1 // Internal policy header for TR1 unordered_set and unordered_map -*- C++ -*- 2 3 // Copyright (C) 2007, 2008, 2009 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_impl/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 _GLIBCXX_BEGIN_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 template<typename _RAIter, typename _Tp> 59 _RAIter 60 __lower_bound(_RAIter __first, _RAIter __last, const _Tp& __val) 61 { 62 typedef typename std::iterator_traits<_RAIter>::difference_type _DType; 63 64 _DType __len = __last - __first; 65 while (__len > 0) 66 { 67 _DType __half = __len >> 1; 68 _RAIter __middle = __first + __half; 69 if (*__middle < __val) 70 { 71 __first = __middle; 72 ++__first; 73 __len = __len - __half - 1; 74 } 75 else 76 __len = __half; 77 } 78 return __first; 79 } 80 81 // Auxiliary types used for all instantiations of _Hashtable: nodes 82 // and iterators. 83 84 // Nodes, used to wrap elements stored in the hash table. A policy 85 // template parameter of class template _Hashtable controls whether 86 // nodes also store a hash code. In some cases (e.g. strings) this 87 // may be a performance win. 88 template<typename _Value, bool __cache_hash_code> 89 struct _Hash_node; 90 91 template<typename _Value> 92 struct _Hash_node<_Value, true> 93 { 94 _Value _M_v; 95 std::size_t _M_hash_code; 96 _Hash_node* _M_next; 97 98 #ifdef _GLIBCXX_INCLUDE_AS_CXX0X 99 template<typename... _Args> 100 _Hash_node(_Args&&... __args) 101 : _M_v(std::forward<_Args>(__args)...), 102 _M_hash_code(), _M_next() { } 103 #endif 104 }; 105 106 template<typename _Value> 107 struct _Hash_node<_Value, false> 108 { 109 _Value _M_v; 110 _Hash_node* _M_next; 111 112 #ifdef _GLIBCXX_INCLUDE_AS_CXX0X 113 template<typename... _Args> 114 _Hash_node(_Args&&... __args) 115 : _M_v(std::forward<_Args>(__args)...), 116 _M_next() { } 117 #endif 118 }; 119 120 // Local iterators, used to iterate within a bucket but not between 121 // buckets. 122 template<typename _Value, bool __cache> 123 struct _Node_iterator_base 124 { 125 _Node_iterator_base(_Hash_node<_Value, __cache>* __p) 126 : _M_cur(__p) { } 127 128 void 129 _M_incr() 130 { _M_cur = _M_cur->_M_next; } 131 132 _Hash_node<_Value, __cache>* _M_cur; 133 }; 134 135 template<typename _Value, bool __cache> 136 inline bool 137 operator==(const _Node_iterator_base<_Value, __cache>& __x, 138 const _Node_iterator_base<_Value, __cache>& __y) 139 { return __x._M_cur == __y._M_cur; } 140 141 template<typename _Value, bool __cache> 142 inline bool 143 operator!=(const _Node_iterator_base<_Value, __cache>& __x, 144 const _Node_iterator_base<_Value, __cache>& __y) 145 { return __x._M_cur != __y._M_cur; } 146 147 template<typename _Value, bool __constant_iterators, bool __cache> 148 struct _Node_iterator 149 : public _Node_iterator_base<_Value, __cache> 150 { 151 typedef _Value value_type; 152 typedef typename 153 __gnu_cxx::__conditional_type<__constant_iterators, 154 const _Value*, _Value*>::__type 155 pointer; 156 typedef typename 157 __gnu_cxx::__conditional_type<__constant_iterators, 158 const _Value&, _Value&>::__type 159 reference; 160 typedef std::ptrdiff_t difference_type; 161 typedef std::forward_iterator_tag iterator_category; 162 163 _Node_iterator() 164 : _Node_iterator_base<_Value, __cache>(0) { } 165 166 explicit 167 _Node_iterator(_Hash_node<_Value, __cache>* __p) 168 : _Node_iterator_base<_Value, __cache>(__p) { } 169 170 reference 171 operator*() const 172 { return this->_M_cur->_M_v; } 173 174 pointer 175 operator->() const 176 { return &this->_M_cur->_M_v; } 