/*

 * Copyright (C) 2009 Apple Inc. All Rights Reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    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. ``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

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef DateInstanceCache_h

#define DateInstanceCache_h

#include <wtf/DateMath.h>

#include <wtf/HashFunctions.h>

#include <wtf/PassRefPtr.h>

#include <wtf/RefCounted.h>

namespace JSC {

    extern const double NaN;

    class DateInstanceData : public RefCounted<DateInstanceData> {

    public:

        static PassRefPtr<DateInstanceData> create() { return adoptRef(new DateInstanceData); }

        double m_gregorianDateTimeCachedForMS;

        GregorianDateTime m_cachedGregorianDateTime;

        double m_gregorianDateTimeUTCCachedForMS;

        GregorianDateTime m_cachedGregorianDateTimeUTC;

    private:

        DateInstanceData()

            : m_gregorianDateTimeCachedForMS(NaN)

            , m_gregorianDateTimeUTCCachedForMS(NaN)

        {

        }

    };

    class DateInstanceCache {

    public:

        DateInstanceCache()

        {

            reset();

        }

        void reset()

        {

            for (size_t i = 0; i < cacheSize; ++i)

                m_cache[i].key = NaN;

        }

        DateInstanceData* add(double d)

        {

            CacheEntry& entry = lookup(d);

            if (d == entry.key)

                return entry.value.get();

            entry.key = d;

            entry.value = DateInstanceData::create();

            return entry.value.get();

        }

    private:

        static const size_t cacheSize = 16;

        struct CacheEntry {

            double key;

            RefPtr<DateInstanceData> value;

        };

        CacheEntry& lookup(double d) { return m_cache[WTF::FloatHash<double>::hash(d) & (cacheSize - 1)]; }

        FixedArray<CacheEntry, cacheSize> m_cache;

    };

} // namespace JSC

#endif // DateInstanceCache_h