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aka_repeat_iterator.hh
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/**
* 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_iterator_tools.hh"
/* -------------------------------------------------------------------------- */
#include <cmath>
#include <utility>
/* -------------------------------------------------------------------------- */
#ifndef AKANTU_AKA_REPEAT_ITERATOR_HH
#define AKANTU_AKA_REPEAT_ITERATOR_HH
namespace AKANTU_ITERATORS_NAMESPACE {
namespace iterators AKA_ITERATOR_EXPORT_NAMESPACE {
template <class Iterator, typename N>
class RepeatNIterator
: public details::CopyAssignmentEnabler<
aka::conjunction<std::is_copy_assignable<Iterator>,
std::is_copy_constructible<Iterator>>::value>,
public details::MoveAssignmentEnabler<
aka::conjunction<std::is_move_assignable<Iterator>,
std::is_move_constructible<Iterator>>::value> {
private:
using it_traits = typename std::iterator_traits<Iterator>;
public:
using value_type = typename it_traits::value_type;
using difference_type = typename it_traits::difference_type;
using pointer = typename it_traits::pointer;
using reference = typename it_traits::reference;
using iterator_category = typename it_traits::iterator_category;
explicit RepeatNIterator(Iterator iterator, N n)
: iterator(std::move(iterator)), n(std::move(n)) {}
// input iterator ++it
auto operator++() -> RepeatNIterator & {
++i;
if (i == n) {
++iterator;
i = 0;
}
return *this;
}
// input iterator it++
auto operator++(int) -> RepeatNIterator {
auto cpy = *this;
this->operator++();
return cpy;
}
// input iterator it != other_it
auto operator!=(const RepeatNIterator & other) const -> bool {
return iterator != other.iterator or i != other.i;
}
// input iterator dereference *it
auto operator*() -> decltype(auto) { return *iterator; }
template <class iterator_category_ = iterator_category,
std::enable_if_t<aka::is_iterator_category_at_least<
iterator_category_,
std::bidirectional_iterator_tag>::value> * = nullptr>
auto operator--() -> RepeatNIterator & {
if (i == 0) {
--iterator;
i = n - 1;
} else {
--i;
}
return *this;
}
template <class iterator_category_ = iterator_category,
std::enable_if_t<aka::is_iterator_category_at_least<
iterator_category_,
std::bidirectional_iterator_tag>::value> * = nullptr>
auto operator--(int) -> RepeatNIterator {
auto cpy = *this;
this->operator--();
return cpy;
}
template <class iterator_category_ = iterator_category,
std::enable_if_t<aka::is_iterator_category_at_least<
iterator_category_,
std::random_access_iterator_tag>::value> * = nullptr>
auto operator-(const RepeatNIterator & other) const -> difference_type {
return (iterator - other.iterator) + (i - other.i);
}
// random iterator it[idx]
template <class iterator_category_ = iterator_category,
std::enable_if_t<aka::is_iterator_category_at_least<
iterator_category_,
std::random_access_iterator_tag>::value> * = nullptr>
auto operator[](const N & idx) -> decltype(auto) {
return iterator[(i + idx) / n];
}
// random iterator it + n
template <class iterator_category_ = iterator_category,
std::enable_if_t<aka::is_iterator_category_at_least<
iterator_category_,
std::random_access_iterator_tag>::value> * = nullptr>
auto operator+(const N & n_) const -> decltype(auto) {
auto it = RepeatNIterator(iterator + n_ / n, n);
it.i = (i + n_) % n;
return it;
}
// random iterator it - n
template <class iterator_category_ = iterator_category,
std::enable_if_t<aka::is_iterator_category_at_least<
iterator_category_,
std::random_access_iterator_tag>::value> * = nullptr>
auto operator-(const N & n_) const -> decltype(auto) {
auto it = RepeatNIterator(iterator + N(std::floor(double(-n_) / n)), n);
it.i = (i + n - n_) % n;
return it;
}
template <
class iterator_category_ = iterator_category,
std::enable_if_t<aka::is_iterator_category_at_least<
iterator_category_, std::forward_iterator_tag>::value> * = nullptr>
auto operator==(const RepeatNIterator & other) const -> bool {
return not this->operator!=(other);
}
private:
Iterator iterator;
const N n;
N i{0};
};
template <class Iterator, typename N>
inline constexpr auto repeat_n(Iterator && iterator, N n) -> decltype(auto) {
return RepeatNIterator<Iterator, N>(std::forward<Iterator>(iterator),
std::move(n));
}
} // namespace AKA_ITERATOR_EXPORT_NAMESPACE
namespace containers AKA_ITERATOR_EXPORT_NAMESPACE {
template <class Container, typename N> class RepeatNContainer {
public:
using size_type = typename std::decay_t<Container>::size_type;
explicit RepeatNContainer(Container && container, N n)
: container(std::forward<Container>(container)), n(std::move(n)) {}
auto begin() -> decltype(auto) {
return iterators::repeat_n(container.begin(), n);
}
auto begin() const -> decltype(auto) {
return iterators::repeat_n(container.begin(), n);
}
auto end() -> decltype(auto) {
return iterators::repeat_n(container.end(), n);
}
auto end() const -> decltype(auto) {
return iterators::repeat_n(container.end(), n);
}
private:
Container container;
N n;
};
} // namespace AKA_ITERATOR_EXPORT_NAMESPACE
template <class Container, typename N>
inline constexpr auto repeat_n(Container && container, N n) -> decltype(auto) {
return containers::RepeatNContainer<Container, N>(
std::forward<Container>(container), std::move(n));
}
} // namespace AKANTU_ITERATORS_NAMESPACE
namespace std {
template <class Iterator, typename N>
struct iterator_traits<
::AKANTU_ITERATORS_NAMESPACE::iterators::RepeatNIterator<Iterator, N>> {
private:
using iterator_type =
typename ::AKANTU_ITERATORS_NAMESPACE::iterators::RepeatNIterator<
Iterator, N>;
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 /* AKANTU_AKA_REPEAT_ITERATOR_HH */

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