Centralize the handling of all the toXxx (integral) functions

By way of templates. This makes the code a lot cleaner.

Change-Id: Ie369561c7631b0d34d76a6852883716cc0aa89d4
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

5 files changed, 140 insertions, 242 deletions

diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index 2a74801c42..0396fbc0c7 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -1029,6 +1029,9 @@ namespace QtPrivate {
 //like std::enable_if
 template <bool B, typename T = void> struct QEnableIf;
 template <typename T> struct QEnableIf<true, T> { typedef T Type; };
+
+template <bool B, typename T, typename F> struct QConditional { typedef T Type; };
+template <typename T, typename F> struct QConditional<false, T, F> { typedef F Type; };
 }
 
 #ifndef Q_FORWARD_DECLARE_OBJC_CLASS
diff --git a/src/corelib/tools/qbytearray.cpp b/src/corelib/tools/qbytearray.cpp
index e9e94c3692..5755bc6ffe 100644
--- a/src/corelib/tools/qbytearray.cpp
+++ b/src/corelib/tools/qbytearray.cpp
@@ -3266,6 +3266,39 @@ QByteArray QByteArray::rightJustified(int width, char fill, bool truncate) const
 
 bool QByteArray::isNull() const { return d == QArrayData::sharedNull(); }
 
+static qlonglong toIntegral_helper(const char *data, bool *ok, int base, qlonglong)
+{
+    return QLocaleData::bytearrayToLongLong(data, base, ok);
+}
+
+static qulonglong toIntegral_helper(const char *data, bool *ok, int base, qulonglong)
+{
+    return QLocaleData::bytearrayToUnsLongLong(data, base, ok);
+}
+
+template <typename T> static inline
+T toIntegral_helper(const char *data, bool *ok, int base)
+{
+    // ### Qt6: use std::conditional<std::is_unsigned<T>::value, qulonglong, qlonglong>::type
+    const bool isUnsigned = T(0) < T(-1);
+    typedef typename QtPrivate::QConditional<isUnsigned, qulonglong, qlonglong>::Type Int64;
+
+#if defined(QT_CHECK_RANGE)
+    if (base != 0 && (base < 2 || base > 36)) {
+        qWarning("QByteArray::toIntegral: Invalid base %d", base);
+        base = 10;
+    }
+#endif
+
+    // we select the right overload by the last, unused parameter
+    Int64 val = toIntegral_helper(data, ok, base, Int64());
+    if (T(val) != val) {
+        if (ok)
+            *ok = false;
+        val = 0;
+    }
+    return T(val);
+}
 
 /*!
     Returns the byte array converted to a \c {long long} using base \a
@@ -3289,14 +3322,7 @@ bool QByteArray::isNull() const { return d == QArrayData::sharedNull(); }
 
 qlonglong QByteArray::toLongLong(bool *ok, int base) const
 {
-#if defined(QT_CHECK_RANGE)
-    if (base != 0 && (base < 2 || base > 36)) {
-        qWarning("QByteArray::toLongLong: Invalid base %d", base);
-        base = 10;
-    }
-#endif
-
-    return QLocaleData::bytearrayToLongLong(nulTerminated().constData(), base, ok);
+    return toIntegral_helper<qlonglong>(nulTerminated().constData(), ok, base);
 }
 
 /*!
@@ -3322,17 +3348,9 @@ qlonglong QByteArray::toLongLong(bool *ok, int base) const
 
 qulonglong QByteArray::toULongLong(bool *ok, int base) const
 {
-#if defined(QT_CHECK_RANGE)
-    if (base != 0 && (base < 2 || base > 36)) {
-        qWarning("QByteArray::toULongLong: Invalid base %d", base);
-        base = 10;
-    }
-#endif
-
-    return QLocaleData::bytearrayToUnsLongLong(nulTerminated().constData(), base, ok);
+    return toIntegral_helper<qulonglong>(nulTerminated().constData(), ok, base);
 }
 
