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1 | ////////////////////////////////////////////////////////////////////////////// |
2 | // | |
3 | // (C) Copyright Ion Gaztanaga 2014-2015. Distributed under the Boost | |
4 | // Software License, Version 1.0. (See accompanying file | |
5 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
6 | // | |
7 | // See http://www.boost.org/libs/container for documentation. | |
8 | // | |
9 | ////////////////////////////////////////////////////////////////////////////// | |
10 | #ifndef BOOST_CONTAINER_DETAIL_NEXT_CAPACITY_HPP | |
11 | #define BOOST_CONTAINER_DETAIL_NEXT_CAPACITY_HPP | |
12 | ||
13 | #ifndef BOOST_CONFIG_HPP | |
14 | # include <boost/config.hpp> | |
15 | #endif | |
16 | ||
17 | #if defined(BOOST_HAS_PRAGMA_ONCE) | |
18 | # pragma once | |
19 | #endif | |
20 | ||
21 | // container | |
22 | #include <boost/container/throw_exception.hpp> | |
23 | // container/detail | |
24 | #include <boost/container/detail/min_max.hpp> | |
25 | ||
26 | namespace boost { | |
27 | namespace container { | |
28 | namespace container_detail { | |
29 | ||
30 | enum NextCapacityOption { NextCapacityDouble, NextCapacity60Percent }; | |
31 | ||
32 | template<class SizeType, NextCapacityOption Option> | |
33 | struct next_capacity_calculator; | |
34 | ||
35 | template<class SizeType> | |
36 | struct next_capacity_calculator<SizeType, NextCapacityDouble> | |
37 | { | |
38 | static SizeType get(const SizeType max_size | |
39 | ,const SizeType capacity | |
40 | ,const SizeType n) | |
41 | { | |
42 | const SizeType remaining = max_size - capacity; | |
43 | if ( remaining < n ) | |
44 | boost::container::throw_length_error("get_next_capacity, allocator's max_size reached"); | |
45 | const SizeType additional = max_value(n, capacity); | |
46 | return ( remaining < additional ) ? max_size : ( capacity + additional ); | |
47 | } | |
48 | }; | |
49 | ||
50 | template<class SizeType> | |
51 | struct next_capacity_calculator<SizeType, NextCapacity60Percent> | |
52 | { | |
53 | static SizeType get(const SizeType max_size | |
54 | ,const SizeType capacity | |
55 | ,const SizeType n) | |
56 | { | |
57 | const SizeType remaining = max_size - capacity; | |
58 | if ( remaining < n ) | |
59 | boost::container::throw_length_error("get_next_capacity, allocator's max_size reached"); | |
60 | const SizeType m3 = max_size/3; | |
61 | ||
62 | if (capacity < m3) | |
63 | return capacity + max_value(3*(capacity+1)/5, n); | |
64 | ||
65 | if (capacity < m3*2) | |
66 | return capacity + max_value((capacity+1)/2, n); | |
67 | return max_size; | |
68 | } | |
69 | }; | |
70 | ||
71 | } //namespace container_detail { | |
72 | } //namespace container { | |
73 | } //namespace boost { | |
74 | ||
75 | #endif //#ifndef BOOST_CONTAINER_DETAIL_NEXT_CAPACITY_HPP |