121 lines
2.9 KiB
C++
121 lines
2.9 KiB
C++
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/// @file dpf/zip_iterable.hpp
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/// @brief defines the `dpf::zip_itrable` class and associated helpers
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/// @details
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/// @author Ryan Henry <ryan.henry@ucalgary.ca>
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/// @copyright Copyright (c) 2019-2024 Ryan Henry and [others](@ref authors)
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/// @license Released under a GNU General Public v2.0 (GPLv2) license;
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/// see [LICENSE.md](@ref license) for details.
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#ifndef LIBDPF_INCLUDE_DPF_ZIP_ITERABLE_HPP__
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#define LIBDPF_INCLUDE_DPF_ZIP_ITERABLE_HPP__
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#include <tuple>
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#include <iterator>
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#include "hedley/hedley.h"
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namespace dpf
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{
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template <typename ...Iterables> struct zip_iterator;
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template <typename ...Iterables>
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struct zip_iterable
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{
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using value_type = std::tuple<typename Iterables::iterator...>;
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using iterator = zip_iterator<Iterables...>;
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zip_iterable(value_type && begin, value_type && end)
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: begin_{begin}, end_{end} { }
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auto begin()
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{
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return iterator{begin_};
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}
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auto begin() const
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{
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return iterator{begin_};
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}
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auto cbegin() const
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{
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return begin();
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}
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auto end()
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{
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return iterator{end_};
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}
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auto end() const
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{
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return iterator{end_};
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}
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auto cend() const
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{
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return end();
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}
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value_type begin_, end_;
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};
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template <typename ...Iterables>
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struct zip_iterator
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{
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using value_type = std::tuple<typename Iterables::iterator...>;
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auto operator*() const
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{
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return std::apply([](auto && ...its){ return std::make_tuple(*its...); }, wrapped_iterators);
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}
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zip_iterator & operator++()
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{
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std::apply([](auto && ...its){ (++its, ...); }, wrapped_iterators);
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return *this;
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}
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zip_iterator operator++(int)
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{
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zip_iterator old = *this;
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++(*this);
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return old;
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}
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zip_iterator & operator--()
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{
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std::apply([](auto && ...its){ (--its, ...); }, wrapped_iterators);
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return *this;
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}
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zip_iterator operator--(int)
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{
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zip_iterator old = *this;
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--(*this);
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return old;
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}
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bool operator==(const zip_iterator & rhs) const
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{
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return wrapped_iterators == rhs.wrapped_iterators;
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}
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bool operator!=(const zip_iterator & rhs) const
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{
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return wrapped_iterators != rhs.wrapped_iterators;
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}
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value_type wrapped_iterators;
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};
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template <typename ...Iterables>
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HEDLEY_ALWAYS_INLINE
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zip_iterable<Iterables...> tuple_as_zip(std::tuple<Iterables...> & tup) noexcept
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{
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return zip_iterable<Iterables...>(
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std::apply([](auto && ...elements){ return std::make_tuple(std::begin(elements)...); }, tup),
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std::apply([](auto && ...elements){ return std::make_tuple(std::end(elements)...); }, tup));
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}
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template <typename TupleT,
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typename UnaryFunction>
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HEDLEY_ALWAYS_INLINE
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void for_each_in_zip(TupleT && tuple, UnaryFunction f)
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{
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for (auto i : tuple_as_zip(tuple)) f(i);
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}
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} // namespace dpf
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#endif // LIBDPF_INCLUDE_DPF_ZIP_ITERABLE_HPP__
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