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