policy_block_allocator.hpp

/*****************************************************************************
 * \file
 * \brief This header contains a block allocator that uses policy-based design
 *        to componentize entries
 *****************************************************************************/

/*
  The MIT License (MIT)

  Copyright (c) 2018 Matthew Rodusek

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
#ifndef BIT_MEMORY_BLOCK_ALLOCATORS_POLICY_BLOCK_ALLOCATOR_HPP
#define BIT_MEMORY_BLOCK_ALLOCATORS_POLICY_BLOCK_ALLOCATOR_HPP

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

#include "../utilities/ebo_storage.hpp"      // detail::ebo_storage
#include "../utilities/allocator_info.hpp"         // allocator_info
#include "../utilities/memory_block.hpp"           // memory_block
#include "../utilities/owner.hpp"                  // owner

#include "../concepts/BlockAllocator.hpp" // block_allocator_has

#include "../traits/block_allocator_traits.hpp" // block_allocator_traits

#include <cstddef> // std::size_t
#include <tuple>   // std::tuple, std::forward_as_tuple
#include <mutex>   // std::lock_guard

namespace bit {
  namespace memory {
    namespace detail {

      template<typename BlockAllocator,
               bool HasAlignment = block_allocator_has_default_block_alignment<BlockAllocator>::value>
      struct policy_block_allocator_base
      {

      };

      template<typename BlockAllocator>
      struct policy_block_allocator_base<BlockAllocator,true>
      {
        using default_block_alignment = typename BlockAllocator::default_block_alignment;
      };
    } // namespae detail


    template<typename BlockAllocator,
             typename MemoryTagger,
             typename MemoryTracker,
             typename BasicLockable>
    class policy_block_allocator
      : private ebo_storage<BlockAllocator,MemoryTagger,MemoryTracker,BasicLockable>,
        public detail::policy_block_allocator_base<BlockAllocator>
    {
      using traits_type = block_allocator_traits<BlockAllocator>;
      using base_type = ebo_storage<BlockAllocator,
                                            MemoryTagger,
                                            MemoryTracker,
                                            BasicLockable>;

      //-----------------------------------------------------------------------
      // Public Member Types
      //-----------------------------------------------------------------------
    public:

      using lock_type    = BasicLockable;
      using tracker_type = MemoryTracker;

      //-----------------------------------------------------------------------
      // Constructors
      //-----------------------------------------------------------------------
    public:

      policy_block_allocator() = default;

      template<typename Arg0, typename...Args,
               typename = std::enable_if_t<
                 std::is_constructible<BlockAllocator,Arg0,Args...>::value &&
                 !std::is_same<Arg0,std::decay_t<policy_block_allocator>>::value>>
      policy_block_allocator( Arg0&& arg0, Args&&...args );

      policy_block_allocator( policy_block_allocator&& other ) = default;

      policy_block_allocator( const policy_block_allocator& other ) = default;

      //-----------------------------------------------------------------------

      ~policy_block_allocator();

      //-----------------------------------------------------------------------

      policy_block_allocator& operator=( policy_block_allocator&& other ) = default;

      policy_block_allocator& operator=( const policy_block_allocator& other ) = default;

      //-----------------------------------------------------------------------
      // Block Allocation
      //-----------------------------------------------------------------------
    public:

      owner<memory_block> allocate_block();

      void deallocate_block( owner<memory_block> block );

      //-----------------------------------------------------------------------
      // Observers
      //-----------------------------------------------------------------------
    public:

      const tracker_type& tracker() const noexcept;

      allocator_info info() const noexcept;

      std::size_t next_block_size() const noexcept;
    };

  } // namespace memory
} // namespace memory

#include "detail/policy_block_allocator.inl"

#endif /* BIT_MEMORY_BLOCK_ALLOCATORS_POLICY_BLOCK_ALLOCATOR_HPP */