35#define _GLIBCXX_SPAN 1
37#pragma GCC system_header
39#if __cplusplus > 201703L
47namespace std _GLIBCXX_VISIBILITY(default)
49_GLIBCXX_BEGIN_NAMESPACE_VERSION
51#define __cpp_lib_span 202002L
53 inline constexpr size_t dynamic_extent =
static_cast<size_t>(-1);
55 template<
typename _Type,
size_t _Extent>
60 template<
typename _Tp>
63 template<
typename _Tp,
size_t _Num>
64 struct __is_std_span<span<_Tp, _Num>> :
true_type { };
66 template<
typename _Tp>
69 template<
typename _Tp,
size_t _Num>
70 struct __is_std_array<
std::array<_Tp, _Num>> :
true_type { };
72 template<
size_t _Extent>
73 class __extent_storage
77 __extent_storage(
size_t)
noexcept
80 static constexpr size_t
86 class __extent_storage<dynamic_extent>
90 __extent_storage(
size_t __extent) noexcept
91 : _M_extent_value(__extent)
95 _M_extent() const noexcept
96 {
return this->_M_extent_value; }
99 size_t _M_extent_value;
103 template<
typename _Type,
size_t _Extent = dynamic_extent>
106 template<
size_t _Offset,
size_t _Count>
107 static constexpr size_t
110 if constexpr (_Count != dynamic_extent)
112 else if constexpr (extent != dynamic_extent)
113 return _Extent - _Offset;
115 return dynamic_extent;
120 template<
typename _Tp,
size_t _ArrayExtent>
121 requires (_Extent == dynamic_extent || _ArrayExtent == _Extent)
122 using __is_compatible_array = __is_array_convertible<_Type, _Tp>;
124 template<
typename _Ref>
125 using __is_compatible_ref
126 = __is_array_convertible<_Type, remove_reference_t<_Ref>>;
130 using element_type = _Type;
131 using value_type = remove_cv_t<_Type>;
132 using size_type = size_t;
133 using difference_type = ptrdiff_t;
134 using pointer = _Type*;
135 using const_pointer =
const _Type*;
136 using reference = element_type&;
137 using const_reference =
const element_type&;
138 using iterator = __gnu_cxx::__normal_iterator<pointer, span>;
142 static constexpr size_t extent = _Extent;
148 requires ((_Extent + 1u) <= 1u)
149 : _M_ptr(
nullptr), _M_extent(0)
152 template<contiguous_iterator _It>
153 requires __is_compatible_ref<iter_reference_t<_It>>::value
154 constexpr explicit(extent != dynamic_extent)
155 span(_It __first, size_type __count)
157 : _M_ptr(std::to_address(__first)), _M_extent(__count)
159 if constexpr (_Extent != dynamic_extent)
161 __glibcxx_assert(__count == _Extent);
163 __glibcxx_requires_valid_range(__first, __first + __count);
166 template<contiguous_iterator _It, sized_sentinel_for<_It> _End>
167 requires __is_compatible_ref<iter_reference_t<_It>>::value
168 && (!is_convertible_v<_End, size_type>)
169 constexpr explicit(extent != dynamic_extent)
170 span(_It __first, _End __last)
171 noexcept(
noexcept(__last - __first))
172 : _M_ptr(std::to_address(__first)),
173 _M_extent(
static_cast<size_type
>(__last - __first))
175 if constexpr (_Extent != dynamic_extent)
177 __glibcxx_assert((__last - __first) == _Extent);
179 __glibcxx_requires_valid_range(__first, __last);
182 template<
size_t _ArrayExtent>
183 requires (_Extent == dynamic_extent || _ArrayExtent == _Extent)
185 span(type_identity_t<element_type> (&__arr)[_ArrayExtent])
noexcept
186 : span(static_cast<pointer>(__arr), _ArrayExtent)
189 template<
typename _Tp,
size_t _ArrayExtent>
190 requires __is_compatible_array<_Tp, _ArrayExtent>::value
192 span(array<_Tp, _ArrayExtent>& __arr) noexcept
193 : span(
static_cast<pointer
>(__arr.data()), _ArrayExtent)
196 template<
typename _Tp,
size_t _ArrayExtent>
197 requires __is_compatible_array<const _Tp, _ArrayExtent>::value
199 span(
const array<_Tp, _ArrayExtent>& __arr) noexcept
200 : span(
static_cast<pointer
>(__arr.data()), _ArrayExtent)
203 template<
