1// Map implementation -*- C++ -*- 2 3// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 4// 2011, 2012 Free Software Foundation, Inc. 5// 6// This file is part of the GNU ISO C++ Library. This library is free 7// software; you can redistribute it and/or modify it under the 8// terms of the GNU General Public License as published by the 9// Free Software Foundation; either version 3, or (at your option) 10// any later version. 11 12// This library is distributed in the hope that it will be useful, 13// but WITHOUT ANY WARRANTY; without even the implied warranty of 14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15// GNU General Public License for more details. 16 17// Under Section 7 of GPL version 3, you are granted additional 18// permissions described in the GCC Runtime Library Exception, version 19// 3.1, as published by the Free Software Foundation. 20 21// You should have received a copy of the GNU General Public License and 22// a copy of the GCC Runtime Library Exception along with this program; 23// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24// <http://www.gnu.org/licenses/>. 25 26/* 27 * 28 * Copyright (c) 1994 29 * Hewlett-Packard Company 30 * 31 * Permission to use, copy, modify, distribute and sell this software 32 * and its documentation for any purpose is hereby granted without fee, 33 * provided that the above copyright notice appear in all copies and 34 * that both that copyright notice and this permission notice appear 35 * in supporting documentation. Hewlett-Packard Company makes no 36 * representations about the suitability of this software for any 37 * purpose. It is provided "as is" without express or implied warranty. 38 * 39 * 40 * Copyright (c) 1996,1997 41 * Silicon Graphics Computer Systems, Inc. 42 * 43 * Permission to use, copy, modify, distribute and sell this software 44 * and its documentation for any purpose is hereby granted without fee, 45 * provided that the above copyright notice appear in all copies and 46 * that both that copyright notice and this permission notice appear 47 * in supporting documentation. Silicon Graphics makes no 48 * representations about the suitability of this software for any 49 * purpose. It is provided "as is" without express or implied warranty. 50 */ 51 52/** @file bits/stl_map.h 53 * This is an internal header file, included by other library headers. 54 * Do not attempt to use it directly. @headername{map} 55 */ 56 57#ifndef _STL_MAP_H 58#define _STL_MAP_H 1 59 60#include <bits/functexcept.h> 61#include <bits/concept_check.h> 62#ifdef __GXX_EXPERIMENTAL_CXX0X__ 63#include <initializer_list> 64#endif 65 66namespace std _GLIBCXX_VISIBILITY(default) 67{ 68_GLIBCXX_BEGIN_NAMESPACE_CONTAINER 69 70 /** 71 * @brief A standard container made up of (key,value) pairs, which can be 72 * retrieved based on a key, in logarithmic time. 73 * 74 * @ingroup associative_containers 75 * 76 * Meets the requirements of a <a href="tables.html#65">container</a>, a 77 * <a href="tables.html#66">reversible container</a>, and an 78 * <a href="tables.html#69">associative container</a> (using unique keys). 79 * For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the 80 * value_type is std::pair<const Key,T>. 81 * 82 * Maps support bidirectional iterators. 83 * 84 * The private tree data is declared exactly the same way for map and 85 * multimap; the distinction is made entirely in how the tree functions are 86 * called (*_unique versus *_equal, same as the standard). 