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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
* id.h
*
* Sun 16 Feb 2020 04:17:19 PM CET
* Copyright 2020 André Nusser
* andre.nusser@googlemail.com
****************************************************************************/
/*
* This file is part of DrumGizmo.
*
* DrumGizmo 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.
*
* DrumGizmo 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 DrumGizmo; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#pragma once
#include <cstdint>
#include <functional>
#include <limits>
// Typesafe ID class such that there are compiler errors if different IDs are
// mixed. The template parameter T is just there to assure this behavior.
// Additionally, we have a member function which can check for validity.
template <typename T>
struct ID
{
public:
using IDType = uint32_t;
static constexpr IDType invalid_value = std::numeric_limits<IDType>::max();
ID(IDType id = invalid_value) : id(id) {}
operator IDType() const { return id; }
IDType operator+(ID<T> other) const { return id + other.id; }
IDType operator+(int offset) const { return id + offset; }
IDType operator+(size_t offset) const { return id + offset; }
IDType operator-(ID<T> other) const { return id - other.id; }
IDType operator-(int offset) const { return id - offset; }
IDType operator/(int div) const { return id/div; }
IDType operator+=(ID<T> other) { return id += other.id; }
IDType operator-=(ID<T> other) { return id -= other.id; }
IDType operator=(ID<T> other) { return id = other.id; }
IDType operator++() { return ++id; }
IDType operator--() { return --id; }
bool operator!=(ID<T> other) const { return id != other.id; }
bool valid() const { return id != invalid_value; }
void invalidate() { id = invalid_value; }
private:
IDType id;
};
// define custom hash function to be able to use IDs with maps/sets
namespace std
{
template <typename T>
struct hash<ID<T>>
{
using IDType = typename ID<T>::IDType;
std::size_t operator()(ID<T> const& id) const noexcept
{
return std::hash<IDType>()(id);
}
};
} // std
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