typename _Range>
204 requires (!__detail::__is_std_span<remove_cvref_t<_Range>>::value)
205 && (!__detail::__is_std_array<remove_cvref_t<_Range>>::value)
206 && (!is_array_v<remove_cvref_t<_Range>>)
207 && ranges::contiguous_range<_Range> && ranges::sized_range<_Range>
208 && (ranges::borrowed_range<_Range> || is_const_v<element_type>)
209 && __is_compatible_ref<ranges::range_reference_t<_Range>>::value
210 constexpr explicit(extent != dynamic_extent)
211 span(_Range&& __range)
212 noexcept(
noexcept(ranges::data(__range))
213 &&
noexcept(ranges::size(__range)))
214 : span(ranges::data(__range), ranges::size(__range))
216 if constexpr (extent != dynamic_extent)
218 __glibcxx_assert(ranges::size(__range) == extent);
223 span(
const span&)
noexcept =
default;
225 template<
typename _OType,
size_t _OExtent>
226 requires (_Extent == dynamic_extent || _OExtent == dynamic_extent
227 || _Extent == _OExtent)
228 && (__is_array_convertible<_Type, _OType>::value)
230 explicit(extent != dynamic_extent && _OExtent == dynamic_extent)
231 span(
const span<_OType, _OExtent>& __s) noexcept
232 : _M_extent(__s.size()), _M_ptr(__s.data())
234 if constexpr (extent != dynamic_extent)
236 __glibcxx_assert(__s.size() == extent);
240 ~span() noexcept = default;
243 operator=(const span&) noexcept = default;
248 size() const noexcept
249 {
return this->_M_extent._M_extent(); }
252 size_bytes() const noexcept
253 {
return this->_M_extent._M_extent() *
sizeof(element_type); }
255 [[nodiscard]]
constexpr bool
256 empty() const noexcept
257 {
return size() == 0; }
262 front() const noexcept
264 __glibcxx_assert(!
empty());
265 return *this->_M_ptr;
269 back() const noexcept
271 __glibcxx_assert(!
empty());
272 return *(this->_M_ptr + (
size() - 1));
276 operator[](size_type __idx)
const noexcept
278 __glibcxx_assert(__idx <
size());
279 return *(this->_M_ptr + __idx);
283 data() const noexcept
284 {
return this->_M_ptr; }
289 begin() const noexcept
290 {
return iterator(this->_M_ptr); }
294 {
return iterator(this->_M_ptr + this->
size()); }
296 constexpr reverse_iterator
298 {
return reverse_iterator(this->
end()); }
300 constexpr reverse_iterator
301 rend() const noexcept
302 {
return reverse_iterator(this->
begin()); }
306 template<
size_t _Count>
307 constexpr span<element_type, _Count>
308 first() const noexcept
310 if constexpr (_Extent == dynamic_extent)
311 __glibcxx_assert(_Count <=
size());
313 static_assert(_Count <= extent);
314 using _Sp = span<element_type, _Count>;
315 return _Sp{ this->
data(), _Count };
318 constexpr span<element_type, dynamic_extent>
319 first(size_type __count)
const noexcept
321 __glibcxx_assert(__count <=
size());
322 return { this->
data(), __count };
325 template<
size_t _Count>
326 constexpr span<element_type, _Count>
327 last() const noexcept
329 if constexpr (_Extent == dynamic_extent)
330 __glibcxx_assert(_Count <=
size());
332 static_assert(_Count <= extent);
333 using _Sp = span<element_type, _Count>;
334 return _Sp{ this->
data() + (this->
size() - _Count), _Count };
337 constexpr span<element_type, dynamic_extent>
338 last(size_type __count)
const noexcept
340 __glibcxx_assert(__count <=
size());
341 return { this->
data() + (this->
size() - __count), __count };
344 template<
size_t _Offset,
size_t _Count = dynamic_extent>
346 subspan() const noexcept
347 -> span<element_type, _S_subspan_extent<_Offset, _Count>()>
349 if constexpr (_Extent == dynamic_extent)
351 __glibcxx_assert(_Offset <=
size());
354 static_assert(_Offset <= extent);
356 using _Sp = span<element_type, _S_subspan_extent<_Offset, _Count>()>;
358 if constexpr (_Count == dynamic_extent)