-
 /*!
     Returns the byte array converted to an \c int using base \a
     base, which is 10 by default and must be between 2 and 36, or 0.
@@ -3357,13 +3375,7 @@ qulonglong QByteArray::toULongLong(bool *ok, int base) const
 
 int QByteArray::toInt(bool *ok, int base) const
 {
-    qlonglong v = toLongLong(ok, base);
-    if (v < INT_MIN || v > INT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return int(v);
+    return toIntegral_helper<int>(nulTerminated().constData(), ok, base);
 }
 
 /*!
@@ -3388,13 +3400,7 @@ int QByteArray::toInt(bool *ok, int base) const
 
 uint QByteArray::toUInt(bool *ok, int base) const
 {
-    qulonglong v = toULongLong(ok, base);
-    if (v > UINT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return uint(v);
+    return toIntegral_helper<uint>(nulTerminated().constData(), ok, base);
 }
 
 /*!
@@ -3422,13 +3428,7 @@ uint QByteArray::toUInt(bool *ok, int base) const
 */
 long QByteArray::toLong(bool *ok, int base) const
 {
-    qlonglong v = toLongLong(ok, base);
-    if (v < LONG_MIN || v > LONG_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return long(v);
+    return toIntegral_helper<long>(nulTerminated().constData(), ok, base);
 }
 
 /*!
@@ -3454,13 +3454,7 @@ long QByteArray::toLong(bool *ok, int base) const
 */
 ulong QByteArray::toULong(bool *ok, int base) const
 {
-    qulonglong v = toULongLong(ok, base);
-    if (v > ULONG_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return ulong(v);
+    return toIntegral_helper<ulong>(nulTerminated().constData(), ok, base);
 }
 
 /*!
@@ -3485,13 +3479,7 @@ ulong QByteArray::toULong(bool *ok, int base) const
 
 short QByteArray::toShort(bool *ok, int base) const
 {
-    qlonglong v = toLongLong(ok, base);
-    if (v < SHRT_MIN || v > SHRT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return short(v);
+    return toIntegral_helper<short>(nulTerminated().constData(), ok, base);
 }
 
 /*!
@@ -3516,13 +3504,7 @@ short QByteArray::toShort(bool *ok, int base) const
 
 ushort QByteArray::toUShort(bool *ok, int base) const
 {
-    qulonglong v = toULongLong(ok, base);
-    if (v > USHRT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return ushort(v);
+    return toIntegral_helper<ushort>(nulTerminated().constData(), ok, base);
 }
 
 
diff --git a/src/corelib/tools/qlocale.cpp b/src/corelib/tools/qlocale.cpp
index f3c492574e..c0e5706af2 100644
--- a/src/corelib/tools/qlocale.cpp
+++ b/src/corelib/tools/qlocale.cpp
@@ -1061,6 +1061,41 @@ QString QLocale::name() const
     return result;
 }
 
+static qlonglong toIntegral_helper(const QLocaleData *d, const QChar *data, int len, bool *ok,
+                                   QLocaleData::GroupSeparatorMode mode, qlonglong)
+{
+    return d->stringToLongLong(data, len, 10, ok, mode);
+}
+
+static qulonglong toIntegral_helper(const QLocaleData *d, const QChar *data, int len, bool *ok,
+                                    QLocaleData::GroupSeparatorMode mode, qulonglong)
+{
+    return d->stringToUnsLongLong(data, len, 10, ok, mode);
+}
+
+template <typename T> static inline
+T toIntegral_helper(const QLocalePrivate *d, const QChar *data, int len, bool *ok)
+{
+    // ### Qt6: use std::conditional<std::is_unsigned<T>::value, qulonglong, qlonglong>::type
+    const bool isUnsigned = T(0) < T(-1);
+    typedef typename QtPrivate::QConditional<isUnsigned, qulonglong, qlonglong>::Type Int64;
+
+    QLocaleData::GroupSeparatorMode mode
+            = d->m_numberOptions & QLocale::RejectGroupSeparator
+              ? QLocaleData::FailOnGroupSeparators
+              : QLocaleData::ParseGroupSeparators;
+
+    // we select the right overload by the last, unused parameter
+    Int64 val = toIntegral_helper(d->m_data, data, len, ok, mode, Int64());
+    if (T(val) != val) {
+        if (ok)
+            *ok = false;
+        val = 0;
+    }
+    return T(val);
+}
+
+
 /*!
     \since 4.8
 