87 */ 88 template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>, 89 typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > > 90 class map 91 { 92 public: 93 typedef _Key key_type; 94 typedef _Tp mapped_type; 95 typedef std::pair<const _Key, _Tp> value_type; 96 typedef _Compare key_compare; 97 typedef _Alloc allocator_type; 98 99 private: 100 // concept requirements 101 typedef typename _Alloc::value_type _Alloc_value_type; 102 __glibcxx_class_requires(_Tp, _SGIAssignableConcept) 103 __glibcxx_class_requires4(_Compare, bool, _Key, _Key, 104 _BinaryFunctionConcept) 105 __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept) 106 107 public: 108 class value_compare 109 : public std::binary_function<value_type, value_type, bool> 110 { 111 friend class map<_Key, _Tp, _Compare, _Alloc>; 112 protected: 113 _Compare comp; 114 115 value_compare(_Compare __c) 116 : comp(__c) { } 117 118 public: 119 bool operator()(const value_type& __x, const value_type& __y) const 120 { return comp(__x.first, __y.first); } 121 }; 122 123 private: 124 /// This turns a red-black tree into a [multi]map. 125 typedef typename _Alloc::template rebind<value_type>::other 126 _Pair_alloc_type; 127 128 typedef _Rb_tree<key_type, value_type, _Select1st<value_type>, 129 key_compare, _Pair_alloc_type> _Rep_type; 130 131 /// The actual tree structure. 132 _Rep_type _M_t; 133 134 public: 135 // many of these are specified differently in ISO, but the following are 136 // "functionally equivalent" 137 typedef typename _Pair_alloc_type::pointer pointer; 138 typedef typename _Pair_alloc_type::const_pointer const_pointer; 139 typedef typename _Pair_alloc_type::reference reference; 140 typedef typename _Pair_alloc_type::const_reference const_reference; 141 typedef typename _Rep_type::iterator iterator; 142 typedef typename _Rep_type::const_iterator const_iterator; 143 typedef typename _Rep_type::size_type size_type; 144 typedef typename _Rep_type::difference_type difference_type; 145 typedef typename _Rep_type::reverse_iterator reverse_iterator; 146 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator; 147 148 // [23.3.1.1] construct/copy/destroy 149 // (get_allocator() is normally listed in this section, but seems to have 150 // been accidentally omitted in the printed standard) 151 /** 152 * @brief Default constructor creates no elements. 153 */ 154 map() 155 : _M_t() { } 156 157 /** 158 * @brief Creates a %map with no elements. 159 * @param __comp A comparison object. 160 * @param __a An allocator object. 161 */ 162 explicit 163 map(const _Compare& __comp, 164 const allocator_type& __a = allocator_type()) 165 : _M_t(__comp, _Pair_alloc_type(__a)) { } 166 167 /** 168 * @brief %Map copy constructor. 169 * @param __x A %map of identical element and allocator types. 170 * 171 * The newly-created %map uses a copy of the allocation object 172 * used by @a __x. 173 */ 174 map(const map& __x) 175 : _M_t(__x._M_t) { } 176 177#ifdef __GXX_EXPERIMENTAL_CXX0X__ 178 /** 179 * @brief %Map move constructor. 180 * @param __x A %map of identical element and allocator types. 181 * 182 * The newly-created %map contains the exact contents of @a __x. 183 * The contents of @a __x are a valid, but unspecified %map. 184 */ 185 map(map&& __x) 186 noexcept(is_nothrow_copy_constructible<_Compare>::value) 187 : _M_t(std::move(__x._M_t)) { } 188 189 /** 190 * @brief Builds a %map from an initializer_list. 191 * @param __l An initializer_list. 192 * @param __comp A comparison object. 193 * @param __a An allocator object. 194 * 195 * Create a %map consisting of copies of the elements in the 196 * initializer_list @a __l. 197 * This is linear in N if the range is already sorted, and NlogN 198 * otherwise (where N is @a __l.size()). 199 */ 200 map(initializer_list<value_type> __l, 201 const _Compare& __comp = _Compare(), 202 const allocator_type& __a = allocator_type()) 203 : _M_t(__comp, _Pair_alloc_type(__a)) 204 { _M_t._M_insert_unique(__l.begin(), __l.end()); } 205#endif 206 207 /** 208 * @brief Builds a %map from a range. 209 * @param __first An input iterator. 210 * @param __last An input iterator. 211 * 212 * Create a %map consisting of copies of the elements from 213 * [__first,__last). This is linear in N if the range is 214 * already sorted, and NlogN otherwise (where N is 215 * distance(__first,__last)). 216 */ 217 template<typename _InputIterator> 218 map(_InputIterator __first, _InputIterator __last) 219 : _M_t() 220 { _M_t._M_insert_unique(__first, __last); } 221 222 /** 223 * @brief Builds a %map from a range. 224 * @param __first An input iterator. 