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