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 <wtf/OwnPtr.h> 25#include <wtf/Ref.h> 26#include <wtf/RefPtr.h> 27#include <utility> 28#include <memory> 29 30namespace WTF { 31 32 class AtomicString; 33 34 template<bool isPod, typename T> 35 struct VectorTraitsBase; 36 37 template<typename T> 38 struct VectorTraitsBase<false, T> 39 { 40 static const bool needsInitialization = true; 41 static const bool canInitializeWithMemset = false; 42 static const bool canMoveWithMemcpy = false; 43 static const bool canCopyWithMemcpy = false; 44 static const bool canFillWithMemset = false; 45 static const bool canCompareWithMemcmp = false; 46 }; 47 48 template<typename T> 49 struct VectorTraitsBase<true, T> 50 { 51 static const bool needsInitialization = false; 52 static const bool canInitializeWithMemset = false; 53 static const bool canMoveWithMemcpy = true; 54 static const bool canCopyWithMemcpy = true; 55 static const bool canFillWithMemset = sizeof(T) == sizeof(char); 56 static const bool canCompareWithMemcmp = true; 57 }; 58 59 template<typename T> 60 struct VectorTraits : VectorTraitsBase<std::is_pod<T>::value, T> { }; 61 62 struct SimpleClassVectorTraits : VectorTraitsBase<false, void> 63 { 64 static const bool canInitializeWithMemset = true; 65 static const bool canMoveWithMemcpy = true; 66 static const bool canCompareWithMemcmp = true; 67 }; 68 69 // We know OwnPtr and RefPtr are simple enough that initializing to 0 and moving with memcpy 70 // (and then not destructing the original) will totally work 71 template<typename P> 72 struct VectorTraits<RefPtr<P>> : SimpleClassVectorTraits { }; 73 74 template<typename P> 75 struct VectorTraits<OwnPtr<P>> : SimpleClassVectorTraits { }; 76 77 template<typename P> 78 struct VectorTraits<std::unique_ptr<P>> : SimpleClassVectorTraits { }; 79 80 template<typename P> 81 struct VectorTraits<Ref<P>> : SimpleClassVectorTraits { }; 82 83 template<> 84 struct VectorTraits<AtomicString> : SimpleClassVectorTraits { }; 85 86 template<typename First, typename Second> 87 struct VectorTraits<std::pair<First, Second>> 88 { 89 typedef VectorTraits<First> FirstTraits; 90 typedef VectorTraits<Second> SecondTraits; 91 92 static const bool needsInitialization = FirstTraits::needsInitialization || SecondTraits::needsInitialization; 93 static const bool canInitializeWithMemset = FirstTraits::canInitializeWithMemset && SecondTraits::canInitializeWithMemset; 94 static const bool canMoveWithMemcpy = FirstTraits::canMoveWithMemcpy && SecondTraits::canMoveWithMemcpy; 95 static const bool canCopyWithMemcpy = FirstTraits::canCopyWithMemcpy && SecondTraits::canCopyWithMemcpy; 96 static const bool canFillWithMemset = false; 97 static const bool canCompareWithMemcmp = FirstTraits::canCompareWithMemcmp && SecondTraits::canCompareWithMemcmp; 98 }; 99 100} // namespace WTF 101 102using WTF::VectorTraits; 103using WTF::SimpleClassVectorTraits; 104 105#endif // WTF_VectorTraits_h 106