225 * @param __last An input iterator. 226 * @param __comp A comparison functor. 227 * @param __a An allocator object. 228 * 229 * Create a %map consisting of copies of the elements from 230 * [__first,__last). This is linear in N if the range is 231 * already sorted, and NlogN otherwise (where N is 232 * distance(__first,__last)). 233 */ 234 template<typename _InputIterator> 235 map(_InputIterator __first, _InputIterator __last, 236 const _Compare& __comp, 237 const allocator_type& __a = allocator_type()) 238 : _M_t(__comp, _Pair_alloc_type(__a)) 239 { _M_t._M_insert_unique(__first, __last); } 240 241 // FIXME There is no dtor declared, but we should have something 242 // generated by Doxygen. I don't know what tags to add to this 243 // paragraph to make that happen: 244 /** 245 * The dtor only erases the elements, and note that if the elements 246 * themselves are pointers, the pointed-to memory is not touched in any 247 * way. Managing the pointer is the user's responsibility. 248 */ 249 250 /** 251 * @brief %Map assignment operator. 252 * @param __x A %map of identical element and allocator types. 253 * 254 * All the elements of @a __x are copied, but unlike the copy 255 * constructor, the allocator object is not copied. 256 */ 257 map& 258 operator=(const map& __x) 259 { 260 _M_t = __x._M_t; 261 return *this; 262 } 263 264#ifdef __GXX_EXPERIMENTAL_CXX0X__ 265 /** 266 * @brief %Map move assignment operator. 267 * @param __x A %map of identical element and allocator types. 268 * 269 * The contents of @a __x are moved into this map (without copying). 270 * @a __x is a valid, but unspecified %map. 271 */ 272 map& 273 operator=(map&& __x) 274 { 275 // NB: DR 1204. 276 // NB: DR 675. 277 this->clear(); 278 this->swap(__x); 279 return *this; 280 } 281 282 /** 283 * @brief %Map list assignment operator. 284 * @param __l An initializer_list. 285 * 286 * This function fills a %map with copies of the elements in the 287 * initializer list @a __l. 288 * 289 * Note that the assignment completely changes the %map and 290 * that the resulting %map's size is the same as the number 291 * of elements assigned. Old data may be lost. 292 */ 293 map& 294 operator=(initializer_list<value_type> __l) 295 { 296 this->clear(); 297 this->insert(__l.begin(), __l.end()); 298 return *this; 299 } 300#endif 301 302 /// Get a copy of the memory allocation object. 303 allocator_type 304 get_allocator() const _GLIBCXX_NOEXCEPT 305 { return allocator_type(_M_t.get_allocator()); } 306 307 // iterators 308 /** 309 * Returns a read/write iterator that points to the first pair in the 310 * %map. 311 * Iteration is done in ascending order according to the keys. 312 */ 313 iterator 314 begin() _GLIBCXX_NOEXCEPT 315 { return _M_t.begin(); } 316 317 /** 318 * Returns a read-only (constant) iterator that points to the first pair 319 * in the %map. Iteration is done in ascending order according to the 320 * keys. 321 */ 322 const_iterator 323 begin() const _GLIBCXX_NOEXCEPT 324 { return _M_t.begin(); } 325 326 /** 327 * Returns a read/write iterator that points one past the last 328 * pair in the %map. Iteration is done in ascending order 329 * according to the keys. 330 */ 331 iterator 332 end() _GLIBCXX_NOEXCEPT 333 { return _M_t.end(); } 334 335 /** 336 * Returns a read-only (constant) iterator that points one past the last 337 * pair in the %map. Iteration is done in ascending order according to 338 * the keys. 339 */ 340 const_iterator 341 end() const _GLIBCXX_NOEXCEPT 342 { return _M_t.end(); } 343 344 /** 345 * Returns a read/write reverse iterator that points to the last pair in 346 * the %map. Iteration is done in descending order according to the 347 * keys. 348 */ 349 reverse_iterator 350 rbegin() _GLIBCXX_NOEXCEPT 351 { return _M_t.rbegin(); } 352 353 /** 354 * Returns a read-only (constant) reverse iterator that points to the 355 * last pair in the %map. Iteration is done in descending order 356 * according to the keys. 357 */ 358 const_reverse_iterator 359 rbegin() const _GLIBCXX_NOEXCEPT 360 { return _M_t.rbegin(); } 361 362 /** 363 * Returns a read/write reverse iterator that points to one before the 364 * first pair in the %map. Iteration is done in descending order 365 * according to the keys. 366 */ 367 reverse_iterator 368 rend() _GLIBCXX_NOEXCEPT 369 { return _M_t.rend(); } 370 371 /** 372 * Returns a read-only (constant) reverse iterator that points to one 373 * before the first pair in the %map. Iteration is done in descending 374 * order according to the keys. 375 */ 376 const_reverse_iterator 377 rend() const _GLIBCXX_NOEXCEPT 378 { return _M_t.rend(); } 379 380#ifdef __GXX_EXPERIMENTAL_CXX0X__ 381 /** 382 * Returns a read-only (constant) iterator that points to the first pair 383 * in the %map. Iteration is done in ascending order according to the 384 * keys. 385 */ 386 const_iterator 387 cbegin() const noexcept 388 { return _M_t.begin(); } 389 390 /** 391 * Returns a read-only (constant) iterator that points one past the last 392 * pair in the %map. Iteration is done in ascending order according to 393 * the keys. 394 */ 395 const_iterator 396 cend() const noexcept 397 { return _M_t.end(); } 398 399 /** 400 * Returns a read-only (constant) reverse iterator that points to the 401 * last pair in the %map. Iteration is done in descending order 402 * according to the keys. 403 */ 404 const_reverse_iterator 405 crbegin() const noexcept 406 { return _M_t.rbegin(); } 407 408 /** 409 * Returns a read-only (constant) reverse iterator that points to one 410 * before the first pair in the %map. Iteration is done in descending 411 * order according to the keys. 412 */ 413 const_reverse_iterator 414 crend() const noexcept 415 { return _M_t.rend(); } 416#endif 417 418 // capacity 419 /** Returns true if the %map is empty. (Thus begin() would equal 420 * end().) 421 */ 422 bool 423 empty() const _GLIBCXX_NOEXCEPT 424 { return _M_t.empty(); } 425 426 /** Returns the size of the %map. */ 427 size_type 428 size() const _GLIBCXX_NOEXCEPT 429 { return _M_t.size(); } 430 431 /** Returns the maximum size of the %map. */ 432 size_type 433 max_size() const _GLIBCXX_NOEXCEPT 434 { return _M_t.max_size(); } 435 436 // [23.3.1.2] element access 437 /** 438 * @brief Subscript ( @c [] ) access to %map data. 439 * @param __k The key for which data should be retrieved. 440 * @return A reference to the data of the (key,data) %pair. 441 * 442 * Allows for easy lookup with the subscript ( @c [] ) 443 * operator. Returns data associated with the key specified in 444 * subscript. If the key does not exist, a pair with that key 445 * is created using default values, which is then returned. 446 * 447 * Lookup requires logarithmic time. 448 */ 449 mapped_type& 450 operator[](const key_type& __k) 451 { 452 // concept requirements 453 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>) 454 455 iterator __i = lower_bound(__k); 456 // __i->first is greater than or equivalent to __k. 457 if (__i == end() || key_comp()(__k, (*__i).first)) 458 __i = insert(__i, value_type(__k, mapped_type())); 459 return (*__i).second; 460 } 461 462#ifdef __GXX_EXPERIMENTAL_CXX0X__ 463 mapped_type& 464 operator[](key_type&& __k) 465 { 466 // concept requirements 467 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>) 468 469 iterator __i = lower_bound(__k); 470 // __i->first is greater than or equivalent to __k. 471 if (__i == end() || key_comp()(__k, (*__i).first)) 472 __i = insert(__i, std::make_pair(std::move(__k), mapped_type())); 473 return (*__i).second; 474 } 475#endif 476 477 // _GLIBCXX_RESOLVE_LIB_DEFECTS 478 // DR 464. Suggestion for new member functions in standard containers. 479 /** 480 * @brief Access to %map data. 481 * @param __k The key for which data should be retrieved. 482 * @return A reference to the data whose key is equivalent to @a __k, if 483 * such a data is present in the %map. 484 * @throw std::out_of_range If no such data is present. 