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 *NTy) {}
84 void removeNodeFromList(NodeTy *NTy) {}
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 size_t size_type;
111 typedef typename super::pointer pointer;
112 typedef typename super::reference reference;
116 // operator[] is not defined. Compile error instead of having a runtime bug.
117 void operator[](unsigned) {}
118 void operator[](unsigned) const {}
121 ilist_iterator(pointer NP) : NodePtr(NP) {}
122 ilist_iterator(reference NR) : NodePtr(&NR) {}
123 ilist_iterator() : NodePtr(0) {}
125 // This is templated so that we can allow constructing a const iterator from
126 // a nonconst iterator...
127 template<class node_ty>
128 ilist_iterator(const ilist_iterator<node_ty> &RHS)
129 : NodePtr(RHS.getNodePtrUnchecked()) {}
131 // This is templated so that we can allow assigning to a const iterator from
132 // a nonconst iterator...
133 template<class node_ty>
134 const ilist_iterator &operator=(const ilist_iterator<node_ty> &RHS) {
135 NodePtr = RHS.getNodePtrUnchecked();
140 operator pointer() const {
141 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
145 reference operator*() const {
146 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
149 pointer operator->() const { return &operator*(); }
151 // Comparison operators
152 bool operator==(const ilist_iterator &RHS) const {
153 return NodePtr == RHS.NodePtr;
155 bool operator!=(const ilist_iterator &RHS) const {
156 return NodePtr != RHS.NodePtr;
159 // Increment and decrement operators...
160 ilist_iterator &operator--() { // predecrement - Back up
161 NodePtr = Traits::getPrev(NodePtr);
162 assert(Traits::getNext(NodePtr) && "--'d off the beginning of an ilist!");
165 ilist_iterator &operator++() { // preincrement - Advance
166 NodePtr = Traits::getNext(NodePtr);
167 assert(NodePtr && "++'d off the end of an ilist!");
170 ilist_iterator operator--(int) { // postdecrement operators...
171 ilist_iterator tmp = *this;
175 ilist_iterator operator++(int) { // postincrement operators...
176 ilist_iterator tmp = *this;
181 // Internal interface, do not use...
182 pointer getNodePtrUnchecked() const { return NodePtr; }
185 // do not implement. this is to catch errors when people try to use
186 // them as random access iterators
188 void operator-(int, ilist_iterator<T>);
190 void operator-(ilist_iterator<T>,int);
193 void operator+(int, ilist_iterator<T>);
195 void operator+(ilist_iterator<T>,int);
197 // operator!=/operator== - Allow mixed comparisons without dereferencing
198 // the iterator, which could very likely be pointing to end().
200 bool operator!=(const T* LHS, const ilist_iterator<const T> &RHS) {
201 return LHS != RHS.getNodePtrUnchecked();
204 bool operator==(const T* LHS, const ilist_iterator<const T> &RHS) {
205 return LHS == RHS.getNodePtrUnchecked();
208 bool operator!=(T* LHS, const ilist_iterator<T> &RHS) {
209 return LHS != RHS.getNodePtrUnchecked();
212 bool operator==(T* LHS, const ilist_iterator<T> &RHS) {
213 return LHS == RHS.getNodePtrUnchecked();
217 // Allow ilist_iterators to convert into pointers to a node automatically when
218 // used by the dyn_cast, cast, isa mechanisms...
220 template<typename From> struct simplify_type;
222 template<typename NodeTy> struct simplify_type<ilist_iterator<NodeTy> > {
223 typedef NodeTy* SimpleType;
225 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
229 template<typename NodeTy> struct simplify_type<const ilist_iterator<NodeTy> > {
230 typedef NodeTy* SimpleType;
232 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
238 //===----------------------------------------------------------------------===//
240 /// iplist - The subset of list functionality that can safely be used on nodes
241 /// of polymorphic types, i.e. a heterogenous list with a common base class that
242 /// holds the next/prev pointers. The only state of the list itself is a single
243 /// pointer to the head of the list.
