1// -*- C++ -*- 2//===------------------------------ span ---------------------------------===// 3// 4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5// See https://llvm.org/LICENSE.txt for license information. 6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7// 8//===---------------------------------------------------------------------===// 9 10#ifndef _LIBCPP_SPAN 11#define _LIBCPP_SPAN 12 13/* 14 span synopsis 15 16namespace std { 17 18// constants 19inline constexpr size_t dynamic_extent = numeric_limits<size_t>::max(); 20 21// [views.span], class template span 22template <class ElementType, size_t Extent = dynamic_extent> 23 class span; 24 25template<class ElementType, size_t Extent> 26 inline constexpr bool ranges::enable_view<span<ElementType, Extent>> = true; 27 28template<class ElementType, size_t Extent> 29 inline constexpr bool ranges::enable_borrowed_range<span<ElementType, Extent>> = true; 30 31// [span.objectrep], views of object representation 32template <class ElementType, size_t Extent> 33 span<const byte, ((Extent == dynamic_extent) ? dynamic_extent : 34 (sizeof(ElementType) * Extent))> as_bytes(span<ElementType, Extent> s) noexcept; 35 36template <class ElementType, size_t Extent> 37 span< byte, ((Extent == dynamic_extent) ? dynamic_extent : 38 (sizeof(ElementType) * Extent))> as_writable_bytes(span<ElementType, Extent> s) noexcept; 39 40 41template <class ElementType, size_t Extent = dynamic_extent> 42class span { 43public: 44 // constants and types 45 using element_type = ElementType; 46 using value_type = remove_cv_t<ElementType>; 47 using size_type = size_t; 48 using difference_type = ptrdiff_t; 49 using pointer = element_type*; 50 using const_pointer = const element_type*; 51 using reference = element_type&; 52 using const_reference = const element_type&; 53 using iterator = implementation-defined; 54 using reverse_iterator = std::reverse_iterator<iterator>; 55 static constexpr size_type extent = Extent; 56 57 // [span.cons], span constructors, copy, assignment, and destructor 58 constexpr span() noexcept; 59 constexpr explicit(Extent != dynamic_extent) span(pointer ptr, size_type count); 60 constexpr explicit(Extent != dynamic_extent) span(pointer firstElem, pointer lastElem); 61 template <size_t N> 62 constexpr span(element_type (&arr)[N]) noexcept; 63 template <size_t N> 64 constexpr span(array<value_type, N>& arr) noexcept; 65 template <size_t N> 66 constexpr span(const array<value_type, N>& arr) noexcept; 67 template <class Container> 68 constexpr explicit(Extent != dynamic_extent) span(Container& cont); 69 template <class Container> 70 constexpr explicit(Extent != dynamic_extent) span(const Container& cont); 71 constexpr span(const span& other) noexcept = default; 72 template <class OtherElementType, size_t OtherExtent> 73 constexpr explicit(Extent != dynamic_extent) span(const span<OtherElementType, OtherExtent>& s) noexcept; 74 ~span() noexcept = default; 75 constexpr span& operator=(const span& other) noexcept = default; 76 77 // [span.sub], span subviews 78 template <size_t Count> 79 constexpr span<element_type, Count> first() const; 80 template <size_t Count> 81 constexpr span<element_type, Count> last() const; 82 template <size_t Offset, size_t Count = dynamic_extent> 83 constexpr span<element_type, see below> subspan() const; 84 85 constexpr span<element_type, dynamic_extent> first(size_type count) const; 86 constexpr span<element_type, dynamic_extent> last(size_type count) const; 87 constexpr span<element_type, dynamic_extent> subspan(size_type offset, size_type count = dynamic_extent) const; 88 89 // [span.obs], span observers 90 constexpr size_type size() const noexcept; 91 constexpr size_type size_bytes() const noexcept; 92 constexpr bool empty() const noexcept; 93 94 // [span.elem], span