Tools/TestWebKitAPI/Tests/WTF/DeletedAddressOfOperator.h

/*
 * Copyright (C) 2016 Apple Inc. All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
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 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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 */

#pragma once

#include <wtf/HashFunctions.h>
#include <wtf/HashTraits.h>

class DeletedAddressOfOperator {
public:
    DeletedAddressOfOperator()
        : m_value(0)
    {
    }

    DeletedAddressOfOperator(unsigned value)
        : m_value(value)
    {
    }

    DeletedAddressOfOperator* operator&() = delete;

    unsigned value() const
    {
        return m_value;
    }

    friend bool operator==(const DeletedAddressOfOperator& a, const DeletedAddressOfOperator& b)
    {
        return a.m_value == b.m_value;
    }

private:
    unsigned m_value;
};

namespace WTF {

template<> struct HashTraits<DeletedAddressOfOperator> : public GenericHashTraits<DeletedAddressOfOperator> {
    static const bool emptyValueIsZero = true;

    static void constructDeletedValue(DeletedAddressOfOperator& slot) { slot = DeletedAddressOfOperator(std::numeric_limits<unsigned>::max()); }
    static bool isDeletedValue(const DeletedAddressOfOperator& slot) { return slot.value() == std::numeric_limits<unsigned>::max(); }
};

template<> struct DefaultHash<DeletedAddressOfOperator> {
    struct Hash {
        static unsigned hash(const DeletedAddressOfOperator& key)
        {
            return intHash(key.value());
        }

        static bool equal(const DeletedAddressOfOperator& a, const DeletedAddressOfOperator& b)
        {
            return a == b;
        }

        static const bool safeToCompareToEmptyOrDeleted = true;
    };
};
}