245 /// This list can be in one of three interesting states:
246 /// 1. The list may be completely unconstructed. In this case, the head
247 /// pointer is null. When in this form, any query for an iterator (e.g.
248 /// begin() or end()) causes the list to transparently change to state #2.
249 /// 2. The list may be empty, but contain a sentinal for the end iterator. This
250 /// sentinal is created by the Traits::createSentinel method and is a link
251 /// in the list. When the list is empty, the pointer in the iplist points
252 /// to the sentinal. Once the sentinal is constructed, it
253 /// is not destroyed until the list is.
254 /// 3. The list may contain actual objects in it, which are stored as a doubly
255 /// linked list of nodes. One invariant of the list is that the predecessor
256 /// of the first node in the list always points to the last node in the list,
257 /// and the successor pointer for the sentinal (which always stays at the
258 /// end of the list) is always null.
260 template<typename NodeTy, typename Traits=ilist_traits<NodeTy> >
261 class iplist : public Traits {
262 mutable NodeTy *Head;
264 // Use the prev node pointer of 'head' as the tail pointer. This is really a
265 // circularly linked list where we snip the 'next' link from the sentinel node
266 // back to the first node in the list (to preserve assertions about going off
267 // the end of the list).
268 NodeTy *getTail() { return getPrev(Head); }
269 const NodeTy *getTail() const { return getPrev(Head); }
270 void setTail(NodeTy *N) const { setPrev(Head, N); }
272 /// CreateLazySentinal - This method verifies whether the sentinal for the
273 /// list has been created and lazily makes it if not.
274 void CreateLazySentinal() const {
275 if (Head != 0) return;
276 Head = Traits::createSentinel();
281 static bool op_less(NodeTy &L, NodeTy &R) { return L < R; }
282 static bool op_equal(NodeTy &L, NodeTy &R) { return L == R; }
284 // No fundamental reason why iplist can't by copyable, but the default
285 // copy/copy-assign won't do.
286 iplist(const iplist &); // do not implement
287 void operator=(const iplist &); // do not implement
290 typedef NodeTy *pointer;
291 typedef const NodeTy *const_pointer;
292 typedef NodeTy &reference;
293 typedef const NodeTy &const_reference;
294 typedef NodeTy value_type;
295 typedef ilist_iterator<NodeTy> iterator;
296 typedef ilist_iterator<const NodeTy> const_iterator;
297 typedef size_t size_type;
298 typedef ptrdiff_t difference_type;
299 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
300 typedef std::reverse_iterator<iterator> reverse_iterator;
302 iplist() : Head(0) {}
306 Traits::destroySentinel(getTail());
309 // Iterator creation methods.
311 CreateLazySentinal();
312 return iterator(Head);
314 const_iterator begin() const {
315 CreateLazySentinal();
316 return const_iterator(Head);
319 CreateLazySentinal();
320 return iterator(getTail());
322 const_iterator end() const {
323 CreateLazySentinal();
324 return const_iterator(getTail());
327 // reverse iterator creation methods.
328 reverse_iterator rbegin() { return reverse_iterator(end()); }
329 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
330 reverse_iterator rend() { return reverse_iterator(begin()); }
331 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
334 // Miscellaneous inspection routines.
335 size_type max_size() const { return size_type(-1); }
336 bool empty() const { return Head == 0 || Head == getTail(); }
338 // Front and back accessor functions...
340 assert(!empty() && "Called front() on empty list!");
343 const_reference front() const {
344 assert(!empty() && "Called front() on empty list!");
348 assert(!empty() && "Called back() on empty list!");
349 return *getPrev(getTail());
351 const_reference back() const {
352 assert(!empty() && "Called back() on empty list!");
353 return *getPrev(getTail());
356 void swap(iplist &RHS) {
357 abort(); // Swap does not use list traits callback correctly yet!
358 std::swap(Head, RHS.Head);
361 iterator insert(iterator where, NodeTy *New) {
362 NodeTy *CurNode = where.getNodePtrUnchecked(), *PrevNode = getPrev(CurNode);
363 setNext(New, CurNode);
364 setPrev(New, PrevNode);
366 if (CurNode != Head) // Is PrevNode off the beginning of the list?
