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 | |
34 | namespace 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 | |