359 return _Sp{ this->
data() + _Offset, this->
size() - _Offset };
362 if constexpr (_Extent == dynamic_extent)
364 __glibcxx_assert(_Count <=
size());
365 __glibcxx_assert(_Count <= (
size() - _Offset));
369 static_assert(_Count <= extent);
370 static_assert(_Count <= (extent - _Offset));
372 return _Sp{ this->
data() + _Offset, _Count };
376 constexpr span<element_type, dynamic_extent>
377 subspan(size_type __offset, size_type __count = dynamic_extent)
const
380 __glibcxx_assert(__offset <=
size());
381 if (__count == dynamic_extent)
382 __count = this->
size() - __offset;
385 __glibcxx_assert(__count <=
size());
386 __glibcxx_assert(__offset + __count <=
size());
388 return {this->
data() + __offset, __count};
393 [[no_unique_address]] __detail::__extent_storage<extent> _M_extent;
398 template<
typename _Type,
size_t _ArrayExtent>
399 span(_Type(&)[_ArrayExtent]) -> span<_Type, _ArrayExtent>;
401 template<
typename _Type,
size_t _ArrayExtent>
402 span(array<_Type, _ArrayExtent>&) -> span<_Type, _ArrayExtent>;
404 template<
typename _Type,
size_t _ArrayExtent>
405 span(
const array<_Type, _ArrayExtent>&)
406 -> span<const _Type, _ArrayExtent>;
408 template<contiguous_iterator _Iter,
typename _End>
410 -> span<remove_reference_t<iter_reference_t<_Iter>>>;
412 template<ranges::contiguous_range _Range>
414 -> span<remove_reference_t<ranges::range_reference_t<_Range&>>>;
416 template<
typename _Type,
size_t _Extent>
418 span<
const byte, _Extent == dynamic_extent
419 ? dynamic_extent : _Extent *
sizeof(_Type)>
420 as_bytes(span<_Type, _Extent> __sp)
noexcept
422 auto data =
reinterpret_cast<const byte*
>(__sp.data());
423 auto size = __sp.size_bytes();
424 constexpr auto extent = _Extent == dynamic_extent
425 ? dynamic_extent : _Extent *
sizeof(_Type);
426 return span<const byte, extent>{
data,
size};
429 template<
typename _Type,
size_t _Extent>
430 requires (!is_const_v<_Type>)
432 span<
byte, _Extent == dynamic_extent
433 ? dynamic_extent : _Extent * sizeof(_Type)>
434 as_writable_bytes(span<_Type, _Extent> __sp) noexcept
436 auto data =
reinterpret_cast<byte*
>(__sp.data());
437 auto size = __sp.size_bytes();
438 constexpr auto extent = _Extent == dynamic_extent
439 ? dynamic_extent : _Extent *
sizeof(_Type);
440 return span<byte, extent>{
data,
size};
446 template<
typename _ElementType,
size_t _Extent>
447 inline constexpr bool
448 enable_borrowed_range<span<_ElementType, _Extent>> =
true;
451 template<
typename _ElementType,
size_t _Extent>
452 inline constexpr bool
453 enable_view<span<_ElementType, _Extent>> =
true;
455_GLIBCXX_END_NAMESPACE_VERSION
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
_Tp * end(valarray< _Tp > &__va) noexcept
Return an iterator pointing to one past the last element of the valarray.
_Tp * begin(valarray< _Tp > &__va) noexcept
Return an iterator pointing to the first element of the valarray.
ISO C++ entities toplevel namespace is std.
constexpr auto rend(_Container &__cont) -> decltype(__cont.rend())
Return a reverse iterator pointing one past the first element of the container.
constexpr auto empty(const _Container &__cont) noexcept(noexcept(__cont.empty())) -> decltype(__cont.empty())
Return whether a container is empty.
constexpr auto size(const _Container &__cont) noexcept(noexcept(__cont.size())) -> decltype(__cont.size())
Return the size of a container.
constexpr auto rbegin(_Container &__cont) -> decltype(__cont.rbegin())
Return a reverse iterator pointing to the last element of the container.
constexpr auto data(_Container &__cont) noexcept(noexcept(__cont.data())) -> decltype(__cont.data())
Return the data pointer of a container.