Add toInt() and friends to QStringView

Make the API more symmetric with regards to both QString and QStringRef.
Having this available helps making QStringView more of a drop-in
replacement for QStringRef. QStringRef is planned to get removed in Qt 6.

Change-Id: Ife036c0b55970078f42e1335442ff9ee5f4a2f0d
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

5 files changed, 371 insertions, 0 deletions

diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp
index b1313f0d39..12759c4a5b 100644
--- a/src/corelib/text/qstring.cpp
+++ b/src/corelib/text/qstring.cpp
@@ -12127,4 +12127,14 @@ void QAbstractConcatenable::appendLatin1To(const char *a, int len, QChar *out) n
     qt_from_latin1(reinterpret_cast<char16_t *>(out), a, uint(len));
 }
 
+double QStringView::toDouble(bool *ok) const
+{
+    return QLocaleData::c()->stringToDouble(*this, ok, QLocale::RejectGroupSeparator);
+}
+
+float QStringView::toFloat(bool *ok) const
+{
+    return QLocaleData::convertDoubleToFloat(toDouble(ok), ok);
+}
+
 QT_END_NAMESPACE
diff --git a/src/corelib/text/qstring.h b/src/corelib/text/qstring.h
index 54c286b945..45eb5f2474 100644
--- a/src/corelib/text/qstring.h
+++ b/src/corelib/text/qstring.h
@@ -1016,6 +1016,23 @@ public:
 QString QStringView::toString() const
 { return Q_ASSERT(size() == length()), QString(data(), length()); }
 
+qint64 QStringView::toLongLong(bool *ok, int base) const
+{ return QString::toIntegral_helper<qint64>(*this, ok, base); }
+quint64 QStringView::toULongLong(bool *ok, int base) const
+{ return QString::toIntegral_helper<quint64>(*this, ok, base); }
+long QStringView::toLong(bool *ok, int base) const
+{ return QString::toIntegral_helper<long>(*this, ok, base); }
+ulong QStringView::toULong(bool *ok, int base) const
+{ return QString::toIntegral_helper<ulong>(*this, ok, base); }
+int QStringView::toInt(bool *ok, int base) const
+{ return QString::toIntegral_helper<int>(*this, ok, base); }
+uint QStringView::toUInt(bool *ok, int base) const
+{ return QString::toIntegral_helper<uint>(*this, ok, base); }
+short QStringView::toShort(bool *ok, int base) const
+{ return QString::toIntegral_helper<short>(*this, ok, base); }
+ushort QStringView::toUShort(bool *ok, int base) const
+{ return QString::toIntegral_helper<ushort>(*this, ok, base); }
+
 //
 // QString inline members
 //
@@ -1073,6 +1090,7 @@ inline QString QString::arg(short a, int fieldWidth, int base, QChar fillChar) c
 { return arg(qlonglong(a), fieldWidth, base, fillChar); }
 inline QString QString::arg(ushort a, int fieldWidth, int base, QChar fillChar) const
 { return arg(qulonglong(a), fieldWidth, base, fillChar); }
+
 #if QT_STRINGVIEW_LEVEL < 2
 inline QString QString::arg(const QString &a1, const QString &a2) const
 { return qToStringViewIgnoringNull(*this).arg(a1, a2); }
diff --git a/src/corelib/text/qstringview.cpp b/src/corelib/text/qstringview.cpp
index 16ccfa8352..8f87943204 100644
--- a/src/corelib/text/qstringview.cpp
+++ b/src/corelib/text/qstringview.cpp
@@ -39,6 +39,7 @@
 
 #include "qstringview.h"
 #include "qstring.h"
+#include "qlocale_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -912,4 +913,222 @@ QT_BEGIN_NAMESPACE
     \sa QString::toWCharArray()
 */
 