367 setNext(PrevNode, New);
370 setPrev(CurNode, New);
372 addNodeToList(New); // Notify traits that we added a node...
376 NodeTy *remove(iterator &IT) {
377 assert(IT != end() && "Cannot remove end of list!");
379 NodeTy *NextNode = getNext(Node);
380 NodeTy *PrevNode = getPrev(Node);
382 if (Node != Head) // Is PrevNode off the beginning of the list?
383 setNext(PrevNode, NextNode);
386 setPrev(NextNode, PrevNode);
388 removeNodeFromList(Node); // Notify traits that we removed a node...
390 // Set the next/prev pointers of the current node to null. This isn't
391 // strictly required, but this catches errors where a node is removed from
392 // an ilist (and potentially deleted) with iterators still pointing at it.
393 // When those iterators are incremented or decremented, they will assert on
394 // the null next/prev pointer instead of "usually working".
400 NodeTy *remove(const iterator &IT) {
402 return remove(MutIt);
405 // erase - remove a node from the controlled sequence... and delete it.
406 iterator erase(iterator where) {
407 deleteNode(remove(where));
413 // transfer - The heart of the splice function. Move linked list nodes from
414 // [first, last) into position.
416 void transfer(iterator position, iplist &L2, iterator first, iterator last) {
417 assert(first != last && "Should be checked by callers");
419 if (position != last) {
420 // Note: we have to be careful about the case when we move the first node
421 // in the list. This node is the list sentinel node and we can't move it.
422 NodeTy *ThisSentinel = getTail();
424 NodeTy *L2Sentinel = L2.getTail();
427 // Remove [first, last) from its old position.
428 NodeTy *First = &*first, *Prev = getPrev(First);
429 NodeTy *Next = last.getNodePtrUnchecked(), *Last = getPrev(Next);
436 // Splice [first, last) into its new position.
437 NodeTy *PosNext = position.getNodePtrUnchecked();
438 NodeTy *PosPrev = getPrev(PosNext);
440 // Fix head of list...
442 setNext(PosPrev, First);
445 setPrev(First, PosPrev);
447 // Fix end of list...
448 setNext(Last, PosNext);
449 setPrev(PosNext, Last);
451 transferNodesFromList(L2, First, PosNext);
453 // Now that everything is set, restore the pointers to the list sentinals.
454 L2.setTail(L2Sentinel);
455 setTail(ThisSentinel);
461 //===----------------------------------------------------------------------===
462 // Functionality derived from other functions defined above...
465 size_type size() const {
466 if (Head == 0) return 0; // Don't require construction of sentinal if empty.
468 // GCC 2.95 has a broken std::distance
469 size_type Result = 0;
470 std::distance(begin(), end(), Result);
473 return std::distance(begin(), end());
477 iterator erase(iterator first, iterator last) {
478 while (first != last)
479 first = erase(first);
483 void clear() { if (Head) erase(begin(), end()); }
485 // Front and back inserters...
486 void push_front(NodeTy *val) { insert(begin(), val); }
487 void push_back(NodeTy *val) { insert(end(), val); }
489 assert(!empty() && "pop_front() on empty list!");
493 assert(!empty() && "pop_back() on empty list!");
494 iterator t = end(); erase(--t);
497 // Special forms of insert...
498 template<class InIt> void insert(iterator where, InIt first, InIt last) {
499 for (; first != last; ++first) insert(where, *first);
502 // Splice members - defined in terms of transfer...
503 void splice(iterator where, iplist &L2) {
505 transfer(where, L2, L2.begin(), L2.end());
507 void splice(iterator where, iplist &L2, iterator first) {
508 iterator last = first; ++last;
509 if (where == first || where == last) return; // No change
510 transfer(where, L2, first, last);
512 void splice(iterator where, iplist &L2, iterator first, iterator last) {
513 if (first != last) transfer(where, L2, first, last);
518 //===----------------------------------------------------------------------===
519 // High-Level Functionality that shouldn't really be here, but is part of list
522 // These two functions are actually called remove/remove_if in list<>, but
523 // they actually do the job of erase, rename them accordingly.
