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/allocate_at_least.h> 21#include <__memory/allocator.h> 22#include <__memory/allocator_traits.h> 23#include <__memory/compressed_pair.h> 24#include <__memory/pointer_traits.h> 25#include <__memory/swap_allocator.h> 26#include <__type_traits/add_lvalue_reference.h> 27#include <__type_traits/enable_if.h> 28#include <__type_traits/integral_constant.h> 29#include <__type_traits/is_nothrow_assignable.h> 30#include <__type_traits/is_nothrow_constructible.h> 31#include <__type_traits/is_swappable.h> 32#include <__type_traits/is_trivially_destructible.h> 33#include <__type_traits/remove_reference.h> 34#include <__utility/forward.h> 35#include <__utility/move.h> 36#include <cstddef> 37 38#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 39# pragma GCC system_header 40#endif 41 42_LIBCPP_PUSH_MACROS 43#include <__undef_macros> 44 45_LIBCPP_BEGIN_NAMESPACE_STD 46 47// __split_buffer allocates a contiguous chunk of memory and stores objects in the range [__begin_, __end_). 48// It has uninitialized memory in the ranges [__first_, __begin_) and [__end_, __end_cap_.first()). That allows 49// it to grow both in the front and back without having to move the data. 50 51template <class _Tp, class _Allocator = allocator<_Tp> > 52struct __split_buffer { 53public: 54 using value_type = _Tp; 55 using allocator_type = _Allocator; 56 using __alloc_rr = __libcpp_remove_reference_t<allocator_type>; 57 using __alloc_traits = allocator_traits<__alloc_rr>; 58 using reference = value_type&; 59 using const_reference = const value_type&; 60 using size_type = typename __alloc_traits::size_type; 61 using difference_type = typename __alloc_traits::difference_type; 62 using pointer = typename __alloc_traits::pointer; 63 using const_pointer = typename __alloc_traits::const_pointer; 64 using iterator = pointer; 65 using const_iterator = const_pointer; 66 67 pointer __first_; 68 pointer __begin_; 69 pointer __end_; 70 __compressed_pair<pointer, allocator_type> __end_cap_; 71 72 using __alloc_ref = __add_lvalue_reference_t<allocator_type>; 73 using __alloc_const_ref = __add_lvalue_reference_t<allocator_type>; 74 75 __split_buffer(const __split_buffer&) = delete; 76 __split_buffer& operator=(const __split_buffer&) = delete; 77 78 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer() 79 _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value) 80 : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __default_init_tag()) {} 81 82 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI explicit __split_buffer(__alloc_rr& __a) 83 : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a) {} 84 85 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI explicit __split_buffer(const __alloc_rr& __a) 86 : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a) {} 87 88 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI 89 __split_buffer(size_type __cap, size_type __start, __alloc_rr& __a); 90 91 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer(__split_buffer&& __c) 92 _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value); 93 94 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer(__split_buffer&& __c, const __alloc_rr& __a); 95 96 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer& operator=(__split_buffer&& __c) 97 _NOEXCEPT_((__alloc_traits::propagate_on_container_move_assignment::value && 98 is_nothrow_move_assignable<allocator_type>::value) || 99 !