+/*!
+  \fn qint64 QStringView::toLongLong(bool *ok, int base) const
+
+    Returns the string converted to a \c{long long} using base \a
+    base, which is 10 by default and must be between 2 and 36, or 0.
+    Returns 0 if the conversion fails.
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    If \a base is 0, the C language convention is used: If the string
+    begins with "0x", base 16 is used; if the string begins with "0",
+    base 8 is used; otherwise, base 10 is used.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toLongLong()
+
+    \sa QString::toLongLong()
+
+    \since 6.0
+*/
+
+/*!
+  \fn quint64 QStringView::toULongLong(bool *ok, int base) const
+
+    Returns the string converted to an \c{unsigned long long} using base \a
+    base, which is 10 by default and must be between 2 and 36, or 0.
+    Returns 0 if the conversion fails.
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    If \a base is 0, the C language convention is used: If the string
+    begins with "0x", base 16 is used; if the string begins with "0",
+    base 8 is used; otherwise, base 10 is used.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toULongLong()
+
+    \sa QString::toULongLong()
+
+    \since 6.0
+*/
+
+/*!
+    \fn long QStringView::toLong(bool *ok, int base) const
+
+    Returns the string converted to a \c long using base \a
+    base, which is 10 by default and must be between 2 and 36, or 0.
+    Returns 0 if the conversion fails.
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    If \a base is 0, the C language convention is used: If the string
+    begins with "0x", base 16 is used; if the string begins with "0",
+    base 8 is used; otherwise, base 10 is used.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toLong()
+
+    \sa QString::toLong()
+
+    \since 6.0
+*/
+
+/*!
+    \fn ulong QStringView::toULong(bool *ok, int base) const
+
+    Returns the string converted to an \c{unsigned long} using base \a
+    base, which is 10 by default and must be between 2 and 36, or 0.
+    Returns 0 if the conversion fails.
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    If \a base is 0, the C language convention is used: If the string
+    begins with "0x", base 16 is used; if the string begins with "0",
+    base 8 is used; otherwise, base 10 is used.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toULongLong()
+
+    \sa QString::toULong()
+
+    \since 6.0
+*/
+
+/*!
+  \fn int QStringView::toInt(bool *ok, int base) const
+
+    Returns the string converted to an \c int using base \a
+    base, which is 10 by default and must be between 2 and 36, or 0.
+    Returns 0 if the conversion fails.
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    If \a base is 0, the C language convention is used: If the string
+    begins with "0x", base 16 is used; if the string begins with "0",
+    base 8 is used; otherwise, base 10 is used.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toInt()
+
+    \sa QString::toInt()
+
+    \since 6.0
+*/
+
+/*!
+  \fn uint QStringView::toUInt(bool *ok, int base) const
+
+    Returns the string converted to an \c{unsigned int} using base \a
+    base, which is 10 by default and must be between 2 and 36, or 0.
+    Returns 0 if the conversion fails.
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    If \a base is 0, the C language convention is used: If the string
+    begins with "0x", base 16 is used; if the string begins with "0",
+    base 8 is used; otherwise, base 10 is used.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toUInt()
+
+    \sa QString::toUInt()
+
+    \since 6.0
+*/
+
+/*!
+  \fn short QStringView::toShort(bool *ok, int base) const
+
+    Returns the string converted to a \c short using base \a
+    base, which is 10 by default and must be between 2 and 36, or 0.
+    Returns 0 if the conversion fails.
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    If \a base is 0, the C language convention is used: If the string
+    begins with "0x", base 16 is used; if the string begins with "0",
+    base 8 is used; otherwise, base 10 is used.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toShort()
+
+    \sa QString::toShort()
+
+    \since 6.0
+*/
+
+/*!
+  \fn ushort QStringView::toUShort(bool *ok, int base) const
+
+    Returns the string converted to an \c{unsigned short} using base \a
+    base, which is 10 by default and must be between 2 and 36, or 0.
+    Returns 0 if the conversion fails.
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    If \a base is 0, the C language convention is used: If the string
+    begins with "0x", base 16 is used; if the string begins with "0",
+    base 8 is used; otherwise, base 10 is used.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toUShort()
+
+    \sa QString::toUShort()
+
+    \since 6.0
+*/
+
+/*!
+  \fn double QStringView::toDouble(bool *ok) const
+
+    Returns the string converted to a \c double value.
+
+    Returns an infinity if the conversion overflows or 0.0 if the
+    conversion fails for other reasons (e.g. underflow).
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toDouble()
+
+    For historic reasons, this function does not handle
+    thousands group separators. If you need to convert such numbers,
+    use QLocale::toDouble().
+
+    \sa QString::toDouble()
+
+    \since 6.0
+*/
+
+/*!
+  \fn float QStringView::toFloat(bool *ok) const
+
+    Returns the string converted to a \c float value.
+
+    Returns an infinity if the conversion overflows or 0.0 if the
+    conversion fails for other reasons (e.g. underflow).
+
+    If \a ok is not \nullptr, failure is reported by setting *\a{ok}
+    to \c false, and success by setting *\a{ok} to \c true.
+
+    The string conversion will always happen in the 'C' locale. For locale
+    dependent conversion use QLocale::toFloat()
+
+    \sa QString::toFloat()
+
+    \since 6.0
+*/
+
 QT_END_NAMESPACE
diff --git a/src/corelib/text/qstringview.h b/src/corelib/text/qstringview.h
index 0ae1772530..2b7863e156 100644
--- a/src/corelib/text/qstringview.h
+++ b/src/corelib/text/qstringview.h
@@ -320,6 +320,17 @@ public:
     Q_REQUIRED_RESULT bool isValidUtf16() const noexcept
     { return QtPrivate::isValidUtf16(*this); }
 
