Prepare for QByteArrayView number parsing modernization

Remove the unholy bool out parameter and make QtPrivate::to{Double,
Float,{Signed,Unsigned}Integer}() return a struct instead.

The struct contains what we'll most likely need for a full
QParsedNumber in the future: the value, an error code (always zero
atm), and a pointer to the first character that wasn't parsed (always
nullptr atm), so we don't need to change the ABI when QParsedNumber
eventually lands.

As an immediate positive contribution, even without the backend ported
away from bool out parameters, the functions can now be marked as PURE
and, in case of the FP versions, also noexcept (the int versions have
a narrow contract d/t the base argument, which, unlike the return
value, can be fixed later, by overloading).

Pick-to: 6.3
Change-Id: I67945af80a9b53d6f170502a6df3384895e82d3e
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/src/corelib/text/qbytearrayview.h b/src/corelib/text/qbytearrayview.h
index 03acaa50d8..57d4711fdb 100644
--- a/src/corelib/text/qbytearrayview.h
+++ b/src/corelib/text/qbytearrayview.h
@@ -261,9 +261,19 @@ public:
     [[nodiscard]] qulonglong toULongLong(bool *ok = nullptr, int base = 10) const
     { return QtPrivate::toIntegral<qulonglong>(*this, ok, base); }
     [[nodiscard]] float toFloat(bool *ok = nullptr) const
-    { return QtPrivate::toFloat(*this, ok); }
+    {
+        const auto r = QtPrivate::toFloat(*this);
+        if (ok)
+            *ok = bool(r);
+        return r.value_or(0.0f);
+    }
     [[nodiscard]] double toDouble(bool *ok = nullptr) const
-    { return QtPrivate::toDouble(*this, ok); }
+    {
+        const auto r = QtPrivate::toDouble(*this);
+        if (ok)
+            *ok = bool(r);
+        return r.value_or(0.0);
+    }
 
     [[nodiscard]] bool startsWith(QByteArrayView other) const noexcept
     { return QtPrivate::startsWith(*this, other); }