@@ -1135,13 +1170,7 @@ QString QLocale::scriptToString(QLocale::Script script)
 
 short QLocale::toShort(const QString &s, bool *ok) const
 {
-    qlonglong i = toLongLong(s, ok);
-    if (i < SHRT_MIN || i > SHRT_MAX) {
-        if (ok != 0)
-            *ok = false;
-        return 0;
-    }
-    return short(i);
+    return toIntegral_helper<short>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1159,13 +1188,7 @@ short QLocale::toShort(const QString &s, bool *ok) const
 
 ushort QLocale::toUShort(const QString &s, bool *ok) const
 {
-    qulonglong i = toULongLong(s, ok);
-    if (i > USHRT_MAX) {
-        if (ok != 0)
-            *ok = false;
-        return 0;
-    }
-    return ushort(i);
+    return toIntegral_helper<ushort>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1183,13 +1206,7 @@ ushort QLocale::toUShort(const QString &s, bool *ok) const
 
 int QLocale::toInt(const QString &s, bool *ok) const
 {
-    qlonglong i = toLongLong(s, ok);
-    if (i < INT_MIN || i > INT_MAX) {
-        if (ok != 0)
-            *ok = false;
-        return 0;
-    }
-    return int(i);
+    return toIntegral_helper<int>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1207,13 +1224,7 @@ int QLocale::toInt(const QString &s, bool *ok) const
 
 uint QLocale::toUInt(const QString &s, bool *ok) const
 {
-    qulonglong i = toULongLong(s, ok);
-    if (i > UINT_MAX) {
-        if (ok != 0)
-            *ok = false;
-        return 0;
-    }
-    return uint(i);
+    return toIntegral_helper<uint>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1232,12 +1243,7 @@ uint QLocale::toUInt(const QString &s, bool *ok) const
 
 qlonglong QLocale::toLongLong(const QString &s, bool *ok) const
 {
-    QLocaleData::GroupSeparatorMode mode
-        = d->m_numberOptions & RejectGroupSeparator
-            ? QLocaleData::FailOnGroupSeparators
-            : QLocaleData::ParseGroupSeparators;
-
-    return d->m_data->stringToLongLong(s.constData(), s.size(), 10, ok, mode);
+    return toIntegral_helper<qlonglong>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1256,12 +1262,7 @@ qlonglong QLocale::toLongLong(const QString &s, bool *ok) const
 
 qulonglong QLocale::toULongLong(const QString &s, bool *ok) const
 {
-    QLocaleData::GroupSeparatorMode mode
-        = d->m_numberOptions & RejectGroupSeparator
-            ? QLocaleData::FailOnGroupSeparators
-            : QLocaleData::ParseGroupSeparators;
-
-    return d->m_data->stringToUnsLongLong(s.constData(), s.size(), 10, ok, mode);
+    return toIntegral_helper<qulonglong>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1340,13 +1341,7 @@ double QLocale::toDouble(const QString &s, bool *ok) const
 
 short QLocale::toShort(const QStringRef &s, bool *ok) const
 {
-    qlonglong i = toLongLong(s, ok);
-    if (i < SHRT_MIN || i > SHRT_MAX) {
-        if (ok)
-            *ok = false;
-        return 0;
-    }
-    return short(i);
+    return toIntegral_helper<short>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1366,13 +1361,7 @@ short QLocale::toShort(const QStringRef &s, bool *ok) const
 
 ushort QLocale::toUShort(const QStringRef &s, bool *ok) const
 {
-    qulonglong i = toULongLong(s, ok);
-    if (i > USHRT_MAX) {
-        if (ok)
-            *ok = false;
-        return 0;
-    }
-    return ushort(i);
+    return toIntegral_helper<ushort>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1392,13 +1381,7 @@ ushort QLocale::toUShort(const QStringRef &s, bool *ok) const
 
