mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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262 lines
8.9 KiB
C++
262 lines
8.9 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2013 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_ITERATOR_STEP_ITERATOR_HPP
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#define SPROUT_ITERATOR_STEP_ITERATOR_HPP
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#include <iterator>
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#include <utility>
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#include <sprout/config.hpp>
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#include <sprout/iterator/next.hpp>
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#include <sprout/iterator/prev.hpp>
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#include <sprout/iterator/distance.hpp>
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#include <sprout/utility/swap.hpp>
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#include HDR_ALGORITHM_MIN_MAX_SSCRISK_CEL_OR_SPROUT
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namespace sprout {
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//
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// step_iterator
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//
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template<typename Iterator>
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class step_iterator
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: public std::iterator<
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typename std::iterator_traits<Iterator>::iterator_category,
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typename std::iterator_traits<Iterator>::value_type,
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typename std::iterator_traits<Iterator>::difference_type,
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typename std::iterator_traits<Iterator>::pointer,
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typename std::iterator_traits<Iterator>::reference
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>
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{
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public:
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typedef Iterator iterator_type;
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typedef typename std::iterator_traits<iterator_type>::iterator_category iterator_category;
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typedef typename std::iterator_traits<iterator_type>::value_type value_type;
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typedef typename std::iterator_traits<iterator_type>::difference_type difference_type;
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typedef typename std::iterator_traits<iterator_type>::pointer pointer;
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typedef typename std::iterator_traits<iterator_type>::reference reference;
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private:
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static SPROUT_CONSTEXPR iterator_type get_back(iterator_type it, difference_type wid, iterator_type last) {
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return sprout::next(it, (sprout::distance(it, last) - 1) / wid * wid);
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}
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static SPROUT_CONSTEXPR difference_type next_distance(step_iterator const& it, difference_type n) {
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return n >= 0 ? NS_SSCRISK_CEL_OR_SPROUT::min(sprout::distance(it.current, it.back), n * it.wid)
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: it.is_last ? 0
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: NS_SSCRISK_CEL_OR_SPROUT::max(-sprout::distance(it.current, it.back), n * it.wid)
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;
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}
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protected:
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iterator_type current;
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iterator_type last;
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difference_type wid;
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private:
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iterator_type back;
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bool is_last;
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private:
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SPROUT_CONSTEXPR step_iterator(step_iterator const& other, difference_type n)
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: current(sprout::next(other.current, next_distance(other, n))), last(other.last), wid(other.wid)
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, back(other.back), is_last(next_distance(other, n) == 0)
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{}
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public:
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SPROUT_CONSTEXPR step_iterator()
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: current(), last(), wid(1)
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, back(), is_last()
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{}
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SPROUT_CONSTEXPR step_iterator(step_iterator const& other)
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: current(other.current), last(other.last), wid(other.wid)
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, back(other.back), is_last(other.is_last)
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{}
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explicit SPROUT_CONSTEXPR step_iterator(iterator_type it, difference_type wid = 1, iterator_type last = iterator_type())
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: current(it), last(last), wid(wid)
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, back(get_back(it, wid, last)), is_last(it == last)
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{}
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template<typename U>
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SPROUT_CONSTEXPR step_iterator(step_iterator<U> const& it)
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: current(it.base()), last(it.end()), wid(it.width())
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, back(get_back(it.base(), it.width(), it.end())), is_last(it.is_end())
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{}
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template<typename U>
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SPROUT_CXX14_CONSTEXPR step_iterator& operator=(step_iterator<U> const& it) {
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step_iterator temp(it);
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temp.swap(*this);
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return *this;
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}
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SPROUT_CONSTEXPR iterator_type base() const {
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return current;
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}
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SPROUT_CONSTEXPR difference_type width() const {
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return wid;
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}
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SPROUT_CONSTEXPR iterator_type end() const {
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return last;
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}
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SPROUT_CONSTEXPR bool is_end() const {
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return is_last;
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}
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SPROUT_CONSTEXPR reference operator*() const {
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return *current;
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}
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SPROUT_CONSTEXPR pointer operator->() const {
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return &*current;
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}
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SPROUT_CXX14_CONSTEXPR step_iterator& operator++() {
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if (current == back) {
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is_last = true;
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}
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current += next_distance(*this, 1);
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return *this;
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}
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SPROUT_CXX14_CONSTEXPR step_iterator operator++(int) {
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step_iterator result(*this);
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if (current == back) {
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is_last = true;
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}
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current += next_distance(*this, 1);
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return result;
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}
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SPROUT_CXX14_CONSTEXPR step_iterator& operator--() {
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current += next_distance(*this, -1);
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if (current != back) {
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is_last = false;
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}
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return *this;
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}
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SPROUT_CXX14_CONSTEXPR step_iterator operator--(int) {
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step_iterator temp(*this);
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current += next_distance(*this, -1);
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if (current != back) {
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is_last = false;
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}
