/* -*- mode: C++; tab-width: 4; c-basic-offset: 4; indent-tabs-mode:nil; -*- */

/*

 * libopenraw - option.hpp

 *

 * Copyright (C) 2017 Hubert Figuière

 *

 * This library is free software: you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public License

 * as published by the Free Software Foundation, either version 3 of

 * the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library.  If not, see

 * <http://www.gnu.org/licenses/>.

 */

// an option<> template class inspired by Rust

#pragma once

#include <stdexcept>

template<class T>

class Option

{

public:

  typedef T data_type;

  Option()

    : m_none(true)

    , m_data()

  {

  }

  Option(T&& data)

    : m_none(false)

    , m_data(data)

  {

  }

  Option(const T& data)

    : m_none(false)

    , m_data(data)

  {

  }

  template<class... Args>

  Option(Args&&... args)

    : m_none(false)

    , m_data(args...)

  {

  }

  T&& unwrap()

  {

    if (m_none) {

      throw std::runtime_error("none option value");

    }

    m_none = true;

    return std::move(m_data);

  }

  T&& unwrap_or(T&& def)

  {

    if (m_none) {

      return std::move(def);

    }

    m_none = true;

    return std::move(m_data);

  }

  bool empty() const

  { return m_none; }

  bool ok() const

  { return !m_none; }

private:

  bool m_none;

  T m_data;

};