 int QLocale::toInt(const QStringRef &s, bool *ok) const
 {
-    qlonglong i = toLongLong(s, ok);
-    if (i < INT_MIN || i > INT_MAX) {
-        if (ok)
-            *ok = false;
-        return 0;
-    }
-    return int(i);
+    return toIntegral_helper<int>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1418,13 +1401,7 @@ int QLocale::toInt(const QStringRef &s, bool *ok) const
 
 uint QLocale::toUInt(const QStringRef &s, bool *ok) const
 {
-    qulonglong i = toULongLong(s, ok);
-    if (i > UINT_MAX) {
-        if (ok)
-            *ok = false;
-        return 0;
-    }
-    return uint(i);
+    return toIntegral_helper<uint>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1445,12 +1422,7 @@ uint QLocale::toUInt(const QStringRef &s, bool *ok) const
 
 qlonglong QLocale::toLongLong(const QStringRef &s, bool *ok) const
 {
-    QLocaleData::GroupSeparatorMode mode
-        = d->m_numberOptions & RejectGroupSeparator
-            ? QLocaleData::FailOnGroupSeparators
-            : QLocaleData::ParseGroupSeparators;
-
-    return d->m_data->stringToLongLong(s.constData(), s.size(), 10, ok, mode);
+    return toIntegral_helper<qlonglong>(d, s.constData(), s.size(), ok);
 }
 
 /*!
@@ -1471,12 +1443,7 @@ qlonglong QLocale::toLongLong(const QStringRef &s, bool *ok) const
 
 qulonglong QLocale::toULongLong(const QStringRef &s, bool *ok) const
 {
-    QLocaleData::GroupSeparatorMode mode
-        = d->m_numberOptions & RejectGroupSeparator
-            ? QLocaleData::FailOnGroupSeparators
-            : QLocaleData::ParseGroupSeparators;
-
-    return d->m_data->stringToUnsLongLong(s.constData(), s.size(), 10, ok, mode);
+    return toIntegral_helper<qulonglong>(d, s.constData(), s.size(), ok);
 }
 
 /*!
diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index 0c0bcac1b6..5bc485be7a 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -6068,16 +6068,22 @@ QString &QString::vsprintf(const char* cformat, va_list ap)
 
 qint64 QString::toLongLong(bool *ok, int base) const
 {
+    return toIntegral_helper<qlonglong>(constData(), size(), ok, base);
+}
+
+qlonglong QString::toIntegral_helper(const QChar *data, int len, bool *ok, int base)
+{
 #if defined(QT_CHECK_RANGE)
     if (base != 0 && (base < 2 || base > 36)) {
-        qWarning("QString::toLongLong: Invalid base (%d)", base);
+        qWarning("QString::toULongLong: Invalid base (%d)", base);
         base = 10;
     }
 #endif
 
-    return QLocaleData::c()->stringToLongLong(constData(), size(), base, ok, QLocaleData::FailOnGroupSeparators);
+    return QLocaleData::c()->stringToLongLong(data, len, base, ok, QLocaleData::FailOnGroupSeparators);
 }
 
+
 /*!
     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.
@@ -6102,6 +6108,11 @@ qint64 QString::toLongLong(bool *ok, int base) const
 
 quint64 QString::toULongLong(bool *ok, int base) const
 {
+    return toIntegral_helper<qulonglong>(constData(), size(), ok, base);
+}
+
+qulonglong QString::toIntegral_helper(const QChar *data, uint len, bool *ok, int base)
+{
 #if defined(QT_CHECK_RANGE)
     if (base != 0 && (base < 2 || base > 36)) {
         qWarning("QString::toULongLong: Invalid base (%d)", base);
@@ -6109,7 +6120,7 @@ quint64 QString::toULongLong(bool *ok, int base) const
     }
 #endif
 
-    return QLocaleData::c()->stringToUnsLongLong(constData(), size(), base, ok, QLocaleData::FailOnGroupSeparators);
+    return QLocaleData::c()->stringToUnsLongLong(data, len, base, ok, QLocaleData::FailOnGroupSeparators);
 }
 
