virtual_block_allocator.hpp

/*****************************************************************************
 * \file
 * \brief This header contains an implementation of a virtual-block allocator.
 *****************************************************************************/

/*
  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_VIRTUAL_BLOCK_ALLOCATOR_HPP
#define BIT_MEMORY_BLOCK_ALLOCATORS_VIRTUAL_BLOCK_ALLOCATOR_HPP

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

#include "detail/named_block_allocator.hpp" // detail::named_block_allocator

#include "../regions/virtual_memory.hpp"

#include "../utilities/ebo_storage.hpp"        // ebo_storage
#include "../utilities/dynamic_size_type.hpp"  // dynamic_size, etc
#include "../utilities/allocator_info.hpp"     // allocator_info
#include "../utilities/memory_block_cache.hpp" // memory_block_cache
#include "../utilities/owner.hpp"              // owner

#include "../policies/growth_multipliers/no_growth.hpp" // no_growth

#include <cstddef> // std::size_t
#include <type_traits> // std::enable_if

namespace bit {
  namespace memory {

    template<std::size_t Pages, typename GrowthMultiplier=no_growth_multiplier>
    class virtual_block_allocator
      : ebo_storage<GrowthMultiplier>,
        dynamic_size_type<0,Pages>
    {
      using base_type    = ebo_storage<GrowthMultiplier>;
      using pages_member = dynamic_size_type<0,Pages>;

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

      template<std::size_t UPages=Pages,
               typename=std::enable_if_t<UPages!=dynamic_size>>
      explicit virtual_block_allocator( GrowthMultiplier growth = GrowthMultiplier{} );

      template<std::size_t UPages=Pages,
               typename=std::enable_if_t<UPages==dynamic_size>>
      explicit virtual_block_allocator( std::size_t pages,
                                        GrowthMultiplier growth = GrowthMultiplier{} );

      virtual_block_allocator( virtual_block_allocator&& other ) noexcept;

      // Deleted copy constructor
      virtual_block_allocator( const virtual_block_allocator& other ) = delete;

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

      ~virtual_block_allocator();

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

      // Deleted move-assignment
      virtual_block_allocator& operator=( virtual_block_allocator&& other ) = delete;

      // Deleted copy-assignment
      virtual_block_allocator& operator=( const virtual_block_allocator& other ) = delete;

      //-----------------------------------------------------------------------
      // Block Allocations
      //-----------------------------------------------------------------------
    public:

      owner<memory_block> allocate_block() noexcept;

      void deallocate_block( owner<memory_block> block ) noexcept;

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

      std::size_t next_block_size() const noexcept;

      allocator_info info() const noexcept;

      //-----------------------------------------------------------------------
      // Private Members
      //-----------------------------------------------------------------------
    private:

      void*              m_memory;      
      std::ptrdiff_t     m_active_page; 
      memory_block_cache m_cache;       
    };

    //-------------------------------------------------------------------------
    // Utilities
    //-------------------------------------------------------------------------

    template<std::size_t Pages,
             typename GrowthMultiplier=no_growth_multiplier>
    using named_virtual_block_allocator = detail::named_block_allocator<virtual_block_allocator<Pages,GrowthMultiplier>>;

  } // namespace memory
} // namespace bit

#include "detail/virtual_block_allocator.inl"

#endif /* BIT_MEMORY_BLOCK_ALLOCATORS_VIRTUAL_BLOCK_ALLOCATOR_HPP */