properties.h

/*
 * This file is part of libsidplayfp, a SID player engine.
 *
 * Copyright 2025-2026 Leandro Nini <drfiemost@users.sourceforge.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 
#ifndef PROPERTIES_H
#define PROPERTIES_H
 
#include "sidcxx11.h"
 
#ifdef HAVE_CXX17
#  if __has_include(<optional>)
#    define HAS_OPTIONAL 1
#  endif
#endif
 
#ifdef HAS_OPTIONAL
 
#include <optional>
 
template <typename T>
using Property = std::optional<T>;
 
#else
 
#include <type_traits>
 
template <typename T>
class Property
{
    static_assert(std::is_scalar<T>(), "T must be a scalar type");
 
private:
    T m_val;
    bool m_isSet;
 
public:
    Property() :
        m_isSet(false) {}
 
    inline bool has_value() const { return m_isSet; }
    inline T value() const { return m_val; }
    inline Property<T>& operator =(const T& val) { m_val = val; m_isSet = true;  return *this; }
};
 
#endif // HAVE_CXX17
 
#endif // PROPERTIES_H