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4569a895 AT |
1 | // -*- C++ -*- |
2 | ||
99dee823 | 3 | // Copyright (C) 2005-2021 Free Software Foundation, Inc. |
4569a895 AT |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free | |
6 | // software; you can redistribute it and/or modify it under the terms | |
7 | // of the GNU General Public License as published by the Free Software | |
748086b7 | 8 | // Foundation; either version 3, or (at your option) any later |
4569a895 AT |
9 | // version. |
10 | ||
11 | // This library is distributed in the hope that it will be useful, but | |
12 | // WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | // General Public License for more details. | |
15 | ||
748086b7 JJ |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version | |
18 | // 3.1, as published by the Free Software Foundation. | |
19 | ||
20 | // You should have received a copy of the GNU General Public License and | |
21 | // a copy of the GCC Runtime Library Exception along with this program; | |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | // <http://www.gnu.org/licenses/>. | |
4569a895 AT |
24 | |
25 | // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. | |
26 | ||
27 | // Permission to use, copy, modify, sell, and distribute this software | |
28 | // is hereby granted without fee, provided that the above copyright | |
29 | // notice appears in all copies, and that both that copyright notice | |
30 | // and this permission notice appear in supporting documentation. None | |
31 | // of the above authors, nor IBM Haifa Research Laboratories, make any | |
32 | // representation about the suitability of this software for any | |
33 | // purpose. It is provided "as is" without express or implied | |
34 | // warranty. | |
35 | ||
36 | /** | |
a345e45d | 37 | * @file lu_counter_metadata.hpp |
4569a895 AT |
38 | * Contains implementation of a lu counter policy's metadata. |
39 | */ | |
40 | ||
5e11f978 | 41 | namespace __gnu_pbds |
4569a895 AT |
42 | { |
43 | namespace detail | |
44 | { | |
4569a895 | 45 | template<typename Size_Type> |
a345e45d | 46 | class lu_counter_policy_base; |
4569a895 | 47 | |
a345e45d BK |
48 | /// A list-update metadata type that moves elements to the front of |
49 | /// the list based on the counter algorithm. | |
8fc81078 | 50 | template<typename Size_Type = std::size_t> |
a345e45d BK |
51 | class lu_counter_metadata |
52 | { | |
53 | public: | |
54 | typedef Size_Type size_type; | |
4569a895 | 55 | |
a345e45d BK |
56 | private: |
57 | lu_counter_metadata(size_type init_count) : m_count(init_count) | |
58 | { } | |
4569a895 | 59 | |
a345e45d | 60 | friend class lu_counter_policy_base<size_type>; |
4569a895 | 61 | |
a345e45d | 62 | mutable size_type m_count; |
4569a895 AT |
63 | }; |
64 | ||
a345e45d | 65 | /// Base class for list-update counter policy. |
4569a895 | 66 | template<typename Size_Type> |
a345e45d BK |
67 | class lu_counter_policy_base |
68 | { | |
69 | protected: | |
70 | typedef Size_Type size_type; | |
4569a895 | 71 | |
a345e45d BK |
72 | lu_counter_metadata<size_type> |
73 | operator()(size_type max_size) const | |
74 | { return lu_counter_metadata<Size_Type>(std::rand() % max_size); } | |
4569a895 | 75 | |
a345e45d BK |
76 | template<typename Metadata_Reference> |
77 | bool | |
78 | operator()(Metadata_Reference r_data, size_type m_max_count) const | |
79 | { | |
80 | if (++r_data.m_count != m_max_count) | |
81 | return false; | |
82 | r_data.m_count = 0; | |
83 | return true; | |
84 | } | |
85 | }; | |
4569a895 | 86 | } // namespace detail |
5e11f978 | 87 | } // namespace __gnu_pbds |