76 lines
2.4 KiB
C++
76 lines
2.4 KiB
C++
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//////////////////////////////////////////////////////////////////////////////
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//
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// (C) Copyright Ion Gaztanaga 2014-2015. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/container for documentation.
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//
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//////////////////////////////////////////////////////////////////////////////
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#ifndef BOOST_CONTAINER_DETAIL_NEXT_CAPACITY_HPP
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#define BOOST_CONTAINER_DETAIL_NEXT_CAPACITY_HPP
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#ifndef BOOST_CONFIG_HPP
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# include <boost/config.hpp>
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#endif
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#if defined(BOOST_HAS_PRAGMA_ONCE)
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# pragma once
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#endif
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// container
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#include <boost/container/throw_exception.hpp>
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// container/detail
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#include <boost/container/detail/min_max.hpp>
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namespace boost {
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namespace container {
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namespace container_detail {
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enum NextCapacityOption { NextCapacityDouble, NextCapacity60Percent };
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template<class SizeType, NextCapacityOption Option>
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struct next_capacity_calculator;
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template<class SizeType>
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struct next_capacity_calculator<SizeType, NextCapacityDouble>
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{
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static SizeType get(const SizeType max_size
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,const SizeType capacity
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,const SizeType n)
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{
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const SizeType remaining = max_size - capacity;
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if ( remaining < n )
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boost::container::throw_length_error("get_next_capacity, allocator's max_size reached");
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const SizeType additional = max_value(n, capacity);
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return ( remaining < additional ) ? max_size : ( capacity + additional );
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}
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};
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template<class SizeType>
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struct next_capacity_calculator<SizeType, NextCapacity60Percent>
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{
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static SizeType get(const SizeType max_size
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,const SizeType capacity
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,const SizeType n)
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{
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const SizeType remaining = max_size - capacity;
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if ( remaining < n )
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boost::container::throw_length_error("get_next_capacity, allocator's max_size reached");
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const SizeType m3 = max_size/3;
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if (capacity < m3)
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return capacity + max_value(3*(capacity+1)/5, n);
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if (capacity < m3*2)
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return capacity + max_value((capacity+1)/2, n);
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return max_size;
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}
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};
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} //namespace container_detail {
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} //namespace container {
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} //namespace boost {
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#endif //#ifndef BOOST_CONTAINER_DETAIL_NEXT_CAPACITY_HPP
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