freelist.hpp

/*****************************************************************************
 * \file
 * \brief This header contains the definition of a simple freelist utility
 *****************************************************************************/

/*
  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_UTILITIES_FREELIST_HPP
#define BIT_MEMORY_UTILITIES_FREELIST_HPP

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

#include "pointer_utilities.hpp"     // align_of
#include "uninitialized_storage.hpp" // uninitialized_construct_at

#include <cstddef> // std::size_t
#include <cassert> // assert

namespace bit {
  namespace memory {

    class freelist
    {
      //-----------------------------------------------------------------------
      // Constructors
      //-----------------------------------------------------------------------
    public:

      constexpr freelist() noexcept;

      freelist( freelist&& other ) noexcept = default;

      // Deleted copy construction
      freelist( const freelist& other ) = delete;

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

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

      // Deleted copy construction
      freelist& operator=( const freelist& other ) = delete;

      //----------------------------------------------------------------------
      // Modifiers
      //----------------------------------------------------------------------
    public:

      void swap( freelist& other ) noexcept;

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

      bool empty() const noexcept;

      std::size_t size() const noexcept;

      //----------------------------------------------------------------------
      // Modifiers
      //----------------------------------------------------------------------
    public:

      void clear();

      //----------------------------------------------------------------------
      // Caching
      //----------------------------------------------------------------------
    public:

      void* request() noexcept;

      void steal( freelist& other ) noexcept;

      void store( void* p ) noexcept;

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

      void* m_head;

      friend bool operator==( const freelist&, const freelist& ) noexcept;
    };

    //-------------------------------------------------------------------------
    // Comparisons
    //-------------------------------------------------------------------------

    bool operator==( const freelist& lhs, const freelist& rhs ) noexcept;
    bool operator!=( const freelist& lhs, const freelist& rhs ) noexcept;

  } // namespace memory
} // namespace bit

#include "detail/freelist.inl"

#endif /* BIT_MEMORY_UTILITIES_FREELIST_HPP */