485 */ 486 mapped_type& 487 at(const key_type& __k) 488 { 489 iterator __i = lower_bound(__k); 490 if (__i == end() || key_comp()(__k, (*__i).first)) 491 __throw_out_of_range(__N("map::at")); 492 return (*__i).second; 493 } 494 495 const mapped_type& 496 at(const key_type& __k) const 497 { 498 const_iterator __i = lower_bound(__k); 499 if (__i == end() || key_comp()(__k, (*__i).first)) 500 __throw_out_of_range(__N("map::at")); 501 return (*__i).second; 502 } 503 504 // modifiers 505 /** 506 * @brief Attempts to insert a std::pair into the %map. 507 508 * @param __x Pair to be inserted (see std::make_pair for easy 509 * creation of pairs). 510 * 511 * @return A pair, of which the first element is an iterator that 512 * points to the possibly inserted pair, and the second is 513 * a bool that is true if the pair was actually inserted. 514 * 515 * This function attempts to insert a (key, value) %pair into the %map. 516 * A %map relies on unique keys and thus a %pair is only inserted if its 517 * first element (the key) is not already present in the %map. 518 * 519 * Insertion requires logarithmic time. 520 */ 521 std::pair<iterator, bool> 522 insert(const value_type& __x) 523 { return _M_t._M_insert_unique(__x); } 524 525#ifdef __GXX_EXPERIMENTAL_CXX0X__ 526 template<typename _Pair, typename = typename 527 std::enable_if<std::is_constructible<value_type, 528 _Pair&&>::value>::type> 529 std::pair<iterator, bool> 530 insert(_Pair&& __x) 531 { return _M_t._M_insert_unique(std::forward<_Pair>(__x)); } 532#endif 533 534#ifdef __GXX_EXPERIMENTAL_CXX0X__ 535 /** 536 * @brief Attempts to insert a list of std::pairs into the %map. 537 * @param __list A std::initializer_list<value_type> of pairs to be 538 * inserted. 539 * 540 * Complexity similar to that of the range constructor. 541 */ 542 void 543 insert(std::initializer_list<value_type> __list) 544 { insert(__list.begin(), __list.end()); } 545#endif 546 547 /** 548 * @brief Attempts to insert a std::pair into the %map. 549 * @param __position An iterator that serves as a hint as to where the 550 * pair should be inserted. 551 * @param __x Pair to be inserted (see std::make_pair for easy creation 552 * of pairs). 553 * @return An iterator that points to the element with key of 554 * @a __x (may or may not be the %pair passed in). 555 * 556 557 * This function is not concerned about whether the insertion 558 * took place, and thus does not return a boolean like the 559 * single-argument insert() does. Note that the first 560 * parameter is only a hint and can potentially improve the 561 * performance of the insertion process. A bad hint would 562 * cause no gains in efficiency. 563 * 564 * See 565 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html 566 * for more on @a hinting. 567 * 568 * Insertion requires logarithmic time (if the hint is not taken). 569 */ 570 iterator 571#ifdef __GXX_EXPERIMENTAL_CXX0X__ 572 insert(const_iterator __position, const value_type& __x) 573#else 574 insert(iterator __position, const value_type& __x) 575#endif 576 { return _M_t._M_insert_unique_(__position, __x); } 577 578#ifdef __GXX_EXPERIMENTAL_CXX0X__ 579 template<typename _Pair, typename = typename 580 std::enable_if<std::is_constructible<value_type, 581 _Pair&&>::value>::type> 582 iterator 583 insert(const_iterator __position, _Pair&& __x) 584 { return _M_t._M_insert_unique_(__position, 585 std::forward<_Pair>(__x)); } 586#endif 587 588 /** 589 * @brief Template function that attempts to insert a range of elements. 590 * @param __first Iterator pointing to the start of the range to be 591 * inserted. 592 * @param __last Iterator pointing to the end of the range. 593 * 594 * Complexity similar to that of the range constructor. 595 */ 596 template<typename _InputIterator> 597 void 598 insert(_InputIterator __first, _InputIterator __last) 599 { _M_t._M_insert_unique(__first, __last); } 600 601#ifdef __GXX_EXPERIMENTAL_CXX0X__ 602 // _GLIBCXX_RESOLVE_LIB_DEFECTS 603 // DR 130. Associative erase should return an iterator. 604 /** 605 * @brief Erases an element from a %map. 606 * @param __position An iterator pointing to the element to be erased. 