ceph/src/boost/libs/asio/include/boost/asio/detail/thread_info_base.hpp

   1 //
   2 // detail/thread_info_base.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2016 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
  24 namespace boost {
  25 namespace asio {
  26 namespace detail {
  27
  28 class thread_info_base
  29   : private noncopyable
  30 {
  31 public:
  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
  83 private:
  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