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