1 //////////////////////////////////////////////////////////////////////////////
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)
7 // See http://www.boost.org/libs/container for documentation.
9 //////////////////////////////////////////////////////////////////////////////
10 #ifndef BOOST_CONTAINER_DETAIL_NEXT_CAPACITY_HPP
11 #define BOOST_CONTAINER_DETAIL_NEXT_CAPACITY_HPP
13 #ifndef BOOST_CONFIG_HPP
14 # include <boost/config.hpp>
17 #if defined(BOOST_HAS_PRAGMA_ONCE)
22 #include <boost/container/throw_exception.hpp>
24 #include <boost/container/detail/min_max.hpp>
28 namespace container_detail {
30 enum NextCapacityOption { NextCapacityDouble, NextCapacity60Percent };
32 template<class SizeType, NextCapacityOption Option>
33 struct next_capacity_calculator;
35 template<class SizeType>
36 struct next_capacity_calculator<SizeType, NextCapacityDouble>
38 static SizeType get(const SizeType max_size
39 ,const SizeType capacity
42 const SizeType remaining = max_size - capacity;
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 );
50 template<class SizeType>
51 struct next_capacity_calculator<SizeType, NextCapacity60Percent>
53 static SizeType get(const SizeType max_size
54 ,const SizeType capacity
57 const SizeType remaining = max_size - capacity;
59 boost::container::throw_length_error("get_next_capacity, allocator's max_size reached");
60 const SizeType m3 = max_size/3;
63 return capacity + max_value(3*(capacity+1)/5, n);
66 return capacity + max_value((capacity+1)/2, n);
71 } //namespace container_detail {
72 } //namespace container {
75 #endif //#ifndef BOOST_CONTAINER_DETAIL_NEXT_CAPACITY_HPP