525 void erase(const NodeTy &val) {
526 for (iterator I = begin(), E = end(); I != E; ) {
527 iterator next = I; ++next;
528 if (*I == val) erase(I);
532 template<class Pr1> void erase_if(Pr1 pred) {
533 for (iterator I = begin(), E = end(); I != E; ) {
534 iterator next = I; ++next;
535 if (pred(*I)) erase(I);
540 template<class Pr2> void unique(Pr2 pred) {
542 for (iterator I = begin(), E = end(), Next = begin(); ++Next != E;) {
550 void unique() { unique(op_equal); }
552 template<class Pr3> void merge(iplist &right, Pr3 pred) {
553 iterator first1 = begin(), last1 = end();
554 iterator first2 = right.begin(), last2 = right.end();
555 while (first1 != last1 && first2 != last2)
556 if (pred(*first2, *first1)) {
557 iterator next = first2;
558 transfer(first1, right, first2, ++next);
563 if (first2 != last2) transfer(last1, right, first2, last2);
565 void merge(iplist &right) { return merge(right, op_less); }
567 template<class Pr3> void sort(Pr3 pred);
568 void sort() { sort(op_less); }
573 template<typename NodeTy>
574 struct ilist : public iplist<NodeTy> {
575 typedef typename iplist<NodeTy>::size_type size_type;
576 typedef typename iplist<NodeTy>::iterator iterator;
579 ilist(const ilist &right) {
580 insert(this->begin(), right.begin(), right.end());
582 explicit ilist(size_type count) {
583 insert(this->begin(), count, NodeTy());
585 ilist(size_type count, const NodeTy &val) {
586 insert(this->begin(), count, val);
588 template<class InIt> ilist(InIt first, InIt last) {
589 insert(this->begin(), first, last);
593 // Forwarding functions: A workaround for GCC 2.95 which does not correctly
594 // support 'using' declarations to bring a hidden member into scope.
596 iterator insert(iterator a, NodeTy *b){ return iplist<NodeTy>::insert(a, b); }
597 void push_front(NodeTy *a) { iplist<NodeTy>::push_front(a); }
598 void push_back(NodeTy *a) { iplist<NodeTy>::push_back(a); }
601 // Main implementation here - Insert for a node passed by value...
602 iterator insert(iterator where, const NodeTy &val) {
603 return insert(where, createNode(val));
607 // Front and back inserters...
608 void push_front(const NodeTy &val) { insert(this->begin(), val); }
609 void push_back(const NodeTy &val) { insert(this->end(), val); }
611 // Special forms of insert...
612 template<class InIt> void insert(iterator where, InIt first, InIt last) {
613 for (; first != last; ++first) insert(where, *first);
615 void insert(iterator where, size_type count, const NodeTy &val) {
616 for (; count != 0; --count) insert(where, val);
619 // Assign special forms...
620 void assign(size_type count, const NodeTy &val) {
621 iterator I = this->begin();
622 for (; I != this->end() && count != 0; ++I, --count)
625 insert(this->end(), val, val);
627 erase(I, this->end());
629 template<class InIt> void assign(InIt first1, InIt last1) {
630 iterator first2 = this->begin(), last2 = this->end();
631 for ( ; first1 != last1 && first2 != last2; ++first1, ++first2)
634 erase(first1, last1);
636 insert(last1, first2, last2);
641 void resize(size_type newsize, NodeTy val) {
642 iterator i = this->begin();
644 for ( ; i != this->end() && len < newsize; ++i, ++len) /* empty*/ ;
647 erase(i, this->end());
649 insert(this->end(), newsize - len, val);
651 void resize(size_type newsize) { resize(newsize, NodeTy()); }
654 } // End llvm namespace
657 // Ensure that swap uses the fast list swap...
659 void swap(llvm::iplist<Ty> &Left, llvm::iplist<Ty> &Right) {
662 } // End 'std' extensions...
664 #endif // LLVM_ADT_ILIST_H