177 178 _Node_iterator& 179 operator++() 180 { 181 this->_M_incr(); 182 return *this; 183 } 184 185 _Node_iterator 186 operator++(int) 187 { 188 _Node_iterator __tmp(*this); 189 this->_M_incr(); 190 return __tmp; 191 } 192 }; 193 194 template<typename _Value, bool __constant_iterators, bool __cache> 195 struct _Node_const_iterator 196 : public _Node_iterator_base<_Value, __cache> 197 { 198 typedef _Value value_type; 199 typedef const _Value* pointer; 200 typedef const _Value& reference; 201 typedef std::ptrdiff_t difference_type; 202 typedef std::forward_iterator_tag iterator_category; 203 204 _Node_const_iterator() 205 : _Node_iterator_base<_Value, __cache>(0) { } 206 207 explicit 208 _Node_const_iterator(_Hash_node<_Value, __cache>* __p) 209 : _Node_iterator_base<_Value, __cache>(__p) { } 210 211 _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators, 212 __cache>& __x) 213 : _Node_iterator_base<_Value, __cache>(__x._M_cur) { } 214 215 reference 216 operator*() const 217 { return this->_M_cur->_M_v; } 218 219 pointer 220 operator->() const 221 { return &this->_M_cur->_M_v; } 222 223 _Node_const_iterator& 224 operator++() 225 { 226 this->_M_incr(); 227 return *this; 228 } 229 230 _Node_const_iterator 231 operator++(int) 232 { 233 _Node_const_iterator __tmp(*this); 234 this->_M_incr(); 235 return __tmp; 236 } 237 }; 238 239 template<typename _Value, bool __cache> 240 struct _Hashtable_iterator_base 241 { 242 _Hashtable_iterator_base(_Hash_node<_Value, __cache>* __node, 243 _Hash_node<_Value, __cache>** __bucket) 244 : _M_cur_node(__node), _M_cur_bucket(__bucket) { } 245 246 void 247 _M_incr() 248 { 249 _M_cur_node = _M_cur_node->_M_next; 250 if (!_M_cur_node) 251 _M_incr_bucket(); 252 } 253 254 void 255 _M_incr_bucket(); 256 257 _Hash_node<_Value, __cache>* _M_cur_node; 258 _Hash_node<_Value, __cache>** _M_cur_bucket; 259 }; 260 261 // Global iterators, used for arbitrary iteration within a hash 262 // table. Larger and more expensive than local iterators. 263 template<typename _Value, bool __cache> 264 void 265 _Hashtable_iterator_base<_Value, __cache>:: 266 _M_incr_bucket() 267 { 268 ++_M_cur_bucket; 269 270 // This loop requires the bucket array to have a non-null sentinel. 271 while (!*_M_cur_bucket) 272 ++_M_cur_bucket; 273 _M_cur_node = *_M_cur_bucket; 274 } 275 276 template<typename _Value, bool __cache> 277 inline bool 278 operator==(const _Hashtable_iterator_base<_Value, __cache>& __x, 279 const _Hashtable_iterator_base<_Value, __cache>& __y) 280 { return __x._M_cur_node == __y._M_cur_node; } 281 282 template<typename _Value, bool __cache> 283 inline bool 284 operator!=(const _Hashtable_iterator_base<_Value, __cache>& __x, 285 const _Hashtable_iterator_base<_Value, __cache>& __y) 286 { return __x._M_cur_node != __y._M_cur_node; } 287 288 template<typename _Value, bool __constant_iterators, bool __cache> 289 struct _Hashtable_iterator 290 : public _Hashtable_iterator_base<_Value, __cache> 291 { 292 typedef _Value value_type; 293 typedef typename 294 __gnu_cxx::__conditional_type<__constant_iterators, 295 const _Value*, _Value*>::__type 296 pointer; 297 typedef typename 298 __gnu_cxx::__conditional_type<__constant_iterators, 299 const _Value&, _Value&>::__type 300 reference; 301 typedef std::ptrdiff_t difference_type; 302 typedef std::forward_iterator_tag iterator_category; 303 304 _Hashtable_iterator() 305 : _Hashtable_iterator_base<_Value, __cache>(0, 0) { } 306 307 _Hashtable_iterator(_Hash_node<_Value, __cache>* __p, 308 _Hash_node<_Value, __cache>** __b) 