1/*
2 * Copyright (C) 2009 Apple Inc. All Rights Reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef DateInstanceCache_h
27#define DateInstanceCache_h
28
29#include "JSCJSValue.h"
30#include "JSDateMath.h"
31#include <array>
32#include <wtf/HashFunctions.h>
33#include <wtf/PassRefPtr.h>
34#include <wtf/RefCounted.h>
35
36namespace JSC {
37
38    class DateInstanceData : public RefCounted<DateInstanceData> {
39    public:
40        static PassRefPtr<DateInstanceData> create() { return adoptRef(new DateInstanceData); }
41
42        double m_gregorianDateTimeCachedForMS;
43        GregorianDateTime m_cachedGregorianDateTime;
44        double m_gregorianDateTimeUTCCachedForMS;
45        GregorianDateTime m_cachedGregorianDateTimeUTC;
46
47    private:
48        DateInstanceData()
49            : m_gregorianDateTimeCachedForMS(PNaN)
50            , m_gregorianDateTimeUTCCachedForMS(PNaN)
51        {
52        }
53    };
54
55    class DateInstanceCache {
56    public:
57        DateInstanceCache()
58        {
59            reset();
60        }
61
62        void reset()
63        {
64            for (size_t i = 0; i < cacheSize; ++i)
65                m_cache[i].key = PNaN;
66        }
67
68        DateInstanceData* add(double d)
69        {
70            CacheEntry& entry = lookup(d);
71            if (d == entry.key)
72                return entry.value.get();
73
74            entry.key = d;
75            entry.value = DateInstanceData::create();
76            return entry.value.get();
77        }
78
79    private:
80        static const size_t cacheSize = 16;
81
82        struct CacheEntry {
83            double key;
84            RefPtr<DateInstanceData> value;
85        };
86
87        CacheEntry& lookup(double d) { return m_cache[WTF::FloatHash<double>::hash(d) & (cacheSize - 1)]; }
88
89        std::array<CacheEntry, cacheSize> m_cache;
90    };
91
92} // namespace JSC
93
94#endif // DateInstanceCache_h
95