 /*!
@@ -6138,13 +6149,7 @@ quint64 QString::toULongLong(bool *ok, int base) const
 
 long QString::toLong(bool *ok, int base) const
 {
-    qint64 v = toLongLong(ok, base);
-    if (v < LONG_MIN || v > LONG_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return (long)v;
+    return toIntegral_helper<long>(constData(), size(), ok, base);
 }
 
 /*!
@@ -6173,13 +6178,7 @@ long QString::toLong(bool *ok, int base) const
 
 ulong QString::toULong(bool *ok, int base) const
 {
-    quint64 v = toULongLong(ok, base);
-    if (v > ULONG_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return (ulong)v;
+    return toIntegral_helper<ulong>(constData(), size(), ok, base);
 }
 
 
@@ -6207,13 +6206,7 @@ ulong QString::toULong(bool *ok, int base) const
 
 int QString::toInt(bool *ok, int base) const
 {
-    qint64 v = toLongLong(ok, base);
-    if (v < INT_MIN || v > INT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return v;
+    return toIntegral_helper<int>(constData(), size(), ok, base);
 }
 
 /*!
@@ -6240,13 +6233,7 @@ int QString::toInt(bool *ok, int base) const
 
 uint QString::toUInt(bool *ok, int base) const
 {
-    quint64 v = toULongLong(ok, base);
-    if (v > UINT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return (uint)v;
+    return toIntegral_helper<uint>(constData(), size(), ok, base);
 }
 
 /*!
@@ -6273,13 +6260,7 @@ uint QString::toUInt(bool *ok, int base) const
 
 short QString::toShort(bool *ok, int base) const
 {
-    long v = toLongLong(ok, base);
-    if (v < SHRT_MIN || v > SHRT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return (short)v;
+    return toIntegral_helper<short>(constData(), size(), ok, base);
 }
 
 /*!
@@ -6306,13 +6287,7 @@ short QString::toShort(bool *ok, int base) const
 
 ushort QString::toUShort(bool *ok, int base) const
 {
-    ulong v = toULongLong(ok, base);
-    if (v > USHRT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return (ushort)v;
+    return toIntegral_helper<ushort>(constData(), size(), ok, base);
 }
 
 
@@ -9606,14 +9581,7 @@ QStringRef QStringRef::trimmed() const
 
 qint64 QStringRef::toLongLong(bool *ok, int base) const
 {
-#if defined(QT_CHECK_RANGE)
-    if (base != 0 && (base < 2 || base > 36)) {
-        qWarning("QString::toLongLong: Invalid base (%d)", base);
-        base = 10;
-    }
-#endif
-
-    return QLocaleData::c()->stringToLongLong(constData(), size(), base, ok, QLocaleData::FailOnGroupSeparators);
+    return QString::toIntegral_helper<qint64>(constData(), size(), ok, base);
 }
 
 /*!
@@ -9638,14 +9606,7 @@ qint64 QStringRef::toLongLong(bool *ok, int base) const
 
 quint64 QStringRef::toULongLong(bool *ok, int base) const
 {
-#if defined(QT_CHECK_RANGE)
-    if (base != 0 && (base < 2 || base > 36)) {
-        qWarning("QString::toULongLong: Invalid base (%d)", base);
-        base = 10;
-    }
-#endif
-
-    return QLocaleData::c()->stringToUnsLongLong(constData(), size(), base, ok, QLocaleData::FailOnGroupSeparators);
+    return QString::toIntegral_helper<quint64>(constData(), size(), ok, base);
 }
 
 /*!
@@ -9672,13 +9633,7 @@ quint64 QStringRef::toULongLong(bool *ok, int base) const
 
 long QStringRef::toLong(bool *ok, int base) const
 {
-    qint64 v = toLongLong(ok, base);
-    if (v < LONG_MIN || v > LONG_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return long(v);
+    return QString::toIntegral_helper<long>(constData(), size(), ok, base);
 }
 
