1// -*- C++ -*- 2//===-------------------------- iterator ----------------------------------===// 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_ITERATOR 11#define _LIBCPP_ITERATOR 12 13/* 14 iterator synopsis 15 16#include <concepts> 17 18namespace std 19{ 20template<class> struct incrementable_traits; // since C++20 21template<class T> 22 using iter_difference_t = see below; // since C++20 23 24template<class> struct indirectly_readable_traits; // since C++20 25template<class T> 26 using iter_value_t = see below; // since C++20 27 28template<class Iterator> 29struct iterator_traits; 30 31template<class T> 32 requires is_object_v<T> // since C++20 33struct iterator_traits<T*>; 34 35template<dereferenceable T> 36 using iter_reference_t = decltype(*declval<T&>()); 37 38namespace ranges::inline unspecified { 39 inline constexpr unspecified iter_move = unspecified; // since C++20, nodiscard as an extension 40}} 41 42template<dereferenceable T> 43 requires ... 44using iter_rvalue_reference_t = decltype(ranges::iter_move(declval<T&>())); // since C++20 45 46// [iterator.concepts], iterator concepts 47// [iterator.concept.readable], concept indirectly_readable 48template<class In> 49 concept indirectly_readable = see below; // since C++20 50 51template<indirectly_readable T> 52 using iter_common_reference_t = 53 common_reference_t<iter_reference_t<T>, iter_value_t<T>&>; // since C++20 54 55// [iterator.concept.writable], concept indirectly_writable 56template<class Out, class T> 57 concept indirectly_writable = see below; // since C++20 58 59// [iterator.concept.winc], concept weakly_incrementable 60template<class I> 61 concept weakly_incrementable = see below; // since C++20 62 63// [iterator.concept.inc], concept incrementable 64template<class I> 65 concept incrementable = see below; // since C++20 66 67// [iterator.concept.iterator], concept input_or_output_iterator 68 template<class I> 69 concept input_or_output_iterator = see below; // since C++20 70 71// [iterator.concept.sentinel], concept sentinel_for 72template<class S, class I> 73 concept sentinel_for = see below; // since C++20 74 75// [iterator.concept.sizedsentinel], concept sized_sentinel_for 76template<class S, class I> 77 inline constexpr bool disable_sized_sentinel_for = false; 78 79template<class S, class I> 80 concept sized_sentinel_for = see below; 81 82// [iterator.concept.input], concept input_iterator 83template<class I> 84 concept input_iterator = see below; // since C++20 85 86// [iterator.concept.output], concept output_iterator 87template<class I, class T> 88 concept output_iterator = see below; // since C++20 89 90// [iterator.concept.forward], concept forward_iterator 91template<class I> 92 concept forward_iterator = see below; // since C++20 93 94// [iterator.concept.bidir], concept bidirectional_iterator 95template<class I> 96 concept bidirectional_iterator = see below; // since C++20 97 98// [iterator.concept.random.access], concept random_access_iterator 99template<class I> 100 concept random_access_iterator = see below; // since C++20 101 102// [indirectcallable] 103// [indirectcallable.indirectinvocable] 104template<class F, class I> 105 concept indirectly_unary_invocable = see below; // since C++20 106 107template<class F, class I> 108 concept indirectly_regular_unary_invocable = see below; // since C++20 109 110template<class F, class I> 111 concept indirect_unary_predicate = see below; // since C++20 112 113template<class F, class I1, class I2> 114 concept indirect_binary_predicate = see below; // since C++20 115 116template<class F, class I1, class I2 = I1> 117 concept indirect_equivalence_relation = see below; // since C++20 118 119template<class F, class I1, class I2 = I1> 120 concept indirect_strict_weak_order = see below; // since C++20 121 122template<class F, class... Is> 123 using indirect_result_t = see below; // since C++20 124 125// [projected], projected 126template<indirectly_readable I, indirectly_regular_unary_invocable<I> Proj> 127 struct projected; // since C++20 128 