From 40736c5763bf61337c8c14e16d8587db021a87d4 Mon Sep 17 00:00:00 2001
From: Simon Hausmann <simon.hausmann@nokia.com>
Date: Fri, 6 Jan 2012 14:44:00 +0100
Subject: Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4
 (http://svn.webkit.org/repository/webkit/trunk@104285)

---
 Source/JavaScriptCore/wtf/HashFunctions.h | 183 ++++++++++++++++++++++++++++++
 1 file changed, 183 insertions(+)
 create mode 100644 Source/JavaScriptCore/wtf/HashFunctions.h

(limited to 'Source/JavaScriptCore/wtf/HashFunctions.h')

diff --git a/Source/JavaScriptCore/wtf/HashFunctions.h b/Source/JavaScriptCore/wtf/HashFunctions.h
new file mode 100644
index 000000000..2c66a2d9f
--- /dev/null
+++ b/Source/JavaScriptCore/wtf/HashFunctions.h
@@ -0,0 +1,183 @@
+/*
+ * Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public License
+ * along with this library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef WTF_HashFunctions_h
+#define WTF_HashFunctions_h
+
+#include "RefPtr.h"
+#include <stdint.h>
+
+namespace WTF {
+
+    template<size_t size> struct IntTypes;
+    template<> struct IntTypes<1> { typedef int8_t SignedType; typedef uint8_t UnsignedType; };
+    template<> struct IntTypes<2> { typedef int16_t SignedType; typedef uint16_t UnsignedType; };
+    template<> struct IntTypes<4> { typedef int32_t SignedType; typedef uint32_t UnsignedType; };
+    template<> struct IntTypes<8> { typedef int64_t SignedType; typedef uint64_t UnsignedType; };
+
+    // integer hash function
+
+    // Thomas Wang's 32 Bit Mix Function: http://www.cris.com/~Ttwang/tech/inthash.htm
+    inline unsigned intHash(uint8_t key8)
+    {
+        unsigned key = key8;
+        key += ~(key << 15);
+        key ^= (key >> 10);
+        key += (key << 3);
+        key ^= (key >> 6);
+        key += ~(key << 11);
+        key ^= (key >> 16);
+        return key;
+    }
+
+    // Thomas Wang's 32 Bit Mix Function: http://www.cris.com/~Ttwang/tech/inthash.htm
+    inline unsigned intHash(uint16_t key16)
+    {
+        unsigned key = key16;
+        key += ~(key << 15);
+        key ^= (key >> 10);
+        key += (key << 3);
+        key ^= (key >> 6);
+        key += ~(key << 11);
+        key ^= (key >> 16);
+        return key;
+    }
+
+    // Thomas Wang's 32 Bit Mix Function: http://www.cris.com/~Ttwang/tech/inthash.htm
+    inline unsigned intHash(uint32_t key) 
+    {
+        key += ~(key << 15);
+        key ^= (key >> 10);
+        key += (key << 3);
+        key ^= (key >> 6);
+        key += ~(key << 11);
+        key ^= (key >> 16);
+        return key;
+    }
+    
+    // Thomas Wang's 64 bit Mix Function: http://www.cris.com/~Ttwang/tech/inthash.htm
+    inline unsigned intHash(uint64_t key)
+    {
+        key += ~(key << 32);
+        key ^= (key >> 22);
+        key += ~(key << 13);
+        key ^= (key >> 8);
+        key += (key << 3);
+        key ^= (key >> 15);
+        key += ~(key << 27);
+        key ^= (key >> 31);
+        return static_cast<unsigned>(key);
+    }
+
+    template<typename T> struct IntHash {
+        static unsigned hash(T key) { return intHash(static_cast<typename IntTypes<sizeof(T)>::UnsignedType>(key)); }
+        static bool equal(T a, T b) { return a == b; }
+        static const bool safeToCompareToEmptyOrDeleted = true;
+    };
+
+    template<typename T> struct FloatHash {
+        static unsigned hash(T key)
+        {
+            union {
+                T key;
+                typename IntTypes<sizeof(T)>::UnsignedType bits;
+            } u;
+            u.key = key;
+            return intHash(u.bits);
+        }
