ilist.h revision 43d1fd449f1a0ac9d9dafa0b9569bb6b2e976198
1//==-- llvm/ADT/ilist.h - Intrusive Linked List Template ---------*- C++ -*-==// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines classes to implement an intrusive doubly linked list class 11// (i.e. each node of the list must contain a next and previous field for the 12// list. 13// 14// The ilist_traits trait class is used to gain access to the next and previous 15// fields of the node type that the list is instantiated with. If it is not 16// specialized, the list defaults to using the getPrev(), getNext() method calls 17// to get the next and previous pointers. 18// 19// The ilist class itself, should be a plug in replacement for list, assuming 20// that the nodes contain next/prev pointers. This list replacement does not 21// provide a constant time size() method, so be careful to use empty() when you 22// really want to know if it's empty. 23// 24// The ilist class is implemented by allocating a 'tail' node when the list is 25// created (using ilist_traits<>::createSentinel()). This tail node is 26// absolutely required because the user must be able to compute end()-1. Because 27// of this, users of the direct next/prev links will see an extra link on the 28// end of the list, which should be ignored. 29// 30// Requirements for a user of this list: 31// 32// 1. The user must provide {g|s}et{Next|Prev} methods, or specialize 33// ilist_traits to provide an alternate way of getting and setting next and 34// prev links. 35// 36//===----------------------------------------------------------------------===// 37 38#ifndef LLVM_ADT_ILIST 39#define LLVM_ADT_ILIST 40 41#include "llvm/ADT/iterator.h" 42#include <cassert> 43#include <cstdlib> 44 45namespace llvm { 46 47template<typename NodeTy, typename Traits> class iplist; 48template<typename NodeTy> class ilist_iterator; 49 50// Template traits for intrusive list. By specializing this template class, you 51// can change what next/prev fields are used to store the links... 52template<typename NodeTy> 53struct ilist_traits { 54 static NodeTy *getPrev(NodeTy *N) { return N->getPrev(); } 55 static NodeTy *getNext(NodeTy *N) { return N->getNext(); } 56 static const NodeTy *getPrev(const NodeTy *N) { return N->getPrev(); } 57 static const NodeTy *getNext(const NodeTy *N) { return N->getNext(); } 58 59 static void setPrev(NodeTy *N, NodeTy *Prev) { N->setPrev(Prev); } 60 static void setNext(NodeTy *N, NodeTy *Next) { N->setNext(Next); } 61 62 static NodeTy *createNode(const NodeTy &V) { return new NodeTy(V); } 63 64 static NodeTy *createSentinel() { return new NodeTy(); } 65 static void destroySentinel(NodeTy *N) { delete N; } 66 67 void addNodeToList(NodeTy *NTy) {} 68 void removeNodeFromList(NodeTy *NTy) {} 69 void transferNodesFromList(iplist<NodeTy, ilist_traits> &L2, 70 ilist_iterator<NodeTy> first, 71 ilist_iterator<NodeTy> last) {} 72}; 73 74// Const traits are the same as nonconst traits... 75template<typename Ty> 76struct ilist_traits<const Ty> : public ilist_traits<Ty> {}; 77 78 79//===----------------------------------------------------------------------===// 80// ilist_iterator<Node> - Iterator for intrusive list. 81// 82template<typename NodeTy> 83class ilist_iterator 84 : public bidirectional_iterator<NodeTy, ptrdiff_t> { 85 typedef ilist_traits<NodeTy> Traits; 86 typedef bidirectional_iterator<NodeTy, ptrdiff_t> super; 87 88public: 89 typedef size_t size_type; 90 typedef typename super::pointer pointer; 91 typedef typename super::reference reference; 92private: 93 pointer NodePtr; 94public: 95 96 ilist_iterator(pointer NP) : NodePtr(NP) {} 97 ilist_iterator(reference NR) : NodePtr(&NR) {} 98 ilist_iterator() : NodePtr(0) {} 99 100 // This is templated so that we can allow constructing a const iterator from 101 // a nonconst iterator... 102 template<class node_ty> 103 ilist_iterator(const ilist_iterator<node_ty> &RHS) 104 : NodePtr(RHS.getNodePtrUnchecked()) {} 105 106 // This is templated so that we can allow assigning to a const iterator from 107 // a nonconst iterator... 108 template<class node_ty> 109 const ilist_iterator &operator=(const ilist_iterator<node_ty> &RHS) { 110 NodePtr = RHS.getNodePtrUnchecked(); 111 return *this; 112 } 113 114 // Accessors... 