Merge from Chromium at DEPS revision r167172
This commit was generated by merge_to_master.py.
Change-Id: Iead6b4948cd90f0aac77a0e5e2b6c1749577569b
diff --git a/Source/WTF/wtf/HashFunctions.h b/Source/WTF/wtf/HashFunctions.h
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+/*
+ * 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 <wtf/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);
+ }
+
+ // Compound integer hash method: http://opendatastructures.org/versions/edition-0.1d/ods-java/node33.html#SECTION00832000000000000000
+ inline unsigned pairIntHash(unsigned key1, unsigned key2)
+ {
+ unsigned shortRandom1 = 277951225; // A random 32-bit value.
+ unsigned shortRandom2 = 95187966; // A random 32-bit value.
+ uint64_t longRandom = 19248658165952622LL; // A random 64-bit value.
+
+ uint64_t product = longRandom * (shortRandom1 * key1 + shortRandom2 * key2);
+ unsigned highBits = static_cast<unsigned>(product >> (sizeof(uint64_t) - sizeof(unsigned)));
+ return highBits;
+ }
+
+ 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 {
+ typedef typename IntTypes<sizeof(T)>::UnsignedType Bits;
+ static unsigned hash(T key)
+ {
+ return intHash(bitwise_cast<Bits>(key));
+ }
+ static bool equal(T a, T b)
+ {
+ return bitwise_cast<Bits>(a) == bitwise_cast<Bits>(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 pairIntHash(DefaultHash<T>::Hash::hash(p.first), 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;
+ };
+
+ template<typename T, typename U> struct IntPairHash {
+ static unsigned hash(const std::pair<T, U>& p) { return pairIntHash(p.first, p.second); }
+ static bool equal(const std::pair<T, U>& a, const std::pair<T, U>& b) { return PairHash<T, T>::equal(a, b); }
+ static const bool safeToCompareToEmptyOrDeleted = PairHash<T, U>::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; };
+
+ // make IntPairHash the default hash function for pairs of (at most) 32-bit integers.
+
+ template<> struct DefaultHash<std::pair<short, short> > { typedef IntPairHash<short, short> Hash; };
+ template<> struct DefaultHash<std::pair<short, unsigned short> > { typedef IntPairHash<short, unsigned short> Hash; };
+ template<> struct DefaultHash<std::pair<short, int> > { typedef IntPairHash<short, int> Hash; };
+ template<> struct DefaultHash<std::pair<short, unsigned> > { typedef IntPairHash<short, unsigned> Hash; };
+ template<> struct DefaultHash<std::pair<unsigned short, short> > { typedef IntPairHash<unsigned short, short> Hash; };
+ template<> struct DefaultHash<std::pair<unsigned short, unsigned short> > { typedef IntPairHash<unsigned short, unsigned short> Hash; };
+ template<> struct DefaultHash<std::pair<unsigned short, int> > { typedef IntPairHash<unsigned short, int> Hash; };
+ template<> struct DefaultHash<std::pair<unsigned short, unsigned> > { typedef IntPairHash<unsigned short, unsigned> Hash; };
+ template<> struct DefaultHash<std::pair<int, short> > { typedef IntPairHash<int, short> Hash; };
+ template<> struct DefaultHash<std::pair<int, unsigned short> > { typedef IntPairHash<int, unsigned short> Hash; };
+ template<> struct DefaultHash<std::pair<int, int> > { typedef IntPairHash<int, int> Hash; };
+ template<> struct DefaultHash<std::pair<int, unsigned> > { typedef IntPairHash<unsigned, unsigned> Hash; };
+ template<> struct DefaultHash<std::pair<unsigned, short> > { typedef IntPairHash<unsigned, short> Hash; };
+ template<> struct DefaultHash<std::pair<unsigned, unsigned short> > { typedef IntPairHash<unsigned, unsigned short> Hash; };
+ template<> struct DefaultHash<std::pair<unsigned, int> > { typedef IntPairHash<unsigned, int> Hash; };
+ template<> struct DefaultHash<std::pair<unsigned, unsigned> > { typedef IntPairHash<unsigned, unsigned> Hash; };
+
+ // make PairHash the default hash function for pairs of arbitrary values.
+
+ 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