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 <wtf/DateMath.h>
30#include <wtf/HashFunctions.h>
31#include <wtf/PassRefPtr.h>
32#include <wtf/RefCounted.h>
33
34namespace JSC {
35
36 extern const double NaN;
37
38 class DateInstanceData : public RefCounted<DateInstanceData> {
39 public:
40 static PassRefPtr<DateInstanceData> create() { return adoptRef(p: 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(NaN)
50 , m_gregorianDateTimeUTCCachedForMS(NaN)
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 = NaN;
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(key: d) & (cacheSize - 1)]; }
88
89 CacheEntry m_cache[cacheSize];
90 };
91
92} // namespace JSC
93
94#endif // DateInstanceCache_h
95

source code of qtscript/src/3rdparty/javascriptcore/JavaScriptCore/runtime/DateInstanceCache.h