ceph/src/boost/boost/container/detail/next_capacity.hpp

   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