__alloc_traits::propagate_on_container_move_assignment::value); 100 101 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI ~__split_buffer(); 102 103 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __alloc_rr& __alloc() _NOEXCEPT { return __end_cap_.second(); } 104 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const __alloc_rr& __alloc() const _NOEXCEPT { 105 return __end_cap_.second(); 106 } 107 108 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI pointer& __end_cap() _NOEXCEPT { return __end_cap_.first(); } 109 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const pointer& __end_cap() const _NOEXCEPT { 110 return __end_cap_.first(); 111 } 112 113 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __begin_; } 114 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __begin_; } 115 116 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __end_; } 117 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __end_; } 118 119 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { __destruct_at_end(__begin_); } 120 121 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type size() const { 122 return static_cast<size_type>(__end_ - __begin_); 123 } 124 125 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI bool empty() const { return __end_ == __begin_; } 126 127 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type capacity() const { 128 return static_cast<size_type>(__end_cap() - __first_); 129 } 130 131 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type __front_spare() const { 132 return static_cast<size_type>(__begin_ - __first_); 133 } 134 135 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type __back_spare() const { 136 return static_cast<size_type>(__end_cap() - __end_); 137 } 138 139 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI reference front() { return *__begin_; } 140 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_reference front() const { return *__begin_; } 141 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI reference back() { return *(__end_ - 1); } 142 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_reference back() const { return *(__end_ - 1); } 143 144 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void reserve(size_type __n); 145 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void shrink_to_fit() _NOEXCEPT; 146 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_front(const_reference __x); 147 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_back(const_reference __x); 148 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_front(value_type&& __x); 149 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_back(value_type&& __x); 150 151 template <class... _Args> 152 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void emplace_back(_Args&&... __args); 153 154 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_front() { __destruct_at_begin(__begin_ + 1); } 155 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_back() { __destruct_at_end(__end_ - 1); } 156 157 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n); 158 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n, const_reference __x); 159 160 template <class _InputIter, __enable_if_t<__has_exactly_input_iterator_category<_InputIter>::value, int> = 0> 161 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(_InputIter __first, _InputIter __last); 162 163 template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> = 0> 164 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void 165 __construct_at_end(_ForwardIterator __first, _ForwardIterator __last); 166 167 template <class _Iterator, class _Sentinel> 168 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void 169 __construct_at_end_with_sentinel(_Iterator __first, _Sentinel __last); 170 171 template <class _Iterator> 172 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void 173 __construct_at_end_with_size(_Iterator __first, size_type __n); 174 175 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_begin(pointer __new_begin) { 176 __destruct_at_begin(__new_begin, is_trivially_destructible<value_type>()); 177 } 178 179 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_begin(pointer __new_begin, false_type); 180 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_begin(pointer __new_begin, true_type); 