607 * @return An iterator pointing to the element immediately following 608 * @a position prior to the element being erased. If no such 609 * element exists, end() is returned. 610 * 611 * This function erases an element, pointed to by the given 612 * iterator, from a %map. Note that this function only erases 613 * the element, and that if the element is itself a pointer, 614 * the pointed-to memory is not touched in any way. Managing 615 * the pointer is the user's responsibility. 616 */ 617 iterator 618 erase(const_iterator __position) 619 { return _M_t.erase(__position); } 620 621 // LWG 2059. 622 iterator 623 erase(iterator __position) 624 { return _M_t.erase(__position); } 625#else 626 /** 627 * @brief Erases an element from a %map. 628 * @param __position An iterator pointing to the element to be erased. 629 * 630 * This function erases an element, pointed to by the given 631 * iterator, from a %map. Note that this function only erases 632 * the element, and that if the element is itself a pointer, 633 * the pointed-to memory is not touched in any way. Managing 634 * the pointer is the user's responsibility. 635 */ 636 void 637 erase(iterator __position) 638 { _M_t.erase(__position); } 639#endif 640 641 /** 642 * @brief Erases elements according to the provided key. 643 * @param __x Key of element to be erased. 644 * @return The number of elements erased. 645 * 646 * This function erases all the elements located by the given key from 647 * a %map. 648 * Note that this function only erases the element, and that if 649 * the element is itself a pointer, the pointed-to memory is not touched 650 * in any way. Managing the pointer is the user's responsibility. 651 */ 652 size_type 653 erase(const key_type& __x) 654 { return _M_t.erase(__x); } 655 656#ifdef __GXX_EXPERIMENTAL_CXX0X__ 657 // _GLIBCXX_RESOLVE_LIB_DEFECTS 658 // DR 130. Associative erase should return an iterator. 659 /** 660 * @brief Erases a [first,last) range of elements from a %map. 661 * @param __first Iterator pointing to the start of the range to be 662 * erased. 663 * @param __last Iterator pointing to the end of the range to 664 * be erased. 665 * @return The iterator @a __last. 666 * 667 * This function erases a sequence of elements from a %map. 668 * Note that this function only erases the element, and that if 669 * the element is itself a pointer, the pointed-to memory is not touched 670 * in any way. Managing the pointer is the user's responsibility. 671 */ 672 iterator 673 erase(const_iterator __first, const_iterator __last) 674 { return _M_t.erase(__first, __last); } 675#else 676 /** 677 * @brief Erases a [__first,__last) range of elements from a %map. 678 * @param __first Iterator pointing to the start of the range to be 679 * erased. 680 * @param __last Iterator pointing to the end of the range to 681 * be erased. 682 * 683 * This function erases a sequence of elements from a %map. 684 * Note that this function only erases the element, and that if 685 * the element is itself a pointer, the pointed-to memory is not touched 686 * in any way. Managing the pointer is the user's responsibility. 687 */ 688 void 689 erase(iterator __first, iterator __last) 690 { _M_t.erase(__first, __last); } 691#endif 692 693 /** 694 * @brief Swaps data with another %map. 695 * @param __x A %map of the same element and allocator types. 696 * 697 * This exchanges the elements between two maps in constant 698 * time. (It is only swapping a pointer, an integer, and an 699 * instance of the @c Compare type (which itself is often 700 * stateless and empty), so it should be quite fast.) Note 701 * that the global std::swap() function is specialized such 702 * that std::swap(m1,m2) will feed to this function. 703 */ 704 void 705 swap(map& __x) 706 { _M_t.swap(__x._M_t); } 707 708 /** 709 * Erases all elements in a %map. Note that this function only 710 * erases the elements, and that if the elements themselves are 711 * pointers, the pointed-to memory is not touched in any way. 712 * Managing the pointer is the user's responsibility. 