115 operator pointer() const { 116 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!"); 117 return NodePtr; 118 } 119 120 reference operator*() const { 121 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!"); 122 return *NodePtr; 123 } 124 pointer operator->() { return &operator*(); } 125 const pointer operator->() const { return &operator*(); } 126 127 // Comparison operators 128 bool operator==(const ilist_iterator &RHS) const { 129 return NodePtr == RHS.NodePtr; 130 } 131 bool operator!=(const ilist_iterator &RHS) const { 132 return NodePtr != RHS.NodePtr; 133 } 134 135 // Increment and decrement operators... 136 ilist_iterator &operator--() { // predecrement - Back up 137 NodePtr = Traits::getPrev(NodePtr); 138 assert(Traits::getNext(NodePtr) && "--'d off the beginning of an ilist!"); 139 return *this; 140 } 141 ilist_iterator &operator++() { // preincrement - Advance 142 NodePtr = Traits::getNext(NodePtr); 143 assert(NodePtr && "++'d off the end of an ilist!"); 144 return *this; 145 } 146 ilist_iterator operator--(int) { // postdecrement operators... 147 ilist_iterator tmp = *this; 148 --*this; 149 return tmp; 150 } 151 ilist_iterator operator++(int) { // postincrement operators... 152 ilist_iterator tmp = *this; 153 ++*this; 154 return tmp; 155 } 156 157 // Internal interface, do not use... 158 pointer getNodePtrUnchecked() const { return NodePtr; } 159}; 160 161// do not implement. this is to catch errors when people try to use 162// them as random access iterators 163template<typename T> 164void operator-(int, ilist_iterator<T>); 165template<typename T> 166void operator-(ilist_iterator<T>,int); 167 168template<typename T> 169void operator+(int, ilist_iterator<T>); 170template<typename T> 171void operator+(ilist_iterator<T>,int); 172 173// operator!=/operator== - Allow mixed comparisons without dereferencing 174// the iterator, which could very likely be pointing to end(). 175template<typename T> 176bool operator!=(const T* LHS, const ilist_iterator<const T> &RHS) { 177 return LHS != RHS.getNodePtrUnchecked(); 178} 179template<typename T> 180bool operator==(const T* LHS, const ilist_iterator<const T> &RHS) { 181 return LHS == RHS.getNodePtrUnchecked(); 182} 183template<typename T> 184bool operator!=(T* LHS, const ilist_iterator<T> &RHS) { 185 return LHS != RHS.getNodePtrUnchecked(); 186} 187template<typename T> 188bool operator==(T* LHS, const ilist_iterator<T> &RHS) { 189 return LHS == RHS.getNodePtrUnchecked(); 190} 191 192 193// Allow ilist_iterators to convert into pointers to a node automatically when 194// used by the dyn_cast, cast, isa mechanisms... 195 196template<typename From> struct simplify_type; 197 198template<typename NodeTy> struct simplify_type<ilist_iterator<NodeTy> > { 199 typedef NodeTy* SimpleType; 200 201 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) { 202 return &*Node; 203 } 204}; 205template<typename NodeTy> struct simplify_type<const ilist_iterator<NodeTy> > { 206 typedef NodeTy* SimpleType; 207 208 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) { 209 return &*Node; 210 } 211}; 212 213 214//===----------------------------------------------------------------------===// 215// 216/// iplist - The subset of list functionality that can safely be used on nodes 217/// of polymorphic types, i.e. a heterogenous list with a common base class that 218/// holds the next/prev pointers. The only state of the list itself is a single 219/// pointer to the head of the list. 220/// 221/// This list can be in one of three interesting states: 222/// 1. The list may be completely unconstructed. In this case, the head 223/// pointer is null. When in this form, any query for an iterator (e.g. 224/// begin() or end()) causes the list to transparently change to state #2. 