129template<weakly_incrementable I, indirectly_regular_unary_invocable<I> Proj> 130 struct incrementable_traits<projected<I, Proj>>; // since C++20 131 132// [alg.req.ind.move], concept indirectly_movable 133template<class In, class Out> 134 concept indirectly_movable = see below; // since C++20 135 136template<class In, class Out> 137 concept indirectly_movable_storable = see below; // since C++20 138 139// [alg.req.ind.swap], concept indirectly_swappable 140template<class I1, class I2 = I1> 141 concept indirectly_swappable = see below; // since C++20 142 143template<input_or_output_iterator I, sentinel_for<I> S> 144 requires (!same_as<I, S> && copyable<I>) 145class common_iterator; // since C++20 146 147template<class Category, class T, class Distance = ptrdiff_t, 148 class Pointer = T*, class Reference = T&> 149struct iterator // deprecated in C++17 150{ 151 typedef T value_type; 152 typedef Distance difference_type; 153 typedef Pointer pointer; 154 typedef Reference reference; 155 typedef Category iterator_category; 156}; 157 158struct input_iterator_tag {}; 159struct output_iterator_tag {}; 160struct forward_iterator_tag : public input_iterator_tag {}; 161struct bidirectional_iterator_tag : public forward_iterator_tag {}; 162struct random_access_iterator_tag : public bidirectional_iterator_tag {}; 163 164// 27.4.3, iterator operations 165template <class InputIterator, class Distance> // constexpr in C++17 166 constexpr void advance(InputIterator& i, Distance n); 167 168template <class InputIterator> // constexpr in C++17 169 constexpr typename iterator_traits<InputIterator>::difference_type 170 distance(InputIterator first, InputIterator last); 171 172template <class InputIterator> // constexpr in C++17 173 constexpr InputIterator next(InputIterator x, 174typename iterator_traits<InputIterator>::difference_type n = 1); 175 176template <class BidirectionalIterator> // constexpr in C++17 177 constexpr BidirectionalIterator prev(BidirectionalIterator x, 178 typename iterator_traits<BidirectionalIterator>::difference_type n = 1); 179 180// [range.iter.ops], range iterator operations 181namespace ranges { 182 // [range.iter.op.advance], ranges::advance 183 template<input_or_output_iterator I> 184 constexpr void advance(I& i, iter_difference_t<I> n); // since C++20 185 template<input_or_output_iterator I, sentinel_for<I> S> 186 constexpr void advance(I& i, S bound); // since C++20 187 template<input_or_output_iterator I, sentinel_for<I> S> 188 constexpr iter_difference_t<I> advance(I& i, iter_difference_t<I> n, S bound); // since C++20 189} 190 191template <class Iterator> 192class reverse_iterator 193 : public iterator<typename iterator_traits<Iterator>::iterator_category, // until C++17 194 typename iterator_traits<Iterator>::value_type, 195 typename iterator_traits<Iterator>::difference_type, 196 typename iterator_traits<Iterator>::pointer, 197 typename iterator_traits<Iterator>::reference> 198{ 199protected: 200 Iterator current; 201public: 202 typedef Iterator iterator_type; 203 typedef typename iterator_traits<Iterator>::difference_type difference_type; 204 typedef typename iterator_traits<Iterator>::reference reference; 205 typedef typename iterator_traits<Iterator>::pointer pointer; 206 207 constexpr reverse_iterator(); 208 constexpr explicit reverse_iterator(Iterator x); 209 template <class U> constexpr reverse_iterator(const reverse_iterator<U>& u); 210 template <class U> constexpr reverse_iterator& operator=(const reverse_iterator<U>& u); 211 constexpr Iterator base() const; 212 constexpr reference operator*() const; 213 constexpr pointer operator->() const; 214 constexpr reverse_iterator& operator++(); 215 constexpr reverse_iterator operator++(int); 216 constexpr reverse_iterator& operator--(); 217 constexpr reverse_iterator operator--(int); 218 constexpr reverse_iterator operator+ (difference_type n) const; 219 constexpr reverse_iterator& operator+=(difference_type n); 220 constexpr reverse_iterator operator- (difference_type n) const; 221 constexpr reverse_iterator& operator-=(difference_type n); 222 constexpr reference operator[](difference_type n) const; 223}; 224 225template <class Iterator1, class Iterator2> 226constexpr bool // constexpr in C++17 227operator==(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); 228 229template <class Iterator1, class Iterator2> 230constexpr bool // constexpr in C++17 231operator<(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); 232 233template <class Iterator1, class Iterator2> 234constexpr bool // constexpr in C++17 235operator!