+    Q_REQUIRED_RESULT inline short toShort(bool *ok = nullptr, int base = 10) const;
+    Q_REQUIRED_RESULT inline ushort toUShort(bool *ok = nullptr, int base = 10) const;
+    Q_REQUIRED_RESULT inline int toInt(bool *ok = nullptr, int base = 10) const;
+    Q_REQUIRED_RESULT inline uint toUInt(bool *ok = nullptr, int base = 10) const;
+    Q_REQUIRED_RESULT inline long toLong(bool *ok = nullptr, int base = 10) const;
+    Q_REQUIRED_RESULT inline ulong toULong(bool *ok = nullptr, int base = 10) const;
+    Q_REQUIRED_RESULT inline qlonglong toLongLong(bool *ok = nullptr, int base = 10) const;
+    Q_REQUIRED_RESULT inline qulonglong toULongLong(bool *ok = nullptr, int base = 10) const;
+    Q_REQUIRED_RESULT Q_CORE_EXPORT float toFloat(bool *ok = nullptr) const;
+    Q_REQUIRED_RESULT Q_CORE_EXPORT double toDouble(bool *ok = nullptr) const;
+
     Q_REQUIRED_RESULT inline int toWCharArray(wchar_t *array) const; // defined in qstring.h
 
     //
diff --git a/tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp b/tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp
index ed01d46dcd..0fdad63b24 100644
--- a/tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp
+++ b/tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp
@@ -589,6 +589,20 @@ private Q_SLOTS:
     void trim_trimmed_QByteArray_data() { trimmed_data(); }
     void trim_trimmed_QByteArray() { trimmed_impl<QByteArray>(); }
 
+private:
+    void toNumber_data();
+    template <typename String> void toNumber_impl();
+
+private Q_SLOTS:
+    void toNumber_QString_data() { toNumber_data(); }
+    void toNumber_QString() { toNumber_impl<QString>(); }
+    void toNumber_QStringRef_data() { toNumber_data(); }
+    void toNumber_QStringRef() { toNumber_impl<QStringRef>(); }
+    void toNumber_QStringView_data() { toNumber_data(); }
+    void toNumber_QStringView() { toNumber_impl<QStringView>(); }
+    void toNumber_QByteArray_data() { toNumber_data(); }
+    void toNumber_QByteArray() { toNumber_impl<QByteArray>(); }
+
     //
     // UTF-16-only checks:
     //
@@ -1600,6 +1614,105 @@ void tst_QStringApiSymmetry::trimmed_impl()
     }
 }
 
