1//
2// detail/thread_info_base.hpp
3// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
4//
5// Copyright (c) 2003-2015 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_THREAD_INFO_BASE_HPP
12#define BOOST_ASIO_DETAIL_THREAD_INFO_BASE_HPP
13
14#if defined(_MSC_VER) && (_MSC_VER >= 1200)
15# pragma once
16#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
17
18#include <climits>
19#include <cstddef>
20#include <boost/asio/detail/noncopyable.hpp>
21
22#include <boost/asio/detail/push_options.hpp>
23
24namespace boost {
25namespace asio {
26namespace detail {
27
28class thread_info_base
29 : private noncopyable
30{
31public:
32 thread_info_base()
33 : reusable_memory_(0)
34 {
35 }
36
37 ~thread_info_base()
38 {
39 if (reusable_memory_)
40 ::operator delete(reusable_memory_);
41 }
42
43 static void* allocate(thread_info_base* this_thread, std::size_t size)
44 {
45 if (this_thread && this_thread->reusable_memory_)
46 {
47 void* const pointer = this_thread->reusable_memory_;
48 this_thread->reusable_memory_ = 0;
49
50 unsigned char* const mem = static_cast<unsigned char*>(pointer);
51 if (static_cast<std::size_t>(mem[0]) >= size)
52 {
53 mem[size] = mem[0];
54 return pointer;
55 }
56
57 ::operator delete(pointer);
58 }
59
60 void* const pointer = ::operator new(size + 1);
61 unsigned char* const mem = static_cast<unsigned char*>(pointer);
62 mem[size] = (size <= UCHAR_MAX) ? static_cast<unsigned char>(size) : 0;
63 return pointer;
64 }
65
66 static void deallocate(thread_info_base* this_thread,
67 void* pointer, std::size_t size)
68 {
69 if (size <= UCHAR_MAX)
70 {
71 if (this_thread && this_thread->reusable_memory_ == 0)
72 {
73 unsigned char* const mem = static_cast<unsigned char*>(pointer);
74 mem[0] = mem[size];
75 this_thread->reusable_memory_ = pointer;
76 return;
77 }
78 }
79
80 ::operator delete(pointer);
81 }
82
83private:
84 void* reusable_memory_;
85};
86
87} // namespace detail
88} // namespace asio
89} // namespace boost
90
91#include <boost/asio/detail/pop_options.hpp>
92
93#endif // BOOST_ASIO_DETAIL_THREAD_INFO_BASE_HPP
94

source code of boost/boost/asio/detail/thread_info_base.hpp