=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); 236 237template <class Iterator1, class Iterator2> 238constexpr bool // constexpr in C++17 239operator>(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); 240 241template <class Iterator1, class Iterator2> 242constexpr bool // constexpr in C++17 243operator>=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); 244 245template <class Iterator1, class Iterator2> 246constexpr bool // constexpr in C++17 247operator<=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); 248 249template <class Iterator1, class Iterator2> 250constexpr auto 251operator-(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y) 252-> decltype(__y.base() - __x.base()); // constexpr in C++17 253 254template <class Iterator> 255constexpr reverse_iterator<Iterator> 256operator+(typename reverse_iterator<Iterator>::difference_type n, 257 const reverse_iterator<Iterator>& x); // constexpr in C++17 258 259template <class Iterator> 260constexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14, constexpr in C++17 261 262template <class Container> 263class back_insert_iterator 264 : public iterator<output_iterator_tag, void, void, void, void> // until C++17 265{ 266protected: 267 Container* container; 268public: 269 typedef Container container_type; 270 typedef void value_type; 271 typedef void difference_type; // until C++20 272 typedef ptrdiff_t difference_type; // since C++20 273 typedef void reference; 274 typedef void pointer; 275 276 explicit back_insert_iterator(Container& x); // constexpr in C++20 277 back_insert_iterator& operator=(const typename Container::value_type& value); // constexpr in C++20 278 back_insert_iterator& operator*(); // constexpr in C++20 279 back_insert_iterator& operator++(); // constexpr in C++20 280 back_insert_iterator operator++(int); // constexpr in C++20 281}; 282 283template <class Container> back_insert_iterator<Container> back_inserter(Container& x); // constexpr in C++20 284 285template <class Container> 286class front_insert_iterator 287 : public iterator<output_iterator_tag, void, void, void, void> // until C++17 288{ 289protected: 290 Container* container; 291public: 292 typedef Container container_type; 293 typedef void value_type; 294 typedef void difference_type; // until C++20 295 typedef ptrdiff_t difference_type; // since C++20 296 typedef void reference; 297 typedef void pointer; 298 299 explicit front_insert_iterator(Container& x); // constexpr in C++20 300 front_insert_iterator& operator=(const typename Container::value_type& value); // constexpr in C++20 301 front_insert_iterator& operator*(); // constexpr in C++20 302 front_insert_iterator& operator++(); // constexpr in C++20 303 front_insert_iterator operator++(int); // constexpr in C++20 304}; 305 306template <class Container> front_insert_iterator<Container> front_inserter(Container& x); // constexpr in C++20 307 308template <class Container> 309class insert_iterator 310 : public iterator<output_iterator_tag, void, void, void, void> // until C++17 311{ 312protected: 313 Container* container; 314 typename Container::iterator iter; 315public: 316 typedef Container container_type; 317 typedef void value_type; 318 typedef void difference_type; // until C++20 319 typedef ptrdiff_t difference_type; // since C++20 320 typedef void reference; 321 typedef void pointer; 322 323 insert_iterator(Container& x, typename Container::iterator i); // constexpr in C++20 324 insert_iterator& operator=(const typename Container::value_type& value); // constexpr in C++20 325 