1 //===-- Support/ilist - Intrusive Linked List Template ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines classes to implement an intrusive doubly linked list class
11 // (ie 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 // provides 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<>::createEndMarker()). 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 //===----------------------------------------------------------------------===//
42 #include <Support/iterator>
45 template<typename NodeTy, typename Traits> class iplist;
46 template<typename NodeTy> class ilist_iterator;
48 // Template traits for intrusive list. By specializing this template class, you
49 // can change what next/prev fields are used to store the links...
50 template<typename NodeTy>
52 static NodeTy *getPrev(NodeTy *N) { return N->getPrev(); }
53 static NodeTy *getNext(NodeTy *N) { return N->getNext(); }
54 static const NodeTy *getPrev(const NodeTy *N) { return N->getPrev(); }
55 static const NodeTy *getNext(const NodeTy *N) { return N->getNext(); }
57 static void setPrev(NodeTy *N, NodeTy *Prev) { N->setPrev(Prev); }
58 static void setNext(NodeTy *N, NodeTy *Next) { N->setNext(Next); }
60 static NodeTy *createNode() { return new NodeTy(); }
61 static NodeTy *createNode(const NodeTy &V) { return new NodeTy(V); }
64 void addNodeToList(NodeTy *NTy) {}
65 void removeNodeFromList(NodeTy *NTy) {}
66 void transferNodesFromList(iplist<NodeTy, ilist_traits> &L2,
67 ilist_iterator<NodeTy> first,
68 ilist_iterator<NodeTy> last) {}
71 // Const traits are the same as nonconst traits...
73 struct ilist_traits<const Ty> : public ilist_traits<Ty> {};
76 //===----------------------------------------------------------------------===//
77 // ilist_iterator<Node> - Iterator for intrusive list.
79 template<typename NodeTy>
81 : public bidirectional_iterator<NodeTy, ptrdiff_t> {
82 typedef ilist_traits<NodeTy> Traits;
83 typedef bidirectional_iterator<NodeTy, ptrdiff_t> super;
86 typedef size_t size_type;
87 typedef typename super::pointer pointer;
88 typedef typename super::reference reference;
93 ilist_iterator(pointer NP) : NodePtr(NP) {}
94 ilist_iterator(reference NR) : NodePtr(&NR) {}
95 ilist_iterator() : NodePtr(0) {}
97 // This is templated so that we can allow constructing a const iterator from
98 // a nonconst iterator...
99 template<class node_ty>
100 ilist_iterator(const ilist_iterator<node_ty> &RHS)
101 : NodePtr(RHS.getNodePtrUnchecked()) {}
103 // This is templated so that we can allow assigning to a const iterator from
104 // a nonconst iterator...
105 template<class node_ty>
106 const ilist_iterator &operator=(const ilist_iterator<node_ty> &RHS) {
107 NodePtr = RHS.getNodePtrUnchecked();
112 operator pointer() const {
113 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
117 reference operator*() const {
118 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
121 pointer operator->() { return &operator*(); }
122 const pointer operator->() const { return &operator*(); }
124 // Comparison operators
125 bool operator==(const ilist_iterator &RHS) const {
126 return NodePtr == RHS.NodePtr;
128 bool operator!=(const ilist_iterator &RHS) const {
129 return NodePtr != RHS.NodePtr;
132 // Increment and decrement operators...
133 ilist_iterator &operator--() { // predecrement - Back up
134 NodePtr = Traits::getPrev(NodePtr);
135 assert(NodePtr && "--'d off the beginning of an ilist!");
138 ilist_iterator &operator++() { // preincrement - Advance
139 NodePtr = Traits::getNext(NodePtr);
140 assert(NodePtr && "++'d off the end of an ilist!");
143 ilist_iterator operator--(int) { // postdecrement operators...
144 ilist_iterator tmp = *this;
148 ilist_iterator operator++(int) { // postincrement operators...
149 ilist_iterator tmp = *this;
155 // Dummy operators to make errors apparent...
156 template<class X> void operator+(X Val) {}
157 template<class X> void operator-(X Val) {}
159 // Internal interface, do not use...
160 pointer getNodePtrUnchecked() const { return NodePtr; }
163 // Allow ilist_iterators to convert into pointers to a node automatically when
164 // used by the dyn_cast, cast, isa mechanisms...
166 template<typename From> struct simplify_type;
168 template<typename NodeTy> struct simplify_type<ilist_iterator<NodeTy> > {
169 typedef NodeTy* SimpleType;
171 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
175 template<typename NodeTy> struct simplify_type<const ilist_iterator<NodeTy> > {
176 typedef NodeTy* SimpleType;
178 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
184 //===----------------------------------------------------------------------===//
186 // iplist - The subset of list functionality that can safely be used on nodes of
187 // polymorphic types, ie a heterogeneus list with a common base class that holds
188 // the next/prev pointers...
