mirror of https://github.com/OpenTTD/OpenTTD.git
183 lines
9.2 KiB
C++
183 lines
9.2 KiB
C++
/*
|
|
* This file is part of OpenTTD.
|
|
* OpenTTD 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, version 2.
|
|
* OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
/** @file strong_typedef_type.hpp Type (helpers) for making a strong typedef that is a distinct type. */
|
|
|
|
#ifndef STRONG_TYPEDEF_TYPE_HPP
|
|
#define STRONG_TYPEDEF_TYPE_HPP
|
|
|
|
#include "../3rdparty/fmt/format.h"
|
|
|
|
/** Non-templated base for #StrongType::Typedef for use with type trait queries. */
|
|
struct StrongTypedefBase {};
|
|
|
|
namespace StrongType {
|
|
/**
|
|
* Mix-in which makes the new Typedef comparable with itself and its base type.
|
|
*/
|
|
struct Compare {
|
|
template <typename TType, typename TBaseType>
|
|
struct mixin {
|
|
friend constexpr bool operator ==(const TType &lhs, const TType &rhs) { return lhs.value == rhs.value; }
|
|
friend constexpr bool operator ==(const TType &lhs, const TBaseType &rhs) { return lhs.value == rhs; }
|
|
|
|
friend constexpr bool operator !=(const TType &lhs, const TType &rhs) { return lhs.value != rhs.value; }
|
|
friend constexpr bool operator !=(const TType &lhs, const TBaseType &rhs) { return lhs.value != rhs; }
|
|
|
|
friend constexpr bool operator <=(const TType &lhs, const TType &rhs) { return lhs.value <= rhs.value; }
|
|
friend constexpr bool operator <=(const TType &lhs, const TBaseType &rhs) { return lhs.value <= rhs; }
|
|
|
|
friend constexpr bool operator <(const TType &lhs, const TType &rhs) { return lhs.value < rhs.value; }
|
|
friend constexpr bool operator <(const TType &lhs, const TBaseType &rhs) { return lhs.value < rhs; }
|
|
|
|
friend constexpr bool operator >=(const TType &lhs, const TType &rhs) { return lhs.value >= rhs.value; }
|
|
friend constexpr bool operator >=(const TType &lhs, const TBaseType &rhs) { return lhs.value >= rhs; }
|
|
|
|
friend constexpr bool operator >(const TType &lhs, const TType &rhs) { return lhs.value > rhs.value; }
|
|
friend constexpr bool operator >(const TType &lhs, const TBaseType &rhs) { return lhs.value > rhs; }
|
|
};
|
|
};
|
|
|
|
/**
|
|
* Mix-in which makes the new Typedef behave more like an integer. This means you can add and subtract from it.
|
|
*
|
|
* Operators like divide, multiply and module are explicitly denied, as that often makes little sense for the
|
|
* new type. If you want to do these actions on the new Typedef, you are better off first casting it to the
|
|
* base type.
|
|
*/
|
|
struct Integer {
|
|
template <typename TType, typename TBaseType>
|
|
struct mixin {
|
|
friend constexpr TType &operator ++(TType &lhs) { lhs.value++; return lhs; }
|
|
friend constexpr TType &operator --(TType &lhs) { lhs.value--; return lhs; }
|
|
friend constexpr TType operator ++(TType &lhs, int) { TType res = lhs; lhs.value++; return res; }
|
|
friend constexpr TType operator --(TType &lhs, int) { TType res = lhs; lhs.value--; return res; }
|
|
|
|
friend constexpr TType &operator +=(TType &lhs, const TType &rhs) { lhs.value += rhs.value; return lhs; }
|
|
friend constexpr TType operator +(const TType &lhs, const TType &rhs) { return TType{ lhs.value + rhs.value }; }
|
|
friend constexpr TType operator +(const TType &lhs, const TBaseType &rhs) { return TType{ lhs.value + rhs }; }
|
|
|
|
friend constexpr TType &operator -=(TType &lhs, const TType &rhs) { lhs.value -= rhs.value; return lhs; }
|
|
friend constexpr TType operator -(const TType &lhs, const TType &rhs) { return TType{ lhs.value - rhs.value }; }
|
|
friend constexpr TType operator -(const TType &lhs, const TBaseType &rhs) { return TType{ lhs.value - rhs }; }
|
|
|
|
/* For most new types, the rest of the operators make no sense. For example,
|
|
* what does it actually mean to multiply a Year with a value. Or to do a
|
|
* bitwise OR on a Date. Or to divide a TileIndex by 2. Conceptually, they
|
|
* don't really mean anything. So force the user to first cast it to the
|
|
* base type, so the operation no longer returns the new Typedef. */
|
|
|
|
constexpr TType &operator *=(const TType &rhs) = delete;
|
|
constexpr TType operator *(const TType &rhs) = delete;
|
|
constexpr TType operator *(const TBaseType &rhs) = delete;
|
|
|
|
constexpr TType &operator /=(const TType &rhs) = delete;
|
|
constexpr TType operator /(const TType &rhs) = delete;
|
|
constexpr TType operator /(const TBaseType &rhs) = delete;
|
|
|
|
constexpr TType &operator %=(const TType &rhs) = delete;
|
|
constexpr TType operator %(const TType &rhs) = delete;
|
|
constexpr TType operator %(const TBaseType &rhs) = delete;
|
|
|
|
constexpr TType &operator &=(const TType &rhs) = delete;
|
|
constexpr TType operator &(const TType &rhs) = delete;
|
|
constexpr TType operator &(const TBaseType &rhs) = delete;
|
|
|
|
constexpr TType &operator |=(const TType &rhs) = delete;
|
|
constexpr TType operator |(const TType &rhs) = delete;
|
|
constexpr TType operator |(const TBaseType &rhs) = delete;
|
|
|
|
constexpr TType &operator ^=(const TType &rhs) = delete;
|
|
constexpr TType operator ^(const TType &rhs) = delete;
|
|
constexpr TType operator ^(const TBaseType &rhs) = delete;
|
|
|
|
constexpr TType &operator <<=(const TType &rhs) = delete;
|
|
constexpr TType operator <<(const TType &rhs) = delete;
|
|
constexpr TType operator <<(const TBaseType &rhs) = delete;
|
|
|
|
constexpr TType &operator >>=(const TType &rhs) = delete;
|
|
constexpr TType operator >>(const TType &rhs) = delete;
|
|
constexpr TType operator >>(const TBaseType &rhs) = delete;
|
|
|
|
constexpr TType operator ~() = delete;
|
|
constexpr TType operator -() = delete;
|
|
};
|
|
};
|
|
|
|
/**
|
|
* Mix-in which makes the new Typedef compatible with another type (which is not the base type).