225/// 2. The list may be empty, but contain a sentinal for the end iterator. This 226/// sentinal is created by the Traits::createSentinel method and is a link 227/// in the list. When the list is empty, the pointer in the iplist points 228/// to the sentinal. Once the sentinal is constructed, it 229/// is not destroyed until the list is. 230/// 3. The list may contain actual objects in it, which are stored as a doubly 231/// linked list of nodes. One invariant of the list is that the predecessor 232/// of the first node in the list always points to the last node in the list, 233/// and the successor pointer for the sentinal (which always stays at the 234/// end of the list) is always null. 235/// 236template<typename NodeTy, typename Traits=ilist_traits<NodeTy> > 237class iplist : public Traits { 238 mutable NodeTy *Head; 239 240 // Use the prev node pointer of 'head' as the tail pointer. This is really a 241 // circularly linked list where we snip the 'next' link from the sentinel node 242 // back to the first node in the list (to preserve assertions about going off 243 // the end of the list). 244 NodeTy *getTail() { return getPrev(Head); } 245 const NodeTy *getTail() const { return getPrev(Head); } 246 void setTail(NodeTy *N) const { setPrev(Head, N); } 247 248 /// CreateLazySentinal - This method verifies whether the sentinal for the 249 /// list has been created and lazily makes it if not. 250 void CreateLazySentinal() const { 251 if (Head != 0) return; 252 Head = Traits::createSentinel(); 253 setNext(Head, 0); 254 setTail(Head); 255 } 256 257 static bool op_less(NodeTy &L, NodeTy &R) { return L < R; } 258 static bool op_equal(NodeTy &L, NodeTy &R) { return L == R; } 259public: 260 typedef NodeTy *pointer; 261 typedef const NodeTy *const_pointer; 262 typedef NodeTy &reference; 263 typedef const NodeTy &const_reference; 264 typedef NodeTy value_type; 265 typedef ilist_iterator<NodeTy> iterator; 266 typedef ilist_iterator<const NodeTy> const_iterator; 267 typedef size_t size_type; 268 typedef ptrdiff_t difference_type; 269 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 270 typedef std::reverse_iterator<iterator> reverse_iterator; 271 272 iplist() : Head(0) {} 273 ~iplist() { 274 if (!Head) return; 275 clear(); 276 Traits::destroySentinel(getTail()); 277 } 278 279 // Iterator creation methods. 280 iterator begin() { 281 CreateLazySentinal(); 282 return iterator(Head); 283 } 284 const_iterator begin() const { 285 CreateLazySentinal(); 286 return const_iterator(Head); 287 } 288 iterator end() { 289 CreateLazySentinal(); 290 return iterator(getTail()); 291 } 292 const_iterator end() const { 293 CreateLazySentinal(); 294 return const_iterator(getTail()); 295 } 296 297 // reverse iterator creation methods. 298 reverse_iterator rbegin() { return reverse_iterator(end()); } 299 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); } 300 reverse_iterator rend() { return reverse_iterator(begin()); } 301 const_reverse_iterator rend() const { return const_reverse_iterator(begin());} 302 303 304 // Miscellaneous inspection routines. 305 size_type max_size() const { return size_type(-1); } 306 bool empty() const { return Head == 0 || Head == getTail(); } 307 308 // Front and back accessor functions... 309 reference front() { 310 assert(!empty() && "Called front() on empty list!"); 311 return *Head; 312 } 313 const_reference front() const { 314 assert(!empty() && "Called front() on empty list!"); 315 return *Head; 316 } 317 reference back() { 318 assert(!empty() && "Called back() on empty list!"); 319 return *getPrev(getTail()); 320 } 321 const_reference back() const { 322 assert(!empty() && "Called back() on empty list!"); 323 return *getPrev(getTail()); 324 } 325 326 void swap(iplist &RHS) { 327 abort(); // Swap does not use list traits callback correctly yet! 328 std::swap(Head, RHS.Head); 329 } 330 331 iterator insert(iterator where, NodeTy *New) { 332 NodeTy *CurNode = where.getNodePtrUnchecked(), *PrevNode = getPrev(CurNode); 333 setNext(New, CurNode); 334 setPrev(New, PrevNode); 335 336 if (CurNode != Head) // Is PrevNode off the beginning of the list? 337 setNext(PrevNode, New); 338 else 339 Head = New; 340 setPrev(CurNode, New); 341 342 addNodeToList(New); // Notify traits that we added a node... 343 return New; 344 } 345 346 NodeTy *remove(iterator &IT) { 347 assert(IT != end() && "Cannot remove end of list!"); 348 NodeTy *Node = &*IT; 349 NodeTy *NextNode = getNext(Node); 350 NodeTy *PrevNode = getPrev(Node); 351 352 if (Node != Head) // Is PrevNode off the beginning of the list? 353 setNext(PrevNode, NextNode); 354 else 355 Head = NextNode; 356 setPrev(NextNode, PrevNode); 357 IT = NextNode; 358 removeNodeFromList(Node); // Notify traits that we removed a node... 359 360 // Set the next/prev pointers of the current node to null. This isn't 361 // strictly required, but this catches errors where a node is removed from 362 // an ilist (and potentially deleted) with iterators still pointing at it. 363 // When those iterators are incremented or decremented, they will assert on 364 // the null next/prev pointer instead of "usually working". 