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/RefCounted.h>
34
35namespace JSC {
36
37class DateInstanceData : public RefCounted<DateInstanceData> {
38public:
39 static Ref<DateInstanceData> create() { return adoptRef(*new DateInstanceData); }
40
41 double m_gregorianDateTimeCachedForMS;
42 GregorianDateTime m_cachedGregorianDateTime;
43 double m_gregorianDateTimeUTCCachedForMS;
44 GregorianDateTime m_cachedGregorianDateTimeUTC;
45
46private:
47 DateInstanceData()
48 : m_gregorianDateTimeCachedForMS(PNaN)
49 , m_gregorianDateTimeUTCCachedForMS(PNaN)
50 {
51 }
52};
53
54class DateInstanceCache {
55public:
56 DateInstanceCache()
57 {
58 reset();
59 }
60
61 void reset()
62 {
63 for (size_t i = 0; i < cacheSize; ++i)
64 m_cache[i].key = PNaN;
65 }
66
67 DateInstanceData* add(double d)
68 {
69 CacheEntry& entry = lookup(d);
70 if (d == entry.key)
71 return entry.value.get();
72
73 entry.key = d;
74 entry.value = DateInstanceData::create();
75 return entry.value.get();
76 }
77
78private:
79 static const size_t cacheSize = 16;
80
81 struct CacheEntry {
82 double key;
83 RefPtr<DateInstanceData> value;
84 };
85
86 CacheEntry& lookup(double d) { return m_cache[WTF::FloatHash<double>::hash(d) & (cacheSize - 1)]; }
87
88 std::array<CacheEntry, cacheSize> m_cache;
89};
90
91} // namespace JSC
92
93#endif // DateInstanceCache_h
94