1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329 | #pragma once
#include <cassert><--- 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 <concepts><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <tuple><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <iterator><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include "internal/dev_env.hpp"
#include "internal/ranges.hpp"
#include "internal/type_traits.hpp"
#include "utility/functional.hpp"
#include "numeric/arithmetic.hpp"
namespace uni {
template<std::ranges::input_range View>
requires std::ranges::view<View>
struct stride_view : std::ranges::view_interface<stride_view<View>> {
private:
View _base;
std::ranges::range_difference_t<View> _stride;
template<bool Const> using Base = internal::maybe_const_t<Const, View>;
template<bool Const> struct iterator_tag {};
template<bool Const>
requires std::ranges::forward_range<Base<Const>>
struct iterator_tag<Const> {
private:
static constexpr auto _iterator_category() noexcept {
using category = typename std::iterator_traits<std::ranges::iterator_t<Base<Const>>>::iterator_category;
if constexpr(std::derived_from<category, std::random_access_iterator_tag>)
return std::random_access_iterator_tag{};
else
return category{};
}
public:
using iterator_category = decltype(_iterator_category());
};
public:
template<bool> class iterator;
constexpr explicit stride_view(View base, const std::ranges::range_difference_t<View> stride) noexcept(NO_EXCEPT)
: _base(std::move(base)), _stride(stride) { assert(stride > 0); }
inline constexpr View base() const & noexcept(NO_EXCEPT) requires std::copy_constructible<View>
{
return this->_base;
}
inline constexpr View base() && noexcept(NO_EXCEPT) { return std::move(this->_base); }
inline constexpr std::ranges::range_difference_t<View> stride() const noexcept {
return this->_stride;
}
inline constexpr auto begin() noexcept(NO_EXCEPT)
requires(!internal::simple_view<View>)
{
return iterator<false>(this, std::ranges::begin(this->_base));
}
inline constexpr auto begin() const noexcept(NO_EXCEPT)
requires std::ranges::range<const View>
{
return iterator<true>(this, std::ranges::begin(this->_base));
}
inline constexpr auto end() noexcept(NO_EXCEPT)
requires(!internal::simple_view<View>)
{
if constexpr(std::ranges::common_range<View> && std::ranges::sized_range<View> &&
std::ranges::forward_range<View>) {
const auto missing = (this->_stride - std::ranges::distance(this->_base) % this->_stride) % this->_stride;
return iterator<false>(this, std::ranges::end(this->_base), missing);
} else if constexpr(std::ranges::common_range<View> && !std::ranges::bidirectional_range<View>)
return iterator<false>(this, std::ranges::end(this->_base));
else
return std::default_sentinel;
}
inline constexpr auto end() const noexcept(NO_EXCEPT)
requires std::ranges::range<const View>
{
if constexpr(std::ranges::common_range<const View> && std::ranges::sized_range<const View> && std::ranges::forward_range<const View>)
{
const auto missing = (this->_stride - std::ranges::distance(this->_base) % this->_stride) % this->_stride;
return iterator<true>(this, std::ranges::end(this->_base), missing);
}
else if constexpr(std::ranges::common_range<const View> && !std::ranges::bidirectional_range<const View>)
return iterator<true>(this, std::ranges::end(this->_base));
else
return std::default_sentinel;
}
inline constexpr auto size() noexcept(NO_EXCEPT)
requires std::ranges::sized_range<View>
{
return to_unsigned(div_ceil(std::ranges::distance(this->_base), this->_stride));
}
inline constexpr auto size() const noexcept(NO_EXCEPT)
requires std::ranges::sized_range<const View>
{
return to_unsigned(div_ceil(std::ranges::distance(this->_base), this->_stride));
}
};
template<class Range>
stride_view(Range&& , std::ranges::range_difference_t<Range>) -> stride_view<std::views::all_t<Range>>;
template<std::ranges::input_range View>
requires std::ranges::view<View>
template<bool Const>
struct stride_view<View>::iterator : iterator_tag<Const> {
private:
using Parent = internal::maybe_const_t<Const, stride_view>;
using Base = stride_view::Base<Const>;
std::ranges::iterator_t<Base> _current = std::ranges::iterator_t<Base>();
std::ranges::sentinel_t<Base> _end = std::ranges::sentinel_t<Base>();
std::ranges::range_difference_t<Base> _stride = 0;
std::ranges::range_difference_t<Base> _missing = 0;
constexpr iterator(Parent *const parent, const std::ranges::iterator_t<Base> current, const std::ranges::range_difference_t<Base> missing = 0) noexcept(NO_EXCEPT)
: _current(std::move(current)), _end(std::ranges::end(parent->_base)), _stride(parent->_stride), _missing(missing)
{}
friend stride_view;
public:
using difference_type = std::ranges::range_difference_t<Base>;
using value_type = std::ranges::range_value_t<Base>;
using iterator_concept = typename internal::iterator_concept<Base>;
iterator() noexcept(NO_EXCEPT) requires std::default_initializable<std::ranges::iterator_t<Base>> = default;
constexpr iterator(iterator<!Const> itr) noexcept(NO_EXCEPT)
requires
Const && std::convertible_to<std::ranges::iterator_t<View>, std::ranges::iterator_t<Base>> &&
std::convertible_to<std::ranges::sentinel_t<View>, std::ranges::sentinel_t<Base>>
: _current(std::move(itr._current)), _end(std::move(itr._end)), _stride(itr._stride), _missing(itr._missing)
{}
