Boost performance of QChar::isDigit

Make it inline; add fast checks for ascii digits;
add fallback function that uses the fastcall calling
convention.

On ia32, this change makes isDigit ~370x faster for
ascii digit characters, ~250x faster for non-digit
ascii characters, and ~1.5x faster for non-ascii
characters.

Note that this change is NOT binary compatible.

Also add an autotest with expected results from
before the optimization, to ensure that the
behavior is the same.

Change-Id: I718fadecda3f591d6f4c22374d8e476f4724fd83
Reviewed-on: http://codereview.qt-project.org/4902
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/tests/auto/corelib/tools/qchar/tst_qchar.cpp b/tests/auto/corelib/tools/qchar/tst_qchar.cpp
index 02807f38b3..5a2a4834db 100644
--- a/tests/auto/corelib/tools/qchar/tst_qchar.cpp
+++ b/tests/auto/corelib/tools/qchar/tst_qchar.cpp
@@ -73,6 +73,8 @@ private slots:
     void toLower();
     void toTitle();
     void toCaseFolded();
+    void isDigit_data();
+    void isDigit();
     void isPrint();
     void isUpper();
     void isLower();
@@ -223,6 +225,25 @@ void tst_QChar::toCaseFolded()
     QVERIFY(QChar::toCaseFolded((ushort)0xb5) == 0x3bc);
 }
 
+void tst_QChar::isDigit_data()
+{
+    QTest::addColumn<ushort>("ucs");
+    QTest::addColumn<bool>("expected");
+
+    for (ushort ucs = 0; ucs < 256; ++ucs) {
+        bool isDigit = (ucs <= '9' && ucs >= '0');
+        QString tag = QString::fromLatin1("0x%0").arg(QString::number(ucs, 16));
+        QTest::newRow(tag.toLatin1()) << ucs << isDigit;
+    }
+}
+
+void tst_QChar::isDigit()
+{
+    QFETCH(ushort, ucs);
+    QFETCH(bool, expected);
+    QCOMPARE(QChar(ucs).isDigit(), expected);
+}
+
 void tst_QChar::isPrint()
 {
     QVERIFY(QChar('A').isPrint());