309 : _Hashtable_iterator_base<_Value, __cache>(__p, __b) { } 310 311 explicit 312 _Hashtable_iterator(_Hash_node<_Value, __cache>** __b) 313 : _Hashtable_iterator_base<_Value, __cache>(*__b, __b) { } 314 315 reference 316 operator*() const 317 { return this->_M_cur_node->_M_v; } 318 319 pointer 320 operator->() const 321 { return &this->_M_cur_node->_M_v; } 322 323 _Hashtable_iterator& 324 operator++() 325 { 326 this->_M_incr(); 327 return *this; 328 } 329 330 _Hashtable_iterator 331 operator++(int) 332 { 333 _Hashtable_iterator __tmp(*this); 334 this->_M_incr(); 335 return __tmp; 336 } 337 }; 338 339 template<typename _Value, bool __constant_iterators, bool __cache> 340 struct _Hashtable_const_iterator 341 : public _Hashtable_iterator_base<_Value, __cache> 342 { 343 typedef _Value value_type; 344 typedef const _Value* pointer; 345 typedef const _Value& reference; 346 typedef std::ptrdiff_t difference_type; 347 typedef std::forward_iterator_tag iterator_category; 348 349 _Hashtable_const_iterator() 350 : _Hashtable_iterator_base<_Value, __cache>(0, 0) { } 351 352 _Hashtable_const_iterator(_Hash_node<_Value, __cache>* __p, 353 _Hash_node<_Value, __cache>** __b) 354 : _Hashtable_iterator_base<_Value, __cache>(__p, __b) { } 355 356 explicit 357 _Hashtable_const_iterator(_Hash_node<_Value, __cache>** __b) 358 : _Hashtable_iterator_base<_Value, __cache>(*__b, __b) { } 359 360 _Hashtable_const_iterator(const _Hashtable_iterator<_Value, 361 __constant_iterators, __cache>& __x) 362 : _Hashtable_iterator_base<_Value, __cache>(__x._M_cur_node, 363 __x._M_cur_bucket) { } 364 365 reference 366 operator*() const 367 { return this->_M_cur_node->_M_v; } 368 369 pointer 370 operator->() const 371 { return &this->_M_cur_node->_M_v; } 372 373 _Hashtable_const_iterator& 374 operator++() 375 { 376 this->_M_incr(); 377 return *this; 378 } 379 380 _Hashtable_const_iterator 381 operator++(int) 382 { 383 _Hashtable_const_iterator __tmp(*this); 384 this->_M_incr(); 385 return __tmp; 386 } 387 }; 388 389 390 // Many of class template _Hashtable's template parameters are policy 391 // classes. These are defaults for the policies. 392 393 // Default range hashing function: use division to fold a large number 394 // into the range [0, N). 395 struct _Mod_range_hashing 396 { 397 typedef std::size_t first_argument_type; 398 typedef std::size_t second_argument_type; 399 typedef std::size_t result_type; 400 401 result_type 402 operator()(first_argument_type __num, second_argument_type __den) const 403 { return __num % __den; } 404 }; 405 406 // Default ranged hash function H. In principle it should be a 407 // function object composed from objects of type H1 and H2 such that 408 // h(k, N) = h2(h1(k), N), but that would mean making extra copies of 409 // h1 and h2. So instead we'll just use a tag to tell class template 410 // hashtable to do that composition. 411 struct _Default_ranged_hash { }; 412 413 // Default value for rehash policy. Bucket size is (usually) the 414 // smallest prime that keeps the load factor small enough. 415 struct _Prime_rehash_policy 416 { 417 _Prime_rehash_policy(float __z = 1.0) 418 : _M_max_load_factor(__z), _M_growth_factor(2.f), _M_next_resize(0) { } 419 420 float 421 max_load_factor() const 422 { return _M_max_load_factor; } 423 424 // Return a bucket size no smaller than n. 425 std::size_t 426 _M_next_bkt(std::size_t __n) const; 427 428 // Return a bucket count appropriate for n elements 429 std::size_t 430 _M_bkt_for_elements(std::size_t __n) const; 431 432 // __n_bkt is current bucket count, __n_elt is current element count, 433 // and __n_ins is number of elements to be inserted. Do we need to 434 // increase bucket count? If so, return make_pair(true, n), where n 435 // is the new bucket count. If not, return make_pair(false, 0). 