190 template<typename NodeTy, typename Traits=ilist_traits<NodeTy> >
191 class iplist : public Traits {
194 static bool op_less(NodeTy &L, NodeTy &R) { return L < R; }
195 static bool op_equal(NodeTy &L, NodeTy &R) { return L == R; }
197 typedef NodeTy *pointer;
198 typedef const NodeTy *const_pointer;
199 typedef NodeTy &reference;
200 typedef const NodeTy &const_reference;
201 typedef NodeTy value_type;
202 typedef ilist_iterator<NodeTy> iterator;
203 typedef ilist_iterator<const NodeTy> const_iterator;
204 typedef size_t size_type;
205 typedef ptrdiff_t difference_type;
206 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
207 typedef std::reverse_iterator<iterator> reverse_iterator;
209 iplist() : Head(this->createNode()), Tail(Head) {
213 ~iplist() { clear(); delete Tail; }
215 // Iterator creation methods...
216 iterator begin() { return iterator(Head); }
217 const_iterator begin() const { return const_iterator(Head); }
218 iterator end() { return iterator(Tail); }
219 const_iterator end() const { return const_iterator(Tail); }
221 // reverse iterator creation methods...
222 reverse_iterator rbegin() { return reverse_iterator(end()); }
223 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
224 reverse_iterator rend() { return reverse_iterator(begin()); }
225 const_reverse_iterator rend() const {return const_reverse_iterator(begin());}
227 // Miscellaneous inspection routines...
228 size_type max_size() const { return size_type(-1); }
229 bool empty() const { return Head == Tail; }
231 // Front and back accessor functions...
233 assert(!empty() && "Called front() on empty list!");
236 const_reference front() const {
237 assert(!empty() && "Called front() on empty list!");
241 assert(!empty() && "Called back() on empty list!");
242 return *getPrev(Tail);
244 const_reference back() const {
245 assert(!empty() && "Called back() on empty list!");
246 return *getPrev(Tail);
249 void swap(iplist &RHS) {
250 abort(); // Swap does not use list traits callback correctly yet!
251 std::swap(Head, RHS.Head);
252 std::swap(Tail, RHS.Tail);
255 iterator insert(iterator where, NodeTy *New) {
256 NodeTy *CurNode = where.getNodePtrUnchecked(), *PrevNode = getPrev(CurNode);
257 setNext(New, CurNode);
258 setPrev(New, PrevNode);
261 setNext(PrevNode, New);
264 setPrev(CurNode, New);
266 addNodeToList(New); // Notify traits that we added a node...
270 NodeTy *remove(iterator &IT) {
271 assert(IT != end() && "Cannot remove end of list!");
273 NodeTy *NextNode = getNext(Node);
274 NodeTy *PrevNode = getPrev(Node);
277 setNext(PrevNode, NextNode);
280 setPrev(NextNode, PrevNode);
282 removeNodeFromList(Node); // Notify traits that we added a node...
286 NodeTy *remove(const iterator &IT) {
288 return remove(MutIt);
291 // erase - remove a node from the controlled sequence... and delete it.
292 iterator erase(iterator where) {
293 delete remove(where);
299 // transfer - The heart of the splice function. Move linked list nodes from
300 // [first, last) into position.
302 void transfer(iterator position, iplist &L2, iterator first, iterator last) {
303 assert(first != last && "Should be checked by callers");
304 if (position != last) {
305 // Remove [first, last) from its old position.
306 NodeTy *First = &*first, *Prev = getPrev(First);
307 NodeTy *Next = last.getNodePtrUnchecked(), *Last = getPrev(Next);
314 // Splice [first, last) into its new position.
315 NodeTy *PosNext = position.getNodePtrUnchecked();
316 NodeTy *PosPrev = getPrev(PosNext);
318 // Fix head of list...
320 setNext(PosPrev, First);
323 setPrev(First, PosPrev);
325 // Fix end of list...
326 setNext(Last, PosNext);
327 setPrev(PosNext, Last);
329 transferNodesFromList(L2, First, PosNext);
335 //===----------------------------------------------------------------------===
336 // Functionality derived from other functions defined above...
339 size_type size() const {
341 size_type Result = std::distance(begin(), end());
343 size_type Result = 0;
344 std::distance(begin(), end(), Result);
349 iterator erase(iterator first, iterator last) {
350 while (first != last)
351 first = erase(first);
355 void clear() { erase(begin(), end()); }
357 // Front and back inserters...
358 void push_front(NodeTy *val) { insert(begin(), val); }
359 void push_back(NodeTy *val) { insert(end(), val); }
361 assert(!empty() && "pop_front() on empty list!");
365 assert(!empty() && "pop_back() on empty list!");
366 iterator t = end(); erase(--t);
369 // Special forms of insert...
