Move files in wtf/ to platform/wtf/ (Part 8).

third_party/WebKit/Source/wtf/HashFunctions.h

-/*
- * 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.
- *
- */
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
 
-#ifndef WTF_HashFunctions_h
-#define WTF_HashFunctions_h
+#include "platform/wtf/HashFunctions.h"
 
-#include "wtf/RefPtr.h"
-#include "wtf/StdLibExtras.h"
-#include <memory>
-#include <stdint.h>
-#include <type_traits>
-
-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 hashInt(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 hashInt(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 hashInt(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 hashInt(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 hashInts(unsigned key1, unsigned key2) {
-  unsigned shortRandom1 = 277951225;          // A random 32-bit value.
-  unsigned shortRandom2 = 95187966;           // A random 32-bit value.
-  uint64_t longRandom = 19248658165952623LL;  // A random, odd 64-bit value.
-
-  uint64_t product =
-      longRandom * shortRandom1 * key1 + longRandom * shortRandom2 * key2;
-  unsigned highBits = static_cast<unsigned>(
-      product >> (8 * (sizeof(uint64_t) - sizeof(unsigned))));
-  return highBits;
-}
-
-template <typename T>
-struct IntHash {
-  static unsigned hash(T key) {
-    return hashInt(
-        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 hashInt(bitwiseCast<Bits>(key)); }
-  static bool equal(T a, T b) {
-    return bitwiseCast<Bits>(a) == bitwiseCast<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)
-// work around what seems to be a bug in MSVC's conversion warnings
-#pragma warning(disable : 4244)
-#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 bool equal(std::nullptr_t, T* b) { return !b; }
-  static bool equal(T* a, std::nullptr_t) { return !a; }
-  static const bool safeToCompareToEmptyOrDeleted = true;
-};
-
-template <typename T>
-struct RefPtrHash : PtrHash<T> {
-  using PtrHash<T>::hash;
-  static unsigned hash(const RefPtr<T>& key) { return hash(key.get()); }
-  static unsigned hash(const PassRefPtr<T>& key) { return hash(key.get()); }
-  using PtrHash<T>::equal;
-  static bool equal(const RefPtr<T>& a, const RefPtr<T>& b) { return a == b; }
-  static bool equal(T* a, const RefPtr<T>& b) { return a == b; }
-  static bool equal(const RefPtr<T>& a, T* b) { return a == b; }
-  static bool equal(const RefPtr<T>& a, const PassRefPtr<T>& b) {
-    return a == b;
-  }
-};
-
-template <typename T>
-struct UniquePtrHash : PtrHash<T> {
-  using PtrHash<T>::hash;
-  static unsigned hash(const std::unique_ptr<T>& key) {
-    return hash(key.get());
-  }
-  static bool equal(const std::unique_ptr<T>& a, const std::unique_ptr<T>& b) {
-    return a == b;
-  }
-  static bool equal(const std::unique_ptr<T>& a, const T* b) {
-    return a.get() == b;
-  }
-  static bool equal(const T* a, const std::unique_ptr<T>& b) {
-    return a == b.get();
-  }
-};
-
-// Default hash function for each type.
-template <typename T>
-struct DefaultHash;
-
-// Actual implementation of DefaultHash.
-//
-// The case of |isIntegral| == false is not implemented. If you see a compile
-// error saying DefaultHashImpl<T, false> is not defined, that's because the
-// default hash functions for T are not defined. You need to implement them
-// yourself.
-template <typename T, bool isIntegral>
-struct DefaultHashImpl;
-
-template <typename T>
-struct DefaultHashImpl<T, true> {
-  using Hash = IntHash<typename std::make_unsigned<T>::type>;
-};
-
-// Canonical implementation of DefaultHash.
-template <typename T>
-struct DefaultHash : DefaultHashImpl<T, std::is_integral<T>::value> {};
-
-// Specializations of DefaultHash follow.
-template <>
-struct DefaultHash<float> {
-  using Hash = FloatHash<float>;
-};
-template <>
-struct DefaultHash<double> {
-  using Hash = FloatHash<double>;
-};
-
-// Specializations for pointer types.
-template <typename T>
-struct DefaultHash<T*> {
-  using Hash = PtrHash<T>;
-};
-template <typename T>
-struct DefaultHash<RefPtr<T>> {
-  using Hash = RefPtrHash<T>;
-};
-template <typename T>
-struct DefaultHash<std::unique_ptr<T>> {
-  using Hash = UniquePtrHash<T>;
-};
-
-// Specializations for pairs.
-
-// Generic case (T or U is non-integral):
-template <typename T, typename U, bool areBothIntegral>
-struct PairHashImpl {
-  static unsigned hash(const std::pair<T, U>& p) {
-    return hashInts(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;
-};
-
-// Special version for pairs of integrals:
-template <typename T, typename U>
-struct PairHashImpl<T, U, true> {
-  static unsigned hash(const std::pair<T, U>& p) {
-    return hashInts(p.first, p.second);
-  }
-  static bool equal(const std::pair<T, U>& a, const std::pair<T, U>& b) {
-    return PairHashImpl<T, U, false>::equal(
-        a, b);  // Refer to the generic version.
-  }
-  static const bool safeToCompareToEmptyOrDeleted =
-      PairHashImpl<T, U, false>::safeToCompareToEmptyOrDeleted;
-};
-
-// Combined version:
-template <typename T, typename U>
-struct PairHash
-    : PairHashImpl<T,
-                   U,
-                   std::is_integral<T>::value && std::is_integral<U>::value> {};
-
-template <typename T, typename U>
-struct DefaultHash<std::pair<T, U>> {
-  using Hash = PairHash<T, U>;
-};
-
-}  // namespace WTF
-
-using WTF::DefaultHash;
-using WTF::IntHash;
-using WTF::PtrHash;
-
-#endif  // WTF_HashFunctions_h
+// The contents of this header was moved to platform/wtf as part of
+// WTF migration project. See the following post for details:
+// https://groups.google.com/a/chromium.org/d/msg/blink-dev/tLdAZCTlcAA/bYXVT8gYCAAJ