node_allocator.hpp

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//!An STL node allocator that uses a segment manager as memory 
//!source. The internal pointer type will of the same type (raw, smart) as
//!"typename SegmentManager::void_pointer" type. This allows
//!placing the allocator in shared memory, memory mapped-files, etc...
//!This node allocator shares a segregated storage between all instances 
//!of node_allocator with equal sizeof(T) placed in the same segment 
//!group. NodesPerBlock is the number of nodes allocated at once when the allocator
//!needs runs out of nodes
template < class T
         , class SegmentManager
         , std::size_t NodesPerBlock
         >
class node_allocator
   /// @cond
   :  public detail::node_allocator_base
         < 2
         , T
         , SegmentManager
         , NodesPerBlock
         >
   /// @endcond
{

   #ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
   typedef detail::node_allocator_base
         < 2, T, SegmentManager, NodesPerBlock> base_t;
   public:
   typedef detail::version_type<node_allocator, 2>   version;

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

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

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

   #else //BOOST_INTERPROCESS_DOXYGEN_INVOKED
   public:
   typedef implementation_defined::segment_manager       segment_manager;
   typedef segment_manager::void_pointer                 void_pointer;
   typedef implementation_defined::pointer               pointer;
   typedef implementation_defined::const_pointer         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;

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

   private:
   //!Not assignable from
   //!related node_allocator
   template<class T2, class SegmentManager2, std::size_t N2>
   node_allocator& operator=
      (const node_allocator<T2, SegmentManager2, N2>&);

   //!Not assignable from 
   //!other node_allocator
   //node_allocator& operator=(const node_allocator&);

   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(segment_manager *segment_mngr);

   //!Copy constructor from other node_allocator. Increments the reference 
   //!count of the associated node pool. Never throws
   node_allocator(const node_allocator &other);

   //!Copy constructor from related node_allocator. 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
      (const node_allocator<T2, SegmentManager, NodesPerBlock> &other);

   //!Destructor, removes node_pool_t from memory
   //!if its reference count reaches to zero. Never throws
   ~node_allocator();

   //!Returns a pointer to the node pool.
   //!Never throws
   void* get_node_pool() const;

   //!Returns the segment manager.
   //!Never throws
   segment_manager* get_segment_manager()const;

   //!Returns the number of elements that could be allocated.
   //!Never throws
   size_type max_size() const;

   //!Allocate memory for an array of count elements. 
   //!Throws boost::interprocess::bad_alloc if there is no enough memory
   pointer allocate(size_type count, cvoid_pointer hint = 0);

   //!Deallocate allocated memory.
   //!Never throws
   void deallocate(const pointer &ptr, size_type count);

   //!Deallocates all free blocks
   //!of the pool
   void deallocate_free_blocks();

   //!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);

   //!Returns address of mutable object.
   //!Never throws
   pointer address(reference value) const;

   //!Returns address of non mutable object.
   //!Never throws
   const_pointer address(const_reference value) const;

   //!Copy construct an object. 
   //!Throws if T's copy constructor throws
   void construct(const pointer &ptr, const_reference v);

   //!Destroys object. Throws if object's
   //!destructor throws
   void destroy(const pointer &ptr);

   //!Returns maximum the number of objects the previously allocated memory
   //!pointed by p can hold. This size only works for memory allocated with
   //!allocate, allocation_command and allocate_many.
   size_type size(const pointer &p) const;

   std::pair<pointer, bool>
      allocation_command(allocation_type command,
                         size_type limit_size, 
                         size_type preferred_size,
                         size_type &received_size, const pointer &reuse = 0);

   //!Allocates many elements of size elem_size in a contiguous block
   //!of memory. The minimum number to be allocated is min_elements,
   //!the preferred and maximum number is
   //!preferred_elements. The number of actually allocated elements is
   //!will be assigned to received_size. The elements must be deallocated
   //!with deallocate(...)
   multiallocation_iterator allocate_many(size_type elem_size, std::size_t num_elements);

   //!Allocates n_elements elements, each one of size elem_sizes[i]in a
   //!contiguous block
   //!of memory. The elements must be deallocated
   multiallocation_iterator allocate_many(const size_type *elem_sizes, size_type n_elements);

   //!Allocates many elements of size elem_size in a contiguous block
   //!of memory. The minimum number to be allocated is min_elements,
   //!the preferred and maximum number is
   //!preferred_elements. The number of actually allocated elements is
   //!will be assigned to received_size. The elements must be deallocated
   //!with deallocate(...)
   void deallocate_many(multiallocation_iterator it);

   //!Allocates just one object. Memory allocated with this function
   //!must be deallocated only with deallocate_one().
   //!Throws boost::interprocess::bad_alloc if there is no enough memory
   pointer allocate_one();

   //!Allocates many elements of size == 1 in a contiguous block
   //!of memory. The minimum number to be allocated is min_elements,
   //!the preferred and maximum number is
   //!preferred_elements. The number of actually allocated elements is
   //!will be assigned to received_size. Memory allocated with this function
   //!must be deallocated only with deallocate_one().
   multiallocation_iterator allocate_individual(std::size_t num_elements);

   //!Deallocates memory previously allocated with allocate_one().
   //!You should never use deallocate_one to deallocate memory allocated
   //!with other functions different from allocate_one(). Never throws
   void deallocate_one(const pointer &p);

   //!Allocates many elements of size == 1 in a contiguous block
   //!of memory. The minimum number to be allocated is min_elements,
   //!the preferred and maximum number is
   //!preferred_elements. The number of actually allocated elements is
   //!will be assigned to received_size. Memory allocated with this function
   //!must be deallocated only with deallocate_one().
   void deallocate_individual(multiallocation_iterator it);
   #endif
};

#ifdef BOOST_INTERPROCESS_DOXYGEN_INVOKED

//!Equality test for same type
//!of node_allocator
template<class T, class S, std::size_t NPC> inline
bool operator==(const node_allocator<T, S, NPC> &alloc1, 
                const node_allocator<T, S, NPC> &alloc2);

//!Inequality test for same type
//!of node_allocator
template<class T, class S, std::size_t NPC> inline
bool operator!=(const node_allocator<T, S, NPC> &alloc1, 
                const node_allocator<T, S, NPC> &alloc2);

#endif

}  //namespace interprocess {
}  //namespace boost {

#include <boost/interprocess/detail/config_end.hpp>

#endif   //#ifndef BOOST_INTERPROCESS_NODE_ALLOCATOR_HPP