1// -*- C++ -*- 2//===----------------------------------------------------------------------===// 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___SPLIT_BUFFER 11#define _LIBCPP___SPLIT_BUFFER 12 13#include <__algorithm/max.h> 14#include <__algorithm/move.h> 15#include <__algorithm/move_backward.h> 16#include <__config> 17#include <__iterator/distance.h> 18#include <__iterator/iterator_traits.h> 19#include <__iterator/move_iterator.h> 20#include <__memory/allocator.h> 21#include <__memory/compressed_pair.h> 22#include <__memory/swap_allocator.h> 23#include <__utility/forward.h> 24#include <memory> 25#include <type_traits> 26 27#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 28# pragma GCC system_header 29#endif 30 31_LIBCPP_PUSH_MACROS 32#include <__undef_macros> 33 34 35_LIBCPP_BEGIN_NAMESPACE_STD 36 37template <class _Tp, class _Allocator = allocator<_Tp> > 38struct __split_buffer 39{ 40private: 41 __split_buffer(const __split_buffer&); 42 __split_buffer& operator=(const __split_buffer&); 43public: 44 typedef _Tp value_type; 45 typedef _Allocator allocator_type; 46 typedef typename remove_reference<allocator_type>::type __alloc_rr; 47 typedef allocator_traits<__alloc_rr> __alloc_traits; 48 typedef value_type& reference; 49 typedef const value_type& const_reference; 50 typedef typename __alloc_traits::size_type size_type; 51 typedef typename __alloc_traits::difference_type difference_type; 52 typedef typename __alloc_traits::pointer pointer; 53 typedef typename __alloc_traits::const_pointer const_pointer; 54 typedef pointer iterator; 55 typedef const_pointer const_iterator; 56 57 pointer __first_; 58 pointer __begin_; 59 pointer __end_; 60 __compressed_pair<pointer, allocator_type> __end_cap_; 61 62 typedef typename add_lvalue_reference<allocator_type>::type __alloc_ref; 63 typedef typename add_lvalue_reference<allocator_type>::type __alloc_const_ref; 64 65 _LIBCPP_INLINE_VISIBILITY __alloc_rr& __alloc() _NOEXCEPT {return __end_cap_.second();} 66 _LIBCPP_INLINE_VISIBILITY const __alloc_rr& __alloc() const _NOEXCEPT {return __end_cap_.second();} 67 _LIBCPP_INLINE_VISIBILITY pointer& __end_cap() _NOEXCEPT {return __end_cap_.first();} 68 _LIBCPP_INLINE_VISIBILITY const pointer& __end_cap() const _NOEXCEPT {return __end_cap_.first();} 69 70 _LIBCPP_INLINE_VISIBILITY 71 __split_buffer() 72 _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value); 73 _LIBCPP_INLINE_VISIBILITY 74 explicit __split_buffer(__alloc_rr& __a); 75 _LIBCPP_INLINE_VISIBILITY 76 explicit __split_buffer(const __alloc_rr& __a); 77 __split_buffer(size_type __cap, size_type __start, __alloc_rr& __a); 78 ~__split_buffer(); 79 80 __split_buffer(__split_buffer&& __c) 81 _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value); 82 __split_buffer(__split_buffer&& __c, const __alloc_rr& __a); 83 __split_buffer& operator=(__split_buffer&& __c) 84 _NOEXCEPT_((__alloc_traits::propagate_on_container_move_assignment::value && 85 is_nothrow_move_assignable<allocator_type>::value) || 86 !