+        static bool equal(T a, T b) { return a == b; }
+        static const bool safeToCompareToEmptyOrDeleted = true;
+    };
+
+    // pointer identity hash function
+
+    template<typename T> struct PtrHash {
+        static unsigned hash(T key)
+        {
+#if COMPILER(MSVC)
+#pragma warning(push)
+#pragma warning(disable: 4244) // work around what seems to be a bug in MSVC's conversion warnings
+#endif
+            return IntHash<uintptr_t>::hash(reinterpret_cast<uintptr_t>(key));
+#if COMPILER(MSVC)
+#pragma warning(pop)
+#endif
+        }
+        static bool equal(T a, T b) { return a == b; }
+        static const bool safeToCompareToEmptyOrDeleted = true;
+    };
+    template<typename P> struct PtrHash<RefPtr<P> > : PtrHash<P*> {
+        using PtrHash<P*>::hash;
+        static unsigned hash(const RefPtr<P>& key) { return hash(key.get()); }
+        using PtrHash<P*>::equal;
+        static bool equal(const RefPtr<P>& a, const RefPtr<P>& b) { return a == b; }
+        static bool equal(P* a, const RefPtr<P>& b) { return a == b; }
+        static bool equal(const RefPtr<P>& a, P* b) { return a == b; }
+    };
+
+    // default hash function for each type
+
+    template<typename T> struct DefaultHash;
+
+    template<typename T, typename U> struct PairHash {
+        static unsigned hash(const std::pair<T, U>& p)
+        {
+            return intHash((static_cast<uint64_t>(DefaultHash<T>::Hash::hash(p.first)) << 32 | DefaultHash<U>::Hash::hash(p.second)));
+        }
+        static bool equal(const std::pair<T, U>& a, const std::pair<T, U>& b)
+        {
+            return DefaultHash<T>::Hash::equal(a.first, b.first) && DefaultHash<U>::Hash::equal(a.second, b.second);
+        }
+        static const bool safeToCompareToEmptyOrDeleted = DefaultHash<T>::Hash::safeToCompareToEmptyOrDeleted 
+                                                            && DefaultHash<U>::Hash::safeToCompareToEmptyOrDeleted;
+    };
+
+    // make IntHash the default hash function for many integer types
+
+    template<> struct DefaultHash<short> { typedef IntHash<unsigned> Hash; };
+    template<> struct DefaultHash<unsigned short> { typedef IntHash<unsigned> Hash; };
+    template<> struct DefaultHash<int> { typedef IntHash<unsigned> Hash; };
+    template<> struct DefaultHash<unsigned> { typedef IntHash<unsigned> Hash; };
+    template<> struct DefaultHash<long> { typedef IntHash<unsigned long> Hash; };
+    template<> struct DefaultHash<unsigned long> { typedef IntHash<unsigned long> Hash; };
+    template<> struct DefaultHash<long long> { typedef IntHash<unsigned long long> Hash; };
+    template<> struct DefaultHash<unsigned long long> { typedef IntHash<unsigned long long> Hash; };
+
+#if !COMPILER(MSVC) || defined(_NATIVE_WCHAR_T_DEFINED)
+    template<> struct DefaultHash<wchar_t> { typedef IntHash<wchar_t> Hash; };
+#endif
+
+    template<> struct DefaultHash<float> { typedef FloatHash<float> Hash; };
+    template<> struct DefaultHash<double> { typedef FloatHash<double> Hash; };
+
+    // make PtrHash the default hash function for pointer types that don't specialize
+
+    template<typename P> struct DefaultHash<P*> { typedef PtrHash<P*> Hash; };
+    template<typename P> struct DefaultHash<RefPtr<P> > { typedef PtrHash<RefPtr<P> > Hash; };
+
+    template<typename T, typename U> struct DefaultHash<std::pair<T, U> > { typedef PairHash<T, U> Hash; };
+
+} // namespace WTF
+
+using WTF::DefaultHash;
+using WTF::IntHash;
+using WTF::PtrHash;
+
+#endif // WTF_HashFunctions_h
-- 
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