BlockAllocator.hpp

/*****************************************************************************
 * \file
 * \brief This header contains the definitions for the 'BlockAllocator'
 *        concept and related type-traits
 ****************************************************************************/

/*
  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_CONCEPTS_BLOCKALLOCATOR_HPP
#define BIT_MEMORY_CONCEPTS_BLOCKALLOCATOR_HPP

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

#include "detail/identity.hpp" // detail::identity
#include "detail/void_t.hpp"   // detail::void_t

#include "../utilities/allocator_info.hpp" // allocator_info
#include "../utilities/memory_block.hpp"   // memory_block

#include <type_traits> // std::integral_constants

namespace bit {
  namespace memory {

#if __cplusplus >= 202000L
  // TODO(bitwize) replace 202000L with the correct __cplusplus when certified

    template<typename A>
    concept BlockAllocator = requires( A a, memory_block block )
    {
      { block = a.allocate_block() } -> memory_block;
      { a.deallocate_block( block ) } -> void;
      { a.next_block_size() } -> std::size_t;
    };
#endif

    namespace detail {

      template<typename T, typename = void>
      struct block_allocator_has_allocate_block_impl : std::false_type{};

      template<typename T>
      struct block_allocator_has_allocate_block_impl<T,void_t<
        decltype( std::declval<memory_block&>() = std::declval<T&>().allocate_block() )
      >> : std::true_type{};

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

      template<typename T, typename = void>
      struct block_allocator_has_deallocate_block_impl : std::false_type{};

      template<typename T>
      struct block_allocator_has_deallocate_block_impl<T,void_t<
        decltype( std::declval<T&>().deallocate_block( std::declval<memory_block&>() ) )
      >> : std::true_type{};

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

      template<typename T, typename = void>
      struct block_allocator_has_default_block_alignment_impl : std::false_type{};

      template<typename T>
      struct block_allocator_has_default_block_alignment_impl<T,void_t<
        decltype(T::default_block_alignment)>
      > : std::true_type{};

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

      template<typename T, typename = void>
      struct block_allocator_has_next_block_size_impl : std::false_type{};

      template<typename T>
      struct block_allocator_has_next_block_size_impl<T,void_t<
        decltype(std::declval<std::size_t&>() = std::declval<const T&>().next_block_size())>
      > : std::true_type{};

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

      template<typename T, typename = void>
      struct block_allocator_has_next_block_alignment_impl : std::false_type{};

      template<typename T>
      struct block_allocator_has_next_block_alignment_impl<T,void_t<
        decltype(std::declval<std::size_t&>() = std::declval<const T&>().next_block_alignment())>
      > : std::true_type{};

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

      template<typename T, typename = void>
      struct block_allocator_has_info_impl : std::false_type{};

      template<typename T>
      struct block_allocator_has_info_impl<T,
        void_t<decltype( std::declval<allocator_info>() = std::declval<const T&>().info() )>
      > : std::true_type{};

    } // namespace detail

    template<typename T>
    struct block_allocator_has_default_block_alignment
      : detail::block_allocator_has_default_block_alignment_impl<T>{};

    template<typename T>
    constexpr std::size_t block_allocator_default_block_alignment_v
      = block_allocator_has_default_block_alignment<T>::value;

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

    template<typename T>
    struct block_allocator_has_next_block_size
      : detail::block_allocator_has_next_block_size_impl<T>{};

    template<typename T>
    constexpr std::size_t block_allocator_has_next_block_size_v
      = block_allocator_has_next_block_size<T>::value;

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

    template<typename T>
    struct block_allocator_has_next_block_alignment
      : detail::block_allocator_has_next_block_alignment_impl<T>{};

    template<typename T>
    constexpr std::size_t block_allocator_has_next_block_alignment_v
      = block_allocator_has_next_block_alignment<T>::value;

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

    template<typename T>
    struct block_allocator_has_info
      : detail::block_allocator_has_info_impl<T>{};

    template<typename T>
    constexpr bool block_allocator_has_info_v
      = block_allocator_has_info<T>::value;

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

    template<typename T>
    struct is_block_allocator : std::integral_constant<bool,
      detail::block_allocator_has_allocate_block_impl<T>::value &&
      detail::block_allocator_has_deallocate_block_impl<T>::value &&
      detail::block_allocator_has_next_block_size_impl<T>::value
    >{};

    template<typename T>
    constexpr bool is_block_allocator_v = is_block_allocator<T>::value;

  } // namespace memory
} // namespace bit

#endif /* BIT_MEMORY_CONCEPTS_BLOCKALLOCATOR_HPP */