+void tst_QStringApiSymmetry::toNumber_data()
+{
+    QTest::addColumn<QString>("data");
+    QTest::addColumn<qint64>("result");
+    QTest::addColumn<bool>("ok");
+
+    QTest::addRow("0") << QString::fromUtf8("0") << qint64(0) << true;
+    QTest::addRow("a0") << QString::fromUtf8("a0") << qint64(0) << false;
+    QTest::addRow("10") << QString::fromUtf8("10") << qint64(10) << true;
+    QTest::addRow("-10") << QString::fromUtf8("-10") << qint64(-10) << true;
+    QTest::addRow("32767") << QString::fromUtf8("32767") << qint64(32767) << true;
+    QTest::addRow("32768") << QString::fromUtf8("32768") << qint64(32768) << true;
+    QTest::addRow("-32767") << QString::fromUtf8("-32767") << qint64(-32767) << true;
+    QTest::addRow("-32768") << QString::fromUtf8("-32768") << qint64(-32768) << true;
+    QTest::addRow("100x") << QString::fromUtf8("100x") << qint64(0) << false;
+    QTest::addRow("-100x") << QString::fromUtf8("-100x") << qint64(0) << false;
+}
+
+template<typename T>
+bool inRange(qint64 n)
+{
+    bool checkMax = quint64(std::numeric_limits<T>::max()) <= quint64(std::numeric_limits<qint64>::max());
+    if (checkMax && n > qint64(std::numeric_limits<T>::max()))
+        return false;
+    return qint64(std::numeric_limits<T>::min()) <= n;
+}
+
+template<typename String>
+void tst_QStringApiSymmetry::toNumber_impl()
+{
+    QFETCH(const QString, data);
+    QFETCH(qint64, result);
+    QFETCH(bool, ok);
+
+    const auto utf8 = data.toUtf8();
+    const auto l1s  = data.toLatin1();
+    const auto l1   = l1s.isNull() ? QLatin1String() : QLatin1String(l1s);
+
+    const auto ref = data.isNull() ? QStringRef() : QStringRef(&data);
+    const auto s = make<String>(ref, l1, utf8);
+
+    bool is_ok = false;
+    qint64 n = 0;
+
+    n = s.toShort(&is_ok);
+    QCOMPARE(is_ok, ok && inRange<short>(result));
+    if (is_ok)
+        QCOMPARE(n, result);
+
+    n = s.toUShort(&is_ok);
+    QCOMPARE(is_ok, ok && inRange<ushort>(result));
+    if (is_ok)
+        QCOMPARE(n, result);
+
+    n = s.toInt(&is_ok);
+    QCOMPARE(is_ok, ok && inRange<int>(result));
+    if (is_ok)
+        QCOMPARE(n, result);
+
+    n = s.toUInt(&is_ok);
+    QCOMPARE(is_ok, ok && inRange<uint>(result));
+    if (is_ok)
+        QCOMPARE(n, result);
+
+    n = s.toLong(&is_ok);
+    QCOMPARE(is_ok, ok && inRange<long>(result));
+    if (is_ok)
+        QCOMPARE(n, result);
+
+    n = s.toULong(&is_ok);
+    QCOMPARE(is_ok, ok && inRange<ulong>(result));
+    if (is_ok)
+        QCOMPARE(n, result);
+
+    n = s.toLongLong(&is_ok);
+    QCOMPARE(is_ok, ok && inRange<qlonglong>(result));
+    if (is_ok)
+        QCOMPARE(n, result);
+
+    n = s.toULongLong(&is_ok);
+    QCOMPARE(is_ok, ok && inRange<qulonglong>(result));
+    if (is_ok)
+        QCOMPARE(n, result);
+
+    if (qint64(float(n)) == n) {
+        float f = s.toFloat(&is_ok);
+        QCOMPARE(is_ok, ok);
+        if (is_ok)
+            QCOMPARE(qint64(f), result);
+    }
+
+    if (qint64(double(n)) == n) {
+        double d = s.toDouble(&is_ok);
+        QCOMPARE(is_ok, ok);
+        if (is_ok)
+            QCOMPARE(qint64(d), result);
+    }
+}
+
 //
 //
 // UTF-16-only checks: