WTF

VectorTraits.h

00001 // -*- mode: c++; c-basic-offset: 4 -*-
00002 /*
00003  * This file is part of the KDE libraries
00004  * Copyright (C) 2006 Apple Computer, Inc.
00005  *
00006  * This library is free software; you can redistribute it and/or
00007  * modify it under the terms of the GNU Library General Public
00008  * License as published by the Free Software Foundation; either
00009  * version 2 of the License, or (at your option) any later version.
00010  *
00011  * This library is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014  * Library General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU Library General Public License
00017  * along with this library; see the file COPYING.LIB.  If not, write to
00018  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
00019  * Boston, MA 02110-1301, USA.
00020  *
00021  */
00022 
00023 #ifndef WTF_VectorTraits_h
00024 #define WTF_VectorTraits_h
00025 
00026 #include "RefPtr.h"
00027 #include <utility>
00028 
00029 using std::pair;
00030 
00031 namespace WTF {
00032 
00033     template <typename T> struct IsPod           { static const bool value = false; };
00034     template <> struct IsPod<bool>               { static const bool value = true; };
00035     template <> struct IsPod<char>               { static const bool value = true; };
00036     template <> struct IsPod<signed char>        { static const bool value = true; };
00037     template <> struct IsPod<unsigned char>      { static const bool value = true; };
00038     template <> struct IsPod<short>              { static const bool value = true; };
00039     template <> struct IsPod<unsigned short>     { static const bool value = true; };
00040     template <> struct IsPod<int>                { static const bool value = true; };
00041     template <> struct IsPod<unsigned int>       { static const bool value = true; };
00042     template <> struct IsPod<long>               { static const bool value = true; };
00043     template <> struct IsPod<unsigned long>      { static const bool value = true; };
00044     template <> struct IsPod<long long>          { static const bool value = true; };
00045     template <> struct IsPod<unsigned long long> { static const bool value = true; };
00046     template <> struct IsPod<float>              { static const bool value = true; };
00047     template <> struct IsPod<double>             { static const bool value = true; };
00048     template <> struct IsPod<long double>        { static const bool value = true; };
00049     template <typename P> struct IsPod<P *>      { static const bool value = true; };
00050 
00051     template<bool isPod, typename T>
00052     struct VectorTraitsBase;
00053 
00054     template<typename T>
00055     struct VectorTraitsBase<false, T>
00056     {
00057         static const bool needsDestruction = true;
00058         static const bool needsInitialization = true;
00059         static const bool canInitializeWithMemset = false;
00060         static const bool canMoveWithMemcpy = false;
00061         static const bool canCopyWithMemcpy = false;
00062         static const bool canFillWithMemset = false;
00063     };
00064 
00065     template<typename T>
00066     struct VectorTraitsBase<true, T>
00067     {
00068         static const bool needsDestruction = false;
00069         static const bool needsInitialization = false;
00070         static const bool canInitializeWithMemset = false;
00071         static const bool canMoveWithMemcpy = true;
00072         static const bool canCopyWithMemcpy = true;
00073         static const bool canFillWithMemset = sizeof(T) == sizeof(char);
00074     };
00075 
00076     template<typename T>
00077     struct VectorTraits : VectorTraitsBase<IsPod<T>::value, T> { };
00078 
00079     struct SimpleClassVectorTraits
00080     {
00081         static const bool needsDestruction = true;
00082         static const bool needsInitialization = true;
00083         static const bool canInitializeWithMemset = true;
00084         static const bool canMoveWithMemcpy = true;
00085         static const bool canCopyWithMemcpy = false;
00086         static const bool canFillWithMemset = false;
00087     };
00088 
00089     // we know RefPtr is simple enough that initializing to 0 and moving with memcpy
00090     // (and then not destructing the original) will totally work
00091     template<typename P>
00092     struct VectorTraits<RefPtr<P> > : SimpleClassVectorTraits { };
00093     
00094     template<typename First, typename Second>
00095     struct VectorTraits<pair<First, Second> >
00096     {
00097         typedef VectorTraits<First> FirstTraits;
00098         typedef VectorTraits<Second> SecondTraits;
00099 
00100         static const bool needsDestruction = FirstTraits::needsDestruction || SecondTraits::needsDestruction;
00101         static const bool needsInitialization = FirstTraits::needsInitialization || SecondTraits::needsInitialization;
00102         static const bool canInitializeWithMemset = FirstTraits::canInitializeWithMemset && SecondTraits::canInitializeWithMemset;
00103         static const bool canMoveWithMemcpy = FirstTraits::canMoveWithMemcpy && SecondTraits::canMoveWithMemcpy;
00104         static const bool canCopyWithMemcpy = FirstTraits::canCopyWithMemcpy && SecondTraits::canCopyWithMemcpy;
00105         static const bool canFillWithMemset = false;
00106     };
00107 
00108 } // namespace WTF
00109 
00110 using WTF::VectorTraits;
00111 using WTF::SimpleClassVectorTraits;
00112 
00113 #endif // WTF_VectorTraits_h
WTF

VectorTraits.h

WTF

kdelibs
