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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 <kjs/global.h>
 #if HAVE_STDINT_H
 #include <stdint.h>
 #endif
 
 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)
     {
         return intHash(*reinterpret_cast<typename IntTypes<sizeof(T)>::UnsignedType *>(&key));
     }
     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 defined(WTF_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 defined(WTF_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 !defined(WTF_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