1 // Internal policy header for TR1 unordered_set and unordered_map -*- C++ -*- 2 3 // Copyright (C) 2010 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file tr1/hashtable_policy.h 26 * This is an internal header file, included by other library headers. 27 * You should not attempt to use it directly. 28 */ 29 30 namespace std 31 { 32 namespace tr1 33 { 34 namespace __detail 35 { 36 // Helper function: return distance(first, last) for forward 37 // iterators, or 0 for input iterators. 38 template<class _Iterator> 39 inline typename std::iterator_traits<_Iterator>::difference_type 40 __distance_fw(_Iterator __first, _Iterator __last, 41 std::input_iterator_tag) 42 { return 0; } 43 44 template<class _Iterator> 45 inline typename std::iterator_traits<_Iterator>::difference_type 46 __distance_fw(_Iterator __first, _Iterator __last, 47 std::forward_iterator_tag) 48 { return std::distance(__first, __last); } 49 50 template<class _Iterator> 51 inline typename std::iterator_traits<_Iterator>::difference_type 52 __distance_fw(_Iterator __first, _Iterator __last) 53 { 54 typedef typename std::iterator_traits<_Iterator>::iterator_category _Tag; 55 return __distance_fw(__first, __last, _Tag()); 56 } 57 58 // Auxiliary types used for all instantiations of _Hashtable: nodes 59 // and iterators. 60 61 // Nodes, used to wrap elements stored in the hash table. A policy 62 // template parameter of class template _Hashtable controls whether 63 // nodes also store a hash code. In some cases (e.g. strings) this 64 // may be a performance win. 65 template<typename _Value, bool __cache_hash_code> 66 struct _Hash_node; 67 68 template<typename _Value> 69 struct _Hash_node<_Value, true> 70 { 71 _Value _M_v; 72 std::size_t _M_hash_code; 73 _Hash_node* _M_next; 74 }; 75 76 template<typename _Value> 77 struct _Hash_node<_Value, false> 78 { 79 _Value _M_v; 80 _Hash_node* _M_next; 81 }; 82 83 // Local iterators, used to iterate within a bucket but not between 84 // buckets. 85 template<typename _Value, bool __cache> 86 struct _Node_iterator_base 87 { 88 _Node_iterator_base(_Hash_node<_Value, __cache>* __p) 89 : _M_cur(__p) { } 90 91 void 92 _M_incr() 93 { _M_cur = _M_cur->_M_next; } 94 95 _Hash_node<_Value, __cache>* _M_cur; 96 }; 97 98 template<typename _Value, bool __cache> 99 inline bool 100 operator==(const _Node_iterator_base<_Value, __cache>& __x, 101 const _Node_iterator_base<_Value, __cache>& __y) 102 { return __x._M_cur == __y._M_cur; } 103 104 template<typename _Value, bool __cache> 105 inline bool 106 operator!=(const _Node_iterator_base<_Value, __cache>& __x, 107 const _Node_iterator_base<_Value, __cache>& __y) 108 { return __x._M_cur != __y._M_cur; } 109 110 template<typename _Value, bool __constant_iterators, bool __cache> 111 struct _Node_iterator 112 : public _Node_iterator_base<_Value, __cache> 113 { 114 typedef _Value value_type; 115 typedef typename 116 __gnu_cxx::__conditional_type<__constant_iterators, 117 const _Value*, _Value*>::__type 118 pointer; 119 typedef typename 120 __gnu_cxx::__conditional_type<__constant_iterators, 121 const _Value&, _Value&>::__type 122 reference; 123 typedef std::ptrdiff_t difference_type; 124 typedef std::forward_iterator_tag iterator_category; 125 126 _Node_iterator() 127 : _Node_iterator_base<_Value, __cache>(0) { } 128 129 explicit 130 _Node_iterator(_Hash_node<_Value, __cache>* __p) 131 : _Node_iterator_base<_Value, __cache>(__p) { } 132 133 reference 134 operator*() const 135 { return this->_M_cur->_M_v; } 136 137 pointer 138 operator->() const 139 { return &this->_M_cur->_M_v; } 140 141 _Node_iterator& 142 operator++() 143 { 144 this->_M_incr(); 145 return *this; 146 } 147 148 _Node_iterator 149 operator++(int) 150 { 151 _Node_iterator __tmp(*this); 152 this->_M_incr(); 153 return __tmp; 154 } 155 }; 156 157 template<typename _Value, bool __constant_iterators, bool __cache> 158 struct _Node_const_iterator 159 : public _Node_iterator_base<_Value, __cache> 160 { 161 typedef _Value value_type; 162 typedef const _Value* pointer; 163 typedef const _Value& reference; 164 typedef std::ptrdiff_t difference_type; 165 typedef std::forward_iterator_tag iterator_category; 166 167 _Node_const_iterator() 168 : _Node_iterator_base<_Value, __cache>(0) { } 169 170 explicit 171 _Node_const_iterator(_Hash_node<_Value, __cache>* __p) 172 : _Node_iterator_base<_Value, __cache>(__p) { } 173 174 _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators, 175 __cache>& __x) 176 : _Node_iterator_base<_Value, __cache>(__x._M_cur) { } 177 178 reference 179 operator*() const 180 { return this->_M_cur->_M_v; } 181 182 pointer 183 operator->() const 184 { return &this->_M_cur->_M_v; } 185 186 _Node_const_iterator& 187 operator++() 188 { 189 this->_M_incr(); 190 return *this; 191 } 192 193 _Node_const_iterator 194 operator++(int) 195 { 196 _Node_const_iterator __tmp(*this); 197 this->_M_incr(); 198 return __tmp; 199 } 200 }; 201 202 template<typename _Value, bool __cache> 203 struct _Hashtable_iterator_base 204 { 205 _Hashtable_iterator_base(_Hash_node<_Value, __cache>* __node, 206 _Hash_node<_Value, __cache>** __bucket) 207 : _M_cur_node(__node), _M_cur_bucket(__bucket) { } 208 209 void 210 _M_incr() 211 { 212 _M_cur_node = _M_cur_node->_M_next; 213 if (!_M_cur_node) 214 _M_incr_bucket(); 215 } 216 217 void 218 _M_incr_bucket(); 219 220 _Hash_node<_Value, __cache>* _M_cur_node; 221 _Hash_node<_Value, __cache>** _M_cur_bucket; 222 }; 223 224 // Global iterators, used for arbitrary iteration within a hash 225 // table. Larger and more expensive than local iterators. 226 template<typename _Value, bool __cache> 227 void 228 _Hashtable_iterator_base<_Value, __cache>:: 229 _M_incr_bucket() 230 { 231 ++_M_cur_bucket; 232 233 // This loop requires the bucket array to have a non-null sentinel. 234 while (!*_M_cur_bucket) 235 ++_M_cur_bucket; 236 _M_cur_node = *_M_cur_bucket; 237 } 238 239 template<typename _Value, bool __cache> 240 inline bool 241 operator==(const _Hashtable_iterator_base<_Value, __cache>& __x, 242 const _Hashtable_iterator_base<_Value, __cache>& __y) 243 { return __x._M_cur_node == __y._M_cur_node; } 244 245 template<typename _Value, bool __cache> 246 inline bool 247 operator!=(const _Hashtable_iterator_base<_Value, __cache>& __x, 248 const _Hashtable_iterator_base<_Value, __cache>& __y) 249 { return __x._M_cur_node != __y._M_cur_node; } 250 251 template<typename _Value, bool __constant_iterators, bool __cache> 252 struct _Hashtable_iterator 253 : public _Hashtable_iterator_base<_Value, __cache> 254 { 255 typedef _Value value_type; 256 typedef typename 257 __gnu_cxx::__conditional_type<__constant_iterators, 258 const _Value*, _Value*>::__type 259 pointer; 260 typedef typename 261 __gnu_cxx::__conditional_type<__constant_iterators, 262 const _Value&, _Value&>::__type 263 reference; 264 typedef std::ptrdiff_t difference_type; 265 typedef std::forward_iterator_tag iterator_category; 266 267 _Hashtable_iterator() 268 : _Hashtable_iterator_base<_Value, __cache>(0, 0) { } 269 270 _Hashtable_iterator(_Hash_node<_Value, __cache>* __p, 271 _Hash_node<_Value, __cache>** __b) 272 : _Hashtable_iterator_base<_Value, __cache>(__p, __b) { } 273 274 explicit 275 _Hashtable_iterator(_Hash_node<_Value, __cache>** __b) 276 : _Hashtable_iterator_base<_Value, __cache>(*__b, __b) { } 277 278 reference 279 operator*() const 280 { return this->_M_cur_node->_M_v; } 281 282 pointer 283 operator->() const 284 { return &this->_M_cur_node->_M_v; } 285 286 _Hashtable_iterator& 287 operator++() 288 { 289 this->_M_incr(); 290 return *this; 291 } 292 293 _Hashtable_iterator 294 operator++(int) 295 { 296 _Hashtable_iterator __tmp(*this); 297 this->_M_incr(); 298 return __tmp; 299 } 300 }; 301 