1//===- llvm/ADT/ilist_iterator.h - Intrusive List Iterator ------*- 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#ifndef LLVM_ADT_ILIST_ITERATOR_H
11#define LLVM_ADT_ILIST_ITERATOR_H
12
13#include "llvm/ADT/ilist_node.h"
14#include <cassert>
15#include <cstddef>
16#include <iterator>
17#include <type_traits>
18
19namespace llvm {
20
21namespace ilist_detail {
22
23/// Find const-correct node types.
24template <class OptionsT, bool IsConst> struct IteratorTraits;
25template <class OptionsT> struct IteratorTraits<OptionsT, false> {
26 using value_type = typename OptionsT::value_type;
27 using pointer = typename OptionsT::pointer;
28 using reference = typename OptionsT::reference;
29 using node_pointer = ilist_node_impl<OptionsT> *;
30 using node_reference = ilist_node_impl<OptionsT> &;
31};
32template <class OptionsT> struct IteratorTraits<OptionsT, true> {
33 using value_type = const typename OptionsT::value_type;
34 using pointer = typename OptionsT::const_pointer;
35 using reference = typename OptionsT::const_reference;
36 using node_pointer = const ilist_node_impl<OptionsT> *;
37 using node_reference = const ilist_node_impl<OptionsT> &;
38};
39
40template <bool IsReverse> struct IteratorHelper;
41template <> struct IteratorHelper<false> : ilist_detail::NodeAccess {
42 using Access = ilist_detail::NodeAccess;
43
44 template <class T> static void increment(T *&I) { I = Access::getNext(*I); }
45 template <class T> static void decrement(T *&I) { I = Access::getPrev(*I); }
46};
47template <> struct IteratorHelper<true> : ilist_detail::NodeAccess {
48 using Access = ilist_detail::NodeAccess;
49
50 template <class T> static void increment(T *&I) { I = Access::getPrev(*I); }
51 template <class T> static void decrement(T *&I) { I = Access::getNext(*I); }
52};
53
54} // end namespace ilist_detail
55
56/// Iterator for intrusive lists based on ilist_node.
57template <class OptionsT, bool IsReverse, bool IsConst>
58class ilist_iterator : ilist_detail::SpecificNodeAccess<OptionsT> {
59 friend ilist_iterator<OptionsT, IsReverse, !IsConst>;
60 friend ilist_iterator<OptionsT, !IsReverse, IsConst>;
61 friend ilist_iterator<OptionsT, !IsReverse, !IsConst>;
62
63 using Traits = ilist_detail::IteratorTraits<OptionsT, IsConst>;
64 using Access = ilist_detail::SpecificNodeAccess<OptionsT>;
65
66public:
67 using value_type = typename Traits::value_type;
68 using pointer = typename Traits::pointer;
69 using reference = typename Traits::reference;
70 using difference_type = ptrdiff_t;
71 using iterator_category = std::bidirectional_iterator_tag;
72 using const_pointer = typename OptionsT::const_pointer;
73 using const_reference = typename OptionsT::const_reference;
74
75private:
76 using node_pointer = typename Traits::node_pointer;
77 using node_reference = typename Traits::node_reference;
78
79 node_pointer NodePtr = nullptr;
80
81public:
82 /// Create from an ilist_node.
83 explicit ilist_iterator(node_reference N) : NodePtr(&N) {}
84
85 explicit ilist_iterator(pointer NP) : NodePtr(Access::getNodePtr(NP)) {}
86 explicit ilist_iterator(reference NR) : NodePtr(Access::getNodePtr(&NR)) {}
87 ilist_iterator() = default;
88
89 // This is templated so that we can allow constructing a const iterator from
90 // a nonconst iterator...
91 template <bool RHSIsConst>
92 ilist_iterator(
93 const ilist_iterator<OptionsT, IsReverse, RHSIsConst> &RHS,
94 typename std::enable_if<IsConst || !RHSIsConst, void *>::type = nullptr)
95 : NodePtr(RHS.NodePtr) {}
96
97 // This is templated so that we can allow assigning to a const iterator from
98 // a nonconst iterator...