inline constexpr std::ranges::iterator_t<Base> base() && noexcept(NO_EXCEPT) { return std::move(this->_current); }
inline constexpr const std::ranges::iterator_t<Base>& base() const & noexcept {
return this->_current;
}
inline constexpr decltype(auto) operator*() const noexcept(NO_EXCEPT)
{
return *this->_current;
}
inline constexpr iterator& operator++() noexcept(NO_EXCEPT)
{
assert(this->_current != _end);
this->_missing = std::ranges::advance(this->_current, this->_stride, this->_end);
return *this;
}
inline constexpr void operator++(int) noexcept(NO_EXCEPT) { ++*this; }
inline constexpr iterator operator++(int) noexcept(NO_EXCEPT)
requires std::ranges::forward_range<Base>
{
const auto res = *this; ++*this; return res;
}
inline constexpr iterator& operator--() noexcept(NO_EXCEPT)
requires std::ranges::bidirectional_range<Base>
{
std::ranges::advance(this->_current, this->_missing - this->_stride);
this->_missing = 0;
return *this;
}
inline constexpr iterator operator--(int) noexcept(NO_EXCEPT)
requires std::ranges::bidirectional_range<Base>
{
const auto res = *this; --*this; return res;
}
inline constexpr iterator& operator+=(const difference_type diff) noexcept(NO_EXCEPT)
requires std::ranges::random_access_range<Base>
{
if(diff > 0) {
assert(std::ranges::distance(this->_current, this->_end) > this->_stride * (diff - 1));
this->_missing = std::ranges::advance(this->_current, this->_stride * diff, this->_end);
}
if(diff < 0) {
std::ranges::advance(this->_current, this->_stride * diff + this->_missing);
this->_missing = 0;
}
return *this;
}
inline constexpr iterator& operator-=(const difference_type diff) noexcept(NO_EXCEPT)
requires std::ranges::random_access_range<Base>
{
return *this += -diff;
}
inline constexpr decltype(auto) operator[](const difference_type diff) const noexcept(NO_EXCEPT)
requires std::ranges::random_access_range<Base>
{
return *(*this + diff);
}
friend inline constexpr bool operator==(const iterator& lhs, std::default_sentinel_t) noexcept(NO_EXCEPT)
{
return lhs._current == lhs._end;
}
friend inline constexpr bool operator==(const iterator& lhs, const iterator& rhs) noexcept(NO_EXCEPT)
requires std::equality_comparable<std::ranges::iterator_t<Base>>
{
return lhs._current == rhs._current;
}
friend inline constexpr auto operator<=>(const iterator& lhs, const iterator& rhs) noexcept(NO_EXCEPT)
requires std::ranges::random_access_range<Base> && std::three_way_comparable<std::ranges::iterator_t<Base>>
{
return lhs._current <=> rhs._current;
}
friend inline constexpr iterator operator+(const iterator& itr, const difference_type diff) noexcept(NO_EXCEPT)
requires std::ranges::random_access_range<Base>
{
auto res = itr; res += diff; return res;
}
friend inline constexpr iterator operator+(const difference_type diff, const iterator& itr) noexcept(NO_EXCEPT)
requires std::ranges::random_access_range<Base>
{
return itr + diff;
}
friend inline constexpr iterator operator-(const iterator& itr, const difference_type diff) noexcept(NO_EXCEPT)
requires std::ranges::random_access_range<Base>
{
auto res = itr; res -= diff; return res;
}
friend inline constexpr const difference_type operator-(const iterator& lhs, const iterator& rhs) noexcept(NO_EXCEPT)
requires std::sized_sentinel_for<std::ranges::iterator_t<Base>, std::ranges::iterator_t<Base>>
{
const auto diff = lhs._current - rhs._current;
if constexpr(std::ranges::forward_range<Base>)
return (diff + lhs._missing - rhs._missing) / lhs._stride;
else if(diff < 0)
return -div_ceil(-diff, lhs._stride);
else
return div_ceil(diff, lhs._stride);
}
friend inline constexpr const difference_type operator-(std::default_sentinel_t, const iterator& rhs) noexcept(NO_EXCEPT)
requires std::sized_sentinel_for<std::ranges::sentinel_t<Base>, std::ranges::iterator_t<Base>>
{
return div_ceil(rhs._end - rhs._current, rhs._stride);
}
friend inline constexpr const difference_type operator-(const iterator& lhs, std::default_sentinel_t rhs) noexcept(NO_EXCEPT)
requires std::sized_sentinel_for<std::ranges::sentinel_t<Base>, std::ranges::iterator_t<Base>>
{
return -(rhs - lhs);
}
friend inline constexpr std::ranges::range_rvalue_reference_t<Base> iter_move(const iterator& itr) noexcept(NO_EXCEPT)
{
return std::ranges::iter_move(itr._current);
}
friend inline constexpr void iter_swap(const iterator& lhs, const iterator& rhs) noexcept(NO_EXCEPT)
requires std::indirectly_swappable<std::ranges::iterator_t<Base>>
{
std::ranges::iter_swap(lhs._current, rhs._current);
}
};
namespace views {
namespace internal {
template<class Range, class T>
concept can_stride_view = requires { stride_view(std::declval<Range>(), std::declval<T>()); };
}
struct Stride : adaptor::range_adaptor<Stride> {
template<std::ranges::viewable_range Range, class T = std::ranges::range_difference_t<Range>>
requires internal::can_stride_view<Range, T>
inline constexpr auto operator() [[nodiscard]] (Range&& res, std::type_identity_t<T> diff) const
{
return stride_view(std::forward<Range>(res), diff);
}
using adaptor::range_adaptor<Stride>::operator();
static constexpr int arity = 2;
static constexpr bool has_simple_call_op = true;
};
inline constexpr Stride stride;
} // namespace views
} // namespace uni
namespace std::ranges {
template<class View>
inline constexpr bool enable_borrowed_range<uni::stride_view<View>> = enable_borrowed_range<View>;
} // namespace std::ranges
|