1 //==-- llvm/ADT/ilist.h - Intrusive Linked List Template ---------*- C++ -*-==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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
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.
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.
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.
30 // Requirements for a user of this list:
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
36 //===----------------------------------------------------------------------===//
38 #ifndef LLVM_ADT_ILIST_H
39 #define LLVM_ADT_ILIST_H
41 #include "llvm/ADT/iterator.h"
47 template<typename NodeTy, typename Traits> class iplist;
48 template<typename NodeTy> class ilist_iterator;
50 /// ilist_nextprev_traits - A fragment for template traits for intrusive list
51 /// that provides default next/prev implementations for common operations.
53 template<typename NodeTy>
54 struct ilist_nextprev_traits {
55 static NodeTy *getPrev(NodeTy *N) { return N->getPrev(); }
56 static NodeTy *getNext(NodeTy *N) { return N->getNext(); }
57 static const NodeTy *getPrev(const NodeTy *N) { return N->getPrev(); }
58 static const NodeTy *getNext(const NodeTy *N) { return N->getNext(); }
60 static void setPrev(NodeTy *N, NodeTy *Prev) { N->setPrev(Prev); }
61 static void setNext(NodeTy *N, NodeTy *Next) { N->setNext(Next); }
64 /// ilist_sentinel_traits - A fragment for template traits for intrusive list
65 /// that provides default sentinel implementations for common operations.
67 template<typename NodeTy>
68 struct ilist_sentinel_traits {
69 static NodeTy *createSentinel() { return new NodeTy(); }
70 static void destroySentinel(NodeTy *N) { delete N; }
73 /// ilist_default_traits - Default template traits for intrusive list.
74 /// By inheriting from this, you can easily use default implementations
75 /// for all common operations.
77 template<typename NodeTy>
78 struct ilist_default_traits : ilist_nextprev_traits<NodeTy>,
79 ilist_sentinel_traits<NodeTy> {
80 static NodeTy *createNode(const NodeTy &V) { return new NodeTy(V); }
81 static void deleteNode(NodeTy *V) { delete V; }
83 void addNodeToList(NodeTy *) {}
84 void removeNodeFromList(NodeTy *) {}
85 void transferNodesFromList(ilist_default_traits & /*SrcTraits*/,
86 ilist_iterator<NodeTy> /*first*/,
87 ilist_iterator<NodeTy> /*last*/) {}
90 // Template traits for intrusive list. By specializing this template class, you
91 // can change what next/prev fields are used to store the links...
92 template<typename NodeTy>
93 struct ilist_traits : ilist_default_traits<NodeTy> {};
95 // Const traits are the same as nonconst traits...
97 struct ilist_traits<const Ty> : public ilist_traits<Ty> {};
99 //===----------------------------------------------------------------------===//
100 // ilist_iterator<Node> - Iterator for intrusive list.
102 template<typename NodeTy>
104 : public bidirectional_iterator<NodeTy, ptrdiff_t> {
107 typedef ilist_traits<NodeTy> Traits;
108 typedef bidirectional_iterator<NodeTy, ptrdiff_t> super;
110 typedef typename super::value_type value_type;
111 typedef typename super::difference_type difference_type;
112 typedef typename super::pointer pointer;
113 typedef typename super::reference reference;
117 // ilist_iterator is not a random-access iterator, but it has an
118 // implicit conversion to pointer-type, which is. Declare (but
119 // don't define) these functions as private to help catch
120 // accidental misuse.
121 void operator[](difference_type) const;
122 void operator+(difference_type) const;
123 void operator-(difference_type) const;
124 void operator+=(difference_type) const;
125 void operator-=(difference_type) const;
126 template<class T> void operator<(T) const;
127 template<class T> void operator<=(T) const;
128 template<class T> void operator>(T) const;
129 template<class T> void operator>=(T) const;
130 template<class T> void operator-(T) const;
133 ilist_iterator(pointer NP) : NodePtr(NP) {}
134 ilist_iterator(reference NR) : NodePtr(&NR) {}
135 ilist_iterator() : NodePtr(0) {}
137 // This is templated so that we can allow constructing a const iterator from
138 // a nonconst iterator...