element access 95 constexpr reference operator[](size_type idx) const; 96 constexpr reference front() const; 97 constexpr reference back() const; 98 constexpr pointer data() const noexcept; 99 100 // [span.iterators], span iterator support 101 constexpr iterator begin() const noexcept; 102 constexpr iterator end() const noexcept; 103 constexpr reverse_iterator rbegin() const noexcept; 104 constexpr reverse_iterator rend() const noexcept; 105 106private: 107 pointer data_; // exposition only 108 size_type size_; // exposition only 109}; 110 111template<class T, size_t N> 112 span(T (&)[N]) -> span<T, N>; 113 114template<class T, size_t N> 115 span(array<T, N>&) -> span<T, N>; 116 117template<class T, size_t N> 118 span(const array<T, N>&) -> span<const T, N>; 119 120template<class Container> 121 span(Container&) -> span<typename Container::value_type>; 122 123template<class Container> 124 span(const Container&) -> span<const typename Container::value_type>; 125 126} // namespace std 127 128*/ 129 130#include <__config> 131#include <__debug> 132#include <__ranges/enable_borrowed_range.h> 133#include <__ranges/enable_view.h> 134#include <array> // for array 135#include <cstddef> // for byte 136#include <iterator> // for iterators 137#include <type_traits> // for remove_cv, etc 138 139#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 140#pragma GCC system_header 141#endif 142 143_LIBCPP_PUSH_MACROS 144#include <__undef_macros> 145 146_LIBCPP_BEGIN_NAMESPACE_STD 147 148#if _LIBCPP_STD_VER > 17 149 150inline constexpr size_t dynamic_extent = numeric_limits<size_t>::max(); 151template <typename _Tp, size_t _Extent = dynamic_extent> class span; 152 153 154template <class _Tp> 155struct __is_span_impl : public false_type {}; 156 157template <class _Tp, size_t _Extent> 158struct __is_span_impl<span<_Tp, _Extent>> : public true_type {}; 159 160template <class _Tp> 161struct __is_span : public __is_span_impl<remove_cv_t<_Tp>> {}; 162 163template <class _Tp> 164struct __is_std_array_impl : public false_type {}; 165 166template <class _Tp, size_t _Sz> 167struct __is_std_array_impl<array<_Tp, _Sz>> : public true_type {}; 168 169template <class _Tp> 170struct __is_std_array : public __is_std_array_impl<remove_cv_t<_Tp>> {}; 171 172template <class _Tp, class _ElementType, class = void> 173struct __is_span_compatible_container : public false_type {}; 174 175template <class _Tp, class _ElementType> 176struct __is_span_compatible_container<_Tp, _ElementType, 177 void_t< 178 // is not a specialization of span 179 typename enable_if<!__is_span<_Tp>::value, nullptr_t>::type, 180 // is not a specialization of array 181 typename enable_if<!__is_std_array<_Tp>::value, nullptr_t>::type, 182 // is_array_v<Container> is false, 183 typename enable_if<!is_array_v<_Tp>, nullptr_t>::type, 184 // data(cont) and size(cont) are well formed 185 decltype(data(declval<_Tp>())), 186 decltype(size(declval<_Tp>())), 187 // remove_pointer_t<decltype(data(cont))>(*)[] is convertible to ElementType(*)[] 188 typename enable_if< 189 is_convertible_v<remove_pointer_t<decltype(data(declval<_Tp &>()))>(*)[], 190 _ElementType(*)[]>, 191 nullptr_t>::type 192 >> 193 : public true_type {}; 194 195 196template <typename _Tp, size_t _Extent> 197class _LIBCPP_TEMPLATE_VIS span { 198public: 199// constants and types 200 using element_type = _Tp; 201 using value_type = remove_cv_t<_Tp>; 202 using size_type = size_t; 203 using difference_type = ptrdiff_t; 204 using pointer = _Tp *; 205 using const_pointer = const _Tp *; 206 using reference = _Tp &; 207 using const_reference = const _Tp &; 208#if (_LIBCPP_DEBUG_LEVEL == 2) || defined(_LIBCPP_ABI_SPAN_POINTER_ITERATORS) 209 using iterator = pointer; 210#else 211 using iterator = __wrap_iter<pointer>; 212#endif 213 using reverse_iterator = _VSTD::reverse_iterator<iterator>; 214 215 static constexpr size_type extent = _Extent; 216 217// [span.cons], span constructors, copy, assignment, and destructor 218 template <size_t _Sz = _Extent, enable_if_t<_Sz == 0, nullptr_t> = nullptr> 219 _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr} {} 220 221 constexpr span (const span&) noexcept = default; 222 constexpr span& operator=(const span&) noexcept = default; 223 224 _LIBCPP_INLINE_VISIBILITY constexpr explicit span(pointer __ptr, size_type __count) : __data{__ptr} 225 { (void)__count; _LIBCPP_ASSERT(_Extent == __count, "size mismatch in span's constructor (ptr, len)"); } 226 _LIBCPP_INLINE_VISIBILITY constexpr explicit span(pointer __f, pointer __l) : __data{__f} 227 { (void)__l; _LIBCPP_ASSERT(_Extent == distance(__f, __l), "size mismatch in span's constructor (ptr, ptr)"); } 228 229 _LIBCPP_INLINE_VISIBILITY constexpr span(element_type (&__arr)[_Extent]) noexcept : __data{__arr} {} 230 231 template <class _OtherElementType, 232 enable_if_t<is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr> 233 _LIBCPP_INLINE_VISIBILITY 234 constexpr span(array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {} 235 236 template <class _OtherElementType, 237 enable_if_t<is_convertible_v<const _OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr> 238 _LIBCPP_INLINE_VISIBILITY 239 constexpr span(const array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {} 240 241 template <class _Container> 242 _LIBCPP_INLINE_VISIBILITY 243 constexpr explicit span( _Container& __c, 244 enable_if_t<__is_span_compatible_container<_Container, _Tp>::value, nullptr_t> = nullptr) 245 : __data{_VSTD::data(__c)} { 246 _LIBCPP_ASSERT(_Extent == _VSTD::size(__c), "size mismatch in span's constructor (range)"); 247 } 248 249 template <class _Container> 250 _LIBCPP_INLINE_VISIBILITY 251 constexpr explicit span(const _Container& __c, 252 enable_if_t<__is_span_compatible_container<const _Container, _Tp>::value, nullptr_t> = nullptr) 253 : __data{_VSTD::data(__c)} { 254 _LIBCPP_ASSERT(_Extent == _VSTD::size(__c), "size mismatch in span's constructor (range)"); 255 } 256 257 template <class _OtherElementType> 258 _LIBCPP_INLINE_VISIBILITY 259 constexpr span(const span<_OtherElementType, _Extent>& __other, 260 enable_if_t< 261 is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, 262 nullptr_t> = nullptr) 263 : __data{__other.data()} {} 264 265 template <class _OtherElementType> 266 _LIBCPP_INLINE_VISIBILITY 267 constexpr explicit span(const span<_OtherElementType, dynamic_extent>& __other, 268 enable_if_t< 269 is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, 270 nullptr_t> = nullptr) noexcept 271 : __data{__other.data()} { _LIBCPP_ASSERT(_Extent == __other.size(), "size mismatch in span's constructor (other span)"); } 272 273 274// ~span() noexcept = default; 275 276 template <size_t _Count> 277 _LIBCPP_INLINE_VISIBILITY 278 constexpr span<element_type, _Count> first() const noexcept 279 { 280 static_assert(_Count <= _Extent, "Count out of range in span::first()"); 281 return span<element_type, _Count>{data(), _Count}; 282 } 283 284 template <size_t _Count> 285 _LIBCPP_INLINE_VISIBILITY 286 constexpr span<element_type, _Count> last() const noexcept 287 { 288 static_assert(_Count <= _Extent, "Count out of range in span::last()"); 289 return span<element_type, _Count>{data() + size() - _Count, _Count}; 290 } 291 292 _LIBCPP_INLINE_VISIBILITY 293 constexpr span<element_type, dynamic_extent> first(size_type __count) const noexcept 294 { 295 _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::first(count)"); 296 return {data(), __count}; 297 } 298 299 _LIBCPP_INLINE_VISIBILITY 300 constexpr span<element_type, dynamic_extent> last(size_type __count) const noexcept 301 { 302 _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::last(count)"); 303 return {data() + size() - __count, __count}; 304 } 305 306 template <size_t _Offset, size_t _Count = dynamic_extent> 307 _LIBCPP_INLINE_VISIBILITY 308 constexpr auto subspan() const noexcept 309 -> span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset> 310 { 311 static_assert(_Offset <= _Extent, "Offset out of range in span::subspan()"); 312 static_assert(_Count == dynamic_extent || _Count <= _Extent - _Offset, "Offset + count out of range in span::subspan()"); 313 314 using _ReturnType = span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset>; 315 return _ReturnType{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; 316 } 317 318 319 _LIBCPP_INLINE_VISIBILITY 320 constexpr span<element_type, dynamic_extent> 321 subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept 322 { 323 _LIBCPP_ASSERT(__offset <= size(), "Offset out of range in span::subspan(offset, count)"); 324 _LIBCPP_ASSERT(__count <= size() || __count == dynamic_extent, "Count out of range in span::subspan(offset, count)"); 325 if (__count == dynamic_extent) 326 return {data() + __offset, size() - __offset}; 327 _LIBCPP_ASSERT(__count <= size() - __offset, "Offset + count out of range in span::subspan(offset, count)"); 328 return {data() + __offset, __count}; 329 } 330 331 _LIBCPP_INLINE_VISIBILITY constexpr size_type size() const noexcept { return _Extent; } 332 _LIBCPP_INLINE_VISIBILITY constexpr size_type size_bytes() const noexcept { return _Extent * sizeof(element_type); } 333 _LIBCPP_INLINE_VISIBILITY constexpr bool empty() const noexcept { return _Extent == 0; } 334 335 _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](size_type __idx) const noexcept 336 { 337 _LIBCPP_ASSERT(__idx < size(), "span<T,N>[] index out of bounds"); 338 return __data[__idx]; 339 } 340 341 _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept 342 { 343 _LIBCPP_ASSERT(!empty(), "span<T, N>::front() on empty span"); 344 return __data[0]; 345 } 346 347 _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept 348 { 349 _LIBCPP_ASSERT(!empty(), "span<T, N>::back() on empty span"); 350 return __data[size()-1]; 351 } 352 353 _LIBCPP_INLINE_VISIBILITY constexpr pointer data() const noexcept { return __data; } 354 355// [span.iter], span iterator support 356 _LIBCPP_INLINE_VISIBILITY constexpr iterator begin() const noexcept { return iterator(data()); } 357 _LIBCPP_INLINE_VISIBILITY constexpr iterator end() const noexcept { return iterator(data() + size()); } 358 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(end()); } 359 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rend() const noexcept { return reverse_iterator(begin()); } 360 361 _LIBCPP_INLINE_VISIBILITY span<const byte, _Extent * sizeof(element_type)> __as_bytes() const noexcept 362 { return span<const byte, _Extent * sizeof(element_type)>{reinterpret_cast<const byte *>(data()), size_bytes()}; } 363 364 _LIBCPP_INLINE_VISIBILITY span<byte, _Extent * sizeof(element_type)> __as_writable_bytes() const noexcept 365 { return span<byte, _Extent * sizeof(element_type)>{reinterpret_cast<byte *>(data()), size_bytes()}; } 366 367private: 368 pointer __data; 369 370}; 371 372 373template <typename _Tp> 374class _LIBCPP_TEMPLATE_VIS span<_Tp, dynamic_extent> { 375private: 376 377public: 378// constants and types 379 using element_type = _Tp; 380 using value_type = remove_cv_t<_Tp>; 381 using size_type = size_t; 382 using difference_type = ptrdiff_t; 383 using pointer = _Tp *; 384 using const_pointer = const _Tp *; 385 using reference = _Tp &; 386 using const_reference = const _Tp &; 387#if (_LIBCPP_DEBUG_LEVEL == 2) || defined(_LIBCPP_ABI_SPAN_POINTER_ITERATORS) 388 using iterator = pointer; 389#else 390 using iterator = __wrap_iter<pointer>; 391#endif 