__alloc_traits::propagate_on_container_move_assignment::value); 87 88 _LIBCPP_INLINE_VISIBILITY iterator begin() _NOEXCEPT {return __begin_;} 89 _LIBCPP_INLINE_VISIBILITY const_iterator begin() const _NOEXCEPT {return __begin_;} 90 _LIBCPP_INLINE_VISIBILITY iterator end() _NOEXCEPT {return __end_;} 91 _LIBCPP_INLINE_VISIBILITY const_iterator end() const _NOEXCEPT {return __end_;} 92 93 _LIBCPP_INLINE_VISIBILITY 94 void clear() _NOEXCEPT 95 {__destruct_at_end(__begin_);} 96 _LIBCPP_INLINE_VISIBILITY size_type size() const {return static_cast<size_type>(__end_ - __begin_);} 97 _LIBCPP_INLINE_VISIBILITY bool empty() const {return __end_ == __begin_;} 98 _LIBCPP_INLINE_VISIBILITY size_type capacity() const {return static_cast<size_type>(__end_cap() - __first_);} 99 _LIBCPP_INLINE_VISIBILITY size_type __front_spare() const {return static_cast<size_type>(__begin_ - __first_);} 100 _LIBCPP_INLINE_VISIBILITY size_type __back_spare() const {return static_cast<size_type>(__end_cap() - __end_);} 101 102 _LIBCPP_INLINE_VISIBILITY reference front() {return *__begin_;} 103 _LIBCPP_INLINE_VISIBILITY const_reference front() const {return *__begin_;} 104 _LIBCPP_INLINE_VISIBILITY reference back() {return *(__end_ - 1);} 105 _LIBCPP_INLINE_VISIBILITY const_reference back() const {return *(__end_ - 1);} 106 107 void reserve(size_type __n); 108 void shrink_to_fit() _NOEXCEPT; 109 void push_front(const_reference __x); 110 _LIBCPP_INLINE_VISIBILITY void push_back(const_reference __x); 111 void push_front(value_type&& __x); 112 void push_back(value_type&& __x); 113 template <class... _Args> 114 void emplace_back(_Args&&... __args); 115 116 _LIBCPP_INLINE_VISIBILITY void pop_front() {__destruct_at_begin(__begin_+1);} 117 _LIBCPP_INLINE_VISIBILITY void pop_back() {__destruct_at_end(__end_-1);} 118 119 void __construct_at_end(size_type __n); 120 void __construct_at_end(size_type __n, const_reference __x); 121 template <class _InputIter> 122 __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIter>::value> 123 __construct_at_end(_InputIter __first, _InputIter __last); 124 template <class _ForwardIterator> 125 __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value> 126 __construct_at_end(_ForwardIterator __first, _ForwardIterator __last); 127 128 _LIBCPP_INLINE_VISIBILITY void __destruct_at_begin(pointer __new_begin) 129 {__destruct_at_begin(__new_begin, is_trivially_destructible<value_type>());} 130 _LIBCPP_INLINE_VISIBILITY 131 void __destruct_at_begin(pointer __new_begin, false_type); 132 _LIBCPP_INLINE_VISIBILITY 133 void __destruct_at_begin(pointer __new_begin, true_type); 134 135 _LIBCPP_INLINE_VISIBILITY 136 void __destruct_at_end(pointer __new_last) _NOEXCEPT 137 {__destruct_at_end(__new_last, false_type());} 138 _LIBCPP_INLINE_VISIBILITY 139 void __destruct_at_end(pointer __new_last, false_type) _NOEXCEPT; 140 _LIBCPP_INLINE_VISIBILITY 141 void __destruct_at_end(pointer __new_last, true_type) _NOEXCEPT; 142 143 void swap(__split_buffer& __x) 144 _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value|| 145 __is_nothrow_swappable<__alloc_rr>::value); 146 147 bool __invariants() const; 148 149private: 150 _LIBCPP_INLINE_VISIBILITY 151 void __move_assign_alloc(__split_buffer& __c, true_type) 152 _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value) 153 { 154 __alloc() = _VSTD::move(__c.__alloc()); 155 } 156 157 _LIBCPP_INLINE_VISIBILITY 158 void __move_assign_alloc(__split_buffer&, false_type) _NOEXCEPT 159 {} 160 161 struct _ConstructTransaction { 162 explicit _ConstructTransaction(pointer* __p, size_type __n) _NOEXCEPT 163 : __pos_(*__p), __end_(*__p + __n), __dest_(__p) { 164 } 165 ~_ConstructTransaction() { 166 *__dest_ = __pos_; 167 } 168 pointer __pos_; 169 const pointer __end_; 170 private: 171 pointer *__dest_; 172 }; 173}; 174 175template <class _Tp, class _Allocator> 176bool 177__split_buffer<_Tp, _Allocator>::__invariants() const 