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rAKA/include/iterators/aka_enumerate_iterator.hh
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aka_enumerate_iterator.hh
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/**
* @file aka_enumerate_iterator.hh
*
* @author Nicolas Richart
*
* @date creation jeu déc 12 2019
*
* @brief implementation of enumerate.
*
* @section LICENSE
*
* Copyright (©) 2010-2011 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* akantu-iterators is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or (at your
* option) any later version.
*
* akantu-iterators 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with akantu-iterators. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "iterators/aka_zip_iterator.hh"
/* -------------------------------------------------------------------------- */
#include <iterator>
#include <utility>
/* -------------------------------------------------------------------------- */
#ifndef AKA_ENUMERATE_ITERATOR_HH
#define AKA_ENUMERATE_ITERATOR_HH
#ifndef AKANTU_ITERATORS_NAMESPACE
#define AKANTU_ITERATORS_NAMESPACE akantu
#endif
namespace AKANTU_ITERATORS_NAMESPACE {
/* -------------------------------------------------------------------------- */
namespace iterators {
template <class Iterator> class EnumerateIterator {
public:
using value_type =
std::tuple<std::size_t,
typename std::iterator_traits<Iterator>::value_type>;
using difference_type = std::size_t;
using pointer =
std::tuple<std::size_t,
typename std::iterator_traits<Iterator>::pointer>;
using reference =
std::tuple<std::size_t,
typename std::iterator_traits<Iterator>::reference>;
using iterator_category = std::input_iterator_tag;
public:
explicit EnumerateIterator(Iterator && iterator) : iterator(iterator) {}
// input iterator ++it
EnumerateIterator & operator++() {
++iterator;
++index;
return *this;
}
// input iterator it++
EnumerateIterator operator++(int) {
auto cpy = *this;
this->operator++();
return cpy;
}
// input iterator it != other_it
bool operator!=(const EnumerateIterator & other) const {
return iterator != other.iterator;
}
// input iterator dereference *it
decltype(auto) operator*() {
return std::tuple_cat(std::make_tuple(index), *iterator);
}
bool operator==(const EnumerateIterator & other) const {
return not this->operator!=(other);
}
private:
Iterator iterator;
size_t index{0};
};
template <class Iterator>
inline constexpr decltype(auto) enumerate(Iterator && iterator) {
return EnumerateIterator<Iterator>(std::forward<Iterator>(iterator));
}
} // namespace iterators
namespace containers {
template <class... Containers> class EnumerateContainer {
public:
explicit EnumerateContainer(Containers &&... containers)
: zip_container(std::forward<Containers>(containers)...) {}
decltype(auto) begin() {
return iterators::enumerate(zip_container.begin());
}
decltype(auto) begin() const {
return iterators::enumerate(zip_container.begin());
}
decltype(auto) end() { return iterators::enumerate(zip_container.end()); }
decltype(auto) end() const {
return iterators::enumerate(zip_container.end());
}
private:
ZipContainer<Containers...> zip_container;
};
} // namespace containers
template <class... Container>
inline constexpr decltype(auto) enumerate(Container &&... container) {
return containers::EnumerateContainer<Container...>(
std::forward<Container>(container)...);
}
} // namespace AKANTU_ITERATORS_NAMESPACE
namespace std {
template <class Iterator>
struct iterator_traits<
::AKANTU_ITERATORS_NAMESPACE::iterators::EnumerateIterator<Iterator>> {
private:
using iterator_type =
typename ::AKANTU_ITERATORS_NAMESPACE::iterators::EnumerateIterator<
Iterator>;
public:
using iterator_category = typename iterator_type::iterator_category;
using value_type = typename iterator_type::value_type;
using difference_type = typename iterator_type::difference_type;
using pointer = typename iterator_type::pointer;
using reference = typename iterator_type::reference;
};
} // namespace std
#endif /* AKA_ENUMERATE_ITERATOR_HH */
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