163 lines
4.5 KiB
C++
163 lines
4.5 KiB
C++
/*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*
|
|
* Copyright 2015-2018 Danny Robson <danny@nerdcruft.net>
|
|
*/
|
|
|
|
#ifndef CRUFT_UTIL_TUPLE_TYPE_HPP
|
|
#define CRUFT_UTIL_TUPLE_TYPE_HPP
|
|
|
|
#include "../types.hpp"
|
|
|
|
#include "../types/traits.hpp"
|
|
|
|
#include <cstddef>
|
|
#include <tuple>
|
|
|
|
|
|
namespace util::tuple::type {
|
|
///////////////////////////////////////////////////////////////////////////
|
|
/// call a provided FunctorT with type_tag<T> for each type in the
|
|
/// tuple-like type TupleT.
|
|
template<
|
|
typename TupleT,
|
|
typename FunctorT,
|
|
size_t S = 0
|
|
>
|
|
void
|
|
each (FunctorT &&func)
|
|
{
|
|
static_assert (S < std::tuple_size_v<TupleT>);
|
|
using value_type = typename std::tuple_element<S,TupleT>::type;
|
|
|
|
func (util::type_tag<value_type> {});
|
|
|
|
if constexpr (S + 1 < std::tuple_size_v<TupleT>) {
|
|
each<TupleT,FunctorT,S+1> (std::forward<FunctorT> (func));
|
|
}
|
|
}
|
|
|
|
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
/// Statically map the member types of a tuple via F<>::type
|
|
///
|
|
/// TupleT: tuple type
|
|
/// FieldT: type mapping object, conversion uses FieldT<>::type
|
|
/// Indices: tuple indexing helper
|
|
template <
|
|
typename TupleT,
|
|
template <
|
|
typename
|
|
> class FieldT,
|
|
typename Indices = std::make_index_sequence<
|
|
std::tuple_size<TupleT>::value
|
|
>
|
|
>
|
|
struct map;
|
|
|
|
|
|
//-----------------------------------------------------------------------------
|
|
template <
|
|
typename TupleT,
|
|
template <
|
|
typename
|
|
> class FieldT,
|
|
size_t ...Indices
|
|
>
|
|
struct map<
|
|
TupleT,
|
|
FieldT,
|
|
std::index_sequence<Indices...>
|
|
> {
|
|
typedef std::tuple<
|
|
typename FieldT<
|
|
typename std::tuple_element<Indices, TupleT>::type
|
|
>::type...
|
|
> type;
|
|
};
|
|
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
/// query the index of the first occurrence of type `T' in the tuple-like
|
|
/// type `TupleT'.
|
|
///
|
|
/// if the query type does not occur in the tuple type a compiler error
|
|
/// should be generated.
|
|
template<
|
|
typename TupleT,
|
|
typename ValueT,
|
|
typename = std::make_index_sequence<
|
|
std::tuple_size_v<TupleT>
|
|
>
|
|
>
|
|
struct index { };
|
|
|
|
|
|
//-------------------------------------------------------------------------
|
|
// specialisation for tuples with matching first elements. the index is 0.
|
|
template<
|
|
typename ValueT,
|
|
typename ...TailT,
|
|
size_t ...Indices
|
|
>
|
|
struct index<
|
|
std::tuple<ValueT, TailT...>,
|
|
ValueT,
|
|
std::index_sequence<Indices...>
|
|
> {
|
|
static constexpr std::size_t value = 0;
|
|
};
|
|
|
|
|
|
//-------------------------------------------------------------------------
|
|
// specialisation for tuples with non-matching first elements.
|
|
// increment and recurse.
|
|
template<
|
|
typename ValueT,
|
|
typename HeadT,
|
|
typename ...TailT,
|
|
size_t ...Indices
|
|
>
|
|
struct index<
|
|
std::tuple<HeadT, TailT...>,
|
|
ValueT,
|
|
std::index_sequence<Indices...>
|
|
> {
|
|
static constexpr std::size_t value = 1u + index<std::tuple<TailT...>,ValueT>::value;
|
|
};
|
|
|
|
|
|
//-------------------------------------------------------------------------
|
|
// convert the tuple type (which is not a tuple or it would have matched
|
|
// the tuple specialisation, into the equivalent std::tuple and requery
|
|
// against that.
|
|
template <
|
|
typename TupleT,
|
|
typename ValueT,
|
|
size_t ...Indices
|
|
> struct index<
|
|
TupleT,
|
|
ValueT,
|
|
std::index_sequence<Indices...>
|
|
> {
|
|
static constexpr std::size_t value = index<
|
|
std::tuple<std::tuple_element_t<Indices,TupleT>...>,
|
|
ValueT,
|
|
std::index_sequence<Indices...>
|
|
>::value;
|
|
};
|
|
};
|
|
|
|
|
|
#endif
|