170 lines
4.1 KiB
C++
170 lines
4.1 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2015 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_TUPLE_HPP
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#define __UTIL_TUPLE_HPP
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#include "types.hpp"
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#include "variadic.hpp"
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#include <tuple>
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#include <type_traits>
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namespace util { namespace tuple {
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///////////////////////////////////////////////////////////////////////////
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/// call a provided object with type_tag<T> for each type in a tuple
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template <
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typename T,
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typename F,
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size_t S = 0
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>
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typename std::enable_if<
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S == std::tuple_size<T>::value,
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void
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>::type
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for_type (F)
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{ }
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//-------------------------------------------------------------------------
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template<
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typename T,
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typename F,
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size_t S = 0
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>
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typename std::enable_if<
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S < std::tuple_size<T>::value,
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void
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>::type
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for_type (F f)
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{
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using E = typename std::tuple_element<S,T>::type;
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f (type_tag<E> {});
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for_type<T,F,S+1> (f);
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}
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//-------------------------------------------------------------------------
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template <typename T, typename F>
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auto for_type (F f, T t)
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{ return for_type<decltype(t)> (f); }
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///////////////////////////////////////////////////////////////////////////
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// unpack a tuple as function arguments
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namespace detail {
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template <
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typename Func,
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typename ...Args,
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size_t ...I
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>
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auto
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call (const Func &func, std::tuple<Args...> args, indices<I...>)
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{
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// quiet unused variable warning with zero args
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(void)args;
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// XXX: Use `std::invoke' when gcc catches up with c++17
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return func (std::get<I> (args)...);
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}
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}
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template <
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typename Func,
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typename ...Args
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>
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auto
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call (const Func &func, std::tuple<Args...> args)
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{
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return detail::call (func, args, typename make_indices<sizeof...(Args)>::type {});
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}
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///////////////////////////////////////////////////////////////////////////
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/// call a provided object with each value in a tuple
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template <
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size_t S = 0,
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typename F,
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typename ...T
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>
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typename std::enable_if<
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S == sizeof...(T),
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void
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>::type
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for_each (F, const std::tuple<T...>&)
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{ }
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//-------------------------------------------------------------------------
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template<
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size_t S = 0,
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typename F,
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typename ...T
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>
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typename std::enable_if<
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S < sizeof...(T),
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void
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>::type
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for_each (F f, const std::tuple<T...> &t)
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{
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f (std::get<S> (t));
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for_each<S+1,F,T...> (f, t);
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}
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///////////////////////////////////////////////////////////////////////////////
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/// Statically map the member types of a tuple via F<>::type
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///
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/// T: tuple type
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/// F: type mapping object, conversion uses F<>::type
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/// I: tuple indexing helper
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template <
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typename T,
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template <
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typename
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> class F,
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typename I = typename make_indices<
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std::tuple_size<T>::value
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>::type
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>
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struct map;
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//-----------------------------------------------------------------------------
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template <
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typename T,
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template <
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typename
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> class F,
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size_t ...I
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>
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struct map<
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T,
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F,
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indices<I...>
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> {
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typedef std::tuple<
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typename F<
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typename std::tuple_element<I, T>::type
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>::type...
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> type;
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};
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} }
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#endif
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