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: create()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: DateInstanceData()48 DateInstanceData() 49 : m_gregorianDateTimeCachedForMS(NaN) 50 , m_gregorianDateTimeUTCCachedForMS(NaN) 51 { 52 } 53 }; 54 55 class DateInstanceCache { 56 public: DateInstanceCache()57 DateInstanceCache() 58 { 59 reset(); 60 } 61 reset()62 void reset() 63 { 64 for (size_t i = 0; i < cacheSize; ++i) 65 m_cache[i].key = NaN; 66 } 67 add(double d)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 lookup(double d)87 CacheEntry& lookup(double d) { return m_cache[WTF::FloatHash<double>::hash(d) & (cacheSize - 1)]; } 88 89 FixedArray<CacheEntry, cacheSize> m_cache; 90 }; 91 92 } // namespace JSC 93 94 #endif // DateInstanceCache_h 95