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347 | #pragma once
#include <concepts><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <ranges><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include "internal/ranges.hpp"
#include "numeric/arithmetic.hpp"
namespace uni {
namespace internal {
template<class View>
concept slide_caches_nothing = std::ranges::random_access_range<View> && std::ranges::sized_range<View>;
template<class View>
concept slide_caches_last = !slide_caches_nothing<View> && std::ranges::bidirectional_range<View> && std::ranges::common_range<View>;
template<class View>
concept slide_caches_first = !slide_caches_nothing<View> && !slide_caches_last<View>;
} // namespace internal
template<std::ranges::forward_range View>
requires std::ranges::view<View>
struct slide_view : std::ranges::view_interface<slide_view<View>> {
private:
View _base;
std::ranges::range_difference_t<View> _n;
[[no_unique_address]] internal::maybe_present_t<internal::slide_caches_first<View>, internal::cached_position<View>, 0> _cache_begin;
[[no_unique_address]] internal::maybe_present_t<internal::slide_caches_last<View>, internal::cached_position<View>, 1> _cache_end;
template<bool> struct iterator;
struct sentinel;
public:
constexpr explicit slide_view(View base, std::ranges::range_difference_t<View> n)
: _base(std::move(base)), _n(n)
{
assert(n > 0);
}
constexpr auto begin()
requires(!(internal::simple_view<View> && internal::slide_caches_nothing<const View>))
{
if constexpr(internal::slide_caches_first<View>) {
std::ranges::iterator_t<View> itr;
if(this->_cache_begin.has_value()) {
itr = this->_cache_begin.get(this->_base);
}
else {
itr = std::ranges::next(std::ranges::begin(this->_base), this->_n - 1, std::ranges::end(this->_base));
this->_cache_begin.set(this->_base, itr);
}
return iterator<false>(std::ranges::begin(this->_base), std::move(itr), this->_n);
}
else {
return iterator<false>(std::ranges::begin(this->_base), this->_n);
}
}
constexpr auto begin() const
requires internal::slide_caches_nothing<const View>
{
return iterator<true>(std::ranges::begin(this->_base), this->_n);
}
constexpr auto end()
requires (!(internal::simple_view<View> && internal::slide_caches_nothing<const View>))
{
if constexpr(internal::slide_caches_nothing<View>) {
return iterator<false>(std::ranges::begin(this->_base) + std::ranges::range_difference_t<View>(this->size()), this->_n);
}
else if constexpr(internal::slide_caches_last<View>) {
std::ranges::iterator_t<View> itr;
if(this->_cache_end.has_value()) {
itr = this->_cache_end.get(this->_base);
}
else {
itr = std::ranges::prev(std::ranges::end(this->_base), this->_n - 1, std::ranges::begin(this->_base));
this->_cache_end.set(this->_base, itr);
}
return iterator<false>(std::move(itr), this->_n);
}
else if constexpr(std::ranges::common_range<View>) {
return iterator<false>(std::ranges::end(this->_base), std::ranges::end(this->_base), this->_n);
}
else {
return sentinel(std::ranges::end(this->_base));
}
}
constexpr auto end() const
requires internal::slide_caches_nothing<const View>
{
return this->begin() + std::ranges::range_difference_t<const View>(this->size());
}
constexpr auto size()
requires std::ranges::sized_range<View>
{
auto size = std::ranges::distance(this->_base) - this->_n + 1;
if(size < 0) size = 0;
return to_unsigned(size);
}
constexpr auto size() const
requires std::ranges::sized_range<const View>
{
auto size = std::ranges::distance(this->_base) - this->_n + 1;
if(size < 0) size = 0;
return to_unsigned(size);
}
};
template<class Range>
slide_view(Range &&, std::ranges::range_difference_t<Range>) -> slide_view<std::views::all_t<Range>>;
template<std::ranges::forward_range View>
requires std::ranges::view<View>
template<bool CONST>
struct slide_view<View>::iterator {
private:
using Base = internal::maybe_const_t<CONST, View>;
static constexpr bool LAST_PRESENT = internal::slide_caches_first<Base>;
std::ranges::iterator_t<Base> _current = std::ranges::iterator_t<Base>();
[[no_unique_address]] internal::maybe_present_t<LAST_PRESENT, std::ranges::iterator_t<Base>> _last = decltype(_last)();
std::ranges::range_difference_t<Base> _n = 0;
constexpr iterator(std::ranges::iterator_t<Base> current, std::ranges::range_difference_t<Base> n)
requires (!LAST_PRESENT)
: _current(current), _n(n)
{}
constexpr iterator(std::ranges::iterator_t<Base> current, std::ranges::iterator_t<Base> last, std::ranges::range_difference_t<Base> n)
requires (LAST_PRESENT)
: _current(current), _last(last), _n(n)
{}
friend slide_view;
friend slide_view::sentinel;
public:
using iterator_category = std::input_iterator_tag;
