diff -r 000000000000 -r 4f2f89ce4247 JavaScriptCore/runtime/DateInstanceCache.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JavaScriptCore/runtime/DateInstanceCache.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2009 Apple Inc. All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef DateInstanceCache_h
+#define DateInstanceCache_h
+
+#include <wtf/DateMath.h>
+#include <wtf/HashFunctions.h>
+#include <wtf/PassRefPtr.h>
+#include <wtf/RefCounted.h>
+
+namespace JSC {
+
+    extern const double NaN;
+
+    class DateInstanceData : public RefCounted<DateInstanceData> {
+    public:
+        static PassRefPtr<DateInstanceData> create() { return adoptRef(new DateInstanceData); }
+
+        double m_gregorianDateTimeCachedForMS;
+        GregorianDateTime m_cachedGregorianDateTime;
+        double m_gregorianDateTimeUTCCachedForMS;
+        GregorianDateTime m_cachedGregorianDateTimeUTC;
+
+    private:
+        DateInstanceData()
+            : m_gregorianDateTimeCachedForMS(NaN)
+            , m_gregorianDateTimeUTCCachedForMS(NaN)
+        {
+        }
+    };
+
+    class DateInstanceCache {
+    public:
+        DateInstanceCache()
+        {
+            reset();
+        }
+        
+        void reset()
+        {
+            for (size_t i = 0; i < cacheSize; ++i)
+                m_cache[i].key = NaN;
+        }
+        
+        DateInstanceData* add(double d)
+        {
+            CacheEntry& entry = lookup(d);
+            if (d == entry.key)
+                return entry.value.get();
+
+            entry.key = d;
+            entry.value = DateInstanceData::create();
+            return entry.value.get();
+        }
+
+    private:
+        static const size_t cacheSize = 16;
+
+        struct CacheEntry {
+            double key;
+            RefPtr<DateInstanceData> value;
+        };
+
+        CacheEntry& lookup(double d) { return m_cache[WTF::FloatHash<double>::hash(d) & (cacheSize - 1)]; }
+
+        FixedArray<CacheEntry, cacheSize> m_cache;
+    };
+
+} // namespace JSC
+
+#endif // DateInstanceCache_h