Add QUuid::toRfc4122() and fromRfc4122()

Following the RFC4122, provide the interfaces between QUuid
and QByteArray, they are simpler then toByteArray() and
relevant.

Thanks for the suggestion and brief code from Robin Burchell.

Task-number: QTBUG-19420
Reviewed-by: joao
(cherry picked from commit 06873e467d98ad60d827afae29500bf2ff783c03)

Change-Id: I4623ae3363f1d5affa45de73fac616bb67a9eaa1
Reviewed-on: http://codereview.qt.nokia.com/168
Reviewed-by: Liang Qi <liang.qi@nokia.com>

src/corelib/plugin/quuid.cpp

@@ -386,6 +386,45 @@ QUuid::QUuid(const QByteArray &text)
 }
 #endif
 
+/*!
+  Creates a QUuid object from the binary representation of the UUID, as
+  specified by RFC 4122 section 4.1.2. See toRfc4122() for a further
+  explanation of the order of bytes required.
+
+  The byte array accepted is NOT a human readable format.
+
+  If the conversion fails, a null UUID is created.
+
+    \since 4.8
+
+    \sa toRfc4122(), QUuid()
+*/
+QUuid QUuid::fromRfc4122(const QByteArray &bytes)
+{
+    if (bytes.isEmpty() || bytes.length() != 16)
+        return QUuid();
+
+    uint d1;
+    ushort d2, d3;
+    uchar d4[8];
+
+    const uchar *data = reinterpret_cast<const uchar *>(bytes.constData());
+
+    d1 = qFromBigEndian<quint32>(data);
+    data += sizeof(quint32);
+    d2 = qFromBigEndian<quint16>(data);
+    data += sizeof(quint16);
+    d3 = qFromBigEndian<quint16>(data);
+    data += sizeof(quint16);
+
+    for (int i = 0; i < 8; ++i) {
+        d4[i] = *(data);
+        data++;
+    }
+
+    return QUuid(d1, d2, d3, d4[0], d4[1], d4[2], d4[3], d4[4], d4[5], d4[6], d4[7]);
+}
+
 /*!
     \fn bool QUuid::operator==(const QUuid &other) const
 
@@ -499,6 +538,59 @@ QByteArray QUuid::toByteArray() const
 }
 #endif
 
+/*!
+    Returns the binary representation of this QUuid. The byte array is in big
+    endian format, and formatted according to RFC 4122, section 4.1.2 -
+    "Layout and byte order".
+
+    The order is as follows:
+
+    \table
+    \header
+    \o Field #
+    \o Source
+
+    \row
+    \o 1
+    \o data1
+
+    \row
+    \o 2
+    \o data2
+
+    \row
+    \o 3
+    \o data3
+
+    \row
+    \o 4
+    \o data4[0] .. data4[7]
+
+    \endtable
+
+    \since 4.8
+*/
+QByteArray QUuid::toRfc4122() const
+{
+    // we know how many bytes a UUID has, I hope :)
+    QByteArray bytes(16, Qt::Uninitialized);
+    uchar *data = reinterpret_cast<uchar*>(bytes.data());
+
+    qToBigEndian(data1, data);
+    data += sizeof(quint32);
+    qToBigEndian(data2, data);
+    data += sizeof(quint16);
+    qToBigEndian(data3, data);
+    data += sizeof(quint16);
+
+    for (int i = 0; i < 8; ++i) {
+        *(data) = data4[i];
+        data++;
+    }
+
+    return bytes;
+}
+
 #ifndef QT_NO_DATASTREAM
 /*!
     \relates QUuid

src/corelib/plugin/quuid.h

@@ -112,6 +112,8 @@ struct Q_CORE_EXPORT QUuid
     QUuid(const QByteArray &);
     QByteArray toByteArray() const;
 #endif
+    QByteArray toRfc4122() const;
+    static QUuid fromRfc4122(const QByteArray &);
     bool isNull() const;
 
     bool operator==(const QUuid &orig) const

tests/auto/quuid/tst_quuid.cpp

@@ -65,6 +65,8 @@ private slots:
     void fromString();
     void toByteArray();
     void fromByteArray();
+    void toRfc4122();
+    void fromRfc4122();
     void check_QDataStream();
     void isNull();
     void equal();
@@ -147,6 +149,20 @@ void tst_QUuid::fromByteArray()
     QCOMPARE(uuidB, QUuid(QByteArray("{1ab6e93a-b1cb-4a87-ba47-ec7e99039a7b}")));
 }
 
+void tst_QUuid::toRfc4122()
+{
+    QCOMPARE(uuidA.toRfc4122(), QByteArray::fromHex("fc69b59ecc344436a43cee95d128b8c5"));
+
+    QCOMPARE(uuidB.toRfc4122(), QByteArray::fromHex("1ab6e93ab1cb4a87ba47ec7e99039a7b"));
+}
+
+void tst_QUuid::fromRfc4122()
+{
+    QCOMPARE(uuidA, QUuid::fromRfc4122(QByteArray::fromHex("fc69b59ecc344436a43cee95d128b8c5")));
+
+    QCOMPARE(uuidB, QUuid::fromRfc4122(QByteArray::fromHex("1ab6e93ab1cb4a87ba47ec7e99039a7b")));
+}
+
 void tst_QUuid::check_QDataStream()
 {
     QUuid tmp;

tests/benchmarks/corelib/plugin/quuid/tst_quuid.cpp

@@ -58,6 +58,8 @@ private slots:
     void fromString();
     void toByteArray();
     void fromByteArray();
+    void toRfc4122();
+    void fromRfc4122();
     void toDataStream();
     void fromDataStream();
     void isNull();
@@ -111,6 +113,22 @@ void tst_bench_QUuid::fromByteArray()
     }
 }
 
+void tst_bench_QUuid::toRfc4122()
+{
+    QUuid uuid = QUuid::createUuid();
+    QBENCHMARK {
+        uuid.toRfc4122();
+    }
+}
+
+void tst_bench_QUuid::fromRfc4122()
+{
+    QByteArray string = QByteArray::fromHex("67C8770B44F1410AAB9AF9B5446F13EE");
+    QBENCHMARK {
+        QUuid uuid = QUuid::fromRfc4122(string);
+    }
+}
+
 void tst_bench_QUuid::toDataStream()
 {
     QUuid uuid1, uuid2;