1 //===- llvm/ADT/DenseSet.h - Dense probed hash table ------------*- 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 the DenseSet and SmallDenseSet classes.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ADT_DENSESET_H
15 #define LLVM_ADT_DENSESET_H
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/DenseMapInfo.h"
19 #include "llvm/Support/type_traits.h"
22 #include <initializer_list>
30 struct DenseSetEmpty {};
32 // Use the empty base class trick so we can create a DenseMap where the buckets
33 // contain only a single item.
34 template <typename KeyT> class DenseSetPair : public DenseSetEmpty {
38 KeyT &getFirst() { return key; }
39 const KeyT &getFirst() const { return key; }
40 DenseSetEmpty &getSecond() { return *this; }
41 const DenseSetEmpty &getSecond() const { return *this; }
44 /// Base class for DenseSet and DenseSmallSet.
46 /// MapTy should be either
48 /// DenseMap<ValueT, detail::DenseSetEmpty, ValueInfoT,
49 /// detail::DenseSetPair<ValueT>>
51 /// or the equivalent SmallDenseMap type. ValueInfoT must implement the
52 /// DenseMapInfo "concept".
53 template <typename ValueT, typename MapTy, typename ValueInfoT>
55 static_assert(sizeof(typename MapTy::value_type) == sizeof(ValueT),
56 "DenseMap buckets unexpectedly large!");
60 using const_arg_type_t = typename const_pointer_or_const_ref<T>::type;
63 using key_type = ValueT;
64 using value_type = ValueT;
65 using size_type = unsigned;
67 explicit DenseSetImpl(unsigned InitialReserve = 0) : TheMap(InitialReserve) {}
69 DenseSetImpl(std::initializer_list<ValueT> Elems)
70 : DenseSetImpl(Elems.size()) {
71 insert(Elems.begin(), Elems.end());
74 bool empty() const { return TheMap.empty(); }
75 size_type size() const { return TheMap.size(); }
76 size_t getMemorySize() const { return TheMap.getMemorySize(); }
78 /// Grow the DenseSet so that it has at least Size buckets. Will not shrink
79 /// the Size of the set.
80 void resize(size_t Size) { TheMap.resize(Size); }
82 /// Grow the DenseSet so that it can contain at least \p NumEntries items
83 /// before resizing again.
84 void reserve(size_t Size) { TheMap.reserve(Size); }
90 /// Return 1 if the specified key is in the set, 0 otherwise.
91 size_type count(const_arg_type_t<ValueT> V) const {
92 return TheMap.count(V);
95 bool erase(const ValueT &V) {
96 return TheMap.erase(V);
99 void swap(DenseSetImpl &RHS) { TheMap.swap(RHS.TheMap); }
106 typename MapTy::iterator I;
107 friend class DenseSetImpl;
108 friend class ConstIterator;
111 using difference_type = typename MapTy::iterator::difference_type;
112 using value_type = ValueT;
113 using pointer = value_type *;
114 using reference = value_type &;
115 using iterator_category = std::forward_iterator_tag;
117 Iterator() = default;
118 Iterator(const typename MapTy::iterator &i) : I(i) {}
120 ValueT &operator*() { return I->getFirst(); }
121 const ValueT &operator*() const { return I->getFirst(); }
122 ValueT *operator->() { return &I->getFirst(); }
123 const ValueT *operator->() const { return &I->getFirst(); }
125 Iterator& operator++() { ++I; return *this; }
126 Iterator operator++(int) { auto T = *this; ++I; return T; }
127 bool operator==(const ConstIterator& X) const { return I == X.I; }
128 bool operator!=(const ConstIterator& X) const { return I != X.I; }
131 class ConstIterator {
132 typename MapTy::const_iterator I;
133 friend class DenseSet;
134 friend class Iterator;
137 using difference_type = typename MapTy::const_iterator::difference_type;
138 using value_type = ValueT;
139 using pointer = value_type *;
140 using reference = value_type &;
141 using iterator_category = std::forward_iterator_tag;
143 ConstIterator() = default;
144 ConstIterator(const Iterator &B) : I(B.I) {}
145 ConstIterator(const typename MapTy::const_iterator &i) : I(i) {}
147 const ValueT &operator*() const { return I->getFirst(); }
148 const ValueT *operator->() const { return &I->getFirst(); }
150 ConstIterator& operator++() { ++I; return *this; }
151 ConstIterator operator++(int) { auto T = *this; ++I; return T; }
152 bool operator==(const ConstIterator& X) const { return I == X.I; }
153 bool operator!=(const ConstIterator& X) const { return I != X.I; }
156 using iterator = Iterator;
157 using const_iterator = ConstIterator;
159 iterator begin() { return Iterator(TheMap.begin()); }
160 iterator end() { return Iterator(TheMap.end()); }
162 const_iterator begin() const { return ConstIterator(TheMap.begin()); }
163 const_iterator end() const { return ConstIterator(TheMap.end()); }
165 iterator find(const_arg_type_t<ValueT> V) { return Iterator(TheMap.find(V)); }
166 const_iterator find(const_arg_type_t<ValueT> V) const {
167 return ConstIterator(TheMap.find(V));
170 /// Alternative version of find() which allows a different, and possibly less
171 /// expensive, key type.