302 template<typename _Value, bool __constant_iterators, bool __cache> 303 struct _Hashtable_const_iterator 304 : public _Hashtable_iterator_base<_Value, __cache> 305 { 306 typedef _Value value_type; 307 typedef const _Value* pointer; 308 typedef const _Value& reference; 309 typedef std::ptrdiff_t difference_type; 310 typedef std::forward_iterator_tag iterator_category; 311 312 _Hashtable_const_iterator() 313 : _Hashtable_iterator_base<_Value, __cache>(0, 0) { } 314 315 _Hashtable_const_iterator(_Hash_node<_Value, __cache>* __p, 316 _Hash_node<_Value, __cache>** __b) 317 : _Hashtable_iterator_base<_Value, __cache>(__p, __b) { } 318 319 explicit 320 _Hashtable_const_iterator(_Hash_node<_Value, __cache>** __b) 321 : _Hashtable_iterator_base<_Value, __cache>(*__b, __b) { } 322 323 _Hashtable_const_iterator(const _Hashtable_iterator<_Value, 324 __constant_iterators, __cache>& __x) 325 : _Hashtable_iterator_base<_Value, __cache>(__x._M_cur_node, 326 __x._M_cur_bucket) { } 327 328 reference 329 operator*() const 330 { return this->_M_cur_node->_M_v; } 331 332 pointer 333 operator->() const 334 { return &this->_M_cur_node->_M_v; } 335 336 _Hashtable_const_iterator& 337 operator++() 338 { 339 this->_M_incr(); 340 return *this; 341 } 342 343 _Hashtable_const_iterator 344 operator++(int) 345 { 346 _Hashtable_const_iterator __tmp(*this); 347 this->_M_incr(); 348 return __tmp; 349 } 350 }; 351 352 353 // Many of class template _Hashtable's template parameters are policy 354 // classes. These are defaults for the policies. 355 356 // Default range hashing function: use division to fold a large number 357 // into the range [0, N). 358 struct _Mod_range_hashing 359 { 360 typedef std::size_t first_argument_type; 361 typedef std::size_t second_argument_type; 362 typedef std::size_t result_type; 363 364 result_type 365 operator()(first_argument_type __num, second_argument_type __den) const 366 { return __num % __den; } 367 }; 368 369 // Default ranged hash function H. In principle it should be a 370 // function object composed from objects of type H1 and H2 such that 371 // h(k, N) = h2(h1(k), N), but that would mean making extra copies of 372 // h1 and h2. So instead we'll just use a tag to tell class template 373 // hashtable to do that composition. 374 struct _Default_ranged_hash { }; 375 376 // Default value for rehash policy. Bucket size is (usually) the 377 // smallest prime that keeps the load factor small enough. 378 struct _Prime_rehash_policy 379 { 380 _Prime_rehash_policy(float __z = 1.0) 381 : _M_max_load_factor(__z), _M_growth_factor(2.f), _M_next_resize(0) { } 382 383 float 384 max_load_factor() const 385 { return _M_max_load_factor; } 386 387 // Return a bucket size no smaller than n. 388 std::size_t 389 _M_next_bkt(std::size_t __n) const; 390 391 // Return a bucket count appropriate for n elements 392 std::size_t 393 _M_bkt_for_elements(std::size_t __n) const; 394 395 // __n_bkt is current bucket count, __n_elt is current element count, 396 // and __n_ins is number of elements to be inserted. Do we need to 397 // increase bucket count? If so, return make_pair(true, n), where n 398 // is the new bucket count. If not, return make_pair(false, 0). 399 std::pair<bool, std::size_t> 400 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt, 401 std::size_t __n_ins) const; 402 403 enum { _S_n_primes = sizeof(unsigned long) != 8 ? 256 : 256 + 48 }; 404 405 float _M_max_load_factor; 406 float _M_growth_factor; 407 mutable std::size_t _M_next_resize; 408 }; 409 410 extern const unsigned long __prime_list[]; 411 412 // XXX This is a hack. There's no good reason for any of 413 // _Prime_rehash_policy's member functions to be inline. 