stack_allocator.hpp

/*****************************************************************************
 * \file
 * \brief This header contains the definition of a stack allocator for
 *        temporary, automatic reclamation
 *****************************************************************************/

/*
  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_STACK_ALLOCATOR_HPP
#define BIT_MEMORY_ALLOCATORS_STACK_ALLOCATOR_HPP

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

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

#include "../utilities/macros.hpp"            // BIT_MEMORY_UNLIKELY
#include "../utilities/pointer_utilities.hpp" // offset_align_forward

#include <cstddef>     // std::size_t, std::max_align_t
#include <type_traits> // std::true_type, std::integral_constant
#include <cassert>     // assert

namespace bit {
  namespace memory {

    template<std::size_t Size, std::size_t Align = alignof(std::max_align_t)>
    class stack_allocator
    {
      //-----------------------------------------------------------------------
      // Public Member Types
      //-----------------------------------------------------------------------
    public:

      using max_alignment = std::integral_constant<std::size_t,Align>;

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

      stack_allocator() noexcept;

      // Deleted move constructor.
      stack_allocator( stack_allocator&& other ) = delete;

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

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

      ~stack_allocator();

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

      // Deleted copy assignment
      stack_allocator& operator=( const stack_allocator& ) = delete;

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

      //-----------------------------------------------------------------------
      // Allocations / Deallocations
      //-----------------------------------------------------------------------
    public:

      void* try_allocate( std::size_t size,
                          std::size_t align,
                          std::size_t offset = 0 ) noexcept;

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

      void deallocate_all();

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

      bool owns( const void* p ) const noexcept;

      allocator_info info() const noexcept;

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

      alignas(Align) char m_storage[Size];
      void* m_current;
    };

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

    template<std::size_t Size, std::size_t Align = alignof(std::max_align_t)>
    using named_stack_allocator = detail::named_allocator<stack_allocator<Size,Align>>;

  } // namespace memory
} // namespace bit

#include "detail/stack_allocator.inl"

#endif /* BIT_MEMORY_ALLOCATORS_STACK_ALLOCATOR_HPP */