178{ 179 if (__first_ == nullptr) 180 { 181 if (__begin_ != nullptr) 182 return false; 183 if (__end_ != nullptr) 184 return false; 185 if (__end_cap() != nullptr) 186 return false; 187 } 188 else 189 { 190 if (__begin_ < __first_) 191 return false; 192 if (__end_ < __begin_) 193 return false; 194 if (__end_cap() < __end_) 195 return false; 196 } 197 return true; 198} 199 200// Default constructs __n objects starting at __end_ 201// throws if construction throws 202// Precondition: __n > 0 203// Precondition: size() + __n <= capacity() 204// Postcondition: size() == size() + __n 205template <class _Tp, class _Allocator> 206void 207__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n) 208{ 209 _ConstructTransaction __tx(&this->__end_, __n); 210 for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) { 211 __alloc_traits::construct(this->__alloc(), _VSTD::__to_address(__tx.__pos_)); 212 } 213} 214 215// Copy constructs __n objects starting at __end_ from __x 216// throws if construction throws 217// Precondition: __n > 0 218// Precondition: size() + __n <= capacity() 219// Postcondition: size() == old size() + __n 220// Postcondition: [i] == __x for all i in [size() - __n, __n) 221template <class _Tp, class _Allocator> 222void 223__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x) 224{ 225 _ConstructTransaction __tx(&this->__end_, __n); 226 for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) { 227 __alloc_traits::construct(this->__alloc(), 228 _VSTD::__to_address(__tx.__pos_), __x); 229 } 230} 231 232template <class _Tp, class _Allocator> 233template <class _InputIter> 234__enable_if_t<__is_exactly_cpp17_input_iterator<_InputIter>::value> 235__split_buffer<_Tp, _Allocator>::__construct_at_end(_InputIter __first, _InputIter __last) 236{ 237 __alloc_rr& __a = this->__alloc(); 238 for (; __first != __last; ++__first) 239 { 240 if (__end_ == __end_cap()) 241 { 242 size_type __old_cap = __end_cap() - __first_; 243 size_type __new_cap = _VSTD::max<size_type>(2 * __old_cap, 8); 244 __split_buffer __buf(__new_cap, 0, __a); 245 for (pointer __p = __begin_; __p != __end_; ++__p, (void) ++__buf.__end_) 246 __alloc_traits::construct(__buf.__alloc(), 247 _VSTD::__to_address(__buf.__end_), _VSTD::move(*__p)); 248 swap(__buf); 249 } 250 __alloc_traits::construct(__a, _VSTD::__to_address(this->__end_), *__first); 251 ++this->__end_; 252 } 253} 254 255template <class _Tp, class _Allocator> 256template <class _ForwardIterator> 257__enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value> 258__split_buffer<_Tp, _Allocator>::__construct_at_end(_ForwardIterator __first, _ForwardIterator __last) 259{ 260 _ConstructTransaction __tx(&this->__end_, _VSTD::distance(__first, __last)); 261 for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_, (void) ++__first) { 262 __alloc_traits::construct(this->__alloc(), 263 _VSTD::__to_address(__tx.__pos_), *__first); 264 } 265} 266 267template <class _Tp, class _Allocator> 268inline 269void 270__split_buffer<_Tp, _Allocator>::__destruct_at_begin(pointer __new_begin, false_type) 271{ 272 while (__begin_ != __new_begin) 273 __alloc_traits::destroy(__alloc(), _VSTD::__to_address(__begin_++)); 274} 275 276template <class _Tp, class _Allocator> 277inline 278void 279__split_buffer<_Tp, _Allocator>::__destruct_at_begin(pointer __new_begin, true_type) 280{ 281 __begin_ = __new_begin; 282} 283 284template <class _Tp, class _Allocator> 285inline _LIBCPP_INLINE_VISIBILITY 286void 287__split_buffer<_Tp, _Allocator>::__destruct_at_end(pointer __new_last, false_type) _NOEXCEPT 288{ 289 while (__new_last != __end_) 290 __alloc_traits::destroy(__alloc(), _VSTD::__to_address(--__end_)); 291} 292 293template <class _Tp, class _Allocator> 294inline _LIBCPP_INLINE_VISIBILITY 295void 296__split_buffer<_Tp, _Allocator>::__destruct_at_end(pointer __new_last, true_type) _NOEXCEPT 297{ 298 __end_ = __new_last; 299} 300 301template <class _Tp, class _Allocator> 302__split_buffer<_Tp, _Allocator>::__split_buffer(size_type __cap, size_type __start, __alloc_rr& __a) 303 : __end_cap_(nullptr, __a) 304{ 305 if (__cap == 0) { 306 __first_ = nullptr; 307 } else { 308 auto __allocation = std::__allocate_at_least(__alloc(), __cap); 309 __first_ = __allocation.ptr; 310 __cap = __allocation.count; 311 } 312 __begin_ = __end_ = __first_ + __start; 313 __end_cap() = __first_ + __cap; 314} 315 316template <class _Tp, class _Allocator> 317inline 318__split_buffer<_Tp, _Allocator>::__split_buffer() 319 _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value) 320 : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __default_init_tag()) 321{ 322} 323 324template <class _Tp, class _Allocator> 325inline 326__split_buffer<_Tp, _Allocator>::__split_buffer(__alloc_rr& __a) 327 : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a) 328{ 329} 330 331template <class _Tp, class _Allocator> 332inline 333__split_buffer<_Tp, _Allocator>::__split_buffer(const __alloc_rr& __a) 334 : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a) 335{ 336} 337 338template <class _Tp, class _Allocator> 339__split_buffer<_Tp, _Allocator>::~__split_buffer() 340{ 341 clear(); 342 if (__first_) 343 __alloc_traits::deallocate(__alloc(), __first_, capacity()); 344} 345 346template <class _Tp, class _Allocator> 347__split_buffer<_Tp, _Allocator>::__split_buffer(__split_buffer&& __c) 348 _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value) 349 : __first_(_VSTD::move(__c.__first_)), 350 __begin_(_VSTD::move(__c.__begin_)), 351 __end_(_VSTD::move(__c.__end_)), 352 __end_cap_(_VSTD::move(__c.__end_cap_)) 353{ 354 __c.__first_ = nullptr; 355 __c.__begin_ = nullptr; 356 __c.__end_ = nullptr; 357 __c.__end_cap() = nullptr; 358} 359 360template <class _Tp, class _Allocator> 361__split_buffer<_Tp, _Allocator>::__split_buffer(__split_buffer&& __c, const __alloc_rr& __a) 362 : __end_cap_(nullptr, __a) 363{ 364 if (__a == __c.__alloc()) 365 { 366 __first_ = __c.__first_; 367 __begin_ = __c.__begin_; 368 __end_ = __c.__end_; 369 __end_cap() = __c.__end_cap(); 370 __c.__first_ = nullptr; 371 __c.__begin_ = nullptr; 372 __c.__end_ = nullptr; 373 __c.__end_cap() = nullptr; 374 } 375 else 376 { 377 auto __allocation = std::__allocate_at_least(__alloc(), __c.size()); 378 __first_ = __allocation.ptr; 379 __begin_ = __end_ = __first_; 380 __end_cap() = __first_ + __allocation.count; 381 typedef move_iterator<iterator> _Ip; 382 __construct_at_end(_Ip(__c.begin()), _Ip(__c.end())); 383 } 384} 385 386template <class _Tp, class _Allocator> 387__split_buffer<_Tp, _Allocator>& 388__split_buffer<_Tp, _Allocator>::operator=(__split_buffer&& __c) 389 _NOEXCEPT_((__alloc_traits::propagate_on_container_move_assignment::value && 390 is_nothrow_move_assignable<allocator_type>::value) || 391 !__alloc_traits::propagate_on_container_move_assignment::value) 392{ 393 clear(); 394 shrink_to_fit(); 395 __first_ = __c.