1 files changed, 62 insertions, 0 deletions
diff --git a/src/qml/common/qv4stringtoarrayindex_p.h b/src/qml/common/qv4stringtoarrayindex_p.h
new file mode 100644
index 0000000000..7bdabd4f3f
--- /dev/null
+++ b/src/qml/common/qv4stringtoarrayindex_p.h
@@ -0,0 +1,62 @@
+// Copyright (C) 2019 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QV4STRINGTOARRAYINDEX_P_H
+#define QV4STRINGTOARRAYINDEX_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtCore/private/qnumeric_p.h>
+#include <QtCore/qstring.h>
+#include <limits>
+
+QT_BEGIN_NAMESPACE
+
+namespace QV4 {
+
+inline uint charToUInt(const QChar *ch) { return ch->unicode(); }
+inline uint charToUInt(const char *ch) { return static_cast<unsigned char>(*ch); }
+
+template <typename T>
+uint stringToArrayIndex(const T *ch, const T *end)
+{
+    if (ch == end)
+        return std::numeric_limits<uint>::max();
+    uint i = charToUInt(ch) - '0';
+    if (i > 9)
+        return std::numeric_limits<uint>::max();
+    ++ch;
+    // reject "01", "001", ...
+    if (i == 0 && ch != end)
+        return std::numeric_limits<uint>::max();
+
+    while (ch < end) {
+        uint x = charToUInt(ch) - '0';
+        if (x > 9)
+            return std::numeric_limits<uint>::max();
+        if (qMulOverflow(i, uint(10), &i) || qAddOverflow(i, x, &i)) // i = i * 10 + x
+            return std::numeric_limits<uint>::max();
+        ++ch;
+    }
+    return i;
+}
+
+inline uint stringToArrayIndex(const QString &str)
+{
+    return stringToArrayIndex(str.constData(), str.constData() + str.size());
+}
+
+} // namespace QV4
+
+QT_END_NAMESPACE
+
+#endif // QV4STRINGTOARRAYINDEX_P_H