172 /// The DenseMapInfo is responsible for supplying methods
173 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key type
175 template <class LookupKeyT>
176 iterator find_as(const LookupKeyT &Val) {
177 return Iterator(TheMap.find_as(Val));
179 template <class LookupKeyT>
180 const_iterator find_as(const LookupKeyT &Val) const {
181 return ConstIterator(TheMap.find_as(Val));
184 void erase(Iterator I) { return TheMap.erase(I.I); }
185 void erase(ConstIterator CI) { return TheMap.erase(CI.I); }
187 std::pair<iterator, bool> insert(const ValueT &V) {
188 detail::DenseSetEmpty Empty;
189 return TheMap.try_emplace(V, Empty);
192 std::pair<iterator, bool> insert(ValueT &&V) {
193 detail::DenseSetEmpty Empty;
194 return TheMap.try_emplace(std::move(V), Empty);
197 /// Alternative version of insert that uses a different (and possibly less
198 /// expensive) key type.
199 template <typename LookupKeyT>
200 std::pair<iterator, bool> insert_as(const ValueT &V,
201 const LookupKeyT &LookupKey) {
202 return TheMap.insert_as({V, detail::DenseSetEmpty()}, LookupKey);
204 template <typename LookupKeyT>
205 std::pair<iterator, bool> insert_as(ValueT &&V, const LookupKeyT &LookupKey) {
206 return TheMap.insert_as({std::move(V), detail::DenseSetEmpty()}, LookupKey);
209 // Range insertion of values.
210 template<typename InputIt>
211 void insert(InputIt I, InputIt E) {
217 } // end namespace detail
219 /// Implements a dense probed hash-table based set.
220 template <typename ValueT, typename ValueInfoT = DenseMapInfo<ValueT>>
221 class DenseSet : public detail::DenseSetImpl<
222 ValueT, DenseMap<ValueT, detail::DenseSetEmpty, ValueInfoT,
223 detail::DenseSetPair<ValueT>>,
226 detail::DenseSetImpl<ValueT,
227 DenseMap<ValueT, detail::DenseSetEmpty, ValueInfoT,
228 detail::DenseSetPair<ValueT>>,
235 /// Implements a dense probed hash-table based set with some number of buckets
237 template <typename ValueT, unsigned InlineBuckets = 4,
238 typename ValueInfoT = DenseMapInfo<ValueT>>
240 : public detail::DenseSetImpl<
241 ValueT, SmallDenseMap<ValueT, detail::DenseSetEmpty, InlineBuckets,
242 ValueInfoT, detail::DenseSetPair<ValueT>>,
244 using BaseT = detail::DenseSetImpl<
245 ValueT, SmallDenseMap<ValueT, detail::DenseSetEmpty, InlineBuckets,
246 ValueInfoT, detail::DenseSetPair<ValueT>>,
253 } // end namespace llvm
255 #endif // LLVM_ADT_DENSESET_H