436 std::pair<bool, std::size_t> 437 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt, 438 std::size_t __n_ins) const; 439 440 enum { _S_n_primes = sizeof(unsigned long) != 8 ? 256 : 256 + 48 }; 441 442 float _M_max_load_factor; 443 float _M_growth_factor; 444 mutable std::size_t _M_next_resize; 445 }; 446 447 extern const unsigned long __prime_list[]; 448 449 // XXX This is a hack. There's no good reason for any of 450 // _Prime_rehash_policy's member functions to be inline. 451 452 // Return a prime no smaller than n. 453 inline std::size_t 454 _Prime_rehash_policy:: 455 _M_next_bkt(std::size_t __n) const 456 { 457 const unsigned long* __p = __lower_bound(__prime_list, __prime_list 458 + _S_n_primes, __n); 459 _M_next_resize = 460 static_cast<std::size_t>(__builtin_ceil(*__p * _M_max_load_factor)); 461 return *__p; 462 } 463 464 // Return the smallest prime p such that alpha p >= n, where alpha 465 // is the load factor. 466 inline std::size_t 467 _Prime_rehash_policy:: 468 _M_bkt_for_elements(std::size_t __n) const 469 { 470 const float __min_bkts = __n / _M_max_load_factor; 471 const unsigned long* __p = __lower_bound(__prime_list, __prime_list 472 + _S_n_primes, __min_bkts); 473 _M_next_resize = 474 static_cast<std::size_t>(__builtin_ceil(*__p * _M_max_load_factor)); 475 return *__p; 476 } 477 478 // Finds the smallest prime p such that alpha p > __n_elt + __n_ins. 479 // If p > __n_bkt, return make_pair(true, p); otherwise return 480 // make_pair(false, 0). In principle this isn't very different from 481 // _M_bkt_for_elements. 482 483 // The only tricky part is that we're caching the element count at 484 // which we need to rehash, so we don't have to do a floating-point 485 // multiply for every insertion. 486 487 inline std::pair<bool, std::size_t> 488 _Prime_rehash_policy:: 489 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt, 490 std::size_t __n_ins) const 491 { 492 if (__n_elt + __n_ins > _M_next_resize) 493 { 494 float __min_bkts = ((float(__n_ins) + float(__n_elt)) 495 / _M_max_load_factor); 496 if (__min_bkts > __n_bkt) 497 { 498 __min_bkts = std::max(__min_bkts, _M_growth_factor * __n_bkt); 499 const unsigned long* __p = 500 __lower_bound(__prime_list, __prime_list + _S_n_primes, 501 __min_bkts); 502 _M_next_resize = static_cast<std::size_t> 503 (__builtin_ceil(*__p * _M_max_load_factor)); 504 return std::make_pair(true, *__p); 505 } 506 else 507 { 508 _M_next_resize = static_cast<std::size_t> 509 (__builtin_ceil(__n_bkt * _M_max_load_factor)); 510 return std::make_pair(false, 0); 511 } 512 } 513 else 514 return std::make_pair(false, 0); 515 } 516 517 // Base classes for std::tr1::_Hashtable. We define these base 518 // classes because in some cases we want to do different things 519 // depending on the value of a policy class. In some cases the 520 // policy class affects which member functions and nested typedefs 521 // are defined; we handle that by specializing base class templates. 522 // Several of the base class templates need to access other members 523 // of class template _Hashtable, so we use the "curiously recurring 524 // template pattern" for them. 525 526 // class template _Map_base. If the hashtable has a value type of the 527 // form pair<T1, T2> and a key extraction policy that returns the 528 // first part of the pair, the hashtable gets a mapped_type typedef. 