benchmark serves as reality check on the idea that hashing the complete
-string is a good idea.
-
-  Executive summary: It is not a good idea.
-
-////////////////////////////////////////////////////////////////////
-
-********* Start testing of tst_QHash *********
-Config: Using QTest library 5.0.0, Qt 5.0.0
-PASS   : tst_QHash::initTestCase()
-RESULT : tst_QHash::qhash_qt4():
-     0.041 msecs per iteration (total: 85, iterations: 2048)
-PASS   : tst_QHash::qhash_qt4()
-RESULT : tst_QHash::qhash_faster():
-     0.0122 msecs per iteration (total: 100, iterations: 8192)
-PASS   : tst_QHash::qhash_faster()
-PASS   : tst_QHash::cleanupTestCase()
-Totals: 4 passed, 0 failed, 0 skipped
-
-////////////////////////////////////////////////////////////////////
-
-*/
-
-#include "qhash_string.h"
+#include "main.h"
 
 #include <QFile>
 #include <QHash>
@@ -81,51 +54,75 @@ class tst_QHash : public QObject
     Q_OBJECT
 
 private slots:
+    void qhash_qt4_data() { data(); }
     void qhash_qt4();
+    void qhash_faster_data() { data(); }
     void qhash_faster();
+    void javaString_data() { data(); }
+    void javaString();
 
 private:
-    QString data();
+    void data();
 };
 
-const int N = 1000000;
-extern double s;
-
 ///////////////////// QHash /////////////////////
 
-QString tst_QHash::data()
+void tst_QHash::data()
 {
-    QFile file("data.txt");
-    file.open(QIODevice::ReadOnly);
-    return QString::fromLatin1(file.readAll());
+    QFile smallPathsData("paths_small_data.txt");
+    smallPathsData.open(QIODevice::ReadOnly);
+
+    QTest::addColumn<QStringList>("items");
+    QTest::newRow("paths-small")
+            << QString::fromLatin1(smallPathsData.readAll()).split(QLatin1Char('\n'));
 }
 
 void tst_QHash::qhash_qt4()
 {
-    QStringList items = data().split(QLatin1Char('\n'));
+    QFETCH(QStringList, items);
+    QStringList realitems = items; // for copy/paste ease between benchmarks
     QHash<QString, int> hash;
-    
+
     QBENCHMARK {
-        for (int i = 0, n = items.size(); i != n; ++i) {
-            hash[items.at(i)] = i;
+        for (int i = 0, n = realitems.size(); i != n; ++i) {
+            hash[realitems.at(i)] = i;
         }
     }
 }
 
 void tst_QHash::qhash_faster()
 {
-    QList<String> items;
-    foreach (const QString &s, data().split(QLatin1Char('\n')))
-        items.append(s);
+    QFETCH(QStringList, items);
     QHash<String, int> hash;
-    
+
+    QList<String> realitems;
+    foreach (const QString &s, items)
+        realitems.append(s);
+
     QBENCHMARK {
-        for (int i = 0, n = items.size(); i != n; ++i) {
-            hash[items.at(i)] = i;
+        for (int i = 0, n = realitems.size(); i != n; ++i) {
+            hash[realitems.at(i)] = i;
         }
     }
 }
 
+void tst_QHash::javaString()
+{
+    QFETCH(QStringList, items);
+    QHash<JavaString, int> hash;
+
+    QList<JavaString> realitems;
+    foreach (const QString &s, items)
+        realitems.append(s);
+
+    QBENCHMARK {
+        for (int i = 0, n = realitems.size(); i != n; ++i) {
+            hash[realitems.at(i)] = i;
+        }
+    }
+}
+
+
 QTEST_MAIN(tst_QHash)
 