365 setNext(Node, 0); 366 setPrev(Node, 0); 367 return Node; 368 } 369 370 NodeTy *remove(const iterator &IT) { 371 iterator MutIt = IT; 372 return remove(MutIt); 373 } 374 375 // erase - remove a node from the controlled sequence... and delete it. 376 iterator erase(iterator where) { 377 delete remove(where); 378 return where; 379 } 380 381 382private: 383 // transfer - The heart of the splice function. Move linked list nodes from 384 // [first, last) into position. 385 // 386 void transfer(iterator position, iplist &L2, iterator first, iterator last) { 387 assert(first != last && "Should be checked by callers"); 388 389 if (position != last) { 390 // Note: we have to be careful about the case when we move the first node 391 // in the list. This node is the list sentinel node and we can't move it. 392 NodeTy *ThisSentinel = getTail(); 393 setTail(0); 394 NodeTy *L2Sentinel = L2.getTail(); 395 L2.setTail(0); 396 397 // Remove [first, last) from its old position. 398 NodeTy *First = &*first, *Prev = getPrev(First); 399 NodeTy *Next = last.getNodePtrUnchecked(), *Last = getPrev(Next); 400 if (Prev) 401 setNext(Prev, Next); 402 else 403 L2.Head = Next; 404 setPrev(Next, Prev); 405 406 // Splice [first, last) into its new position. 407 NodeTy *PosNext = position.getNodePtrUnchecked(); 408 NodeTy *PosPrev = getPrev(PosNext); 409 410 // Fix head of list... 411 if (PosPrev) 412 setNext(PosPrev, First); 413 else 414 Head = First; 415 setPrev(First, PosPrev); 416 417 // Fix end of list... 418 setNext(Last, PosNext); 419 setPrev(PosNext, Last); 420 421 transferNodesFromList(L2, First, PosNext); 422 423 // Now that everything is set, restore the pointers to the list sentinals. 424 L2.setTail(L2Sentinel); 425 setTail(ThisSentinel); 426 } 427 } 428 429public: 430 431 //===----------------------------------------------------------------------=== 432 // Functionality derived from other functions defined above... 433 // 434 435 size_type size() const { 436 if (Head == 0) return 0; // Don't require construction of sentinal if empty. 437#if __GNUC__ == 2 438 // GCC 2.95 has a broken std::distance 439 size_type Result = 0; 440 std::distance(begin(), end(), Result); 441 return Result; 442#else 443 return std::distance(begin(), end()); 444#endif 445 } 446 447 iterator erase(iterator first, iterator last) { 448 while (first != last) 449 first = erase(first); 450 return last; 451 } 452 453 void clear() { if (Head) erase(begin(), end()); } 454 455 // Front and back inserters... 456 void push_front(NodeTy *val) { insert(begin(), val); } 457 void push_back(NodeTy *val) { insert(end(), val); } 458 void pop_front() { 459 assert(!empty() && "pop_front() on empty list!"); 460 erase(begin()); 461 } 462 void pop_back() { 463 assert(!empty() && "pop_back() on empty list!"); 464 iterator t = end(); erase(--t); 465 } 466 467 // Special forms of insert... 468 template<class InIt> void insert(iterator where, InIt first, InIt last) { 469 for (; first != last; ++first) insert(where, *first); 470 } 471 472 // Splice members - defined in terms of transfer... 473 void splice(iterator where, iplist &L2) { 474 if (!L2.empty()) 475 transfer(where, L2, L2.begin(), L2.end()); 476 } 477 void splice(iterator where, iplist &L2, iterator first) { 478 iterator last = first; ++last; 479 if (where == first || where == last) return; // No change 480 transfer(where, L2, first, last); 481 } 482 void splice(iterator where, iplist &L2, iterator first, iterator last) { 483 if (first != last) transfer(where, L2, first, last); 484 } 485 486 487 488 //===----------------------------------------------------------------------=== 489 // High-Level Functionality that shouldn't really be here, but is part of list 490 // 491 492 // These two functions are actually called remove/remove_if in list<>, but 493 // they actually do the job of erase, rename them accordingly. 