414 415 // Return a prime no smaller than n. 416 inline std::size_t 417 _Prime_rehash_policy:: 418 _M_next_bkt(std::size_t __n) const 419 { 420 const unsigned long* __p = std::lower_bound(__prime_list, __prime_list 421 + _S_n_primes, __n); 422 _M_next_resize = 423 static_cast<std::size_t>(__builtin_ceil(*__p * _M_max_load_factor)); 424 return *__p; 425 } 426 427 // Return the smallest prime p such that alpha p >= n, where alpha 428 // is the load factor. 429 inline std::size_t 430 _Prime_rehash_policy:: 431 _M_bkt_for_elements(std::size_t __n) const 432 { 433 const float __min_bkts = __n / _M_max_load_factor; 434 const unsigned long* __p = std::lower_bound(__prime_list, __prime_list 435 + _S_n_primes, __min_bkts); 436 _M_next_resize = 437 static_cast<std::size_t>(__builtin_ceil(*__p * _M_max_load_factor)); 438 return *__p; 439 } 440 441 // Finds the smallest prime p such that alpha p > __n_elt + __n_ins. 442 // If p > __n_bkt, return make_pair(true, p); otherwise return 443 // make_pair(false, 0). In principle this isn't very different from 444 // _M_bkt_for_elements. 445 446 // The only tricky part is that we're caching the element count at 447 // which we need to rehash, so we don't have to do a floating-point 448 // multiply for every insertion. 449 450 inline std::pair<bool, std::size_t> 451 _Prime_rehash_policy:: 452 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt, 453 std::size_t __n_ins) const 454 { 455 if (__n_elt + __n_ins > _M_next_resize) 456 { 457 float __min_bkts = ((float(__n_ins) + float(__n_elt)) 458 / _M_max_load_factor); 459 if (__min_bkts > __n_bkt) 460 { 461 __min_bkts = std::max(__min_bkts, _M_growth_factor * __n_bkt); 462 const unsigned long* __p = 463 std::lower_bound(__prime_list, __prime_list + _S_n_primes, 464 __min_bkts); 465 _M_next_resize = static_cast<std::size_t> 466 (__builtin_ceil(*__p * _M_max_load_factor)); 467 return std::make_pair(true, *__p); 468 } 469 else 470 { 471 _M_next_resize = static_cast<std::size_t> 472 (__builtin_ceil(__n_bkt * _M_max_load_factor)); 473 return std::make_pair(false, 0); 474 } 475 } 476 else 477 return std::make_pair(false, 0); 478 } 479 480 // Base classes for std::tr1::_Hashtable. We define these base 481 // classes because in some cases we want to do different things 482 // depending on the value of a policy class. In some cases the 483 // policy class affects which member functions and nested typedefs 484 // are defined; we handle that by specializing base class templates. 485 // Several of the base class templates need to access other members 486 // of class template _Hashtable, so we use the "curiously recurring 487 // template pattern" for them. 488 489 // class template _Map_base. If the hashtable has a value type of the 490 // form pair<T1, T2> and a key extraction policy that returns the 491 // first part of the pair, the hashtable gets a mapped_type typedef. 492 // If it satisfies those criteria and also has unique keys, then it 493 // also gets an operator[]. 494 template<typename _Key, typename _Value, typename _Ex, bool __unique, 495 typename _Hashtable> 496 struct _Map_base { }; 497 498 template<typename _Key, typename _Pair, typename _Hashtable> 499 struct _Map_base<_Key, _Pair, std::_Select1st<_Pair>, false, _Hashtable> 500 { 501 typedef typename _Pair::second_type mapped_type; 502 }; 503 504 template<typename _Key, typename _Pair, typename _Hashtable> 505 struct _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable> 506 { 507 typedef typename _Pair::second_type mapped_type; 508 509 mapped_type& 510 operator[](const _Key& __k); 511 }; 512 513 template<typename _Key, typename _Pair, typename _Hashtable> 514 typename _Map_base<_Key, _Pair, std::_Select1st<_Pair>, 515 true, _Hashtable>::mapped_type& 516 _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>:: 517 operator[](const _Key& __k) 518 { 519 _Hashtable* __h = static_cast<_Hashtable*>(this); 520 typename _Hashtable::_Hash_code_type __code = __h->_M_hash_code(__k); 521 std::size_t __n = __h->_M_bucket_index(__k, __code, 522 __h->_M_bucket_count); 523 524 typename _Hashtable::_Node* __p = 525 __h->_M_find_node(__h->_M_buckets[__n], __k, __code); 526 if (!