ladybird/AK/Tuple.h

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/*
* Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/StdLibExtras.h>
#include <AK/TypeList.h>
namespace AK::Detail {
template<typename... Ts>
struct Tuple {
};
template<typename T>
struct Tuple<T> {
Tuple(T&& value) requires(!IsSame<T&&, const T&>)
: value(forward<T>(value))
{
}
Tuple(const T& value)
: value(value)
{
}
template<typename U>
U& get()
{
static_assert(IsSame<T, U>, "Invalid tuple access");
return value;
}
template<typename U>
const U& get() const
{
return const_cast<Tuple<T>&>(*this).get<U>();
}
template<typename U, unsigned index>
U& get_with_index()
{
static_assert(IsSame<T, U> && index == 0, "Invalid tuple access");
return value;
}
template<typename U, unsigned index>
const U& get_with_index() const
{
return const_cast<Tuple<T>&>(*this).get_with_index<U, index>();
}
private:
T value;
};
template<typename T, typename... TRest>
struct Tuple<T, TRest...> : Tuple<TRest...> {
template<typename FirstT, typename... RestT>
Tuple(FirstT&& first, RestT&&... rest)
: Tuple<TRest...>(forward<RestT>(rest)...)
, value(forward<FirstT>(first))
{
}
Tuple(T&& first, TRest&&... rest)
: Tuple<TRest...>(move(rest)...)
, value(move(first))
{
}
template<typename U>
U& get()
{
if constexpr (IsSame<T, U>)
return value;
else
return Tuple<TRest...>::template get<U>();
}
template<typename U>
const U& get() const
{
return const_cast<Tuple<T, TRest...>&>(*this).get<U>();
}
template<typename U, unsigned index>
U& get_with_index()
{
if constexpr (IsSame<T, U> && index == 0)
return value;
else
return Tuple<TRest...>::template get_with_index<U, index - 1>();
}
template<typename U, unsigned index>
const U& get_with_index() const
{
return const_cast<Tuple<T, TRest...>&>(*this).get_with_index<U, index>();
}
private:
T value;
};
}
namespace AK {
template<typename... Ts>
struct Tuple : Detail::Tuple<Ts...> {
using Types = TypeList<Ts...>;
using Detail::Tuple<Ts...>::Tuple;
using Indices = MakeIndexSequence<sizeof...(Ts)>;
Tuple(Tuple&& other)
: Tuple(move(other), Indices())
{
}
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Tuple(Tuple const& other)
: Tuple(other, Indices())
{
}
Tuple& operator=(Tuple&& other)
{
set(move(other), Indices());
return *this;
}
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Tuple& operator=(Tuple const& other)
{
set(other, Indices());
return *this;
}
template<typename T>
auto& get()
{
return Detail::Tuple<Ts...>::template get<T>();
}
template<unsigned index>
auto& get()
{
return Detail::Tuple<Ts...>::template get_with_index<typename Types::template Type<index>, index>();
}
template<typename T>
auto& get() const
{
return Detail::Tuple<Ts...>::template get<T>();
}
template<unsigned index>
auto& get() const
{
return Detail::Tuple<Ts...>::template get_with_index<typename Types::template Type<index>, index>();
}
template<typename F>
auto apply_as_args(F&& f)
{
return apply_as_args(forward<F>(f), Indices());
}
template<typename F>
auto apply_as_args(F&& f) const
{
return apply_as_args(forward<F>(f), Indices());
}
static constexpr auto size() { return sizeof...(Ts); }
private:
template<unsigned... Is>
Tuple(Tuple&& other, IndexSequence<Is...>)
: Detail::Tuple<Ts...>(move(other.get<Is>())...)
{
}
template<unsigned... Is>
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Tuple(Tuple const& other, IndexSequence<Is...>)
: Detail::Tuple<Ts...>(other.get<Is>()...)
{
}
template<unsigned... Is>
void set(Tuple&& other, IndexSequence<Is...>)
{
((get<Is>() = move(other.get<Is>())), ...);
}
template<unsigned... Is>
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void set(Tuple const& other, IndexSequence<Is...>)
{
((get<Is>() = other.get<Is>()), ...);
}
template<typename F, unsigned... Is>
auto apply_as_args(F&& f, IndexSequence<Is...>)
{
return forward<F>(f)(get<Is>()...);
}
template<typename F, unsigned... Is>
auto apply_as_args(F&& f, IndexSequence<Is...>) const
{
return forward<F>(f)(get<Is>()...);
}
};
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template<class... Args>
Tuple(Args... args) -> Tuple<Args...>;
}
#if USING_AK_GLOBALLY
using AK::Tuple;
#endif