181 182 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_end(pointer __new_last) _NOEXCEPT { 183 __destruct_at_end(__new_last, false_type()); 184 } 185 186 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_end(pointer __new_last, false_type) _NOEXCEPT; 187 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_end(pointer __new_last, true_type) _NOEXCEPT; 188 189 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void swap(__split_buffer& __x) 190 _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable<__alloc_rr>::value); 191 192 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI bool __invariants() const; 193 194private: 195 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__split_buffer& __c, true_type) 196 _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value) { 197 __alloc() = std::move(__c.__alloc()); 198 } 199 200 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__split_buffer&, false_type) _NOEXCEPT {} 201 202 struct _ConstructTransaction { 203 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI explicit _ConstructTransaction( 204 pointer* __p, size_type __n) _NOEXCEPT 205 : __pos_(*__p), 206 __end_(*__p + __n), 207 __dest_(__p) {} 208 209 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI ~_ConstructTransaction() { *__dest_ = __pos_; } 210 211 pointer __pos_; 212 const pointer __end_; 213 214 private: 215 pointer* __dest_; 216 }; 217}; 218 219template <class _Tp, class _Allocator> 220_LIBCPP_CONSTEXPR_SINCE_CXX20 bool __split_buffer<_Tp, _Allocator>::__invariants() const { 221 if (__first_ == nullptr) { 222 if (__begin_ != nullptr) 223 return false; 224 if (__end_ != nullptr) 225 return false; 226 if (__end_cap() != nullptr) 227 return false; 228 } else { 229 if (__begin_ < __first_) 230 return false; 231 if (__end_ < __begin_) 232 return false; 233 if (__end_cap() < __end_) 234 return false; 235 } 236 return true; 237} 238 239// Default constructs __n objects starting at __end_ 240// throws if construction throws 241// Precondition: __n > 0 242// Precondition: size() + __n <= capacity() 243// Postcondition: size() == size() + __n 244template <class _Tp, class _Allocator> 245_LIBCPP_CONSTEXPR_SINCE_CXX20 void __split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n) { 246 _ConstructTransaction __tx(&this->__end_, __n); 247 for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) { 248 __alloc_traits::construct(this->__alloc(), std::__to_address(__tx.__pos_)); 249 } 250} 251 252// Copy constructs __n objects starting at __end_ from __x 253// throws if construction throws 254// Precondition: __n > 0 255// Precondition: size() + __n <= capacity() 256// Postcondition: size() == old size() + __n 257// Postcondition: [i] == __x for all i in [size() - __n, __n) 258template <class _Tp, class _Allocator> 259_LIBCPP_CONSTEXPR_SINCE_CXX20 void 260__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x) { 261 _ConstructTransaction __tx(&this->__end_, __n); 262 for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) { 263 __alloc_traits::construct(this->__alloc(), std::__to_address(__tx.__pos_), __x); 264 } 265} 266 267template <class _Tp, class _Allocator> 268template <class _InputIter, __enable_if_t<__has_exactly_input_iterator_category<_InputIter>::value, int> > 269_LIBCPP_CONSTEXPR_SINCE_CXX20 void 270__split_buffer<_Tp, _Allocator>::__construct_at_end(_InputIter __first, _InputIter __last) { 271 __construct_at_end_with_sentinel(__first, __last); 272} 273 274template <class _Tp, class _Allocator> 275template <class _Iterator, class _Sentinel> 276_LIBCPP_CONSTEXPR_SINCE_CXX20 void 277__split_buffer<_Tp, _Allocator>::__construct_at_end_with_sentinel(_Iterator __first, _Sentinel __last) { 278 __alloc_rr& __a = this->__alloc(); 279 for (; __first != __last; ++__first) { 280 if (__end_ == __end_cap()) { 281 size_type __old_cap = __end_cap() - __first_; 282 size_type __new_cap = std::max<size_type>(2 * __old_cap, 8); 283 __split_buffer __buf(__new_cap, 0, __a); 284 for (pointer __p = __begin_; __p != __end_; ++__p, (void)++__buf.