Introduce a new QStringBuilder helper class to speed up building strings

from smaller chunks using expression templates.

Simple test and benchmark included, the class is not yet complete.

2 files changed, 96 insertions, 0 deletions

diff --git a/tests/benchmarks/qstringbuilder/main.cpp b/tests/benchmarks/qstringbuilder/main.cpp
new file mode 100644
index 0000000000..9b2bc99a7c
--- /dev/null
+++ b/tests/benchmarks/qstringbuilder/main.cpp
@@ -0,0 +1,84 @@
+
+#include <QDebug>
+#include <QString>
+
+#include "../../../src/libs/utils/qstringbuilder.h"
+
+#include <qtest.h>
+
+
+class tst_qstringbuilder : public QObject
+{
+    Q_OBJECT
+
+public:
+    tst_qstringbuilder();
+
+private slots:
+    // QStringBuilder based 
+    void builderbased_l1literal_l1literal();
+    void builderbased_l1literal_l1literal_l1literal();
+    void builderbased_l1literal_l1literal_l1literal_l1literal();
+
+    // QString based for comparison
+    void stringbased_l1string_l1string();
+    void stringbased_l1string_l1string_l1string();
+    void stringbased_l1string_l1string_l1string_l1string();
+
+private:
+    const QLatin1Literal l1literal;
+    const QLatin1String l1string;
+};
+
+
+tst_qstringbuilder::tst_qstringbuilder()
+    : l1literal("some literal"), l1string("some literal")
+{}
+
+void tst_qstringbuilder::builderbased_l1literal_l1literal()
+{
+    QString result;
+    QBENCHMARK { result = l1literal % l1literal; }
+    QCOMPARE(result, l1string + l1string);
+}
+
+void tst_qstringbuilder::builderbased_l1literal_l1literal_l1literal()
+{
+    QString result;
+    QBENCHMARK { result = l1literal % l1literal % l1literal; }
+    QCOMPARE(result, l1string + l1string + l1string);
+}
+
+void tst_qstringbuilder::builderbased_l1literal_l1literal_l1literal_l1literal()
+{
+    QString result;
+    QBENCHMARK { result = l1literal % l1literal % l1literal % l1literal; }
+    QCOMPARE(result, l1string + l1string + l1string + l1string);
+}
+
+
+
+void tst_qstringbuilder::stringbased_l1string_l1string()
+{
+    QString result;
+    QBENCHMARK { result = l1string + l1string; }
+    QCOMPARE(result, QString(l1literal % l1literal));
+}
+
+void tst_qstringbuilder::stringbased_l1string_l1string_l1string()
+{
+    QString result;
+    QBENCHMARK { result = l1string + l1string + l1string; }
+    QCOMPARE(result, QString(l1literal % l1literal % l1literal));
+}
+
+void tst_qstringbuilder::stringbased_l1string_l1string_l1string_l1string()
+{
+    QString result;
+    QBENCHMARK { result = l1string + l1string + l1string + l1string; }
+    QCOMPARE(result, QString(l1literal % l1literal % l1literal % l1literal));
+}
+
+QTEST_MAIN(tst_qstringbuilder)
+
+#include "main.moc"
diff --git a/tests/benchmarks/qstringbuilder/qstringbuilder.pro b/tests/benchmarks/qstringbuilder/qstringbuilder.pro
new file mode 100644
index 0000000000..81c42bc565
--- /dev/null
+++ b/tests/benchmarks/qstringbuilder/qstringbuilder.pro
@@ -0,0 +1,12 @@
+load(qttest_p4)
+TEMPLATE = app
+TARGET = tst_qstringbuilder
+DEPENDPATH += .
+INCLUDEPATH += .
+
+QT -= gui
+
+CONFIG += release
+
+# Input
+SOURCES += main.cpp