392 using reverse_iterator = _VSTD::reverse_iterator<iterator>; 393 394 static constexpr size_type extent = dynamic_extent; 395 396// [span.cons], span constructors, copy, assignment, and destructor 397 _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr}, __size{0} {} 398 399 constexpr span (const span&) noexcept = default; 400 constexpr span& operator=(const span&) noexcept = default; 401 402 _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __ptr, size_type __count) : __data{__ptr}, __size{__count} {} 403 _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __f, pointer __l) : __data{__f}, __size{static_cast<size_t>(distance(__f, __l))} {} 404 405 template <size_t _Sz> 406 _LIBCPP_INLINE_VISIBILITY 407 constexpr span(element_type (&__arr)[_Sz]) noexcept : __data{__arr}, __size{_Sz} {} 408 409 template <class _OtherElementType, size_t _Sz, 410 enable_if_t<is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr> 411 _LIBCPP_INLINE_VISIBILITY 412 constexpr span(array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {} 413 414 template <class _OtherElementType, size_t _Sz, 415 enable_if_t<is_convertible_v<const _OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr> 416 _LIBCPP_INLINE_VISIBILITY 417 constexpr span(const array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {} 418 419 template <class _Container> 420 _LIBCPP_INLINE_VISIBILITY 421 constexpr span( _Container& __c, 422 enable_if_t<__is_span_compatible_container<_Container, _Tp>::value, nullptr_t> = nullptr) 423 : __data{_VSTD::data(__c)}, __size{(size_type) _VSTD::size(__c)} {} 424 425 template <class _Container> 426 _LIBCPP_INLINE_VISIBILITY 427 constexpr span(const _Container& __c, 428 enable_if_t<__is_span_compatible_container<const _Container, _Tp>::value, nullptr_t> = nullptr) 429 : __data{_VSTD::data(__c)}, __size{(size_type) _VSTD::size(__c)} {} 430 431 432 template <class _OtherElementType, size_t _OtherExtent> 433 _LIBCPP_INLINE_VISIBILITY 434 constexpr span(const span<_OtherElementType, _OtherExtent>& __other, 435 enable_if_t< 436 is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, 437 nullptr_t> = nullptr) noexcept 438 : __data{__other.data()}, __size{__other.size()} {} 439 440// ~span() noexcept = default; 441 442 template <size_t _Count> 443 _LIBCPP_INLINE_VISIBILITY 444 constexpr span<element_type, _Count> first() const noexcept 445 { 446 _LIBCPP_ASSERT(_Count <= size(), "Count out of range in span::first()"); 447 return span<element_type, _Count>{data(), _Count}; 448 } 449 450 template <size_t _Count> 451 _LIBCPP_INLINE_VISIBILITY 452 constexpr span<element_type, _Count> last() const noexcept 453 { 454 _LIBCPP_ASSERT(_Count <= size(), "Count out of range in span::last()"); 455 return span<element_type, _Count>{data() + size() - _Count, _Count}; 456 } 457 458 _LIBCPP_INLINE_VISIBILITY 459 constexpr span<element_type, dynamic_extent> first(size_type __count) const noexcept 460 { 461 _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::first(count)"); 462 return {data(), __count}; 463 } 464 465 _LIBCPP_INLINE_VISIBILITY 466 constexpr span<element_type, dynamic_extent> last (size_type __count) const noexcept 467 { 468 _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::last(count)"); 469 return {data() + size() - __count, __count}; 470 } 471 472 template <size_t _Offset, size_t _Count = dynamic_extent> 473 _LIBCPP_INLINE_VISIBILITY 474 constexpr span<element_type, _Count> subspan() const noexcept 475 { 476 _LIBCPP_ASSERT(_Offset <= size(), "Offset out of range in span::subspan()"); 477 _LIBCPP_ASSERT(_Count == dynamic_extent || _Count <= size() - _Offset, "Offset + count out of range in span::subspan()"); 478 return span<element_type, _Count>{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; 479 } 480 481 constexpr