Add qstrntod as qstrtod overload, which takes a len parameter

Add qstrntod as an overload for qstrtod, which takes a len parameter,
so one can pass character arrays which are not null-terminated.

Change-Id: I8c1c6c3627043c1d6ec6eb712efa3abc9e5e9e00
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

src/corelib/tools/qlocale_tools.cpp

@@ -534,11 +534,21 @@ QString &exponentForm(QChar zero, QChar decimal, QChar exponential,
 }
 
 double qstrtod(const char *s00, const char **se, bool *ok)
+{
+    const int len = static_cast<int>(strlen(s00));
+    Q_ASSERT(len >= 0);
+    return qstrntod(s00, len, se, ok);
+}
+
+/*!
+  \internal
+
+  Converts the initial portion of the string pointed to by \a s00 to a double, using the 'C' locale.
+ */
+double qstrntod(const char *s00, int len, const char **se, bool *ok)
 {
     int processed = 0;
     bool nonNullOk = false;
-    int len = static_cast<int>(strlen(s00));
-    Q_ASSERT(len >= 0);
     double d = asciiToDouble(s00, len, nonNullOk, processed, TrailingJunkAllowed);
     if (se)
         *se = s00 + processed;

src/corelib/tools/qlocale_tools_p.h

@@ -115,6 +115,7 @@ inline bool isZero(double d)
 }
 
 Q_CORE_EXPORT double qstrtod(const char *s00, char const **se, bool *ok);
+Q_CORE_EXPORT double qstrntod(const char *s00, int len, char const **se, bool *ok);
 qlonglong qstrtoll(const char *nptr, const char **endptr, int base, bool *ok);
 qulonglong qstrtoull(const char *nptr, const char **endptr, int base, bool *ok);