529 // If it satisfies those criteria and also has unique keys, then it 530 // also gets an operator[]. 531 template<typename _Key, typename _Value, typename _Ex, bool __unique, 532 typename _Hashtable> 533 struct _Map_base { }; 534 535 template<typename _Key, typename _Pair, typename _Hashtable> 536 struct _Map_base<_Key, _Pair, std::_Select1st<_Pair>, false, _Hashtable> 537 { 538 typedef typename _Pair::second_type mapped_type; 539 }; 540 541 template<typename _Key, typename _Pair, typename _Hashtable> 542 struct _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable> 543 { 544 typedef typename _Pair::second_type mapped_type; 545 546 mapped_type& 547 operator[](const _Key& __k); 548 549 #ifdef _GLIBCXX_INCLUDE_AS_CXX0X 550 // _GLIBCXX_RESOLVE_LIB_DEFECTS 551 // DR 761. unordered_map needs an at() member function. 552 mapped_type& 553 at(const _Key& __k); 554 555 const mapped_type& 556 at(const _Key& __k) const; 557 #endif 558 }; 559 560 template<typename _Key, typename _Pair, typename _Hashtable> 561 typename _Map_base<_Key, _Pair, std::_Select1st<_Pair>, 562 true, _Hashtable>::mapped_type& 563 _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>:: 564 operator[](const _Key& __k) 565 { 566 _Hashtable* __h = static_cast<_Hashtable*>(this); 567 typename _Hashtable::_Hash_code_type __code = __h->_M_hash_code(__k); 568 std::size_t __n = __h->_M_bucket_index(__k, __code, 569 __h->_M_bucket_count); 570 571 typename _Hashtable::_Node* __p = 572 __h->_M_find_node(__h->_M_buckets[__n], __k, __code); 573 if (!__p) 574 return __h->_M_insert_bucket(std::make_pair(__k, mapped_type()), 575 __n, __code)->second; 576 return (__p->_M_v).second; 577 } 578 579 #ifdef _GLIBCXX_INCLUDE_AS_CXX0X 580 template<typename _Key, typename _Pair, typename _Hashtable> 581 typename _Map_base<_Key, _Pair, std::_Select1st<_Pair>, 582 true, _Hashtable>::mapped_type& 583 _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>:: 584 at(const _Key& __k) 585 { 586 _Hashtable* __h = static_cast<_Hashtable*>(this); 587 typename _Hashtable::_Hash_code_type __code = __h->_M_hash_code(__k); 588 std::size_t __n = __h->_M_bucket_index(__k, __code, 589 __h->_M_bucket_count); 590 591 typename _Hashtable::_Node* __p = 592 __h->_M_find_node(__h->_M_buckets[__n], __k, __code); 593 if (!__p) 594 __throw_out_of_range(__N("_Map_base::at")); 595 return (__p->_M_v).second; 596 } 597 598 template<typename _Key, typename _Pair, typename _Hashtable> 599 const typename _Map_base<_Key, _Pair, std::_Select1st<_Pair>, 600 true, _Hashtable>::mapped_type& 601 _Map_base<_Key, _Pair, std::_Select1st<_Pair>, true, _Hashtable>:: 602 at(const _Key& __k) const 603 { 604 const _Hashtable* __h = static_cast<const _Hashtable*>(this); 605 typename _Hashtable::_Hash_code_type __code = __h->_M_hash_code(__k); 606 std::size_t __n = __h->_M_bucket_index(__k, __code, 607 __h->_M_bucket_count); 608 609 typename _Hashtable::_Node* __p = 610 __h->_M_find_node(__h->_M_buckets[__n], __k, __code); 611 if (!__p) 612 __throw_out_of_range(__N("_Map_base::at")); 613 return (__p->_M_v).second; 614 } 615 #endif 616 617 // class template _Rehash_base. Give hashtable the max_load_factor 618 // functions iff the rehash policy is _Prime_rehash_policy. 