 /*!
@@ -9705,13 +9660,7 @@ long QStringRef::toLong(bool *ok, int base) const
 
 ulong QStringRef::toULong(bool *ok, int base) const
 {
-    quint64 v = toULongLong(ok, base);
-    if (v > ULONG_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return ulong(v);
+    return QString::toIntegral_helper<ulong>(constData(), size(), ok, base);
 }
 
 
@@ -9737,13 +9686,7 @@ ulong QStringRef::toULong(bool *ok, int base) const
 
 int QStringRef::toInt(bool *ok, int base) const
 {
-    qint64 v = toLongLong(ok, base);
-    if (v < INT_MIN || v > INT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return int(v);
+    return QString::toIntegral_helper<int>(constData(), size(), ok, base);
 }
 
 /*!
@@ -9768,13 +9711,7 @@ int QStringRef::toInt(bool *ok, int base) const
 
 uint QStringRef::toUInt(bool *ok, int base) const
 {
-    quint64 v = toULongLong(ok, base);
-    if (v > UINT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return uint(v);
+    return QString::toIntegral_helper<uint>(constData(), size(), ok, base);
 }
 
 /*!
@@ -9799,13 +9736,7 @@ uint QStringRef::toUInt(bool *ok, int base) const
 
 short QStringRef::toShort(bool *ok, int base) const
 {
-    long v = toLongLong(ok, base);
-    if (v < SHRT_MIN || v > SHRT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return short(v);
+    return QString::toIntegral_helper<short>(constData(), size(), ok, base);
 }
 
 /*!
@@ -9830,13 +9761,7 @@ short QStringRef::toShort(bool *ok, int base) const
 
 ushort QStringRef::toUShort(bool *ok, int base) const
 {
-    ulong v = toULongLong(ok, base);
-    if (v > USHRT_MAX) {
-        if (ok)
-            *ok = false;
-        v = 0;
-    }
-    return ushort(v);
+    return QString::toIntegral_helper<ushort>(constData(), size(), ok, base);
 }
 
 
diff --git a/src/corelib/tools/qstring.h b/src/corelib/tools/qstring.h
index 8fb817d519..9063f59171 100644
--- a/src/corelib/tools/qstring.h
+++ b/src/corelib/tools/qstring.h
@@ -552,6 +552,7 @@ public:
     int localeAwareCompare(const QStringRef &s) const;
     static int localeAwareCompare(const QString& s1, const QStringRef& s2);
 
+    // ### Qt6: make inline except for the long long versions
     short  toShort(bool *ok=0, int base=10) const;
     ushort toUShort(bool *ok=0, int base=10) const;
     int toInt(bool *ok=0, int base=10) const;
@@ -746,6 +747,8 @@ private:
     static QByteArray toUtf8_helper(const QString &);
     static QByteArray toLocal8Bit_helper(const QChar *data, int size);
     static int toUcs4_helper(const ushort *uc, int length, uint *out);
+    static qlonglong toIntegral_helper(const QChar *data, int len, bool *ok, int base);
+    static qulonglong toIntegral_helper(const QChar *data, uint len, bool *ok, int base);
     void replace_helper(uint *indices, int nIndices, int blen, const QChar *after, int alen);
     friend class QCharRef;
     friend class QTextCodec;
@@ -754,6 +757,24 @@ private:
     friend class QCollator;
     friend struct QAbstractConcatenable;
 
+    template <typename T> static
+    T toIntegral_helper(const QChar *data, int len, bool *ok, int base)
+    {
+        // ### Qt6: use std::conditional<std::is_unsigned<T>::value, qulonglong, qlonglong>::type
+        const bool isUnsigned = T(0) < T(-1);
+        typedef typename QtPrivate::QConditional<isUnsigned, qulonglong, qlonglong>::Type Int64;
+        typedef typename QtPrivate::QConditional<isUnsigned, uint, int>::Type Int32;
+
+        // we select the right overload by casting size() to int or uint
+        Int64 val = toIntegral_helper(data, Int32(len), ok, base);
+        if (T(val) != val) {
+            if (ok)
+                *ok = false;
+            val = 0;
+        }
+        return T(val);
+    }
+
 public:
     typedef Data * DataPtr;
     inline DataPtr &data_ptr() { return d; }