__end_) 285 __alloc_traits::construct(__buf.__alloc(), std::__to_address(__buf.__end_), std::move(*__p)); 286 swap(__buf); 287 } 288 __alloc_traits::construct(__a, std::__to_address(this->__end_), *__first); 289 ++this->__end_; 290 } 291} 292template <class _Tp, class _Allocator> 293template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> > 294_LIBCPP_CONSTEXPR_SINCE_CXX20 void 295__split_buffer<_Tp, _Allocator>::__construct_at_end(_ForwardIterator __first, _ForwardIterator __last) { 296 __construct_at_end_with_size(__first, std::distance(__first, __last)); 297} 298 299template <class _Tp, class _Allocator> 300template <class _ForwardIterator> 301_LIBCPP_CONSTEXPR_SINCE_CXX20 void 302__split_buffer<_Tp, _Allocator>::__construct_at_end_with_size(_ForwardIterator __first, size_type __n) { 303 _ConstructTransaction __tx(&this->__end_, __n); 304 for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_, (void)++__first) { 305 __alloc_traits::construct(this->__alloc(), std::__to_address(__tx.__pos_), *__first); 306 } 307} 308 309template <class _Tp, class _Allocator> 310_LIBCPP_CONSTEXPR_SINCE_CXX20 inline void 311__split_buffer<_Tp, _Allocator>::__destruct_at_begin(pointer __new_begin, false_type) { 312 while (__begin_ != __new_begin) 313 __alloc_traits::destroy(__alloc(), std::__to_address(__begin_++)); 314} 315 316template <class _Tp, class _Allocator> 317_LIBCPP_CONSTEXPR_SINCE_CXX20 inline void 318__split_buffer<_Tp, _Allocator>::__destruct_at_begin(pointer __new_begin, true_type) { 319 __begin_ = __new_begin; 320} 321 322template <class _Tp, class _Allocator> 323_LIBCPP_CONSTEXPR_SINCE_CXX20 inline _LIBCPP_HIDE_FROM_ABI void 324__split_buffer<_Tp, _Allocator>::__destruct_at_end(pointer __new_last, false_type) _NOEXCEPT { 325 while (__new_last != __end_) 326 __alloc_traits::destroy(__alloc(), std::__to_address(--__end_)); 327} 328 329template <class _Tp, class _Allocator> 330_LIBCPP_CONSTEXPR_SINCE_CXX20 inline _LIBCPP_HIDE_FROM_ABI void 331__split_buffer<_Tp, _Allocator>::__destruct_at_end(pointer __new_last, true_type) _NOEXCEPT { 332 __end_ = __new_last; 333} 334 335template <class _Tp, class _Allocator> 336_LIBCPP_CONSTEXPR_SINCE_CXX20 337__split_buffer<_Tp, _Allocator>::__split_buffer(size_type __cap, size_type __start, __alloc_rr& __a) 338 : __end_cap_(nullptr, __a) { 339 if (__cap == 0) { 340 __first_ = nullptr; 341 } else { 342 auto __allocation = std::__allocate_at_least(__alloc(), __cap); 343 __first_ = __allocation.ptr; 344 __cap = __allocation.count; 345 } 346 __begin_ = __end_ = __first_ + __start; 347 __end_cap() = __first_ + __cap; 348} 349 350template <class _Tp, class _Allocator> 351_LIBCPP_CONSTEXPR_SINCE_CXX20 __split_buffer<_Tp, _Allocator>::~__split_buffer() { 352 clear(); 353 if (__first_) 354 __alloc_traits::deallocate(__alloc(), __first_, capacity()); 355} 356 357template <class _Tp, class _Allocator> 358_LIBCPP_CONSTEXPR_SINCE_CXX20 __split_buffer<_Tp, _Allocator>::__split_buffer(__split_buffer&& __c) 359 _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value) 360 : __first_(std::move(__c.__first_)), 361 __begin_(std::move(__c.__begin_)), 362 __end_(std::move(__c.__end_)), 363 __end_cap_(std::move(__c.__end_cap_)) { 364 __c.__first_ = nullptr; 365 __c.__begin_ = nullptr; 366 __c.__end_ = nullptr; 367 __c.__end_cap() = nullptr; 368} 369 370template <class _Tp, class _Allocator> 371_LIBCPP_CONSTEXPR_SINCE_CXX20 372__split_buffer<_Tp, _Allocator>::__split_buffer(__split_buffer&& __c, const __alloc_rr& __a) 373 : __end_cap_(nullptr, __a) { 374 if (__a == __c.__alloc()) { 375 __first_ = __c.__first_; 376 __begin_ = __c.__begin_; 377 __end_ = __c.__end_; 378 __end_cap() = __c.__end_cap(); 379 __c.__first_ = nullptr; 380 __c.__begin_ = nullptr; 381 __c.