__first_; 396 __begin_ = __c.__begin_; 397 __end_ = __c.__end_; 398 __end_cap() = __c.__end_cap(); 399 __move_assign_alloc(__c, 400 integral_constant<bool, 401 __alloc_traits::propagate_on_container_move_assignment::value>()); 402 __c.__first_ = __c.__begin_ = __c.__end_ = __c.__end_cap() = nullptr; 403 return *this; 404} 405 406template <class _Tp, class _Allocator> 407void 408__split_buffer<_Tp, _Allocator>::swap(__split_buffer& __x) 409 _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value|| 410 __is_nothrow_swappable<__alloc_rr>::value) 411{ 412 _VSTD::swap(__first_, __x.__first_); 413 _VSTD::swap(__begin_, __x.__begin_); 414 _VSTD::swap(__end_, __x.__end_); 415 _VSTD::swap(__end_cap(), __x.__end_cap()); 416 _VSTD::__swap_allocator(__alloc(), __x.__alloc()); 417} 418 419template <class _Tp, class _Allocator> 420void 421__split_buffer<_Tp, _Allocator>::reserve(size_type __n) 422{ 423 if (__n < capacity()) 424 { 425 __split_buffer<value_type, __alloc_rr&> __t(__n, 0, __alloc()); 426 __t.__construct_at_end(move_iterator<pointer>(__begin_), 427 move_iterator<pointer>(__end_)); 428 _VSTD::swap(__first_, __t.__first_); 429 _VSTD::swap(__begin_, __t.__begin_); 430 _VSTD::swap(__end_, __t.__end_); 431 _VSTD::swap(__end_cap(), __t.__end_cap()); 432 } 433} 434 435template <class _Tp, class _Allocator> 436void 437__split_buffer<_Tp, _Allocator>::shrink_to_fit() _NOEXCEPT 438{ 439 if (capacity() > size()) 440 { 441#ifndef _LIBCPP_NO_EXCEPTIONS 442 try 443 { 444#endif // _LIBCPP_NO_EXCEPTIONS 445 __split_buffer<value_type, __alloc_rr&> __t(size(), 0, __alloc()); 446 __t.__construct_at_end(move_iterator<pointer>(__begin_), 447 move_iterator<pointer>(__end_)); 448 __t.__end_ = __t.__begin_ + (__end_ - __begin_); 449 _VSTD::swap(__first_, __t.__first_); 450 _VSTD::swap(__begin_, __t.__begin_); 451 _VSTD::swap(__end_, __t.__end_); 452 _VSTD::swap(__end_cap(), __t.__end_cap()); 453#ifndef _LIBCPP_NO_EXCEPTIONS 454 } 455 catch (...) 456 { 457 } 458#endif // _LIBCPP_NO_EXCEPTIONS 459 } 460} 461 462template <class _Tp, class _Allocator> 463void 464__split_buffer<_Tp, _Allocator>::push_front(const_reference __x) 465{ 466 if (__begin_ == __first_) 467 { 468 if (__end_ < __end_cap()) 469 { 470 difference_type __d = __end_cap() - __end_; 471 __d = (__d + 1) / 2; 472 __begin_ = _VSTD::move_backward(__begin_, __end_, __end_ + __d); 473 __end_ += __d; 474 } 475 else 476 { 477 size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 478 __split_buffer<value_type, __alloc_rr&> __t(__c, (__c + 3) / 4, __alloc()); 479 __t.__construct_at_end(move_iterator<pointer>(__begin_), 480 move_iterator<pointer>(__end_)); 481 _VSTD::swap(__first_, __t.__first_); 482 _VSTD::swap(__begin_, __t.__begin_); 483 _VSTD::swap(__end_, __t.__end_); 484 _VSTD::swap(__end_cap(), __t.__end_cap()); 485 } 486 } 487 __alloc_traits::construct(__alloc(), _VSTD::__to_address(__begin_-1), __x); 488 --__begin_; 489} 490 491template <class _Tp, class _Allocator> 492void 493__split_buffer<_Tp, _Allocator>::push_front(value_type&& __x) 494{ 495 if (__begin_ == __first_) 496 { 497 if (__end_ < __end_cap()) 498 { 499 difference_type __d = __end_cap() - __end_; 500 __d = (__d + 1) / 2; 501 __begin_ = _VSTD::move_backward(__begin_, __end_, __end_ + __d); 502 __end_ += __d; 503 } 504 else 505 { 506 size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 507 __split_buffer<value_type, __alloc_rr&> __t(__c, (__c + 3) / 4, __alloc()); 508 __t.