span<element_type, dynamic_extent> 482 _LIBCPP_INLINE_VISIBILITY 483 subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept 484 { 485 _LIBCPP_ASSERT(__offset <= size(), "Offset out of range in span::subspan(offset, count)"); 486 _LIBCPP_ASSERT(__count <= size() || __count == dynamic_extent, "count out of range in span::subspan(offset, count)"); 487 if (__count == dynamic_extent) 488 return {data() + __offset, size() - __offset}; 489 _LIBCPP_ASSERT(__count <= size() - __offset, "Offset + count out of range in span::subspan(offset, count)"); 490 return {data() + __offset, __count}; 491 } 492 493 _LIBCPP_INLINE_VISIBILITY constexpr size_type size() const noexcept { return __size; } 494 _LIBCPP_INLINE_VISIBILITY constexpr size_type size_bytes() const noexcept { return __size * sizeof(element_type); } 495 _LIBCPP_INLINE_VISIBILITY constexpr bool empty() const noexcept { return __size == 0; } 496 497 _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](size_type __idx) const noexcept 498 { 499 _LIBCPP_ASSERT(__idx < size(), "span<T>[] index out of bounds"); 500 return __data[__idx]; 501 } 502 503 _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept 504 { 505 _LIBCPP_ASSERT(!empty(), "span<T>[].front() on empty span"); 506 return __data[0]; 507 } 508 509 _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept 510 { 511 _LIBCPP_ASSERT(!empty(), "span<T>[].back() on empty span"); 512 return __data[size()-1]; 513 } 514 515 516 _LIBCPP_INLINE_VISIBILITY constexpr pointer data() const noexcept { return __data; } 517 518// [span.iter], span iterator support 519 _LIBCPP_INLINE_VISIBILITY constexpr iterator begin() const noexcept { return iterator(data()); } 520 _LIBCPP_INLINE_VISIBILITY constexpr iterator end() const noexcept { return iterator(data() + size()); } 521 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(end()); } 522 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rend() const noexcept { return reverse_iterator(begin()); } 523 524 _LIBCPP_INLINE_VISIBILITY span<const byte, dynamic_extent> __as_bytes() const noexcept 525 { return {reinterpret_cast<const byte *>(data()), size_bytes()}; } 526 527 _LIBCPP_INLINE_VISIBILITY span<byte, dynamic_extent> __as_writable_bytes() const noexcept 528 { return {reinterpret_cast<byte *>(data()), size_bytes()}; } 529 530private: 531 pointer __data; 532 size_type __size; 533}; 534 535#if !defined(_LIBCPP_HAS_NO_RANGES) 536template <class _Tp, size_t _Extent> 537inline constexpr bool ranges::enable_borrowed_range<span<_Tp, _Extent> > = true; 538 539template <class _ElementType, size_t _Extent> 540inline constexpr bool ranges::enable_view<span<_ElementType, _Extent>> = true; 541#endif // !defined(_LIBCPP_HAS_NO_RANGES) 542 543// as_bytes & as_writable_bytes 544template <class _Tp, size_t _Extent> 545_LIBCPP_INLINE_VISIBILITY 546auto as_bytes(span<_Tp, _Extent> __s) noexcept 547-> decltype(__s.__as_bytes()) 548{ return __s.__as_bytes(); } 549 550template <class _Tp, size_t _Extent> 551_LIBCPP_INLINE_VISIBILITY 552auto as_writable_bytes(span<_Tp, _Extent> __s) noexcept 553-> enable_if_t<!is_const_v<_Tp>, decltype(__s.__as_writable_bytes())> 554{ return __s.__as_writable_bytes(); } 555 556// Deduction guides 557template<class _Tp, size_t _Sz> 558 span(_Tp (&)[_Sz]) -> span<_Tp, _Sz>; 559 560template<class _Tp, size_t _Sz> 561 span(array<_Tp, _Sz>&) -> span<_Tp, _Sz>; 562 563template<class _Tp, size_t _Sz> 564 span(const array<_Tp, _Sz>&) -> span<const _Tp, _Sz>; 565 566template<class _Container> 567 span(_Container&) -> span<typename _Container::value_type>; 568 569template<class _Container> 570 span(const _Container&) -> span<const typename _Container::value_type>; 571 572#endif // _LIBCPP_STD_VER > 17 573 574_LIBCPP_END_NAMESPACE_STD 575 576_LIBCPP_POP_MACROS 577 578#endif // _LIBCPP_SPAN 579