139 template<class node_ty>
140 ilist_iterator(const ilist_iterator<node_ty> &RHS)
141 : NodePtr(RHS.getNodePtrUnchecked()) {}
143 // This is templated so that we can allow assigning to a const iterator from
144 // a nonconst iterator...
145 template<class node_ty>
146 const ilist_iterator &operator=(const ilist_iterator<node_ty> &RHS) {
147 NodePtr = RHS.getNodePtrUnchecked();
152 operator pointer() const {
153 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
157 reference operator*() const {
158 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
161 pointer operator->() const { return &operator*(); }
163 // Comparison operators
164 bool operator==(const ilist_iterator &RHS) const {
165 return NodePtr == RHS.NodePtr;
167 bool operator!=(const ilist_iterator &RHS) const {
168 return NodePtr != RHS.NodePtr;
171 // Increment and decrement operators...
172 ilist_iterator &operator--() { // predecrement - Back up
173 NodePtr = Traits::getPrev(NodePtr);
174 assert(Traits::getNext(NodePtr) && "--'d off the beginning of an ilist!");
177 ilist_iterator &operator++() { // preincrement - Advance
178 NodePtr = Traits::getNext(NodePtr);
179 assert(NodePtr && "++'d off the end of an ilist!");
182 ilist_iterator operator--(int) { // postdecrement operators...
183 ilist_iterator tmp = *this;
187 ilist_iterator operator++(int) { // postincrement operators...
188 ilist_iterator tmp = *this;
193 // Internal interface, do not use...
194 pointer getNodePtrUnchecked() const { return NodePtr; }
197 // do not implement. this is to catch errors when people try to use
198 // them as random access iterators
200 void operator-(int, ilist_iterator<T>);
202 void operator-(ilist_iterator<T>,int);
205 void operator+(int, ilist_iterator<T>);
207 void operator+(ilist_iterator<T>,int);
209 // operator!=/operator== - Allow mixed comparisons without dereferencing
210 // the iterator, which could very likely be pointing to end().
212 bool operator!=(const T* LHS, const ilist_iterator<const T> &RHS) {
213 return LHS != RHS.getNodePtrUnchecked();
216 bool operator==(const T* LHS, const ilist_iterator<const T> &RHS) {
217 return LHS == RHS.getNodePtrUnchecked();
220 bool operator!=(T* LHS, const ilist_iterator<T> &RHS) {
221 return LHS != RHS.getNodePtrUnchecked();
224 bool operator==(T* LHS, const ilist_iterator<T> &RHS) {
225 return LHS == RHS.getNodePtrUnchecked();
229 // Allow ilist_iterators to convert into pointers to a node automatically when
230 // used by the dyn_cast, cast, isa mechanisms...
232 template<typename From> struct simplify_type;
234 template<typename NodeTy> struct simplify_type<ilist_iterator<NodeTy> > {
235 typedef NodeTy* SimpleType;
237 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
241 template<typename NodeTy> struct simplify_type<const ilist_iterator<NodeTy> > {
242 typedef NodeTy* SimpleType;
244 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
250 //===----------------------------------------------------------------------===//
252 /// iplist - The subset of list functionality that can safely be used on nodes
253 /// of polymorphic types, i.e. a heterogenous list with a common base class that
254 /// holds the next/prev pointers. The only state of the list itself is a single
255 /// pointer to the head of the list.
257 /// This list can be in one of three interesting states:
258 /// 1. The list may be completely unconstructed. In this case, the head
259 /// pointer is null. When in this form, any query for an iterator (e.g.
260 /// begin() or end()) causes the list to transparently change to state #2.
261 /// 2. The list may be empty, but contain a sentinal for the end iterator. This
262 /// sentinal is created by the Traits::createSentinel method and is a link
263 /// in the list. When the list is empty, the pointer in the iplist points
264 /// to the sentinal. Once the sentinal is constructed, it
265 /// is not destroyed until the list is.
