Significantly speed up insertion into QJsonObject/Array

The code was only allocating memory for the next insertion
leading to a reallocation of the whole data for every
single insertion.

The code now reserves some space and uses a decent growth
strategy to avoid repeated reallocs.

Change-Id: I48b0feab71ba8ca73e7037f8460080f198b2f009
Reviewed-by: Jamey Hicks <jamey.hicks@nokia.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/tests/benchmarks/corelib/json/tst_bench_qtbinaryjson.cpp b/tests/benchmarks/corelib/json/tst_bench_qtbinaryjson.cpp
index e4e10ba2ba..c6956b4747 100644
--- a/tests/benchmarks/corelib/json/tst_bench_qtbinaryjson.cpp
+++ b/tests/benchmarks/corelib/json/tst_bench_qtbinaryjson.cpp
@@ -58,8 +58,12 @@ private Q_SLOTS:
     void parseNumbers();
     void parseJson();
     void parseJsonToVariant();
+
     void toByteArray();
     void fromByteArray();
+
+    void jsonObjectInsert();
+    void variantMapInsert();
 };
 
 BenchmarkQtBinaryJson::BenchmarkQtBinaryJson(QObject *parent) : QObject(parent)
@@ -159,6 +163,30 @@ void BenchmarkQtBinaryJson::fromByteArray()
     }
 }
 
+void BenchmarkQtBinaryJson::jsonObjectInsert()
+{
+    QJsonObject object;
+    QString test(QStringLiteral("testString"));
+    QJsonValue value(1.5);
+
+    QBENCHMARK {
+        for (int i = 0; i < 1000; i++)
+            object.insert("testkey_" + i, value);
+    }
+}
+
+void BenchmarkQtBinaryJson::variantMapInsert()
+{
+    QVariantMap object;
+    QString test(QStringLiteral("testString"));
+    QVariant variantValue(1.5);
+
+    QBENCHMARK {
+        for (int i = 0; i < 1000; i++)
+            object.insert("testkey_" + i, variantValue);
+    }
+}
+
 QTEST_MAIN(BenchmarkQtBinaryJson)
 #include "tst_bench_qtbinaryjson.moc"