insert_iterator& operator*(); // constexpr in C++20 326 insert_iterator& operator++(); // constexpr in C++20 327 insert_iterator& operator++(int); // constexpr in C++20 328}; 329 330template <class Container, class Iterator> 331insert_iterator<Container> inserter(Container& x, Iterator i); // constexpr in C++20 332 333template <class Iterator> 334class move_iterator { 335public: 336 typedef Iterator iterator_type; 337 typedef typename iterator_traits<Iterator>::difference_type difference_type; 338 typedef Iterator pointer; 339 typedef typename iterator_traits<Iterator>::value_type value_type; 340 typedef typename iterator_traits<Iterator>::iterator_category iterator_category; 341 typedef value_type&& reference; 342 343 constexpr move_iterator(); // all the constexprs are in C++17 344 constexpr explicit move_iterator(Iterator i); 345 template <class U> 346 constexpr move_iterator(const move_iterator<U>& u); 347 template <class U> 348 constexpr move_iterator& operator=(const move_iterator<U>& u); 349 constexpr iterator_type base() const; 350 constexpr reference operator*() const; 351 constexpr pointer operator->() const; 352 constexpr move_iterator& operator++(); 353 constexpr move_iterator operator++(int); 354 constexpr move_iterator& operator--(); 355 constexpr move_iterator operator--(int); 356 constexpr move_iterator operator+(difference_type n) const; 357 constexpr move_iterator& operator+=(difference_type n); 358 constexpr move_iterator operator-(difference_type n) const; 359 constexpr move_iterator& operator-=(difference_type n); 360 constexpr unspecified operator[](difference_type n) const; 361private: 362 Iterator current; // exposition only 363}; 364 365template <class Iterator1, class Iterator2> 366constexpr bool // constexpr in C++17 367operator==(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); 368 369template <class Iterator1, class Iterator2> 370constexpr bool // constexpr in C++17 371operator!=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); 372 373template <class Iterator1, class Iterator2> 374constexpr bool // constexpr in C++17 375operator<(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); 376 377template <class Iterator1, class Iterator2> 378constexpr bool // constexpr in C++17 379operator<=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); 380 381template <class Iterator1, class Iterator2> 382constexpr bool // constexpr in C++17 383operator>(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); 384 385template <class Iterator1, class Iterator2> 386constexpr bool // constexpr in C++17 387operator>=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); 388 389template <class Iterator1, class Iterator2> 390constexpr auto // constexpr in C++17 391operator-(const move_iterator<Iterator1>& x, 392 const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base()); 393 394template <class Iterator> 395constexpr move_iterator<Iterator> operator+( // constexpr in C++17 396 typename move_iterator<Iterator>::difference_type n, 397 const move_iterator<Iterator>& x); 398 399template <class Iterator> // constexpr in C++17 400constexpr move_iterator<Iterator> make_move_iterator(const Iterator& i); 401 402// [default.sentinel], default sentinel 403struct default_sentinel_t; 404inline constexpr default_sentinel_t default_sentinel{}; 405 406// [iterators.counted], counted iterators 407template<input_or_output_iterator I> class counted_iterator; 408 409template<input_iterator I> 410 requires see below 411 struct iterator_traits<counted_iterator<I>>; 412 413template <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t> 414class istream_iterator 415 : public iterator<input_iterator_tag, T, Distance, const T*, const T&> // until C++17 416{ 417public: 418 typedef input_iterator_tag iterator_category; 419 typedef T value_type; 420 typedef Distance difference_type; 421 typedef const T* pointer; 422 typedef const T& reference; 423 424 typedef charT char_type; 425 typedef traits traits_type; 426 typedef basic_istream<charT, traits> istream_type; 427 428 constexpr istream_iterator(); 429 istream_iterator(istream_type& s); 430 istream_iterator(const istream_iterator& x); 431 ~istream_iterator(); 432 433 const T& operator*() const; 434 const T* operator->() const; 435 istream_iterator& operator++(); 436 istream_iterator operator++(int); 437}; 438 439template <class T, class charT, class traits, class Distance> 440bool operator==(const istream_iterator<T,charT,traits,Distance>& x, 441 const istream_iterator<T,charT,traits,Distance>& y); 442template <class T, class charT, class traits, class Distance> 443bool operator!