allocator_common.hpp

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      if(count > this->max_size())
         throw bad_alloc();
      else if(Version == 1 && count == 1)
         return pointer(static_cast<value_type*>
         (pool->allocate_node()));
      else
         return pointer(static_cast<value_type*>
            (pool->get_segment_manager()->allocate(sizeof(T)*count)));
   }

   //!Deallocate allocated memory. Never throws
   void deallocate(const pointer &ptr, size_type count)
   {
      (void)count;
      typedef typename node_pool<0>::type node_pool_t;
      node_pool_t *pool = node_pool<0>::get(this->derived()->get_node_pool());
      if(Version == 1 && count == 1)
         pool->deallocate_node(detail::get_pointer(ptr));
      else
         pool->get_segment_manager()->deallocate((void*)detail::get_pointer(ptr));
   }

   //!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()
   {
      typedef typename node_pool<0>::type node_pool_t;
      node_pool_t *pool = node_pool<0>::get(this->derived()->get_node_pool());
      return pointer(static_cast<value_type*>(pool->allocate_node()));
   }

   //!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)
   {
      typedef typename node_pool<0>::type node_pool_t;
      node_pool_t *pool = node_pool<0>::get(this->derived()->get_node_pool());
      return multiallocation_iterator(pool->allocate_nodes(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)
   {
      typedef typename node_pool<0>::type node_pool_t;
      node_pool_t *pool = node_pool<0>::get(this->derived()->get_node_pool());
      pool->deallocate_node(detail::get_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)
   {  node_pool<0>::get(this->derived()->get_node_pool())->deallocate_nodes(it.base());   }

   //!Deallocates all free blocks of the pool
   void deallocate_free_blocks()
   {  node_pool<0>::get(this->derived()->get_node_pool())->deallocate_free_blocks();  }

   //!Deprecated, use deallocate_free_blocks.
   //!Deallocates all free chunks of the pool.
   void deallocate_free_chunks()
   {  node_pool<0>::get(this->derived()->get_node_pool())->deallocate_free_blocks();  }
};

template<class T, class NodePool, unsigned int Version>
class cached_allocator_impl
   :  public array_allocation_impl
         <cached_allocator_impl<T, NodePool, Version>, T, typename NodePool::segment_manager>
{
   cached_allocator_impl & operator=(const cached_allocator_impl& other);
   typedef array_allocation_impl
         < cached_allocator_impl
            <T, NodePool, Version>
         , T
         , typename NodePool::segment_manager> base_t;

   public:
   typedef NodePool                                      node_pool_t;
   typedef typename NodePool::segment_manager            segment_manager;
   typedef typename segment_manager::void_pointer        void_pointer;
   typedef typename detail::
      pointer_to_other<void_pointer, const void>::type   cvoid_pointer;
   typedef typename base_t::pointer                      pointer;
   typedef typename base_t::size_type                    size_type;
   typedef typename base_t::multiallocation_iterator     multiallocation_iterator;
   typedef typename base_t::multiallocation_chain        multiallocation_chain;
   typedef typename base_t::value_type                   value_type;

   public:
   enum { DEFAULT_MAX_CACHED_NODES = 64 };

   cached_allocator_impl(segment_manager *segment_mngr, std::size_t max_cached_nodes)
      : m_cache(segment_mngr, max_cached_nodes)
   {}

   cached_allocator_impl(const cached_allocator_impl &other)
      : m_cache(other.m_cache)
   {}

   //!Copy constructor from related cached_adaptive_pool_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, class NodePool2>
   cached_allocator_impl
      (const cached_allocator_impl
         <T2, NodePool2, Version> &other)
      : m_cache(other.get_segment_manager(), other.get_max_cached_nodes())
   {}

   //!Returns a pointer to the node pool.
   //!Never throws
   node_pool_t* get_node_pool() const
   {  return m_cache.get_node_pool();   }

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

   //!Sets the new max cached nodes value. This can provoke deallocations
   //!if "newmax" is less than current cached nodes. Never throws
   void set_max_cached_nodes(std::size_t newmax)
   {  m_cache.set_max_cached_nodes(newmax);   }

   //!Returns the max cached nodes parameter.
   //!Never throws
   std::size_t get_max_cached_nodes() const
   {  return m_cache.get_max_cached_nodes();   }

   //!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)
   {
      (void)hint;
      void * ret;
      if(count > this->max_size())
         throw bad_alloc();
      else if(Version == 1 && count == 1){
         ret = m_cache.cached_allocation();
      }
      else{
         ret = this->get_segment_manager()->allocate(sizeof(T)*count);
      }   
      return pointer(static_cast<T*>(ret));
   }

   //!Deallocate allocated memory. Never throws
   void deallocate(const pointer &ptr, size_type count)
   {
      (void)count;
      if(Version == 1 && count == 1){
         m_cache.cached_deallocation(detail::get_pointer(ptr));
      }
      else{
         this->get_segment_manager()->deallocate((void*)detail::get_pointer(ptr));
      }
   }