using iterator_concept = internal::most_primitive_iterator_concept<false, Base>;
using value_type = decltype(std::views::counted(_current, _n));
using difference_type = std::ranges::range_difference_t<Base>;
iterator() = default;
constexpr iterator(iterator<!CONST> itr)
requires CONST && std::convertible_to<std::ranges::iterator_t<View>, std::ranges::iterator_t<Base>>
: _current(std::move(itr._current)), _n(itr._n)
{}
constexpr auto operator*() const {
return std::views::counted(_current, _n);
}
constexpr iterator &operator++() {
++this->_current;
if constexpr(LAST_PRESENT) ++this->_last;
return *this;
}
constexpr iterator operator++(int) {
const auto temp = *this;
return ++*this, temp;
}
constexpr iterator &operator--()
requires std::ranges::bidirectional_range<Base>
{
--this->_current;
if constexpr(LAST_PRESENT) --this->_last;
return *this;
}
constexpr iterator operator--(int)
requires std::ranges::bidirectional_range<Base>
{
auto temp = *this;
return --*this, temp;
}
constexpr iterator &operator+=(const difference_type rhs)
requires std::ranges::random_access_range<Base>
{
this->_current += rhs;
if constexpr(LAST_PRESENT) this->_last += rhs;
return *this;
}
constexpr iterator &operator-=(const difference_type rhs)
requires std::ranges::random_access_range<Base>
{
this->_current -= rhs;
if constexpr(LAST_PRESENT) this->_last -= rhs;
return *this;
}
constexpr auto operator[](const difference_type count) const
requires std::ranges::random_access_range<Base>
{
return std::views::counted(this->_current + count, this->_n);
}
friend constexpr bool operator==(const iterator &lhs, const iterator &rhs) {
if constexpr(LAST_PRESENT) return lhs._last == rhs._last;
else return lhs._current == rhs._current;
}
friend constexpr auto operator<=>(const iterator &lhs, const iterator &rhs)
requires std::ranges::random_access_range<Base> && std::three_way_comparable<std::ranges::iterator_t<Base>>
{
return lhs._current <=> rhs._current;
}
friend constexpr iterator operator+(iterator itr, const difference_type count)
requires std::ranges::random_access_range<Base>
{
auto res = itr;
return res += count, res;
}
friend constexpr iterator operator+(const difference_type count, const iterator &itr)
requires std::ranges::random_access_range<Base>
{
auto res = itr;
return res += count, res;
}
friend constexpr iterator operator-(const iterator &itr, difference_type count)
requires std::ranges::random_access_range<Base>
{
auto res = itr;
return res -= count, res;
}
friend constexpr difference_type operator-(const iterator &lhs, const iterator &rhs)
requires std::sized_sentinel_for<std::ranges::iterator_t<Base>, std::ranges::iterator_t<Base>>
{
if constexpr(LAST_PRESENT) return lhs._last - rhs._last;
else return lhs._current - rhs._current;
}
};
template<std::ranges::forward_range View>
requires std::ranges::view<View>
struct slide_view<View>::sentinel {
private:
std::ranges::sentinel_t<View> _end = std::ranges::sentinel_t<View>();
constexpr explicit sentinel(std::ranges::sentinel_t<View> end) : _end(end) {}
friend slide_view;
public:
sentinel() = default;
friend constexpr bool operator==(const iterator<false> &lhs, const sentinel &rhs) {
return lhs._last == rhs._end;
}
friend constexpr std::ranges::range_difference_t<View>
operator-(const iterator<false> &lhs, const sentinel &rhs)
requires std::sized_sentinel_for<std::ranges::sentinel_t<View>, std::ranges::iterator_t<View>>
{
return lhs._last - rhs._end;
}
friend constexpr std::ranges::range_difference_t<View>
operator-(const sentinel &rhs, const iterator<false> &lhs)
requires std::sized_sentinel_for<std::ranges::sentinel_t<View>, std::ranges::iterator_t<View>>
{
return rhs._end - lhs._last;
}
};
namespace views {
namespace internal {
template<class Range, class Diff>
concept can_slide_view = requires { slide_view(std::declval<Range>(), std::declval<Diff>()); };
} // namespace internal
struct Slide : adaptor::range_adaptor<Slide> {
template<std::ranges::viewable_range Range, class Diff = std::ranges::range_difference_t<Range>>
requires internal::can_slide_view<Range, Diff>
constexpr auto operator() [[nodiscard]] (Range &&res, std::type_identity_t<Diff> n) const {
return slide_view(std::forward<Range>(res), n);
}
using adaptor::range_adaptor<Slide>::operator();
static constexpr int arity = 2;
static constexpr bool has_simple_extra_args = true;
};
inline constexpr Slide slide;
} // namespace views
} // namespace uni
namespace std::ranges {
template<class View>
inline constexpr bool enable_borrowed_range<uni::slide_view<View>> = enable_borrowed_range<View>;
}
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