=(const istream_iterator<T,charT,traits,Distance>& x, 444 const istream_iterator<T,charT,traits,Distance>& y); 445 446template <class T, class charT = char, class traits = char_traits<charT> > 447class ostream_iterator 448 : public iterator<output_iterator_tag, void, void, void, void> // until C++17 449{ 450public: 451 typedef output_iterator_tag iterator_category; 452 typedef void value_type; 453 typedef void difference_type; // until C++20 454 typedef ptrdiff_t difference_type; // since C++20 455 typedef void pointer; 456 typedef void reference; 457 458 typedef charT char_type; 459 typedef traits traits_type; 460 typedef basic_ostream<charT,traits> ostream_type; 461 462 ostream_iterator(ostream_type& s); 463 ostream_iterator(ostream_type& s, const charT* delimiter); 464 ostream_iterator(const ostream_iterator& x); 465 ~ostream_iterator(); 466 ostream_iterator& operator=(const T& value); 467 468 ostream_iterator& operator*(); 469 ostream_iterator& operator++(); 470 ostream_iterator& operator++(int); 471}; 472 473template<class charT, class traits = char_traits<charT> > 474class istreambuf_iterator 475 : public iterator<input_iterator_tag, charT, traits::off_type, unspecified, charT> // until C++17 476{ 477public: 478 typedef input_iterator_tag iterator_category; 479 typedef charT value_type; 480 typedef traits::off_type difference_type; 481 typedef unspecified pointer; 482 typedef charT reference; 483 484 typedef charT char_type; 485 typedef traits traits_type; 486 typedef traits::int_type int_type; 487 typedef basic_streambuf<charT, traits> streambuf_type; 488 typedef basic_istream<charT, traits> istream_type; 489 490 istreambuf_iterator() noexcept; 491 istreambuf_iterator(istream_type& s) noexcept; 492 istreambuf_iterator(streambuf_type* s) noexcept; 493 istreambuf_iterator(a-private-type) noexcept; 494 495 charT operator*() const; 496 pointer operator->() const; 497 istreambuf_iterator& operator++(); 498 a-private-type operator++(int); 499 500 bool equal(const istreambuf_iterator& b) const; 501}; 502 503template <class charT, class traits> 504bool operator==(const istreambuf_iterator<charT,traits>& a, 505 const istreambuf_iterator<charT,traits>& b); 506template <class charT, class traits> 507bool operator!=(const istreambuf_iterator<charT,traits>& a, 508 const istreambuf_iterator<charT,traits>& b); 509 510template <class charT, class traits = char_traits<charT> > 511class ostreambuf_iterator 512 : public iterator<output_iterator_tag, void, void, void, void> // until C++17 513{ 514public: 515 typedef output_iterator_tag iterator_category; 516 typedef void value_type; 517 typedef void difference_type; // until C++20 518 typedef ptrdiff_t difference_type; // since C++20 519 typedef void pointer; 520 typedef void reference; 521 522 typedef charT char_type; 523 typedef traits traits_type; 524 typedef basic_streambuf<charT, traits> streambuf_type; 525 typedef basic_ostream<charT, traits> ostream_type; 526 527 ostreambuf_iterator(ostream_type& s) noexcept; 528 ostreambuf_iterator(streambuf_type* s) noexcept; 529 ostreambuf_iterator& operator=(charT c); 530 ostreambuf_iterator& operator*(); 531 ostreambuf_iterator& operator++(); 532 ostreambuf_iterator& operator++(int); 533 bool failed() const noexcept; 534}; 535 536template <class C> constexpr auto begin(C& c) -> decltype(c.begin()); 537template <class C> constexpr auto begin(const C& c) -> decltype(c.begin()); 538template <class C> constexpr auto end(C& c) -> decltype(c.end()); 539template <class C> constexpr auto end(const C& c) -> decltype(c.end()); 540template <class T, size_t N> constexpr T* begin(T (&array)[N]); 541template <class T, size_t N> constexpr T* end(T (&array)[N]); 542 543template <class C> auto constexpr cbegin(const C& c) -> decltype(std::begin(c)); // C++14 544template <class C> auto constexpr cend(const C& c) -> decltype(std::end(c)); // C++14 545template <class C> auto constexpr rbegin(C& c) -> decltype(c.rbegin()); // C++14 546template <class C> auto constexpr rbegin(const C& c) -> decltype(c.rbegin()); // C++14 547template <class C> auto constexpr rend(C& c) -> decltype(c.rend()); // C++14 548template <class C> constexpr auto rend(const C& c) -> decltype(c.rend()); // C++14 549template <class E> reverse_iterator<const E*> constexpr rbegin(initializer_list<E> il); // C++14 550template <class E> reverse_iterator<const E*> constexpr rend(initializer_list<E> il); // C++14 551template <class T, size_t N> reverse_iterator<T*> constexpr rbegin(T (&array)[N]); // C++14 552template <class T, size_t N> reverse_iterator<T*> constexpr rend(T (&array)[N]); // C++14 553template <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c)); // C++14 554template <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c)); // C++14 555 556// 24.8, container access: 557template <class C> constexpr auto size(const C& c) -> decltype(c.size()); // C++17 558template <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17 559 560template <class C> constexpr auto ssize(const C& c) 561 -> common_type_t<ptrdiff_t, make_signed_t<decltype(c.size())>>; // C++20 562template <class T, ptrdiff_t> constexpr ptrdiff_t ssize(const T (&array)[N]) noexcept; // C++20 563 564template <class C> constexpr auto empty(const C& c) -> decltype(c.empty()); // C++17 565template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept; // C++17 566template <class E> constexpr bool empty(initializer_list<E> il) noexcept; // C++17 567template <class C> constexpr auto data(C& c) -> decltype(c.data()); // C++17 568template <class C> constexpr auto data(const C& c) -> decltype(c.data()); // C++17 569template <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept; // C++17 570template <class E> constexpr const E* data(initializer_list<E> il) noexcept; // C++17 571 572} // std 573 574*/ 575 576#include <__config> 577#include <__debug> 578#include <__functional_base> 579#include <__iterator/access.h> 580#include <__iterator/advance.h> 581#include <__iterator/back_insert_iterator.h> 582#include <__iterator/common_iterator.h> 583#include <__iterator/concepts.h> 584#include <__iterator/counted_iterator.h> 585#include <__iterator/data.h> 586#include <__iterator/default_sentinel.h> 587#include <__iterator/distance.h> 588#include <__iterator/empty.h> 589#include <__iterator/erase_if_container.h> 590#include <__iterator/front_insert_iterator.h> 591#include <__iterator/incrementable_traits.h> 592#include <__iterator/insert_iterator.h> 593#include <__iterator/istreambuf_iterator.h> 594#include <__iterator/istream_iterator.h> 595#include <__iterator/iterator.h> 596#include <__iterator/iterator_traits.h> 597#include <__iterator/iter_move.h> 598#include <__iterator/iter_swap.h> 599#include <__iterator/move_iterator.h> 600#include <__iterator/next.h> 601#include <__iterator/ostreambuf_iterator.h> 602#include <__iterator/ostream_iterator.h> 603#include <__iterator/prev.h> 604#include <__iterator/projected.h> 605#include <__iterator/readable_traits.h> 606#include <__iterator/reverse_access.h> 607#include <__iterator/reverse_iterator.h> 608#include <__iterator/size.h> 609#include <__iterator/wrap_iter.h> 610#include <__memory/addressof.h> 611#include <__memory/pointer_traits.h> 612#include <__utility/forward.h> 613#include <compare> 614#include <concepts> // Mandated by the Standard. 615#include <cstddef> 616#include <initializer_list> 617#include <type_traits> 618#include <version> 619 620#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 621#pragma GCC system_header 622#endif 623 624#endif // _LIBCPP_ITERATOR 625