Chris@16: //
Chris@16: // detail/object_pool.hpp
Chris@16: // ~~~~~~~~~~~~~~~~~~~~~~
Chris@16: //
Chris@101: // Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: 
Chris@16: #ifndef BOOST_ASIO_DETAIL_OBJECT_POOL_HPP
Chris@16: #define BOOST_ASIO_DETAIL_OBJECT_POOL_HPP
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: # pragma once
Chris@16: #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: 
Chris@16: #include <boost/asio/detail/noncopyable.hpp>
Chris@16: 
Chris@16: #include <boost/asio/detail/push_options.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace asio {
Chris@16: namespace detail {
Chris@16: 
Chris@16: template <typename Object>
Chris@16: class object_pool;
Chris@16: 
Chris@16: class object_pool_access
Chris@16: {
Chris@16: public:
Chris@16:   template <typename Object>
Chris@16:   static Object* create()
Chris@16:   {
Chris@16:     return new Object;
Chris@16:   }
Chris@16: 
Chris@16:   template <typename Object>
Chris@16:   static void destroy(Object* o)
Chris@16:   {
Chris@16:     delete o;
Chris@16:   }
Chris@16: 
Chris@16:   template <typename Object>
Chris@16:   static Object*& next(Object* o)
Chris@16:   {
Chris@16:     return o->next_;
Chris@16:   }
Chris@16: 
Chris@16:   template <typename Object>
Chris@16:   static Object*& prev(Object* o)
Chris@16:   {
Chris@16:     return o->prev_;
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: template <typename Object>
Chris@16: class object_pool
Chris@16:   : private noncopyable
Chris@16: {
Chris@16: public:
Chris@16:   // Constructor.
Chris@16:   object_pool()
Chris@16:     : live_list_(0),
Chris@16:       free_list_(0)
Chris@16:   {
Chris@16:   }
Chris@16: 
Chris@16:   // Destructor destroys all objects.
Chris@16:   ~object_pool()
Chris@16:   {
Chris@16:     destroy_list(live_list_);
Chris@16:     destroy_list(free_list_);
Chris@16:   }
Chris@16: 
Chris@16:   // Get the object at the start of the live list.
Chris@16:   Object* first()
Chris@16:   {
Chris@16:     return live_list_;
Chris@16:   }
Chris@16: 
Chris@16:   // Allocate a new object.
Chris@16:   Object* alloc()
Chris@16:   {
Chris@16:     Object* o = free_list_;
Chris@16:     if (o)
Chris@16:       free_list_ = object_pool_access::next(free_list_);
Chris@16:     else
Chris@16:       o = object_pool_access::create<Object>();
Chris@16: 
Chris@16:     object_pool_access::next(o) = live_list_;
Chris@16:     object_pool_access::prev(o) = 0;
Chris@16:     if (live_list_)
Chris@16:       object_pool_access::prev(live_list_) = o;
Chris@16:     live_list_ = o;
Chris@16: 
Chris@16:     return o;
Chris@16:   }
Chris@16: 
Chris@16:   // Free an object. Moves it to the free list. No destructors are run.
Chris@16:   void free(Object* o)
Chris@16:   {
Chris@16:     if (live_list_ == o)
Chris@16:       live_list_ = object_pool_access::next(o);
Chris@16: 
Chris@16:     if (object_pool_access::prev(o))
Chris@16:     {
Chris@16:       object_pool_access::next(object_pool_access::prev(o))
Chris@16:         = object_pool_access::next(o);
Chris@16:     }
Chris@16: 
Chris@16:     if (object_pool_access::next(o))
Chris@16:     {
Chris@16:       object_pool_access::prev(object_pool_access::next(o))
Chris@16:         = object_pool_access::prev(o);
Chris@16:     }
Chris@16: 
Chris@16:     object_pool_access::next(o) = free_list_;
Chris@16:     object_pool_access::prev(o) = 0;
Chris@16:     free_list_ = o;
Chris@16:   }
Chris@16: 
Chris@16: private:
Chris@16:   // Helper function to destroy all elements in a list.
Chris@16:   void destroy_list(Object* list)
Chris@16:   {
Chris@16:     while (list)
Chris@16:     {
Chris@16:       Object* o = list;
Chris@16:       list = object_pool_access::next(o);
Chris@16:       object_pool_access::destroy(o);
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   // The list of live objects.
Chris@16:   Object* live_list_;
Chris@16: 
Chris@16:   // The free list.
Chris@16:   Object* free_list_;
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: } // namespace asio
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/asio/detail/pop_options.hpp>
Chris@16: 
Chris@16: #endif // BOOST_ASIO_DETAIL_OBJECT_POOL_HPP