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
30using std::pair;
31
32namespace 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
65    {
66        static const bool needsDestruction = true;
67        static const bool needsInitialization = true;
68        static const bool canInitializeWithMemset = true;
69        static const bool canMoveWithMemcpy = true;
70        static const bool canCopyWithMemcpy = false;
71        static const bool canFillWithMemset = false;
72        static const bool canCompareWithMemcmp = true;
73    };
74
75    // we know OwnPtr and RefPtr are simple enough that initializing to 0 and moving with memcpy
76    // (and then not destructing the original) will totally work
77    template<typename P>
78    struct VectorTraits<RefPtr<P> > : SimpleClassVectorTraits { };
79
80    template<typename P>
81    struct VectorTraits<OwnPtr<P> > : SimpleClassVectorTraits { };
82
83    template<typename P>
84    struct VectorTraits<std::auto_ptr<P> > : SimpleClassVectorTraits { };
85
86    template<typename First, typename Second>
87    struct VectorTraits<pair<First, Second> >
88    {
89        typedef VectorTraits<First> FirstTraits;
90        typedef VectorTraits<Second> SecondTraits;
91
92        static const bool needsDestruction = FirstTraits::needsDestruction || SecondTraits::needsDestruction;
93        static const bool needsInitialization = FirstTraits::needsInitialization || SecondTraits::needsInitialization;
94        static const bool canInitializeWithMemset = FirstTraits::canInitializeWithMemset && SecondTraits::canInitializeWithMemset;
95        static const bool canMoveWithMemcpy = FirstTraits::canMoveWithMemcpy && SecondTraits::canMoveWithMemcpy;
96        static const bool canCopyWithMemcpy = FirstTraits::canCopyWithMemcpy && SecondTraits::canCopyWithMemcpy;
97        static const bool canFillWithMemset = false;
98        static const bool canCompareWithMemcmp = FirstTraits::canCompareWithMemcmp && SecondTraits::canCompareWithMemcmp;
99    };
100
101} // namespace WTF
102
103using WTF::VectorTraits;
104using WTF::SimpleClassVectorTraits;
105
106#endif // WTF_VectorTraits_h
107