619 template<typename _RehashPolicy, typename _Hashtable> 620 struct _Rehash_base { }; 621 622 template<typename _Hashtable> 623 struct _Rehash_base<_Prime_rehash_policy, _Hashtable> 624 { 625 float 626 max_load_factor() const 627 { 628 const _Hashtable* __this = static_cast<const _Hashtable*>(this); 629 return __this->__rehash_policy().max_load_factor(); 630 } 631 632 void 633 max_load_factor(float __z) 634 { 635 _Hashtable* __this = static_cast<_Hashtable*>(this); 636 __this->__rehash_policy(_Prime_rehash_policy(__z)); 637 } 638 }; 639 640 // Class template _Hash_code_base. Encapsulates two policy issues that 641 // aren't quite orthogonal. 642 // (1) the difference between using a ranged hash function and using 643 // the combination of a hash function and a range-hashing function. 644 // In the former case we don't have such things as hash codes, so 645 // we have a dummy type as placeholder. 646 // (2) Whether or not we cache hash codes. Caching hash codes is 647 // meaningless if we have a ranged hash function. 648 // We also put the key extraction and equality comparison function 649 // objects here, for convenience. 650 651 // Primary template: unused except as a hook for specializations. 652 template<typename _Key, typename _Value, 653 typename _ExtractKey, typename _Equal, 654 typename _H1, typename _H2, typename _Hash, 655 bool __cache_hash_code> 656 struct _Hash_code_base; 657 658 // Specialization: ranged hash function, no caching hash codes. H1 659 // and H2 are provided but ignored. We define a dummy hash code type. 660 template<typename _Key, typename _Value, 661 typename _ExtractKey, typename _Equal, 662 typename _H1, typename _H2, typename _Hash> 663 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, 664 _Hash, false> 665 { 666 protected: 667 _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq, 668 const _H1&, const _H2&, const _Hash& __h) 669 : _M_extract(__ex), _M_eq(__eq), _M_ranged_hash(__h) { } 670 671 typedef void* _Hash_code_type; 672 673 _Hash_code_type 674 _M_hash_code(const _Key& __key) const 675 { return 0; } 676 677 std::size_t 678 _M_bucket_index(const _Key& __k, _Hash_code_type, 679 std::size_t __n) const 680 { return _M_ranged_hash(__k, __n); } 681 682 std::size_t 683 _M_bucket_index(const _Hash_node<_Value, false>* __p, 684 std::size_t __n) const 685 { return _M_ranged_hash(_M_extract(__p->_M_v), __n); } 686 687 bool 688 _M_compare(const _Key& __k, _Hash_code_type, 689 _Hash_node<_Value, false>* __n) const 690 { return _M_eq(__k, _M_extract(__n->_M_v)); } 691 692 void 693 _M_store_code(_Hash_node<_Value, false>*, _Hash_code_type) const 694 { } 695 696 void 697 _M_copy_code(_Hash_node<_Value, false>*, 698 const _Hash_node<_Value, false>*) const 699 { } 700 701 void 702 _M_swap(_Hash_code_base& __x) 703 { 704 std::swap(_M_extract, __x._M_extract); 705 std::swap(_M_eq, __x._M_eq); 706 std::swap(_M_ranged_hash, __x._M_ranged_hash); 707 } 708 709 protected: 710 _ExtractKey _M_extract; 711 _Equal _M_eq; 712 _Hash _M_ranged_hash; 713 }; 714 715 716 // No specialization for ranged hash function while caching hash codes. 717 // That combination is meaningless, and trying to do it is an error. 718 719 720 // Specialization: ranged hash function, cache hash codes. This 721 // combination is meaningless, so we provide only a declaration 722 // and no definition. 723 template<typename _Key, typename _Value, 724 typename _ExtractKey, typename _Equal, 725 typename _H1, typename _H2, typename _Hash> 726 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, 727 _Hash, true>; 728 729 // Specialization: hash function and range-hashing function, no 730 // caching of hash codes. H is provided but ignored. Provides 731 // typedef and accessor required by TR1. 