713 */ 714 void 715 clear() _GLIBCXX_NOEXCEPT 716 { _M_t.clear(); } 717 718 // observers 719 /** 720 * Returns the key comparison object out of which the %map was 721 * constructed. 722 */ 723 key_compare 724 key_comp() const 725 { return _M_t.key_comp(); } 726 727 /** 728 * Returns a value comparison object, built from the key comparison 729 * object out of which the %map was constructed. 730 */ 731 value_compare 732 value_comp() const 733 { return value_compare(_M_t.key_comp()); } 734 735 // [23.3.1.3] map operations 736 /** 737 * @brief Tries to locate an element in a %map. 738 * @param __x Key of (key, value) %pair to be located. 739 * @return Iterator pointing to sought-after element, or end() if not 740 * found. 741 * 742 * This function takes a key and tries to locate the element with which 743 * the key matches. If successful the function returns an iterator 744 * pointing to the sought after %pair. If unsuccessful it returns the 745 * past-the-end ( @c end() ) iterator. 746 */ 747 iterator 748 find(const key_type& __x) 749 { return _M_t.find(__x); } 750 751 /** 752 * @brief Tries to locate an element in a %map. 753 * @param __x Key of (key, value) %pair to be located. 754 * @return Read-only (constant) iterator pointing to sought-after 755 * element, or end() if not found. 756 * 757 * This function takes a key and tries to locate the element with which 758 * the key matches. If successful the function returns a constant 759 * iterator pointing to the sought after %pair. If unsuccessful it 760 * returns the past-the-end ( @c end() ) iterator. 761 */ 762 const_iterator 763 find(const key_type& __x) const 764 { return _M_t.find(__x); } 765 766 /** 767 * @brief Finds the number of elements with given key. 768 * @param __x Key of (key, value) pairs to be located. 769 * @return Number of elements with specified key. 770 * 771 * This function only makes sense for multimaps; for map the result will 772 * either be 0 (not present) or 1 (present). 773 */ 774 size_type 775 count(const key_type& __x) const 776 { return _M_t.find(__x) == _M_t.end() ? 0 : 1; } 777 778 /** 779 * @brief Finds the beginning of a subsequence matching given key. 780 * @param __x Key of (key, value) pair to be located. 781 * @return Iterator pointing to first element equal to or greater 782 * than key, or end(). 783 * 784 * This function returns the first element of a subsequence of elements 785 * that matches the given key. If unsuccessful it returns an iterator 786 * pointing to the first element that has a greater value than given key 787 * or end() if no such element exists. 788 */ 789 iterator 790 lower_bound(const key_type& __x) 791 { return _M_t.lower_bound(__x); } 792 793 /** 794 * @brief Finds the beginning of a subsequence matching given key. 795 * @param __x Key of (key, value) pair to be located. 796 * @return Read-only (constant) iterator pointing to first element 797 * equal to or greater than key, or end(). 798 * 799 * This function returns the first element of a subsequence of elements 800 * that matches the given key. If unsuccessful it returns an iterator 801 * pointing to the first element that has a greater value than given key 802 * or end() if no such element exists. 803 */ 804 const_iterator 805 lower_bound(const key_type& __x) const 806 { return _M_t.lower_bound(__x); } 807 808 /** 809 * @brief Finds the end of a subsequence matching given key. 810 * @param __x Key of (key, value) pair to be located. 811 * @return Iterator pointing to the first element 812 * greater than key, or end(). 813 */ 814 iterator 815 upper_bound(const key_type& __x) 816 { return _M_t.upper_bound(__x); } 817 818 /** 819 * @brief Finds the end of a subsequence matching given key. 820 * @param __x Key of (key, value) pair to be located. 821 * @return Read-only (constant) iterator pointing to first iterator 822 * greater than key, or end(). 823 */ 824 const_iterator 825 upper_bound(const key_type& __x) const 826 { return _M_t.upper_bound(__x); } 827 828 /** 829 * @brief Finds a subsequence matching given key. 830 * @param __x Key of (key, value) pairs to be located. 