__p) 527 return __h->_M_insert_bucket(std::make_pair(__k, mapped_type()), 528 __n, __code)->second; 529 return (__p->_M_v).second; 530 } 531 532 // class template _Rehash_base. Give hashtable the max_load_factor 533 // functions iff the rehash policy is _Prime_rehash_policy. 534 template<typename _RehashPolicy, typename _Hashtable> 535 struct _Rehash_base { }; 536 537 template<typename _Hashtable> 538 struct _Rehash_base<_Prime_rehash_policy, _Hashtable> 539 { 540 float 541 max_load_factor() const 542 { 543 const _Hashtable* __this = static_cast<const _Hashtable*>(this); 544 return __this->__rehash_policy().max_load_factor(); 545 } 546 547 void 548 max_load_factor(float __z) 549 { 550 _Hashtable* __this = static_cast<_Hashtable*>(this); 551 __this->__rehash_policy(_Prime_rehash_policy(__z)); 552 } 553 }; 554 555 // Class template _Hash_code_base. Encapsulates two policy issues that 556 // aren't quite orthogonal. 557 // (1) the difference between using a ranged hash function and using 558 // the combination of a hash function and a range-hashing function. 559 // In the former case we don't have such things as hash codes, so 560 // we have a dummy type as placeholder. 561 // (2) Whether or not we cache hash codes. Caching hash codes is 562 // meaningless if we have a ranged hash function. 563 // We also put the key extraction and equality comparison function 564 // objects here, for convenience. 565 566 // Primary template: unused except as a hook for specializations. 567 template<typename _Key, typename _Value, 568 typename _ExtractKey, typename _Equal, 569 typename _H1, typename _H2, typename _Hash, 570 bool __cache_hash_code> 571 struct _Hash_code_base; 572 573 // Specialization: ranged hash function, no caching hash codes. H1 574 // and H2 are provided but ignored. We define a dummy hash code type. 575 template<typename _Key, typename _Value, 576 typename _ExtractKey, typename _Equal, 577 typename _H1, typename _H2, typename _Hash> 578 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, 579 _Hash, false> 580 { 581 protected: 582 _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq, 583 const _H1&, const _H2&, const _Hash& __h) 584 : _M_extract(__ex), _M_eq(__eq), _M_ranged_hash(__h) { } 585 586 typedef void* _Hash_code_type; 587 588 _Hash_code_type 589 _M_hash_code(const _Key& __key) const 590 { return 0; } 591 592 std::size_t 593 _M_bucket_index(const _Key& __k, _Hash_code_type, 594 std::size_t __n) const 595 { return _M_ranged_hash(__k, __n); } 596 597 std::size_t 598 _M_bucket_index(const _Hash_node<_Value, false>* __p, 599 std::size_t __n) const 600 { return _M_ranged_hash(_M_extract(__p->_M_v), __n); } 601 602 bool 603 _M_compare(const _Key& __k, _Hash_code_type, 604 _Hash_node<_Value, false>* __n) const 605 { return _M_eq(__k, _M_extract(__n->_M_v)); } 606 607 void 608 _M_store_code(_Hash_node<_Value, false>*, _Hash_code_type) const 609 { } 610 611 void 612 _M_copy_code(_Hash_node<_Value, false>*, 613 const _Hash_node<_Value, false>*) const 614 { } 615 616 void 617 _M_swap(_Hash_code_base& __x) 618 { 619 std::swap(_M_extract, __x._M_extract); 620 std::swap(_M_eq, __x._M_eq); 621 std::swap(_M_ranged_hash, __x._M_ranged_hash); 622 } 623 624 protected: 625 _ExtractKey _M_extract; 626 _Equal _M_eq; 627 _Hash _M_ranged_hash; 628 }; 629 630 631 // No specialization for ranged hash function while caching hash codes. 632 // That combination is meaningless, and trying to do it is an error. 633 634 635 // Specialization: ranged hash function, cache hash codes. This 636 // combination is meaningless, so we provide only a declaration 637 // and no definition. 