aka_arange_iterator.hh
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aka_arange_iterator.hh
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			/**
			* @file aka_arange_iterator.hh
			*
			* @author Nicolas Richart
			*
			* @date creation jeu déc 12 2019
			*
			* @brief implementation of arange
			*
			* @section LICENSE
			*
			* Copyright (©) 2010-2011 EPFL (Ecole Polytechnique Fédérale de Lausanne)
			* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
			*
			* Akantu 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 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. If not, see <http://www.gnu.org/licenses/>.
			*
			*/
			/* -------------------------------------------------------------------------- */
			#include <cstddef>
			#include <iterator>
			#include <utility>
			/* -------------------------------------------------------------------------- */

			#ifndef AKA_ARANGE_ITERATOR_HH
			#define AKA_ARANGE_ITERATOR_HH

			#ifndef AKANTU_ITERATORS_NAMESPACE
			#define AKANTU_ITERATORS_NAMESPACE akantu
			#endif

			namespace AKANTU_ITERATORS_NAMESPACE {

			namespace containers {

			template <class Iterator> class Range {
			public:
			using iterator = Iterator;
			// ugly trick
			using const_iterator = Iterator;

			explicit Range(Iterator && it1, Iterator && it2)
			: iterators(std::forward<Iterator>(it1), std::forward<Iterator>(it2)) {}

			decltype(auto) begin() const { return std::get<0>(iterators); }
			decltype(auto) begin() { return std::get<0>(iterators); }

			decltype(auto) end() const { return std::get<1>(iterators); }
			decltype(auto) end() { return std::get<1>(iterators); }

			private:
			std::tuple<Iterator, Iterator> iterators;
			};
			} // namespace containers

			template <class Iterator>
			decltype(auto) range(Iterator && it1, Iterator && it2) {
			return containers::Range<Iterator>(std::forward<Iterator>(it1),
			std::forward<Iterator>(it2));
			}
			/* -------------------------------------------------------------------------- */
			/* Arange */
			/* -------------------------------------------------------------------------- */
			namespace iterators {
			template <class T> class ArangeIterator {
			public:
			using value_type = T;
			using pointer = T *;
			using reference = T &;
			using difference_type = size_t;
			using iterator_category = std::forward_iterator_tag;

			constexpr ArangeIterator(T value, T step) : value(value), step(step) {}
			constexpr ArangeIterator(const ArangeIterator &) = default;

			constexpr ArangeIterator & operator++() {
			value += step;
			return *this;
			}

			constexpr T operator*() const { return value; }

			constexpr bool operator==(const ArangeIterator & other) const {
			return (value == other.value) and (step == other.step);
			}

			constexpr bool operator!=(const ArangeIterator & other) const {
			return not operator==(other);
			}

			private:
			T value{0};
			const T step{1};
			};
			} // namespace iterators

			namespace containers {
			template <class T> class ArangeContainer {
			public:
			using iterator = iterators::ArangeIterator<T>;
			using const_iterator = iterators::ArangeIterator<T>;

			constexpr ArangeContainer(T start, T stop, T step = 1)
			: start(start), stop((stop - start) % step == 0
			? stop
			: start + (1 + (stop - start) / step) * step),
			step(step) {}
			explicit constexpr ArangeContainer(T stop) : ArangeContainer(0, stop, 1) {}

			constexpr T operator[](std::size_t i) {
			T val = start + i * step;
			assert(val < stop && "i is out of range");
			return val;
			}

			constexpr T size() { return (stop - start) / step; }

			constexpr iterator begin() { return iterator(start, step); }
			constexpr iterator end() { return iterator(stop, step); }

			private:
			const T start{0}, stop{0}, step{1};
			};
			} // namespace containers

			template <class T,
			typename = std::enable_if_t<std::is_integral<std::decay_t<T>>::value>>
			inline decltype(auto) arange(const T & stop) {
			return containers::ArangeContainer<T>(stop);
			}

			template <class T1, class T2,
			typename = std::enable_if_t<
			std::is_integral<std::common_type_t<T1, T2>>::value>>
			inline constexpr decltype(auto) arange(const T1 & start, const T2 & stop) {
			return containers::ArangeContainer<std::common_type_t<T1, T2>>(start, stop);
			}

			template <class T1, class T2, class T3,
			typename = std::enable_if_t<
			std::is_integral<std::common_type_t<T1, T2, T3>>::value>>
			inline constexpr decltype(auto) arange(const T1 & start, const T2 & stop,
			const T3 & step) {
			return containers::ArangeContainer<std::common_type_t<T1, T2, T3>>(
			start, stop, step);
			}
			} // namespace AKANTU_ITERATORS_NAMESPACE

			namespace std {
			template <class T>
			struct iterator_traits<
			::AKANTU_ITERATORS_NAMESPACE::iterators::ArangeIterator<T>> {
			private:
			using iterator_type =
			typename ::AKANTU_ITERATORS_NAMESPACE::iterators::ArangeIterator<T>;

			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_ARANGE_ITERATOR_HH */

rAKA/include/iterators/aka_arange_iterator.hh3889358d690amaster

aka_arange_iterator.hhView Options

rAKA/include/iterators/aka_arange_iterator.hh
3889358d690amaster

aka_arange_iterator.hh
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