732 template<typename _Key, typename _Value, 733 typename _ExtractKey, typename _Equal, 734 typename _H1, typename _H2> 735 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, 736 _Default_ranged_hash, false> 737 { 738 typedef _H1 hasher; 739 740 hasher 741 hash_function() const 742 { return _M_h1; } 743 744 protected: 745 _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq, 746 const _H1& __h1, const _H2& __h2, 747 const _Default_ranged_hash&) 748 : _M_extract(__ex), _M_eq(__eq), _M_h1(__h1), _M_h2(__h2) { } 749 750 typedef std::size_t _Hash_code_type; 751 752 _Hash_code_type 753 _M_hash_code(const _Key& __k) const 754 { return _M_h1(__k); } 755 756 std::size_t 757 _M_bucket_index(const _Key&, _Hash_code_type __c, 758 std::size_t __n) const 759 { return _M_h2(__c, __n); } 760 761 std::size_t 762 _M_bucket_index(const _Hash_node<_Value, false>* __p, 763 std::size_t __n) const 764 { return _M_h2(_M_h1(_M_extract(__p->_M_v)), __n); } 765 766 bool 767 _M_compare(const _Key& __k, _Hash_code_type, 768 _Hash_node<_Value, false>* __n) const 769 { return _M_eq(__k, _M_extract(__n->_M_v)); } 770 771 void 772 _M_store_code(_Hash_node<_Value, false>*, _Hash_code_type) const 773 { } 774 775 void 776 _M_copy_code(_Hash_node<_Value, false>*, 777 const _Hash_node<_Value, false>*) const 778 { } 779 780 void 781 _M_swap(_Hash_code_base& __x) 782 { 783 std::swap(_M_extract, __x._M_extract); 784 std::swap(_M_eq, __x._M_eq); 785 std::swap(_M_h1, __x._M_h1); 786 std::swap(_M_h2, __x._M_h2); 787 } 788 789 protected: 790 _ExtractKey _M_extract; 791 _Equal _M_eq; 792 _H1 _M_h1; 793 _H2 _M_h2; 794 }; 795 796 // Specialization: hash function and range-hashing function, 797 // caching hash codes. H is provided but ignored. Provides 798 // typedef and accessor required by TR1. 799 template<typename _Key, typename _Value, 800 typename _ExtractKey, typename _Equal, 801 typename _H1, typename _H2> 802 struct _Hash_code_base<_Key, _Value, _ExtractKey, _Equal, _H1, _H2, 803 _Default_ranged_hash, true> 804 { 805 typedef _H1 hasher; 806 807 hasher 808 hash_function() const 809 { return _M_h1; } 810 811 protected: 812 _Hash_code_base(const _ExtractKey& __ex, const _Equal& __eq, 813 const _H1& __h1, const _H2& __h2, 814 const _Default_ranged_hash&) 815 : _M_extract(__ex), _M_eq(__eq), _M_h1(__h1), _M_h2(__h2) { } 816 817 typedef std::size_t _Hash_code_type; 818 819 _Hash_code_type 820 _M_hash_code(const _Key& __k) const 821 { return _M_h1(__k); } 822 823 std::size_t 824 _M_bucket_index(const _Key&, _Hash_code_type __c, 825 std::size_t __n) const 826 { return _M_h2(__c, __n); } 827 828 std::size_t 829 _M_bucket_index(const _Hash_node<_Value, true>* __p, 830 std::size_t __n) const 831 { return _M_h2(__p->_M_hash_code, __n); } 832 833 bool 834 _M_compare(const _Key& __k, _Hash_code_type __c, 835 _Hash_node<_Value, true>* __n) const 836 { return __c == __n->_M_hash_code && _M_eq(__k, _M_extract(__n->_M_v)); } 837 838 void 839 _M_store_code(_Hash_node<_Value, true>* __n, _Hash_code_type __c) const 840 { __n->_M_hash_code = __c; } 841 842 void 843 _M_copy_code(_Hash_node<_Value, true>* __to, 844 const _Hash_node<_Value, true>* __from) const 845 { __to->_M_hash_code = __from->_M_hash_code; } 846 847 void 848 _M_swap(_Hash_code_base& __x) 849 { 850 std::swap(_M_extract, __x._M_extract); 851 std::swap(_M_eq, __x._M_eq); 852 std::swap(_M_h1, __x._M_h1); 853 std::swap(_M_h2, __x._M_h2); 854 } 855 856 protected: 857 _ExtractKey _M_extract; 858 _Equal _M_eq; 859 _H1 _M_h1; 860 _H2 _M_h2; 861 }; 862 } // namespace __detail 863 864 _GLIBCXX_END_NAMESPACE_TR1 865 } 866
