1 /* 2 * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved. 3 * 4 * This library is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Library General Public 6 * License as published by the Free Software Foundation; either 7 * version 2 of the License, or (at your option) any later version. 8 * 9 * This library is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * Library General Public License for more details. 13 * 14 * You should have received a copy of the GNU Library General Public License 15 * along with this library; see the file COPYING.LIB. If not, write to 16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 17 * Boston, MA 02110-1301, USA. 18 * 19 */ 20 21 #ifndef WTF_VectorTraits_h 22 #define WTF_VectorTraits_h 23 24 #include "RefPtr.h" 25 #include <utility> 26 #include <memory> 27 28 using std::pair; 29 30 namespace WTF { 31 32 template <typename T> struct IsPod { static const bool value = false; }; 33 template <> struct IsPod<bool> { static const bool value = true; }; 34 template <> struct IsPod<char> { static const bool value = true; }; 35 template <> struct IsPod<signed char> { static const bool value = true; }; 36 template <> struct IsPod<unsigned char> { static const bool value = true; }; 37 template <> struct IsPod<short> { static const bool value = true; }; 38 template <> struct IsPod<unsigned short> { static const bool value = true; }; 39 template <> struct IsPod<int> { static const bool value = true; }; 40 template <> struct IsPod<unsigned int> { static const bool value = true; }; 41 template <> struct IsPod<long> { static const bool value = true; }; 42 template <> struct IsPod<unsigned long> { static const bool value = true; }; 43 template <> struct IsPod<long long> { static const bool value = true; }; 44 template <> struct IsPod<unsigned long long> { static const bool value = true; }; 45 template <> struct IsPod<float> { static const bool value = true; }; 46 template <> struct IsPod<double> { static const bool value = true; }; 47 template <> struct IsPod<long double> { static const bool value = true; }; 48 template <typename P> struct IsPod<P *> { static const bool value = true; }; 49 50 template<bool isPod, typename T> 51 class VectorTraitsBase; 52 53 template<typename T> 54 struct VectorTraitsBase<false, T> 55 { 56 static const bool needsDestruction = true; 57 static const bool needsInitialization = true; 58 static const bool canInitializeWithMemset = false; 59 static const bool canMoveWithMemcpy = false; 60 static const bool canCopyWithMemcpy = false; 61 static const bool canFillWithMemset = false; 62 static const bool canCompareWithMemcmp = false; 63 }; 64 65 template<typename T> 66 struct VectorTraitsBase<true, T> 67 { 68 static const bool needsDestruction = false; 69 static const bool needsInitialization = false; 70 static const bool canInitializeWithMemset = false; 71 static const bool canMoveWithMemcpy = true; 72 static const bool canCopyWithMemcpy = true; 73 static const bool canFillWithMemset = sizeof(T) == sizeof(char); 74 static const bool canCompareWithMemcmp = true; 75 }; 76 77 template<typename T> 78 struct VectorTraits : VectorTraitsBase<IsPod<T>::value, T> { }; 79 80 struct SimpleClassVectorTraits 81 { 82 static const bool needsDestruction = true; 83 static const bool needsInitialization = true; 84 static const bool canInitializeWithMemset = true; 85 static const bool canMoveWithMemcpy = true; 86 static const bool canCopyWithMemcpy = false; 87 static const bool canFillWithMemset = false; 88 static const bool canCompareWithMemcmp = true; 89 }; 90 91 // we know RefPtr is simple enough that initializing to 0 and moving with memcpy 92 // (and then not destructing the original) will totally work 93 template<typename P> 94 struct VectorTraits<RefPtr<P> > : SimpleClassVectorTraits { }; 95 96 template<typename P> 97 struct VectorTraits<std::auto_ptr<P> > : SimpleClassVectorTraits { }; 98 99 template<typename First, typename Second> 100 struct VectorTraits<pair<First, Second> > 101 { 102 typedef VectorTraits<First> FirstTraits; 103 typedef VectorTraits<Second> SecondTraits; 104 105 static const bool needsDestruction = FirstTraits::needsDestruction || SecondTraits::needsDestruction; 106 static const bool needsInitialization = FirstTraits::needsInitialization || SecondTraits::needsInitialization; 107 static const bool canInitializeWithMemset = FirstTraits::canInitializeWithMemset && SecondTraits::canInitializeWithMemset; 108 static const bool canMoveWithMemcpy = FirstTraits::canMoveWithMemcpy && SecondTraits::canMoveWithMemcpy; 109 static const bool canCopyWithMemcpy = FirstTraits::canCopyWithMemcpy && SecondTraits::canCopyWithMemcpy; 110 static const bool canFillWithMemset = false; 111 static const bool canCompareWithMemcmp = FirstTraits::canCompareWithMemcmp && SecondTraits::canCompareWithMemcmp; 112 }; 113 114 } // namespace WTF 115 116 using WTF::VectorTraits; 117 using WTF::SimpleClassVectorTraits; 118 119 #endif // WTF_VectorTraits_h 120