QBitArray: Add method to get int value

It is useful to use an array of bit as an integer value.
I add also a prarameter to set endianness when converting
value to UInt32.

[ChangeLog][QtCore][QBitArray] Added toUInt32() to return
the bit array's value as a uint32_t.

Change-Id: I9d8c7a33f11e7ce94cb67aa9a50b11fa42d56168
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 129 insertions, 0 deletions

diff --git a/src/corelib/tools/qbitarray.cpp b/src/corelib/tools/qbitarray.cpp
index f0b81cce66..4db0f61599 100644
--- a/src/corelib/tools/qbitarray.cpp
+++ b/src/corelib/tools/qbitarray.cpp
@@ -342,6 +342,40 @@ QBitArray QBitArray::fromBits(const char *data, qsizetype size)
     return result;
 }
 
+/*!
+    \since 5.13
+
+    Returns the array of bit converted to an int. The conversion is based of endianness value.
+    Converts up to the first 32 bits of the array to \c uint32_t and returns it,
+    obeying \a endianness. If the array has more than 32 bits, \a ok is set to false
+    and this function returns zero; otherwise, it's set to true.
+*/
+quint32 QBitArray::toUInt32(QSysInfo::Endian endianness, bool *ok) const noexcept
+{
+    if (size() > 32) {
+        if (ok != nullptr) {
+            *ok = false;
+        }
+
+        return 0;
+    }
+
+    if (ok != nullptr) {
+        *ok = true;
+    }
+
+    auto factor = 1;
+    quint32 total = 0;
+    for (auto i = 0; i < size(); ++i, factor *= 2) {
+        const auto index = endianness == QSysInfo::Endian::LittleEndian ? i : (size() - i - 1);
+        if (testBit(index)) {
+            total += factor;
+        }
+    }
+
+    return total;
+}
+
 /*! \fn bool QBitArray::isDetached() const
 
     \internal
diff --git a/src/corelib/tools/qbitarray.h b/src/corelib/tools/qbitarray.h
index 4ea613a442..ac3a8771d9 100644
--- a/src/corelib/tools/qbitarray.h
+++ b/src/corelib/tools/qbitarray.h
@@ -105,6 +105,8 @@ public:
     const char *bits() const { return isEmpty() ? nullptr : d.constData() + 1; }
     static QBitArray fromBits(const char *data, qsizetype len);
 
+    quint32 toUInt32(QSysInfo::Endian endianness, bool *ok = nullptr) const noexcept;
+
 public:
     typedef QByteArray::DataPointer DataPtr;
     inline DataPtr &data_ptr() { return d.data_ptr(); }
diff --git a/tests/auto/corelib/tools/qbitarray/tst_qbitarray.cpp b/tests/auto/corelib/tools/qbitarray/tst_qbitarray.cpp
index 9a7c099228..b2c7915aa0 100644
--- a/tests/auto/corelib/tools/qbitarray/tst_qbitarray.cpp
+++ b/tests/auto/corelib/tools/qbitarray/tst_qbitarray.cpp
@@ -86,6 +86,9 @@ private slots:
     void resize();
     void fromBits_data();
     void fromBits();
+
+    void toUInt32_data();
+    void toUInt32();
 };
 
 void tst_QBitArray::size_data()
@@ -667,5 +670,95 @@ void tst_QBitArray::fromBits()
     QCOMPARE(QBitArray::fromBits(fromBits.bits(), fromBits.size()), expected);
 }
 
+void tst_QBitArray::toUInt32_data()
+{
+    QTest::addColumn<QBitArray>("data");
+    QTest::addColumn<int>("endianness");
+    QTest::addColumn<bool>("check");
+    QTest::addColumn<quint32>("result");
+
+    QTest::newRow("ctor")           << QBitArray()
+                                    << static_cast<int>(QSysInfo::Endian::LittleEndian)
+                                    << true
+                                    << quint32(0);
+
+    QTest::newRow("empty")          << QBitArray(0)
+                                    << static_cast<int>(QSysInfo::Endian::LittleEndian)
+                                    << true
+                                    << quint32(0);
+
+    QTest::newRow("LittleEndian4")  << QStringToQBitArray(QString("0111"))
+                                    << static_cast<int>(QSysInfo::Endian::LittleEndian)
+                                    << true
+                                    << quint32(14);
+
+    QTest::newRow("BigEndian4")     << QStringToQBitArray(QString("0111"))
+                                    << static_cast<int>(QSysInfo::Endian::BigEndian)
+                                    << true
+                                    << quint32(7);
+
+    QTest::newRow("LittleEndian8")  << QStringToQBitArray(QString("01111111"))
+                                    << static_cast<int>(QSysInfo::Endian::LittleEndian)
+                                    << true
+                                    << quint32(254);
+
+    QTest::newRow("BigEndian8")     << QStringToQBitArray(QString("01111111"))
+                                    << static_cast<int>(QSysInfo::Endian::BigEndian)
+                                    << true
+                                    << quint32(127);
+
+    QTest::newRow("LittleEndian16") << QStringToQBitArray(QString("0111111111111111"))
+                                    << static_cast<int>(QSysInfo::Endian::LittleEndian)
+                                    << true
+                                    << quint32(65534);
+
+    QTest::newRow("BigEndian16")    << QStringToQBitArray(QString("0111111111111111"))
+                                    << static_cast<int>(QSysInfo::Endian::BigEndian)
+                                    << true
+                                    << quint32(32767);
+
+    QTest::newRow("LittleEndian31") << QBitArray(31, true)
+                                    << static_cast<int>(QSysInfo::Endian::LittleEndian)
+                                    << true
+                                    << quint32(2147483647);
+
+    QTest::newRow("BigEndian31")    << QBitArray(31, true)
+                                    << static_cast<int>(QSysInfo::Endian::BigEndian)
+                                    << true
+                                    << quint32(2147483647);
+
+    QTest::newRow("LittleEndian32") << QBitArray(32, true)
+                                    << static_cast<int>(QSysInfo::Endian::LittleEndian)
+                                    << true
+                                    << quint32(4294967295);
+
+    QTest::newRow("BigEndian32")    << QBitArray(32, true)
+                                    << static_cast<int>(QSysInfo::Endian::BigEndian)
+                                    << true
+                                    << quint32(4294967295);
+
+    QTest::newRow("LittleEndian33") << QBitArray(33, true)
+                                    << static_cast<int>(QSysInfo::Endian::LittleEndian)
+                                    << false
+                                    << quint32(0);
+
+    QTest::newRow("BigEndian33")    << QBitArray(33, true)
+                                    << static_cast<int>(QSysInfo::Endian::BigEndian)
+                                    << false
+                                    << quint32(0);
+}
+
+void tst_QBitArray::toUInt32()
+{
+    QFETCH(QBitArray, data);
+    QFETCH(int, endianness);
+    QFETCH(bool, check);
+    QFETCH(quint32, result);
+    bool ok = false;
+
+    QCOMPARE(data.toUInt32(static_cast<QSysInfo::Endian>(endianness), &ok), result);
+    QCOMPARE(ok, check);
+}
+
 QTEST_APPLESS_MAIN(tst_QBitArray)
 #include "tst_qbitarray.moc"