__construct_at_end(move_iterator<pointer>(__begin_), 509 move_iterator<pointer>(__end_)); 510 _VSTD::swap(__first_, __t.__first_); 511 _VSTD::swap(__begin_, __t.__begin_); 512 _VSTD::swap(__end_, __t.__end_); 513 _VSTD::swap(__end_cap(), __t.__end_cap()); 514 } 515 } 516 __alloc_traits::construct(__alloc(), _VSTD::__to_address(__begin_-1), 517 _VSTD::move(__x)); 518 --__begin_; 519} 520 521template <class _Tp, class _Allocator> 522inline _LIBCPP_INLINE_VISIBILITY 523void 524__split_buffer<_Tp, _Allocator>::push_back(const_reference __x) 525{ 526 if (__end_ == __end_cap()) 527 { 528 if (__begin_ > __first_) 529 { 530 difference_type __d = __begin_ - __first_; 531 __d = (__d + 1) / 2; 532 __end_ = _VSTD::move(__begin_, __end_, __begin_ - __d); 533 __begin_ -= __d; 534 } 535 else 536 { 537 size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 538 __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc()); 539 __t.__construct_at_end(move_iterator<pointer>(__begin_), 540 move_iterator<pointer>(__end_)); 541 _VSTD::swap(__first_, __t.__first_); 542 _VSTD::swap(__begin_, __t.__begin_); 543 _VSTD::swap(__end_, __t.__end_); 544 _VSTD::swap(__end_cap(), __t.__end_cap()); 545 } 546 } 547 __alloc_traits::construct(__alloc(), _VSTD::__to_address(__end_), __x); 548 ++__end_; 549} 550 551template <class _Tp, class _Allocator> 552void 553__split_buffer<_Tp, _Allocator>::push_back(value_type&& __x) 554{ 555 if (__end_ == __end_cap()) 556 { 557 if (__begin_ > __first_) 558 { 559 difference_type __d = __begin_ - __first_; 560 __d = (__d + 1) / 2; 561 __end_ = _VSTD::move(__begin_, __end_, __begin_ - __d); 562 __begin_ -= __d; 563 } 564 else 565 { 566 size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 567 __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc()); 568 __t.__construct_at_end(move_iterator<pointer>(__begin_), 569 move_iterator<pointer>(__end_)); 570 _VSTD::swap(__first_, __t.__first_); 571 _VSTD::swap(__begin_, __t.__begin_); 572 _VSTD::swap(__end_, __t.__end_); 573 _VSTD::swap(__end_cap(), __t.__end_cap()); 574 } 575 } 576 __alloc_traits::construct(__alloc(), _VSTD::__to_address(__end_), 577 _VSTD::move(__x)); 578 ++__end_; 579} 580 581template <class _Tp, class _Allocator> 582template <class... _Args> 583void 584__split_buffer<_Tp, _Allocator>::emplace_back(_Args&&... __args) 585{ 586 if (__end_ == __end_cap()) 587 { 588 if (__begin_ > __first_) 589 { 590 difference_type __d = __begin_ - __first_; 591 __d = (__d + 1) / 2; 592 __end_ = _VSTD::move(__begin_, __end_, __begin_ - __d); 593 __begin_ -= __d; 594 } 595 else 596 { 597 size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 598 __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc()); 599 __t.__construct_at_end(move_iterator<pointer>(__begin_), 600 move_iterator<pointer>(__end_)); 601 _VSTD::swap(__first_, __t.__first_); 602 _VSTD::swap(__begin_, __t.__begin_); 603 _VSTD::swap(__end_, __t.__end_); 604 _VSTD::swap(__end_cap(), __t.__end_cap()); 605 } 606 } 607 __alloc_traits::construct(__alloc(), _VSTD::__to_address(__end_), 608 _VSTD::forward<_Args>(__args)...); 609 ++__end_; 610} 611 612template <class _Tp, class _Allocator> 613inline _LIBCPP_INLINE_VISIBILITY 614void 615swap(__split_buffer<_Tp, _Allocator>& __x, __split_buffer<_Tp, _Allocator>& __y) 616 _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) 617{ 618 __x.swap(__y); 619} 620 621_LIBCPP_END_NAMESPACE_STD 622 623_LIBCPP_POP_MACROS 624 625#endif // _LIBCPP___SPLIT_BUFFER 626