policy_allocator.hpp

/*****************************************************************************
 * \file
 * \brief This header contains the definition of a policy-based 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_ALLOCATORS_POLICY_ALLOCATOR_HPP
#define BIT_MEMORY_ALLOCATORS_POLICY_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/debugging.hpp"      // debug_tag_...
#include "../utilities/errors.hpp"         // get_leak_handler, etc
#include "../utilities/macros.hpp"         // BIT_MEMORY_UNLIKELY

#include "../concepts/Allocator.hpp"         // Allocator
#include "../concepts/ExtendedAllocator.hpp" // ExtendedAllocator

#include "../traits/allocator_traits.hpp" // allocator_traits

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

namespace bit {
  namespace memory {

    template<typename ExtendedAllocator,
             typename MemoryTagger,
             typename MemoryTracker,
             typename BoundsChecker,
             typename BasicLockable>
    class policy_allocator
      : private ebo_storage<ExtendedAllocator,
                                    MemoryTagger,
                                    MemoryTracker,
                                    BoundsChecker,
                                    BasicLockable>
    {

      using base_type = ebo_storage<ExtendedAllocator,
                                            MemoryTagger,
                                            MemoryTracker,
                                            BoundsChecker,
                                            BasicLockable>;

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

      // Inherit the various traits specified by the allocation policy;
      // otherwise default back to the same defaults that the allocator_traits
      // will choose.

      using default_alignment = allocator_default_alignment<ExtendedAllocator>;
      using max_alignment     = allocator_max_alignment<ExtendedAllocator>;
      using lock_type         = BasicLockable;
      using tracker_type      = MemoryTracker;

      //-----------------------------------------------------------------------
      // Constructor / Destructor / Assignment
      //-----------------------------------------------------------------------
    public:

      template<typename...Args, typename = std::enable_if_t<std::is_constructible<ExtendedAllocator,Args...>::value>>
      policy_allocator( Args&&...args );

      policy_allocator( policy_allocator&& other ) = default;

      policy_allocator( const policy_allocator& other ) = default;

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

      ~policy_allocator();

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

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

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

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

      const tracker_type& tracker() const noexcept;

      //-----------------------------------------------------------------------
      // Allocation / Deallocation
      //-----------------------------------------------------------------------

      void* try_allocate( std::size_t size, std::size_t align ) noexcept;

      void deallocate( void* p, std::size_t size );

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

      template<typename U = ExtendedAllocator, typename = std::enable_if_t<allocator_can_truncate_deallocations<U>::value>>
      void deallocate_all();

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

      template<typename U = ExtendedAllocator, typename = std::enable_if_t<allocator_knows_ownership<U>::value>>
      bool owns( const void* p ) const noexcept;

      template<typename U = ExtendedAllocator, typename = std::enable_if_t<allocator_has_info<U>::value>>
      allocator_info info() const noexcept;

      //----------------------------------------------------------------------
      // Capacity
      //----------------------------------------------------------------------
    public:

      template<typename U = ExtendedAllocator, typename = std::enable_if_t<allocator_has_max_size<U>::value>>
      std::size_t max_size() const noexcept;

      template<typename U = ExtendedAllocator, typename = std::enable_if_t<allocator_has_min_size<U>::value>>
      std::size_t min_size() const noexcept;
    };

  } // namespace memory
} // namespace bit

#include "detail/policy_allocator.inl"

#endif /* BIT_MEMORY_ALLOCATORS_POLICY_ALLOCATOR_HPP */