-#include "qhash_string.moc"
+#include "main.moc"
diff --git a/tests/benchmarks/corelib/tools/qhash/qhash_string.h b/tests/benchmarks/corelib/tools/qhash/main.h
index 94f142914b..c4cf94e190 100644
--- a/tests/benchmarks/corelib/tools/qhash/qhash_string.h
+++ b/tests/benchmarks/corelib/tools/qhash/main.h
@@ -1,8 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
-** All rights reserved.
-** Contact: Nokia Corporation (qt-info@nokia.com)
+** Contact: http://www.qt-project.org/
 **
 ** This file is part of the QtTest module of the Qt Toolkit.
 **
@@ -35,6 +34,7 @@
 **
 **
 **
+**
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
@@ -50,3 +50,15 @@ struct String : QString
 QT_BEGIN_NAMESPACE
 uint qHash(const String &);
 QT_END_NAMESPACE
+
+
+struct JavaString : QString
+{
+    JavaString() {}
+    JavaString(const QString &s) : QString(s) {}
+};
+
+QT_BEGIN_NAMESPACE
+uint qHash(const JavaString &);
+QT_END_NAMESPACE
+
diff --git a/tests/benchmarks/corelib/tools/qhash/outofline.cpp b/tests/benchmarks/corelib/tools/qhash/outofline.cpp
index 11a5f9e733..162c604a35 100644
--- a/tests/benchmarks/corelib/tools/qhash/outofline.cpp
+++ b/tests/benchmarks/corelib/tools/qhash/outofline.cpp
@@ -1,8 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
-** All rights reserved.
-** Contact: Nokia Corporation (qt-info@nokia.com)
+** Contact: http://www.qt-project.org/
 **
 ** This file is part of the QtTest module of the Qt Toolkit.
 **
@@ -35,11 +34,12 @@
 **
 **
 **
+**
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
 
-#include "qhash_string.h"
+#include "main.h"
 
 static void doHash(const unsigned short *p, uint &h)
 {
@@ -87,4 +87,28 @@ uint qHash(const String &str)
     return h;
 }
 
+// The Java's hashing algorithm for strings is a variation of D. J. Bernstein
+// hashing algorithm appeared here http://cr.yp.to/cdb/cdb.txt
+// and informally known as DJB33XX - DJB's 33 Times Xor.
+// Java uses DJB31XA, that is, 31 Times Add.
+// The original algorithm was a loop around  "(h << 5) + h ^ c",
+// which is indeed "h * 33 ^ c"; it was then changed to
+// "(h << 5) - h ^ c", so "h * 31 ^ c", and the XOR changed to a sum:
+// "(h << 5) - h + c", which can save some assembly instructions.
+// Still, we can avoid writing the multiplication as "(h << 5) - h"
+// -- the compiler will turn it into a shift and an addition anyway
+// (for instance, gcc 4.4 does that even at -O0).
+uint qHash(const JavaString &str)
+{
+    const unsigned short *p = (unsigned short *)str.constData();
+    const int len = str.size();
+
+    uint h = 0;
+
+    for (int i = 0; i < len; ++i)
+        h = 31 * h + p[i];
+
+    return h;
+}
+
 QT_END_NAMESPACE
diff --git a/tests/benchmarks/corelib/tools/qhash/data.txt b/tests/benchmarks/corelib/tools/qhash/paths_small_data.txt
index d5acd28820..d5acd28820 100644
--- a/tests/benchmarks/corelib/tools/qhash/data.txt
+++ b/tests/benchmarks/corelib/tools/qhash/paths_small_data.txt
diff --git a/tests/benchmarks/corelib/tools/qhash/qhash.pro b/tests/benchmarks/corelib/tools/qhash/qhash.pro
index 51d3e7f253..40f661c116 100644
--- a/tests/benchmarks/corelib/tools/qhash/qhash.pro
+++ b/tests/benchmarks/corelib/tools/qhash/qhash.pro
@@ -1,5 +1,5 @@
 TARGET = tst_hash
 QT = core testlib
 INCLUDEPATH += .
-SOURCES += qhash_string.cpp outofline.cpp 
+SOURCES += main.cpp outofline.cpp
 CONFIG += release