|
|
*
|
|
* @note The base type of the new Typedef will be cast to the other type; so make sure they are compatible.
|
|
*
|
|
* @tparam TCompatibleType The other type to be compatible with.
|
|
*/
|
|
template <typename TCompatibleType>
|
|
struct Compatible {
|
|
template <typename TType, typename TBaseType>
|
|
struct mixin {
|
|
friend constexpr bool operator ==(const TType &lhs, TCompatibleType rhs) { return lhs.value == static_cast<TBaseType>(rhs); }
|
|
friend constexpr bool operator !=(const TType &lhs, TCompatibleType rhs) { return lhs.value != static_cast<TBaseType>(rhs); }
|
|
|
|
friend constexpr bool operator <=(const TType &lhs, TCompatibleType rhs) { return lhs.value <= static_cast<TBaseType>(rhs); }
|
|
friend constexpr bool operator <(const TType &lhs, TCompatibleType rhs) { return lhs.value < static_cast<TBaseType>(rhs); }
|
|
friend constexpr bool operator >=(const TType &lhs, TCompatibleType rhs) { return lhs.value >= static_cast<TBaseType>(rhs); }
|
|
friend constexpr bool operator >(const TType &lhs, TCompatibleType rhs) { return lhs.value > static_cast<TBaseType>(rhs); }
|
|
|
|
friend constexpr TType operator +(const TType &lhs, TCompatibleType rhs) { return { static_cast<TBaseType>(lhs.value + rhs) }; }
|
|
friend constexpr TType operator -(const TType &lhs, TCompatibleType rhs) { return { static_cast<TBaseType>(lhs.value - rhs) }; }
|
|
};
|
|
};
|
|
|
|
/**
|
|
* Templated helper to make a type-safe 'typedef' representing a single POD value.
|
|
* A normal 'typedef' is not distinct from its base type and will be treated as
|
|
* identical in many contexts. This class provides a distinct type that can still
|
|
* be assign from and compared to values of its base type.
|
|
*
|
|
* Example usage:
|
|
*
|
|
* using MyType = StrongType::Typedef<int, struct MyTypeTag, StrongType::Explicit, StrongType::Compare, StrongType::Integer>;
|
|
*
|
|
* @tparam TBaseType Type of the derived class (i.e. the concrete usage of this class).
|
|
* @tparam TTag An unique struct to keep types of the same TBaseType distinct.
|
|
* @tparam TProperties A list of mixins to add to the class.
|
|
*/
|
|
template <typename TBaseType, typename TTag, typename... TProperties>
|
|
struct EMPTY_BASES Typedef : public StrongTypedefBase, public TProperties::template mixin<Typedef<TBaseType, TTag, TProperties...>, TBaseType>... {
|
|
using BaseType = TBaseType;
|
|
|
|
constexpr Typedef() = default;
|
|
constexpr Typedef(const Typedef &) = default;
|
|
constexpr Typedef(Typedef &&) = default;
|
|
|
|
constexpr Typedef(const TBaseType &value) : value(value) {}
|
|
|
|
constexpr Typedef &operator =(const Typedef &rhs) { this->value = rhs.value; return *this; }
|
|
constexpr Typedef &operator =(Typedef &&rhs) { this->value = std::move(rhs.value); return *this; }
|
|
constexpr Typedef &operator =(const TBaseType &rhs) { this->value = rhs; return *this; }
|
|
|
|
/* Only allow conversion to BaseType via method. */
|
|
constexpr TBaseType base() const { return this->value; }
|
|
|
|
/* Only allow TProperties classes access to the internal value. Everyone else needs to call .base(). */
|
|
friend struct Compare;
|
|
friend struct Integer;
|
|
template <typename TCompatibleType> friend struct Compatible;
|
|
|
|
/* GCC / MSVC don't pick up on the "friend struct" above, where CLang does.
|
|
* As in our CI we compile for all three targets, it is sufficient to have one
|
|
* that errors on this; but nobody should be using "value" directly. Instead,
|
|
* use base() to convert to the base type. */
|
|
#ifdef __clang__
|
|
protected:
|
|
#endif /* __clang__ */
|
|
TBaseType value{};
|
|
};
|
|
}
|
|
|
|
#endif /* STRONG_TYPEDEF_TYPE_HPP */
|