   //!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()
   {  return pointer(static_cast<value_type*>(this->m_cache.cached_allocation()));   }

   //!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)
   {  return multiallocation_iterator(this->m_cache.cached_allocation(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)
   {  this->m_cache.cached_deallocation(detail::get_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)
   {  m_cache.cached_deallocation(it.base());   }

   //!Deallocates all free blocks of the pool
   void deallocate_free_blocks()
   {  m_cache.get_node_pool()->deallocate_free_blocks();   }

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

   void deallocate_cache()
   {  m_cache.deallocate_all_cached_nodes(); }

   //!Deprecated use deallocate_free_blocks.
   void deallocate_free_chunks()
   {  m_cache.get_node_pool()->deallocate_free_blocks();   }

   /// @cond
   private:
   cache_impl<node_pool_t> m_cache;
};

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

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


//!Pooled shared memory allocator using adaptive pool. Includes
//!a reference count but the class does not delete itself, this is  
//!responsibility of user classes. Node size (NodeSize) and the number of
//!nodes allocated per block (NodesPerBlock) are known at compile time
template<class private_node_allocator_t>
class shared_pool_impl
   : public private_node_allocator_t
{
 public:
   //!Segment manager typedef
   typedef typename private_node_allocator_t::segment_manager segment_manager;
   typedef typename private_node_allocator_t::
      multiallocation_iterator                  multiallocation_iterator;
   typedef typename private_node_allocator_t::
      multiallocation_chain                     multiallocation_chain;

 private:
   typedef typename segment_manager::mutex_family::mutex_type mutex_type;

 public:
   //!Constructor from a segment manager. Never throws
   shared_pool_impl(segment_manager *segment_mngr)
      : private_node_allocator_t(segment_mngr)
   {}

   //!Destructor. Deallocates all allocated blocks. Never throws
   ~shared_pool_impl()
   {}

   //!Allocates array of count elements. Can throw boost::interprocess::bad_alloc
   void *allocate_node()
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      return private_node_allocator_t::allocate_node();
   }
   
   //!Deallocates an array pointed by ptr. Never throws
   void deallocate_node(void *ptr)
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      private_node_allocator_t::deallocate_node(ptr);
   }

   //!Allocates a singly linked list of n nodes ending in null pointer.
   //!can throw boost::interprocess::bad_alloc
   void allocate_nodes(multiallocation_chain &nodes, std::size_t n)
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      return private_node_allocator_t::allocate_nodes(nodes, n);
   }

   //!Allocates n nodes, pointed by the multiallocation_iterator. 
   //!Can throw boost::interprocess::bad_alloc
   multiallocation_iterator allocate_nodes(const std::size_t n)
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      return private_node_allocator_t::allocate_nodes(n);
   }

   //!Deallocates a linked list of nodes ending in null pointer. Never throws
   void deallocate_nodes(multiallocation_chain &nodes, std::size_t num)
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      private_node_allocator_t::deallocate_nodes(nodes, num);
   }

   //!Deallocates a linked list of nodes ending in null pointer. Never throws
   void deallocate_nodes(multiallocation_chain &nodes)
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      private_node_allocator_t::deallocate_nodes(nodes);
   }

   //!Deallocates the nodes pointed by the multiallocation iterator. Never throws
   void deallocate_nodes(multiallocation_iterator it)
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      private_node_allocator_t::deallocate_nodes(it);
   }

   //!Deallocates all the free blocks of memory. Never throws
   void deallocate_free_blocks()
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      private_node_allocator_t::deallocate_free_blocks();
   }

   //!Deallocates all used memory from the common pool.
   //!Precondition: all nodes allocated from this pool should
   //!already be deallocated. Otherwise, undefined behavior. Never throws
   void purge_blocks()
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      private_node_allocator_t::purge_blocks();
   }

   //!Increments internal reference count and returns new count. Never throws
   std::size_t inc_ref_count()
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      return ++m_header.m_usecount;
   }

   //!Decrements internal reference count and returns new count. Never throws
   std::size_t dec_ref_count()
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      assert(m_header.m_usecount > 0);
      return --m_header.m_usecount;
   }

   //!Deprecated, use deallocate_free_blocks.
   void deallocate_free_chunks()
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      private_node_allocator_t::deallocate_free_blocks();
   }

   //!Deprecated, use purge_blocks.
   void purge_chunks()
   {
      //-----------------------
      boost::interprocess::scoped_lock<mutex_type> guard(m_header);
      //-----------------------
      private_node_allocator_t::purge_blocks();
   }

   private:
   //!This struct includes needed data and derives from
   //!interprocess_mutex to allow EBO when using null_mutex
   struct header_t : mutex_type
   {
      std::size_t m_usecount;    //Number of attached allocators

      header_t()
      :  m_usecount(0) {}
   } m_header;
};

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

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

#endif   //#ifndef BOOST_INTERPROCESS_DETAIL_NODE_ALLOCATOR_COMMON_HPP