1 | /* |
2 | Copyright (c) 2010 Volker Krause <vkrause@kde.org> |
3 | |
4 | This library is free software; you can redistribute it and/or modify it |
5 | under the terms of the GNU Library General Public License as published by |
6 | the Free Software Foundation; either version 2 of the License, or (at your |
7 | option) any later version. |
8 | |
9 | This library is distributed in the hope that it will be useful, but WITHOUT |
10 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
11 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public |
12 | 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 the |
16 | Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
17 | 02110-1301, USA. |
18 | */ |
19 | |
20 | #ifndef AKONADI_SHAREDVALUEPOOL_P_H |
21 | #define AKONADI_SHAREDVALUEPOOL_P_H |
22 | |
23 | #include <boost/utility/enable_if.hpp> |
24 | #include <algorithm> |
25 | |
26 | namespace Akonadi { |
27 | namespace Internal { |
28 | |
29 | /*template <typename T> class container_traits |
30 | { |
31 | private: |
32 | typedef char sizeOne; |
33 | typedef struct |
34 | { |
35 | char a[2]; |
36 | } sizeTwo; |
37 | template <typename C> static sizeOne testForKeyType( typename C::key_type const* ); |
38 | template <typename C> static sizeTwo testForKeyType( ... ); |
39 | public: |
40 | enum { |
41 | isAssociative=sizeof(container_traits<T>::testForKeyType<T>(0))==1 |
42 | }; |
43 | };*/ |
44 | |
45 | /** |
46 | * Pool of implicitly shared values, use for optimizing memory use |
47 | * when having a large amount of copies from a small set of different values. |
48 | */ |
49 | template <typename T, template <typename> class Container> |
50 | class SharedValuePool |
51 | { |
52 | public: |
53 | /** Returns the shared value equal to @p value .*/ |
54 | /*template <typename C> |
55 | typename boost::enable_if_c<container_traits<Container<C> >::isAssociative, C>::type sharedValue( const C &value, const int * = 0 ) |
56 | { |
57 | typename Container<T>::const_iterator it = m_pool.constFind( value ); |
58 | if ( it != m_pool.constEnd() ) |
59 | return *it; |
60 | m_pool.insert( value ); |
61 | return value; |
62 | } |
63 | |
64 | template <typename C> |
65 | typename boost::disable_if_c<container_traits<Container<C> >::isAssociative, C>::type sharedValue( const C &value )*/ |
66 | T sharedValue(const T &value) |
67 | { |
68 | // for small pool sizes this is actually faster than using lower_bound and a sorted vector |
69 | typename Container<T>::const_iterator it = std::find(m_pool.constBegin(), m_pool.constEnd(), value); |
70 | if (it != m_pool.constEnd()) { |
71 | return *it; |
72 | } |
73 | m_pool.push_back(value); |
74 | return value; |
75 | } |
76 | |
77 | private: |
78 | Container<T> m_pool; |
79 | }; |
80 | |
81 | } |
82 | } |
83 | |
84 | #endif |
85 | |