831 * @return Pair of iterators that possibly points to the subsequence 832 * matching given key. 833 * 834 * This function is equivalent to 835 * @code 836 * std::make_pair(c.lower_bound(val), 837 * c.upper_bound(val)) 838 * @endcode 839 * (but is faster than making the calls separately). 840 * 841 * This function probably only makes sense for multimaps. 842 */ 843 std::pair<iterator, iterator> 844 equal_range(const key_type& __x) 845 { return _M_t.equal_range(__x); } 846 847 /** 848 * @brief Finds a subsequence matching given key. 849 * @param __x Key of (key, value) pairs to be located. 850 * @return Pair of read-only (constant) iterators that possibly points 851 * to the subsequence matching given key. 852 * 853 * This function is equivalent to 854 * @code 855 * std::make_pair(c.lower_bound(val), 856 * c.upper_bound(val)) 857 * @endcode 858 * (but is faster than making the calls separately). 859 * 860 * This function probably only makes sense for multimaps. 861 */ 862 std::pair<const_iterator, const_iterator> 863 equal_range(const key_type& __x) const 864 { return _M_t.equal_range(__x); } 865 866 template<typename _K1, typename _T1, typename _C1, typename _A1> 867 friend bool 868 operator==(const map<_K1, _T1, _C1, _A1>&, 869 const map<_K1, _T1, _C1, _A1>&); 870 871 template<typename _K1, typename _T1, typename _C1, typename _A1> 872 friend bool 873 operator<(const map<_K1, _T1, _C1, _A1>&, 874 const map<_K1, _T1, _C1, _A1>&); 875 }; 876 877 /** 878 * @brief Map equality comparison. 879 * @param __x A %map. 880 * @param __y A %map of the same type as @a x. 881 * @return True iff the size and elements of the maps are equal. 882 * 883 * This is an equivalence relation. It is linear in the size of the 884 * maps. Maps are considered equivalent if their sizes are equal, 885 * and if corresponding elements compare equal. 886 */ 887 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 888 inline bool 889 operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x, 890 const map<_Key, _Tp, _Compare, _Alloc>& __y) 891 { return __x._M_t == __y._M_t; } 892 893 /** 894 * @brief Map ordering relation. 895 * @param __x A %map. 896 * @param __y A %map of the same type as @a x. 897 * @return True iff @a x is lexicographically less than @a y. 898 * 899 * This is a total ordering relation. It is linear in the size of the 900 * maps. The elements must be comparable with @c <. 901 * 902 * See std::lexicographical_compare() for how the determination is made. 903 */ 904 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 905 inline bool 906 operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x, 907 const map<_Key, _Tp, _Compare, _Alloc>& __y) 908 { return __x._M_t < __y._M_t; } 909 910 /// Based on operator== 911 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 912 inline bool 913 operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x, 914 const map<_Key, _Tp, _Compare, _Alloc>& __y) 915 { return !(__x == __y); } 916 917 /// Based on operator< 918 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 919 inline bool 920 operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x, 921 const map<_Key, _Tp, _Compare, _Alloc>& __y) 922 { return __y < __x; } 923 924 /// Based on operator< 925 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 926 inline bool 927 operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x, 928 const map<_Key, _Tp, _Compare, _Alloc>& __y) 929 { return !(__y < __x); } 930 931 /// Based on operator< 932 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 933 inline bool 934 operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x, 935 const map<_Key, _Tp, _Compare, _Alloc>& __y) 936 { return !(__x < __y); } 937 938 /// See std::map::swap(). 939 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 940 inline void 941 swap(map<_Key, _Tp, _Compare, _Alloc>& __x, 942 map<_Key, _Tp, _Compare, _Alloc>& __y) 943 { __x.swap(__y); } 944 945_GLIBCXX_END_NAMESPACE_CONTAINER 946} // namespace std 947 948#endif /* _STL_MAP_H */ 949