266 /// 3. The list may contain actual objects in it, which are stored as a doubly
267 /// linked list of nodes. One invariant of the list is that the predecessor
268 /// of the first node in the list always points to the last node in the list,
269 /// and the successor pointer for the sentinal (which always stays at the
270 /// end of the list) is always null.
272 template<typename NodeTy, typename Traits=ilist_traits<NodeTy> >
273 class iplist : public Traits {
274 mutable NodeTy *Head;
276 // Use the prev node pointer of 'head' as the tail pointer. This is really a
277 // circularly linked list where we snip the 'next' link from the sentinel node
278 // back to the first node in the list (to preserve assertions about going off
279 // the end of the list).
280 NodeTy *getTail() { return this->getPrev(Head); }
281 const NodeTy *getTail() const { return this->getPrev(Head); }
282 void setTail(NodeTy *N) const { this->setPrev(Head, N); }
284 /// CreateLazySentinal - This method verifies whether the sentinal for the
285 /// list has been created and lazily makes it if not.
286 void CreateLazySentinal() const {
287 if (Head != 0) return;
288 Head = Traits::createSentinel();
289 this->setNext(Head, 0);
293 static bool op_less(NodeTy &L, NodeTy &R) { return L < R; }
294 static bool op_equal(NodeTy &L, NodeTy &R) { return L == R; }
296 // No fundamental reason why iplist can't by copyable, but the default
297 // copy/copy-assign won't do.
298 iplist(const iplist &); // do not implement
299 void operator=(const iplist &); // do not implement
302 typedef NodeTy *pointer;
303 typedef const NodeTy *const_pointer;
304 typedef NodeTy &reference;
305 typedef const NodeTy &const_reference;
306 typedef NodeTy value_type;
307 typedef ilist_iterator<NodeTy> iterator;
308 typedef ilist_iterator<const NodeTy> const_iterator;
309 typedef size_t size_type;
310 typedef ptrdiff_t difference_type;
311 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
312 typedef std::reverse_iterator<iterator> reverse_iterator;
314 iplist() : Head(0) {}
318 Traits::destroySentinel(getTail());
321 // Iterator creation methods.
323 CreateLazySentinal();
324 return iterator(Head);
326 const_iterator begin() const {
327 CreateLazySentinal();
328 return const_iterator(Head);
331 CreateLazySentinal();
332 return iterator(getTail());
334 const_iterator end() const {
335 CreateLazySentinal();
336 return const_iterator(getTail());
339 // reverse iterator creation methods.
340 reverse_iterator rbegin() { return reverse_iterator(end()); }
341 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
342 reverse_iterator rend() { return reverse_iterator(begin()); }
343 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
346 // Miscellaneous inspection routines.
347 size_type max_size() const { return size_type(-1); }
348 bool empty() const { return Head == 0 || Head == getTail(); }
350 // Front and back accessor functions...
352 assert(!empty() && "Called front() on empty list!");
355 const_reference front() const {
356 assert(!empty() && "Called front() on empty list!");
360 assert(!empty() && "Called back() on empty list!");
361 return *this->getPrev(getTail());
363 const_reference back() const {
364 assert(!empty() && "Called back() on empty list!");
365 return *this->getPrev(getTail());
368 void swap(iplist &RHS) {
369 abort(); // Swap does not use list traits callback correctly yet!
370 std::swap(Head, RHS.Head);
373 iterator insert(iterator where, NodeTy *New) {
374 NodeTy *CurNode = where.getNodePtrUnchecked(), *PrevNode = this->getPrev(CurNode);
375 this->setNext(New, CurNode);
376 this->setPrev(New, PrevNode);
378 if (CurNode != Head) // Is PrevNode off the beginning of the list?
379 this->setNext(PrevNode, New);
382 this->setPrev(CurNode, New);
384 this->addNodeToList(New); // Notify traits that we added a node...