494 // 495 void erase(const NodeTy &val) { 496 for (iterator I = begin(), E = end(); I != E; ) { 497 iterator next = I; ++next; 498 if (*I == val) erase(I); 499 I = next; 500 } 501 } 502 template<class Pr1> void erase_if(Pr1 pred) { 503 for (iterator I = begin(), E = end(); I != E; ) { 504 iterator next = I; ++next; 505 if (pred(*I)) erase(I); 506 I = next; 507 } 508 } 509 510 template<class Pr2> void unique(Pr2 pred) { 511 if (empty()) return; 512 for (iterator I = begin(), E = end(), Next = begin(); ++Next != E;) { 513 if (pred(*I)) 514 erase(Next); 515 else 516 I = Next; 517 Next = I; 518 } 519 } 520 void unique() { unique(op_equal); } 521 522 template<class Pr3> void merge(iplist &right, Pr3 pred) { 523 iterator first1 = begin(), last1 = end(); 524 iterator first2 = right.begin(), last2 = right.end(); 525 while (first1 != last1 && first2 != last2) 526 if (pred(*first2, *first1)) { 527 iterator next = first2; 528 transfer(first1, right, first2, ++next); 529 first2 = next; 530 } else { 531 ++first1; 532 } 533 if (first2 != last2) transfer(last1, right, first2, last2); 534 } 535 void merge(iplist &right) { return merge(right, op_less); } 536 537 template<class Pr3> void sort(Pr3 pred); 538 void sort() { sort(op_less); } 539 void reverse(); 540}; 541 542 543template<typename NodeTy> 544struct ilist : public iplist<NodeTy> { 545 typedef typename iplist<NodeTy>::size_type size_type; 546 typedef typename iplist<NodeTy>::iterator iterator; 547 548 ilist() {} 549 ilist(const ilist &right) { 550 insert(this->begin(), right.begin(), right.end()); 551 } 552 explicit ilist(size_type count) { 553 insert(this->begin(), count, NodeTy()); 554 } 555 ilist(size_type count, const NodeTy &val) { 556 insert(this->begin(), count, val); 557 } 558 template<class InIt> ilist(InIt first, InIt last) { 559 insert(this->begin(), first, last); 560 } 561 562 563 // Forwarding functions: A workaround for GCC 2.95 which does not correctly 564 // support 'using' declarations to bring a hidden member into scope. 565 // 566 iterator insert(iterator a, NodeTy *b){ return iplist<NodeTy>::insert(a, b); } 567 void push_front(NodeTy *a) { iplist<NodeTy>::push_front(a); } 568 void push_back(NodeTy *a) { iplist<NodeTy>::push_back(a); } 569 570 571 // Main implementation here - Insert for a node passed by value... 572 iterator insert(iterator where, const NodeTy &val) { 573 return insert(where, createNode(val)); 574 } 575 576 577 // Front and back inserters... 578 void push_front(const NodeTy &val) { insert(this->begin(), val); } 579 void push_back(const NodeTy &val) { insert(this->end(), val); } 580 581 // Special forms of insert... 582 template<class InIt> void insert(iterator where, InIt first, InIt last) { 583 for (; first != last; ++first) insert(where, *first); 584 } 585 void insert(iterator where, size_type count, const NodeTy &val) { 586 for (; count != 0; --count) insert(where, val); 587 } 588 589 // Assign special forms... 590 void assign(size_type count, const NodeTy &val) { 591 iterator I = this->begin(); 592 for (; I != this->end() && count != 0; ++I, --count) 593 *I = val; 594 if (count != 0) 595 insert(this->end(), val, val); 596 else 597 erase(I, this->end()); 598 } 599 template<class InIt> void assign(InIt first1, InIt last1) { 600 iterator first2 = this->begin(), last2 = this->end(); 601 for ( ; first1 != last1 && first2 != last2; ++first1, ++first2) 602 *first1 = *first2; 603 if (first2 == last2) 604 erase(first1, last1); 605 else 606 insert(last1, first2, last2); 607 } 608 609 610 // Resize members... 611 void resize(size_type newsize, NodeTy val) { 612 iterator i = this->begin(); 613 size_type len = 0; 614 for ( ; i != this->end() && len < newsize; ++i, ++len) /* empty*/ ; 615 616 if (len == newsize) 617 erase(i, this->end()); 618 else // i == end() 619 insert(this->end(), newsize - len, val); 620 } 621 void resize(size_type newsize) { resize(newsize, NodeTy()); } 622}; 623 624} // End llvm namespace 625 626namespace std { 627 // Ensure that swap uses the fast list swap... 628 template<class Ty> 629 void swap(llvm::iplist<Ty> &Left, llvm::iplist<Ty> &Right) { 630 Left.swap(Right); 631 } 632} // End 'std' extensions... 633 634#endif 635