370 template<class InIt> void insert(iterator where, InIt first, InIt last) {
371 for (; first != last; ++first) insert(where, *first);
374 // Splice members - defined in terms of transfer...
375 void splice(iterator where, iplist &L2) {
377 transfer(where, L2, L2.begin(), L2.end());
379 void splice(iterator where, iplist &L2, iterator first) {
380 iterator last = first; ++last;
381 if (where == first || where == last) return; // No change
382 transfer(where, L2, first, last);
384 void splice(iterator where, iplist &L2, iterator first, iterator last) {
385 if (first != last) transfer(where, L2, first, last);
390 //===----------------------------------------------------------------------===
391 // High-Level Functionality that shouldn't really be here, but is part of list
394 // These two functions are actually called remove/remove_if in list<>, but
395 // they actually do the job of erase, rename them accordingly.
397 void erase(const NodeTy &val) {
398 for (iterator I = begin(), E = end(); I != E; ) {
399 iterator next = I; ++next;
400 if (*I == val) erase(I);
404 template<class Pr1> void erase_if(Pr1 pred) {
405 for (iterator I = begin(), E = end(); I != E; ) {
406 iterator next = I; ++next;
407 if (pred(*I)) erase(I);
412 template<class Pr2> void unique(Pr2 pred) {
414 for (iterator I = begin(), E = end(), Next = begin(); ++Next != E;) {
422 void unique() { unique(op_equal); }
424 template<class Pr3> void merge(iplist &right, Pr3 pred) {
425 iterator first1 = begin(), last1 = end();
426 iterator first2 = right.begin(), last2 = right.end();
427 while (first1 != last1 && first2 != last2)
428 if (pred(*first2, *first1)) {
429 iterator next = first2;
430 transfer(first1, right, first2, ++next);
435 if (first2 != last2) transfer(last1, right, first2, last2);
437 void merge(iplist &right) { return merge(right, op_less); }
439 template<class Pr3> void sort(Pr3 pred);
440 void sort() { sort(op_less); }
445 template<typename NodeTy>
446 struct ilist : public iplist<NodeTy> {
447 typedef typename iplist<NodeTy>::size_type size_type;
448 typedef typename iplist<NodeTy>::iterator iterator;
451 ilist(const ilist &right) {
452 insert(this->begin(), right.begin(), right.end());
454 explicit ilist(size_type count) {
455 insert(this->begin(), count, NodeTy());
457 ilist(size_type count, const NodeTy &val) {
458 insert(this->begin(), count, val);
460 template<class InIt> ilist(InIt first, InIt last) {
461 insert(this->begin(), first, last);
465 // Forwarding functions: A workaround for GCC 2.95 which does not correctly
466 // support 'using' declarations to bring a hidden member into scope.
468 iterator insert(iterator a, NodeTy *b){ return iplist<NodeTy>::insert(a, b); }
469 void push_front(NodeTy *a) { iplist<NodeTy>::push_front(a); }
470 void push_back(NodeTy *a) { iplist<NodeTy>::push_back(a); }
473 // Main implementation here - Insert for a node passed by value...
474 iterator insert(iterator where, const NodeTy &val) {
475 return insert(where, createNode(val));
479 // Front and back inserters...
480 void push_front(const NodeTy &val) { insert(this->begin(), val); }
481 void push_back(const NodeTy &val) { insert(this->end(), val); }
483 // Special forms of insert...
484 template<class InIt> void insert(iterator where, InIt first, InIt last) {
485 for (; first != last; ++first) insert(where, *first);
487 void insert(iterator where, size_type count, const NodeTy &val) {
488 for (; count != 0; --count) insert(where, val);
491 // Assign special forms...
492 void assign(size_type count, const NodeTy &val) {
493 iterator I = this->begin();
494 for (; I != this->end() && count != 0; ++I, --count)
497 insert(this->end(), val, val);
499 erase(I, this->end());
501 template<class InIt> void assign(InIt first1, InIt last1) {
502 iterator first2 = this->begin(), last2 = this->end();
503 for ( ; first1 != last1 && first2 != last2; ++first1, ++first2)
506 erase(first1, last1);
508 insert(last1, first2, last2);
513 void resize(size_type newsize, NodeTy val) {
514 iterator i = this->begin();
516 for ( ; i != this->end() && len < newsize; ++i, ++len) /* empty*/ ;
519 erase(i, this->end());
521 insert(this->end(), newsize - len, val);
523 void resize(size_type newsize) { resize(newsize, NodeTy()); }
527 // Ensure that swap uses the fast list swap...
529 void swap(iplist<Ty> &Left, iplist<Ty> &Right) {
532 } // End 'std' extensions...