388 NodeTy *remove(iterator &IT) {
389 assert(IT != end() && "Cannot remove end of list!");
391 NodeTy *NextNode = this->getNext(Node);
392 NodeTy *PrevNode = this->getPrev(Node);
394 if (Node != Head) // Is PrevNode off the beginning of the list?
395 this->setNext(PrevNode, NextNode);
398 this->setPrev(NextNode, PrevNode);
400 removeNodeFromList(Node); // Notify traits that we removed a node...
402 // Set the next/prev pointers of the current node to null. This isn't
403 // strictly required, but this catches errors where a node is removed from
404 // an ilist (and potentially deleted) with iterators still pointing at it.
405 // When those iterators are incremented or decremented, they will assert on
406 // the null next/prev pointer instead of "usually working".
407 this->setNext(Node, 0);
408 this->setPrev(Node, 0);
412 NodeTy *remove(const iterator &IT) {
414 return remove(MutIt);
417 // erase - remove a node from the controlled sequence... and delete it.
418 iterator erase(iterator where) {
419 deleteNode(remove(where));
425 // transfer - The heart of the splice function. Move linked list nodes from
426 // [first, last) into position.
428 void transfer(iterator position, iplist &L2, iterator first, iterator last) {
429 assert(first != last && "Should be checked by callers");
431 if (position != last) {
432 // Note: we have to be careful about the case when we move the first node
433 // in the list. This node is the list sentinel node and we can't move it.
434 NodeTy *ThisSentinel = getTail();
436 NodeTy *L2Sentinel = L2.getTail();
439 // Remove [first, last) from its old position.
440 NodeTy *First = &*first, *Prev = getPrev(First);
441 NodeTy *Next = last.getNodePtrUnchecked(), *Last = getPrev(Next);
443 this->setNext(Prev, Next);
446 this->setPrev(Next, Prev);
448 // Splice [first, last) into its new position.
449 NodeTy *PosNext = position.getNodePtrUnchecked();
450 NodeTy *PosPrev = getPrev(PosNext);
452 // Fix head of list...
454 this->setNext(PosPrev, First);
457 this->setPrev(First, PosPrev);
459 // Fix end of list...
460 this->setNext(Last, PosNext);
461 this->setPrev(PosNext, Last);
463 transferNodesFromList(L2, First, PosNext);
465 // Now that everything is set, restore the pointers to the list sentinals.
466 L2.setTail(L2Sentinel);
467 setTail(ThisSentinel);
473 //===----------------------------------------------------------------------===
474 // Functionality derived from other functions defined above...
477 size_type size() const {
478 if (Head == 0) return 0; // Don't require construction of sentinal if empty.
480 // GCC 2.95 has a broken std::distance
481 size_type Result = 0;
482 std::distance(begin(), end(), Result);
485 return std::distance(begin(), end());
489 iterator erase(iterator first, iterator last) {
490 while (first != last)
491 first = erase(first);
495 void clear() { if (Head) erase(begin(), end()); }
497 // Front and back inserters...
498 void push_front(NodeTy *val) { insert(begin(), val); }
499 void push_back(NodeTy *val) { insert(end(), val); }
501 assert(!empty() && "pop_front() on empty list!");
505 assert(!empty() && "pop_back() on empty list!");
506 iterator t = end(); erase(--t);
509 // Special forms of insert...
510 template<class InIt> void insert(iterator where, InIt first, InIt last) {
511 for (; first != last; ++first) insert(where, *first);
514 // Splice members - defined in terms of transfer...
515 void splice(iterator where, iplist &L2) {
517 transfer(where, L2, L2.begin(), L2.end());
519 void splice(iterator where, iplist &L2, iterator first) {
520 iterator last = first; ++last;
521 if (where == first || where == last) return; // No change
522 transfer(where, L2, first, last);
524 void splice(iterator where, iplist &L2, iterator first, iterator last) {
525 if (first != last) transfer(where, L2, first, last);
530 //===----------------------------------------------------------------------===
531 // High-Level Functionality that shouldn't really be here, but is part of list
534 // These two functions are actually called remove/remove_if in list<>, but
535 // they actually do the job of erase, rename them accordingly.