638 template<typename _Key, typename _Value, 639 typename _ExtractKey, typename _Equal, 640 typename _H1, typename _H2, typename _Hash> 641 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, 642 _Hash, true>; 643 644 // Specialization: hash function and range-hashing function, no 645 // caching of hash codes. H is provided but ignored. Provides 646 // typedef and accessor required by TR1. 647 template<typename _Key, typename _Value, 648 typename _ExtractKey, typename _Equal, 649 typename _H1, typename _H2> 650 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, 651 _Default_ranged_hash, false> 652 { 653 typedef _H1 hasher; 654 655 hasher 656 hash_function() const 657 { return _M_h1; } 658 659 protected: 660 _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq, 661 const _H1& __h1, const _H2& __h2, 662 const _Default_ranged_hash&) 663 : _M_extract(__ex), _M_eq(__eq), _M_h1(__h1), _M_h2(__h2) { } 664 665 typedef std::size_t _Hash_code_type; 666 667 _Hash_code_type 668 _M_hash_code(const _Key& __k) const 669 { return _M_h1(__k); } 670 671 std::size_t 672 _M_bucket_index(const _Key&, _Hash_code_type __c, 673 std::size_t __n) const 674 { return _M_h2(__c, __n); } 675 676 std::size_t 677 _M_bucket_index(const _Hash_node<_Value, false>* __p, 678 std::size_t __n) const 679 { return _M_h2(_M_h1(_M_extract(__p->_M_v)), __n); } 680 681 bool 682 _M_compare(const _Key& __k, _Hash_code_type, 683 _Hash_node<_Value, false>* __n) const 684 { return _M_eq(__k, _M_extract(__n->_M_v)); } 685 686 void 687 _M_store_code(_Hash_node<_Value, false>*, _Hash_code_type) const 688 { } 689 690 void 691 _M_copy_code(_Hash_node<_Value, false>*, 692 const _Hash_node<_Value, false>*) const 693 { } 694 695 void 696 _M_swap(_Hash_code_base& __x) 697 { 698 std::swap(_M_extract, __x._M_extract); 699 std::swap(_M_eq, __x._M_eq); 700 std::swap(_M_h1, __x._M_h1); 701 std::swap(_M_h2, __x._M_h2); 702 } 703 704 protected: 705 _ExtractKey _M_extract; 706 _Equal _M_eq; 707 _H1 _M_h1; 708 _H2 _M_h2; 709 }; 710 711 // Specialization: hash function and range-hashing function, 712 // caching hash codes. H is provided but ignored. Provides 713 // typedef and accessor required by TR1. 714 template<typename _Key, typename _Value, 715 typename _ExtractKey, typename _Equal, 716 typename _H1, typename _H2> 717 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, 718 _Default_ranged_hash, true> 719 { 720 typedef _H1 hasher; 721 722 hasher 723 hash_function() const 724 { return _M_h1; } 725 726 protected: 727 _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq, 728 const _H1& __h1, const _H2& __h2, 729 const _Default_ranged_hash&) 730 : _M_extract(__ex), _M_eq(__eq), _M_h1(__h1), _M_h2(__h2) { } 731 732 typedef std::size_t _Hash_code_type; 733 734 _Hash_code_type 735 _M_hash_code(const _Key& __k) const 736 { return _M_h1(__k); } 737 738 std::size_t 739 _M_bucket_index(const _Key&, _Hash_code_type __c, 740 std::size_t __n) const 741 { return _M_h2(__c, __n); } 742 743 std::size_t 744 _M_bucket_index(const _Hash_node<_Value, true>* __p, 745 std::size_t __n) const 746 { return _M_h2(__p->_M_hash_code, __n); } 747 748 bool 749 _M_compare(const _Key& __k, _Hash_code_type __c, 750 _Hash_node<_Value, true>* __n) const 751 { return __c == __n->_M_hash_code && _M_eq(__k, _M_extract(__n->_M_v)); } 752 753 void 754 _M_store_code(_Hash_node<_Value, true>* __n, _Hash_code_type __c) const 755 { __n->_M_hash_code = __c; } 756 757 void 758 _M_copy_code(_Hash_node<_Value, true>* __to, 759 const _Hash_node<_Value, true>* __from) const 760 { __to->_M_hash_code = __from->_M_hash_code; } 761 762 void 763 _M_swap(_Hash_code_base& __x) 764 { 765 std::swap(_M_extract, __x._M_extract); 766 std::swap(_M_eq, __x._M_eq); 767 std::swap(_M_h1, __x._M_h1); 768 std::swap(_M_h2, __x._M_h2); 769 } 770 771 protected: 772 _ExtractKey _M_extract; 773 _Equal _M_eq; 774 _H1 _M_h1; 775 _H2 _M_h2; 776 }; 777 } // namespace __detail 778 } 779 } 780