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include/boost/container/detail/node_pool_impl.hpp  view on Meta::CPAN

   //!Returns the segment manager. Never throws
   segment_manager_base_type* get_segment_manager_base()const
   {  return boost::movelib::to_raw_pointer(mp_segment_mngr_base);  }

   void *allocate_node()
   {  return this->priv_alloc_node();  }

   //!Deallocates an array pointed by ptr. Never throws
   void deallocate_node(void *ptr)
   {  this->priv_dealloc_node(ptr); }

   //!Allocates a singly linked list of n nodes ending in null pointer.
   void allocate_nodes(const size_type n, multiallocation_chain &chain)
   {
      //Preallocate all needed blocks to fulfill the request
      size_type cur_nodes = m_freelist.size();
      if(cur_nodes < n){
         this->priv_alloc_block(((n - cur_nodes) - 1)/m_nodes_per_block + 1);
      }

      //We just iterate the needed nodes to get the last we'll erase
      typedef typename free_nodes_t::iterator free_iterator;
      free_iterator before_last_new_it = m_freelist.before_begin();
      for(size_type j = 0; j != n; ++j){
         ++before_last_new_it;
      }

      //Cache the first node of the allocated range before erasing
      free_iterator first_node(m_freelist.begin());
      free_iterator last_node (before_last_new_it);

      //Erase the range. Since we already have the distance, this is O(1)
      m_freelist.erase_after( m_freelist.before_begin()
                            , ++free_iterator(before_last_new_it)
                            , n);

      //Now take the last erased node and just splice it in the end
      //of the intrusive list that will be traversed by the multialloc iterator.
      chain.incorporate_after(chain.before_begin(), &*first_node, &*last_node, n);
      m_allocated += n;
   }

   void deallocate_nodes(multiallocation_chain &chain)
   {
      typedef typename multiallocation_chain::iterator iterator;
      iterator it(chain.begin()), itend(chain.end());
      while(it != itend){
         void *pElem = &*it;
         ++it;
         this->priv_dealloc_node(pElem);
      }
   }

   //!Deallocates all the free blocks of memory. Never throws
   void deallocate_free_blocks()
   {
      typedef typename free_nodes_t::iterator nodelist_iterator;
      typename blockslist_t::iterator bit(m_blocklist.before_begin()),
                                      it(m_blocklist.begin()),
                                      itend(m_blocklist.end());
      free_nodes_t backup_list;
      nodelist_iterator backup_list_last = backup_list.before_begin();

      //Execute the algorithm and get an iterator to the last value
      size_type blocksize = (get_rounded_size)
         (m_real_node_size*m_nodes_per_block, (size_type) alignment_of<node_t>::value);

      while(it != itend){
         //Collect all the nodes from the block pointed by it
         //and push them in the list
         free_nodes_t free_nodes;
         nodelist_iterator last_it = free_nodes.before_begin();
         const void *addr = get_block_from_hook(&*it, blocksize);

         m_freelist.remove_and_dispose_if
            (is_between(addr, blocksize), push_in_list(free_nodes, last_it));

         //If the number of nodes is equal to m_nodes_per_block
         //this means that the block can be deallocated
         if(free_nodes.size() == m_nodes_per_block){
            //Unlink the nodes
            free_nodes.clear();
            it = m_blocklist.erase_after(bit);
            mp_segment_mngr_base->deallocate((void*)addr);
         }
         //Otherwise, insert them in the backup list, since the
         //next "remove_if" does not need to check them again.
         else{
            //Assign the iterator to the last value if necessary
            if(backup_list.empty() && !m_freelist.empty()){
               backup_list_last = last_it;
            }
            //Transfer nodes. This is constant time.
            backup_list.splice_after
               ( backup_list.before_begin()
               , free_nodes
               , free_nodes.before_begin()
               , last_it
               , free_nodes.size());
            bit = it;
            ++it;
         }
      }
      //We should have removed all the nodes from the free list
      BOOST_ASSERT(m_freelist.empty());

      //Now pass all the node to the free list again
      m_freelist.splice_after
         ( m_freelist.before_begin()
         , backup_list
         , backup_list.before_begin()
         , backup_list_last
         , backup_list.size());
   }

   size_type num_free_nodes()
   {  return m_freelist.size();  }

   //!Deallocates all used memory. Precondition: all nodes allocated from this pool should
   //!already be deallocated. Otherwise, undefined behaviour. Never throws
   void purge_blocks()
   {
      //check for memory leaks
      BOOST_ASSERT(m_allocated==0);
      size_type blocksize = (get_rounded_size)
         (m_real_node_size*m_nodes_per_block, (size_type)alignment_of<node_t>::value);

      //We iterate though the NodeBlock list to free the memory
      while(!m_blocklist.empty()){
         void *addr = get_block_from_hook(&m_blocklist.front(), blocksize);
         m_blocklist.pop_front();
         mp_segment_mngr_base->deallocate((void*)addr);
      }
      //Just clear free node list
      m_freelist.clear();
   }

   void swap(private_node_pool_impl &other)
   {
      BOOST_ASSERT(m_nodes_per_block == other.m_nodes_per_block);
      BOOST_ASSERT(m_real_node_size == other.m_real_node_size);
      std::swap(mp_segment_mngr_base, other.mp_segment_mngr_base);
      m_blocklist.swap(other.m_blocklist);
      m_freelist.swap(other.m_freelist);
      std::swap(m_allocated, other.m_allocated);
   }

   private:

   struct push_in_list
   {
      push_in_list(free_nodes_t &l, typename free_nodes_t::iterator &it)
         :  slist_(l), last_it_(it)
      {}

      void operator()(typename free_nodes_t::pointer p) const
      {
         slist_.push_front(*p);
         if(slist_.size() == 1){ //Cache last element
            ++last_it_ = slist_.begin();
         }
      }

      private:
      free_nodes_t &slist_;
      typename free_nodes_t::iterator &last_it_;
   };

   struct is_between
   {
      typedef typename free_nodes_t::value_type argument_type;
      typedef bool                              result_type;