99 template <bool RHSIsConst>
100 typename std::enable_if<IsConst || !RHSIsConst, ilist_iterator &>::type
101 operator=(const ilist_iterator<OptionsT, IsReverse, RHSIsConst> &RHS) {
102 NodePtr = RHS.NodePtr;
103 return *this;
104 }
105
106 /// Explicit conversion between forward/reverse iterators.
107 ///
108 /// Translate between forward and reverse iterators without changing range
109 /// boundaries. The resulting iterator will dereference (and have a handle)
110 /// to the previous node, which is somewhat unexpected; but converting the
111 /// two endpoints in a range will give the same range in reverse.
112 ///
113 /// This matches std::reverse_iterator conversions.
114 explicit ilist_iterator(
115 const ilist_iterator<OptionsT, !IsReverse, IsConst> &RHS)
116 : ilist_iterator(++RHS.getReverse()) {}
117
118 /// Get a reverse iterator to the same node.
119 ///
120 /// Gives a reverse iterator that will dereference (and have a handle) to the
121 /// same node. Converting the endpoint iterators in a range will give a
122 /// different range; for range operations, use the explicit conversions.
123 ilist_iterator<OptionsT, !IsReverse, IsConst> getReverse() const {
124 if (NodePtr)
125 return ilist_iterator<OptionsT, !IsReverse, IsConst>(*NodePtr);
126 return ilist_iterator<OptionsT, !IsReverse, IsConst>();
127 }
128
129 /// Const-cast.
130 ilist_iterator<OptionsT, IsReverse, false> getNonConst() const {
131 if (NodePtr)
132 return ilist_iterator<OptionsT, IsReverse, false>(
133 const_cast<typename ilist_iterator<OptionsT, IsReverse,
134 false>::node_reference>(*NodePtr));
135 return ilist_iterator<OptionsT, IsReverse, false>();
136 }
137
138 // Accessors...
139 reference operator*() const {
140 assert(!NodePtr->isKnownSentinel());
141 return *Access::getValuePtr(NodePtr);
142 }
143 pointer operator->() const { return &operator*(); }
144
145 // Comparison operators
146 friend bool operator==(const ilist_iterator &LHS, const ilist_iterator &RHS) {
147 return LHS.NodePtr == RHS.NodePtr;
148 }
149 friend bool operator!=(const ilist_iterator &LHS, const ilist_iterator &RHS) {
150 return LHS.NodePtr != RHS.NodePtr;
151 }
152
153 // Increment and decrement operators...
154 ilist_iterator &operator--() {
155 NodePtr = IsReverse ? NodePtr->getNext() : NodePtr->getPrev();
156 return *this;
157 }
158 ilist_iterator &operator++() {
159 NodePtr = IsReverse ? NodePtr->getPrev() : NodePtr->getNext();
160 return *this;
161 }
162 ilist_iterator operator--(int) {
163 ilist_iterator tmp = *this;
164 --*this;
165 return tmp;
166 }
167 ilist_iterator operator++(int) {
168 ilist_iterator tmp = *this;
169 ++*this;
170 return tmp;
171 }
172
173 /// Get the underlying ilist_node.
174 node_pointer getNodePtr() const { return static_cast<node_pointer>(NodePtr); }
175
176 /// Check for end. Only valid if ilist_sentinel_tracking<true>.
177 bool isEnd() const { return NodePtr ? NodePtr->isSentinel() : false; }
178};
179
180template <typename From> struct simplify_type;
181
182/// Allow ilist_iterators to convert into pointers to a node automatically when
183/// used by the dyn_cast, cast, isa mechanisms...
184///
185/// FIXME: remove this, since there is no implicit conversion to NodeTy.
186template <class OptionsT, bool IsConst>
187struct simplify_type<ilist_iterator<OptionsT, false, IsConst>> {
188 using iterator = ilist_iterator<OptionsT, false, IsConst>;
189 using SimpleType = typename iterator::pointer;
190
191 static SimpleType getSimplifiedValue(const iterator &Node) { return &*Node; }
192};
193template <class OptionsT, bool IsConst>
194struct simplify_type<const ilist_iterator<OptionsT, false, IsConst>>
195 : simplify_type<ilist_iterator<OptionsT, false, IsConst>> {};
196
197} // end namespace llvm
198
199#endif // LLVM_ADT_ILIST_ITERATOR_H
200