__end_ = nullptr; 382 __c.__end_cap() = nullptr; 383 } else { 384 auto __allocation = std::__allocate_at_least(__alloc(), __c.size()); 385 __first_ = __allocation.ptr; 386 __begin_ = __end_ = __first_; 387 __end_cap() = __first_ + __allocation.count; 388 typedef move_iterator<iterator> _Ip; 389 __construct_at_end(_Ip(__c.begin()), _Ip(__c.end())); 390 } 391} 392 393template <class _Tp, class _Allocator> 394_LIBCPP_CONSTEXPR_SINCE_CXX20 __split_buffer<_Tp, _Allocator>& 395__split_buffer<_Tp, _Allocator>::operator=(__split_buffer&& __c) 396 _NOEXCEPT_((__alloc_traits::propagate_on_container_move_assignment::value && 397 is_nothrow_move_assignable<allocator_type>::value) || 398 !__alloc_traits::propagate_on_container_move_assignment::value) { 399 clear(); 400 shrink_to_fit(); 401 __first_ = __c.__first_; 402 __begin_ = __c.__begin_; 403 __end_ = __c.__end_; 404 __end_cap() = __c.__end_cap(); 405 __move_assign_alloc(__c, integral_constant<bool, __alloc_traits::propagate_on_container_move_assignment::value>()); 406 __c.__first_ = __c.__begin_ = __c.__end_ = __c.__end_cap() = nullptr; 407 return *this; 408} 409 410template <class _Tp, class _Allocator> 411_LIBCPP_CONSTEXPR_SINCE_CXX20 void __split_buffer<_Tp, _Allocator>::swap(__split_buffer& __x) 412 _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable<__alloc_rr>::value) { 413 std::swap(__first_, __x.__first_); 414 std::swap(__begin_, __x.__begin_); 415 std::swap(__end_, __x.__end_); 416 std::swap(__end_cap(), __x.__end_cap()); 417 std::__swap_allocator(__alloc(), __x.__alloc()); 418} 419 420template <class _Tp, class _Allocator> 421_LIBCPP_CONSTEXPR_SINCE_CXX20 void __split_buffer<_Tp, _Allocator>::reserve(size_type __n) { 422 if (__n < capacity()) { 423 __split_buffer<value_type, __alloc_rr&> __t(__n, 0, __alloc()); 424 __t.__construct_at_end(move_iterator<pointer>(__begin_), move_iterator<pointer>(__end_)); 425 std::swap(__first_, __t.__first_); 426 std::swap(__begin_, __t.__begin_); 427 std::swap(__end_, __t.__end_); 428 std::swap(__end_cap(), __t.__end_cap()); 429 } 430} 431 432template <class _Tp, class _Allocator> 433_LIBCPP_CONSTEXPR_SINCE_CXX20 void __split_buffer<_Tp, _Allocator>::shrink_to_fit() _NOEXCEPT { 434 if (capacity() > size()) { 435#ifndef _LIBCPP_HAS_NO_EXCEPTIONS 436 try { 437#endif // _LIBCPP_HAS_NO_EXCEPTIONS 438 __split_buffer<value_type, __alloc_rr&> __t(size(), 0, __alloc()); 439 __t.__construct_at_end(move_iterator<pointer>(__begin_), move_iterator<pointer>(__end_)); 440 __t.__end_ = __t.__begin_ + (__end_ - __begin_); 441 std::swap(__first_, __t.__first_); 442 std::swap(__begin_, __t.__begin_); 443 std::swap(__end_, __t.__end_); 444 std::swap(__end_cap(), __t.__end_cap()); 445#ifndef _LIBCPP_HAS_NO_EXCEPTIONS 446 } catch (...) { 447 } 448#endif // _LIBCPP_HAS_NO_EXCEPTIONS 449 } 450} 451 452template <class _Tp, class _Allocator> 453_LIBCPP_CONSTEXPR_SINCE_CXX20 void __split_buffer<_Tp, _Allocator>::push_front(const_reference __x) { 454 if (__begin_ == __first_) { 455 if (__end_ < __end_cap()) { 456 difference_type __d = __end_cap() - __end_; 457 __d = (__d + 1) / 2; 458 __begin_ = std::move_backward(__begin_, __end_, __end_ + __d); 459 __end_ += __d; 460 } else { 461 size_type __c = std::max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 462 __split_buffer<value_type, __alloc_rr&> __t(__c, (__c + 3) / 4, __alloc()); 463 __t.__construct_at_end(move_iterator<pointer>(__begin_), move_iterator<pointer>(__end_)); 464 std::swap(__first_, __t.__first_); 465 std::swap(__begin_, __t.__begin_); 466 std::swap(__end_, __t.__end_); 467 std::swap(__end_cap(), __t.