537 void erase(const NodeTy &val) {
538 for (iterator I = begin(), E = end(); I != E; ) {
539 iterator next = I; ++next;
540 if (*I == val) erase(I);
544 template<class Pr1> void erase_if(Pr1 pred) {
545 for (iterator I = begin(), E = end(); I != E; ) {
546 iterator next = I; ++next;
547 if (pred(*I)) erase(I);
552 template<class Pr2> void unique(Pr2 pred) {
554 for (iterator I = begin(), E = end(), Next = begin(); ++Next != E;) {
562 void unique() { unique(op_equal); }
564 template<class Pr3> void merge(iplist &right, Pr3 pred) {
565 iterator first1 = begin(), last1 = end();
566 iterator first2 = right.begin(), last2 = right.end();
567 while (first1 != last1 && first2 != last2)
568 if (pred(*first2, *first1)) {
569 iterator next = first2;
570 transfer(first1, right, first2, ++next);
575 if (first2 != last2) transfer(last1, right, first2, last2);
577 void merge(iplist &right) { return merge(right, op_less); }
579 template<class Pr3> void sort(Pr3 pred);
580 void sort() { sort(op_less); }
585 template<typename NodeTy>
586 struct ilist : public iplist<NodeTy> {
587 typedef typename iplist<NodeTy>::size_type size_type;
588 typedef typename iplist<NodeTy>::iterator iterator;
591 ilist(const ilist &right) {
592 insert(this->begin(), right.begin(), right.end());
594 explicit ilist(size_type count) {
595 insert(this->begin(), count, NodeTy());
597 ilist(size_type count, const NodeTy &val) {
598 insert(this->begin(), count, val);
600 template<class InIt> ilist(InIt first, InIt last) {
601 insert(this->begin(), first, last);
605 // Forwarding functions: A workaround for GCC 2.95 which does not correctly
606 // support 'using' declarations to bring a hidden member into scope.
608 iterator insert(iterator a, NodeTy *b){ return iplist<NodeTy>::insert(a, b); }
609 void push_front(NodeTy *a) { iplist<NodeTy>::push_front(a); }
610 void push_back(NodeTy *a) { iplist<NodeTy>::push_back(a); }
613 // Main implementation here - Insert for a node passed by value...
614 iterator insert(iterator where, const NodeTy &val) {
615 return insert(where, createNode(val));
619 // Front and back inserters...
620 void push_front(const NodeTy &val) { insert(this->begin(), val); }
621 void push_back(const NodeTy &val) { insert(this->end(), val); }
623 // Special forms of insert...
624 template<class InIt> void insert(iterator where, InIt first, InIt last) {
625 for (; first != last; ++first) insert(where, *first);
627 void insert(iterator where, size_type count, const NodeTy &val) {
628 for (; count != 0; --count) insert(where, val);
631 // Assign special forms...
632 void assign(size_type count, const NodeTy &val) {
633 iterator I = this->begin();
634 for (; I != this->end() && count != 0; ++I, --count)
637 insert(this->end(), val, val);
639 erase(I, this->end());
641 template<class InIt> void assign(InIt first1, InIt last1) {
642 iterator first2 = this->begin(), last2 = this->end();
643 for ( ; first1 != last1 && first2 != last2; ++first1, ++first2)
646 erase(first1, last1);
648 insert(last1, first2, last2);
653 void resize(size_type newsize, NodeTy val) {
654 iterator i = this->begin();
656 for ( ; i != this->end() && len < newsize; ++i, ++len) /* empty*/ ;
659 erase(i, this->end());
661 insert(this->end(), newsize - len, val);
663 void resize(size_type newsize) { resize(newsize, NodeTy()); }
666 } // End llvm namespace
669 // Ensure that swap uses the fast list swap...
671 void swap(llvm::iplist<Ty> &Left, llvm::iplist<Ty> &Right) {
674 } // End 'std' extensions...
676 #endif // LLVM_ADT_ILIST_H