node_allocator.hpp

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//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2008. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////

#ifndef BOOST_INTERPROCESS_NODE_ALLOCATOR_HPP
#define BOOST_INTERPROCESS_NODE_ALLOCATOR_HPP

#if (defined _MSC_VER) && (_MSC_VER >= 1200)
#  pragma once
#endif

#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>

#include <boost/interprocess/interprocess_fwd.hpp>
#include <boost/assert.hpp>
#include <boost/utility/addressof.hpp>
#include <boost/interprocess/detail/utilities.hpp>
#include <boost/interprocess/detail/type_traits.hpp>
#include <boost/interprocess/allocators/detail/node_pool.hpp>
#include <boost/interprocess/exceptions.hpp>
#include <boost/interprocess/allocators/detail/allocator_common.hpp>
#include <memory>
#include <algorithm>
#include <cstddef>

//!\file
//!Describes node_allocator pooled shared memory STL compatible allocator 

namespace boost {
namespace interprocess {

/// @cond

namespace detail{

template < unsigned int Version
         , class T
         , class SegmentManager
         , std::size_t NodesPerBlock
         >
class node_allocator_base
   : public node_pool_allocation_impl
   < node_allocator_base
      < Version, T, SegmentManager, NodesPerBlock>
   , Version
   , T
   , SegmentManager
   >
{
   public:
   typedef typename SegmentManager::void_pointer         void_pointer;
   typedef SegmentManager                                segment_manager;
   typedef node_allocator_base
      <Version, T, SegmentManager, NodesPerBlock>   self_t;

   /// @cond

   template <int dummy>
   struct node_pool
   {
      typedef detail::shared_node_pool
      < SegmentManager, sizeof_value<T>::value, NodesPerBlock> type;

      static type *get(void *p)
      {  return static_cast<type*>(p);  }
   };
   /// @endcond

   BOOST_STATIC_ASSERT((Version <=2));

   public:
   //-------
   typedef typename detail::
      pointer_to_other<void_pointer, T>::type            pointer;
   typedef typename detail::
      pointer_to_other<void_pointer, const T>::type      const_pointer;
   typedef T                                             value_type;
   typedef typename detail::add_reference
                     <value_type>::type                  reference;
   typedef typename detail::add_reference
                     <const value_type>::type            const_reference;
   typedef std::size_t                                   size_type;
   typedef std::ptrdiff_t                                difference_type;

   typedef detail::version_type<node_allocator_base, Version>   version;
   typedef transform_iterator
      < typename SegmentManager::
         multiallocation_iterator
      , detail::cast_functor <T> >              multiallocation_iterator;
   typedef typename SegmentManager::
      multiallocation_chain                     multiallocation_chain;

   //!Obtains node_allocator_base from 
   //!node_allocator_base
   template<class T2>
   struct rebind
   {  
      typedef node_allocator_base<Version, T2, SegmentManager, NodesPerBlock>       other;
   };

   /// @cond
   private:
   //!Not assignable from related node_allocator_base
   template<unsigned int Version2, class T2, class SegmentManager2, std::size_t N2>
   node_allocator_base& operator=
      (const node_allocator_base<Version2, T2, SegmentManager2, N2>&);

   //!Not assignable from other node_allocator_base
   //node_allocator_base& operator=(const node_allocator_base&);
   /// @endcond

   public:
   //!Constructor from a segment manager. If not present, constructs a node
   //!pool. Increments the reference count of the associated node pool.
   //!Can throw boost::interprocess::bad_alloc
   node_allocator_base(segment_manager *segment_mngr) 
      : mp_node_pool(detail::get_or_create_node_pool<typename node_pool<0>::type>(segment_mngr)) { }

   //!Copy constructor from other node_allocator_base. Increments the reference 
   //!count of the associated node pool. Never throws
   node_allocator_base(const node_allocator_base &other) 
      : mp_node_pool(other.get_node_pool()) 
   {  
      node_pool<0>::get(detail::get_pointer(mp_node_pool))->inc_ref_count();   
   }

   //!Copy constructor from related node_allocator_base. If not present, constructs
   //!a node pool. Increments the reference count of the associated node pool.
   //!Can throw boost::interprocess::bad_alloc
   template<class T2>
   node_allocator_base
      (const node_allocator_base<Version, T2, SegmentManager, NodesPerBlock> &other)
      : mp_node_pool(detail::get_or_create_node_pool<typename node_pool<0>::type>(other.get_segment_manager())) { }

   //!Assignment from other node_allocator_base
   node_allocator_base& operator=(const node_allocator_base &other)
   {
      node_allocator_base c(other);
      swap(*this, c);
      return *this;
   }

   //!Destructor, removes node_pool_t from memory
   //!if its reference count reaches to zero. Never throws
   ~node_allocator_base() 
   {  detail::destroy_node_pool_if_last_link(node_pool<0>::get(detail::get_pointer(mp_node_pool)));   }

   //!Returns a pointer to the node pool.
   //!Never throws
   void* get_node_pool() const
   {  return detail::get_pointer(mp_node_pool);   }

   //!Returns the segment manager.
   //!Never throws
   segment_manager* get_segment_manager()const
   {  return node_pool<0>::get(detail::get_pointer(mp_node_pool))->get_segment_manager();  }

   //!Swaps allocators. Does not throw. If each allocator is placed in a
   //!different memory segment, the result is undefined.
   friend void swap(self_t &alloc1, self_t &alloc2)
   {  detail::do_swap(alloc1.mp_node_pool, alloc2.mp_node_pool);  }

   /// @cond
   private:
   void_pointer   mp_node_pool;
   /// @endcond
};

//!Equality test for same type
//!of node_allocator_base
template<unsigned int V, class T, class S, std::size_t NPC> inline
bool operator==(const node_allocator_base<V, T, S, NPC> &alloc1, 
                const node_allocator_base<V, T, S, NPC> &alloc2)
   {  return alloc1.get_node_pool() == alloc2.get_node_pool(); }

//!Inequality test for same type
//!of node_allocator_base
template<unsigned int V, class T, class S, std::size_t NPC> inline
bool operator!=(const node_allocator_base<V, T, S, NPC> &alloc1, 
                const node_allocator_base<V, T, S, NPC> &alloc2)
   {  return alloc1.get_node_pool() != alloc2.get_node_pool(); }

template < class T
         , class SegmentManager
         , std::size_t NodesPerBlock = 64
         >
class node_allocator_v1
   :  public node_allocator_base
         < 1
         , T
         , SegmentManager
         , NodesPerBlock
         >
{
   public:
   typedef detail::node_allocator_base
         < 1, T, SegmentManager, NodesPerBlock> base_t;

   template<class T2>
   struct rebind
   {  
      typedef node_allocator_v1<T2, SegmentManager, NodesPerBlock>  other;
   };

   node_allocator_v1(SegmentManager *segment_mngr) 
      : base_t(segment_mngr)
   {}

   template<class T2>
   node_allocator_v1
      (const node_allocator_v1<T2, SegmentManager, NodesPerBlock> &other)
      : base_t(other)
   {}
};

}  //namespace detail{

/// @endcond