__end_cap()); 468 } 469 } 470 __alloc_traits::construct(__alloc(), std::__to_address(__begin_ - 1), __x); 471 --__begin_; 472} 473 474template <class _Tp, class _Allocator> 475_LIBCPP_CONSTEXPR_SINCE_CXX20 void __split_buffer<_Tp, _Allocator>::push_front(value_type&& __x) { 476 if (__begin_ == __first_) { 477 if (__end_ < __end_cap()) { 478 difference_type __d = __end_cap() - __end_; 479 __d = (__d + 1) / 2; 480 __begin_ = std::move_backward(__begin_, __end_, __end_ + __d); 481 __end_ += __d; 482 } else { 483 size_type __c = std::max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 484 __split_buffer<value_type, __alloc_rr&> __t(__c, (__c + 3) / 4, __alloc()); 485 __t.__construct_at_end(move_iterator<pointer>(__begin_), move_iterator<pointer>(__end_)); 486 std::swap(__first_, __t.__first_); 487 std::swap(__begin_, __t.__begin_); 488 std::swap(__end_, __t.__end_); 489 std::swap(__end_cap(), __t.__end_cap()); 490 } 491 } 492 __alloc_traits::construct(__alloc(), std::__to_address(__begin_ - 1), std::move(__x)); 493 --__begin_; 494} 495 496template <class _Tp, class _Allocator> 497_LIBCPP_CONSTEXPR_SINCE_CXX20 inline _LIBCPP_HIDE_FROM_ABI void 498__split_buffer<_Tp, _Allocator>::push_back(const_reference __x) { 499 if (__end_ == __end_cap()) { 500 if (__begin_ > __first_) { 501 difference_type __d = __begin_ - __first_; 502 __d = (__d + 1) / 2; 503 __end_ = std::move(__begin_, __end_, __begin_ - __d); 504 __begin_ -= __d; 505 } else { 506 size_type __c = std::max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 507 __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc()); 508 __t.__construct_at_end(move_iterator<pointer>(__begin_), move_iterator<pointer>(__end_)); 509 std::swap(__first_, __t.__first_); 510 std::swap(__begin_, __t.__begin_); 511 std::swap(__end_, __t.__end_); 512 std::swap(__end_cap(), __t.__end_cap()); 513 } 514 } 515 __alloc_traits::construct(__alloc(), std::__to_address(__end_), __x); 516 ++__end_; 517} 518 519template <class _Tp, class _Allocator> 520_LIBCPP_CONSTEXPR_SINCE_CXX20 void __split_buffer<_Tp, _Allocator>::push_back(value_type&& __x) { 521 if (__end_ == __end_cap()) { 522 if (__begin_ > __first_) { 523 difference_type __d = __begin_ - __first_; 524 __d = (__d + 1) / 2; 525 __end_ = std::move(__begin_, __end_, __begin_ - __d); 526 __begin_ -= __d; 527 } else { 528 size_type __c = std::max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 529 __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc()); 530 __t.__construct_at_end(move_iterator<pointer>(__begin_), move_iterator<pointer>(__end_)); 531 std::swap(__first_, __t.__first_); 532 std::swap(__begin_, __t.__begin_); 533 std::swap(__end_, __t.__end_); 534 std::swap(__end_cap(), __t.__end_cap()); 535 } 536 } 537 __alloc_traits::construct(__alloc(), std::__to_address(__end_), std::move(__x)); 538 ++__end_; 539} 540 541template <class _Tp, class _Allocator> 542template <class... _Args> 543_LIBCPP_CONSTEXPR_SINCE_CXX20 void __split_buffer<_Tp, _Allocator>::emplace_back(_Args&&... __args) { 544 if (__end_ == __end_cap()) { 545 if (__begin_ > __first_) { 546 difference_type __d = __begin_ - __first_; 547 __d = (__d + 1) / 2; 548 __end_ = std::move(__begin_, __end_, __begin_ - __d); 549 __begin_ -= __d; 550 } else { 551 size_type __c = std::max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1); 552 __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc()); 553 __t.__construct_at_end(move_iterator<pointer>(__begin_), move_iterator<pointer>(__end_)); 554 std::swap(__first_, __t.__first_); 555 std::swap(__begin_, __t.__begin_); 556 std::swap(__end_, __t.__end_); 557 std::swap(__end_cap(), __t.__end_cap()); 558 } 559 } 560 __alloc_traits::construct(__alloc(), std::__to_address(__end_), std::forward<_Args>(__args)...); 561 ++__end_; 562} 563 564template <class _Tp, class _Allocator> 565_LIBCPP_CONSTEXPR_SINCE_CXX20 inline _LIBCPP_HIDE_FROM_ABI void 566swap(__split_buffer<_Tp, _Allocator>& __x, __split_buffer<_Tp, _Allocator>& __y) _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) { 567 __x.swap(__y); 568} 569 570_LIBCPP_END_NAMESPACE_STD 571 572_LIBCPP_POP_MACROS 573 574#endif // _LIBCPP___SPLIT_BUFFER 575