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return temp;
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}
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SPROUT_CONSTEXPR step_iterator operator+(difference_type n) const {
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return step_iterator(*this, n);
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}
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SPROUT_CONSTEXPR step_iterator operator-(difference_type n) const {
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return step_iterator(*this, -n);
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}
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SPROUT_CXX14_CONSTEXPR step_iterator& operator+=(difference_type n) {
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step_iterator temp(*this, n);
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temp.swap(*this);
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return *this;
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}
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SPROUT_CXX14_CONSTEXPR step_iterator& operator-=(difference_type n) {
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step_iterator temp(*this, -n);
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temp.swap(*this);
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return *this;
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}
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SPROUT_CONSTEXPR reference operator[](difference_type n) const {
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return *(current + n * wid);
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}
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SPROUT_CONSTEXPR step_iterator next() const {
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return step_iterator(*this, 1);
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}
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SPROUT_CONSTEXPR step_iterator prev() const {
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return step_iterator(*this, -1);
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}
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SPROUT_CXX14_CONSTEXPR void swap(step_iterator& other)
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SPROUT_NOEXCEPT_EXPR(
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SPROUT_NOEXCEPT_EXPR(swap(current, other.current))
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&& SPROUT_NOEXCEPT_EXPR(swap(last, other.last))
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&& SPROUT_NOEXCEPT_EXPR(swap(wid, other.wid))
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&& SPROUT_NOEXCEPT_EXPR(swap(back, other.back))
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&& SPROUT_NOEXCEPT_EXPR(swap(wid, other.wid))
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&& SPROUT_NOEXCEPT_EXPR(swap(is_last, other.is_last))
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)
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{
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swap(current, other.current);
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swap(last, other.last);
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swap(wid, other.wid);
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swap(back, other.back);
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swap(is_last, other.is_last);
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}
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};
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template<typename Iterator1, typename Iterator2>
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inline SPROUT_CONSTEXPR bool
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operator==(sprout::step_iterator<Iterator1> const& lhs, sprout::step_iterator<Iterator2> const& rhs) {
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return lhs.base() == rhs.base() && lhs.is_end() == rhs.is_end();
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}
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template<typename Iterator1, typename Iterator2>
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inline SPROUT_CONSTEXPR bool
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operator!=(sprout::step_iterator<Iterator1> const& lhs, sprout::step_iterator<Iterator2> const& rhs) {
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return !(lhs == rhs);
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}
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template<typename Iterator1, typename Iterator2>
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inline SPROUT_CONSTEXPR bool
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operator<(sprout::step_iterator<Iterator1> const& lhs, sprout::step_iterator<Iterator2> const& rhs) {
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return lhs.base() < rhs.base() || (lhs.base() == rhs.base() && !lhs.is_end() && rhs.is_end());
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}
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template<typename Iterator1, typename Iterator2>
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inline SPROUT_CONSTEXPR bool
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operator>(sprout::step_iterator<Iterator1> const& lhs, sprout::step_iterator<Iterator2> const& rhs) {
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return rhs < lhs;
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}
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template<typename Iterator1, typename Iterator2>
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inline SPROUT_CONSTEXPR bool
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operator<=(sprout::step_iterator<Iterator1> const& lhs, sprout::step_iterator<Iterator2> const& rhs) {
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return !(rhs < lhs);
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}
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template<typename Iterator1, typename Iterator2>
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inline SPROUT_CONSTEXPR bool
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operator>=(sprout::step_iterator<Iterator1> const& lhs, sprout::step_iterator<Iterator2> const& rhs) {
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return !(lhs < rhs);
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}
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template<typename Iterator1, typename Iterator2>
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inline SPROUT_CONSTEXPR decltype(std::declval<Iterator1>() - std::declval<Iterator2>())
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operator-(sprout::step_iterator<Iterator1> const& lhs, sprout::step_iterator<Iterator2> const& rhs) {
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return (lhs.base() - rhs.base()) / lhs.width() + (lhs.is_end() ? 1 : 0) - (rhs.is_end() ? 1 : 0);
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}
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template<typename Iterator>
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inline SPROUT_CONSTEXPR sprout::step_iterator<Iterator>
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operator+(
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typename sprout::step_iterator<Iterator>::difference_type n,
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sprout::step_iterator<Iterator> const& it
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)
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{
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return it + n;
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}
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//
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// make_step_iterator
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//
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template<typename Iterator>
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inline SPROUT_CONSTEXPR sprout::step_iterator<Iterator>
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make_step_iterator(Iterator it, typename sprout::step_iterator<Iterator>::difference_type wid = 1) {
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return sprout::step_iterator<Iterator>(it, wid);
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}
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//
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// swap
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//
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template<typename Iterator>
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inline SPROUT_CXX14_CONSTEXPR void
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swap(sprout::step_iterator<Iterator>& lhs, sprout::step_iterator<Iterator>& rhs)
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SPROUT_NOEXCEPT_EXPR(SPROUT_NOEXCEPT_EXPR(lhs.swap(rhs)))
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{
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lhs.swap(rhs);
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}
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//
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// iterator_next
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//
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template<typename Iterator>
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inline SPROUT_CONSTEXPR sprout::step_iterator<Iterator>
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iterator_next(sprout::step_iterator<Iterator> const& it) {
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return it.next();
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}
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//
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// iterator_prev
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//
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template<typename Iterator>
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inline SPROUT_CONSTEXPR sprout::step_iterator<Iterator>
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iterator_prev(sprout::step_iterator<Iterator> const& it) {
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return it.prev();
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_ITERATOR_STEP_ITERATOR_HPP
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