1 //
2 // detail/recycling_allocator.hpp
3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
6 //
7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9 //
10 
11 #ifndef BOOST_ASIO_DETAIL_RECYCLING_ALLOCATOR_HPP
12 #define BOOST_ASIO_DETAIL_RECYCLING_ALLOCATOR_HPP
13 
14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
15 # pragma once
16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
17 
18 #include <boost/asio/detail/config.hpp>
19 #include <boost/asio/detail/memory.hpp>
20 #include <boost/asio/detail/thread_context.hpp>
21 #include <boost/asio/detail/thread_info_base.hpp>
22 
23 #include <boost/asio/detail/push_options.hpp>
24 
25 namespace boost {
26 namespace asio {
27 namespace detail {
28 
29 template <typename T, typename Purpose = thread_info_base::default_tag>
30 class recycling_allocator
31 {
32 public:
33   typedef T value_type;
34 
35   template <typename U>
36   struct rebind
37   {
38     typedef recycling_allocator<U, Purpose> other;
39   };
40 
recycling_allocator()41   recycling_allocator()
42   {
43   }
44 
45   template <typename U>
recycling_allocator(const recycling_allocator<U,Purpose> &)46   recycling_allocator(const recycling_allocator<U, Purpose>&)
47   {
48   }
49 
allocate(std::size_t n)50   T* allocate(std::size_t n)
51   {
52     typedef thread_context::thread_call_stack call_stack;
53     void* p = thread_info_base::allocate(Purpose(),
54         call_stack::top(), sizeof(T) * n);
55     return static_cast<T*>(p);
56   }
57 
deallocate(T * p,std::size_t n)58   void deallocate(T* p, std::size_t n)
59   {
60     typedef thread_context::thread_call_stack call_stack;
61     thread_info_base::deallocate(Purpose(),
62         call_stack::top(), p, sizeof(T) * n);
63   }
64 };
65 
66 template <typename Purpose>
67 class recycling_allocator<void, Purpose>
68 {
69 public:
70   typedef void value_type;
71 
72   template <typename U>
73   struct rebind
74   {
75     typedef recycling_allocator<U, Purpose> other;
76   };
77 
recycling_allocator()78   recycling_allocator()
79   {
80   }
81 
82   template <typename U>
recycling_allocator(const recycling_allocator<U,Purpose> &)83   recycling_allocator(const recycling_allocator<U, Purpose>&)
84   {
85   }
86 };
87 
88 template <typename Allocator, typename Purpose>
89 struct get_recycling_allocator
90 {
91   typedef Allocator type;
getboost::asio::detail::get_recycling_allocator92   static type get(const Allocator& a) { return a; }
93 };
94 
95 template <typename T, typename Purpose>
96 struct get_recycling_allocator<std::allocator<T>, Purpose>
97 {
98   typedef recycling_allocator<T, Purpose> type;
getboost::asio::detail::get_recycling_allocator99   static type get(const std::allocator<T>&) { return type(); }
100 };
101 
102 } // namespace detail
103 } // namespace asio
104 } // namespace boost
105 
106 #include <boost/asio/detail/pop_options.hpp>
107 
108 #endif // BOOST_ASIO_DETAIL_RECYCLING_ALLOCATOR_HPP
109