1 //===- llvm/ADT/SetVector.h - Set with insert order iteration ---*- 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 implements a set that has insertion order iteration
11 // characteristics. This is useful for keeping a set of things that need to be
12 // visited later but in a deterministic order (insertion order). The interface
13 // is purposefully minimal.
15 // This file defines SetVector and SmallSetVector, which performs no allocations
16 // if the SetVector has less than a certain number of elements.
18 //===----------------------------------------------------------------------===//
20 #ifndef LLVM_ADT_SETVECTOR_H
21 #define LLVM_ADT_SETVECTOR_H
23 #include "llvm/ADT/DenseSet.h"
24 #include "llvm/ADT/SmallSet.h"
31 /// \brief A vector that has set insertion semantics.
33 /// This adapter class provides a way to keep a set of things that also has the
34 /// property of a deterministic iteration order. The order of iteration is the
35 /// order of insertion.
36 template <typename T, typename Vector = std::vector<T>,
37 typename Set = DenseSet<T>>
43 typedef const T& const_reference;
45 typedef Vector vector_type;
46 typedef typename vector_type::const_iterator iterator;
47 typedef typename vector_type::const_iterator const_iterator;
48 typedef typename vector_type::const_reverse_iterator reverse_iterator;
49 typedef typename vector_type::const_reverse_iterator const_reverse_iterator;
50 typedef typename vector_type::size_type size_type;
52 /// \brief Construct an empty SetVector
55 /// \brief Initialize a SetVector with a range of elements
57 SetVector(It Start, It End) {
61 ArrayRef<T> getArrayRef() const { return vector_; }
63 /// \brief Determine if the SetVector is empty or not.
65 return vector_.empty();
68 /// \brief Determine the number of elements in the SetVector.
69 size_type size() const {
70 return vector_.size();
73 /// \brief Get an iterator to the beginning of the SetVector.
75 return vector_.begin();
78 /// \brief Get a const_iterator to the beginning of the SetVector.
79 const_iterator begin() const {
80 return vector_.begin();
83 /// \brief Get an iterator to the end of the SetVector.
88 /// \brief Get a const_iterator to the end of the SetVector.
89 const_iterator end() const {
93 /// \brief Get an reverse_iterator to the end of the SetVector.
94 reverse_iterator rbegin() {
95 return vector_.rbegin();
98 /// \brief Get a const_reverse_iterator to the end of the SetVector.
99 const_reverse_iterator rbegin() const {
100 return vector_.rbegin();
103 /// \brief Get a reverse_iterator to the beginning of the SetVector.
104 reverse_iterator rend() {
105 return vector_.rend();
108 /// \brief Get a const_reverse_iterator to the beginning of the SetVector.
109 const_reverse_iterator rend() const {
110 return vector_.rend();
113 /// \brief Return the last element of the SetVector.
114 const T &back() const {
115 assert(!empty() && "Cannot call back() on empty SetVector!");
116 return vector_.back();
119 /// \brief Index into the SetVector.
120 const_reference operator[](size_type n) const {
121 assert(n < vector_.size() && "SetVector access out of range!");
125 /// \brief Insert a new element into the SetVector.
126 /// \returns true iff the element was inserted into the SetVector.
127 bool insert(const value_type &X) {
128 bool result = set_.insert(X).second;
130 vector_.push_back(X);
134 /// \brief Insert a range of elements into the SetVector.
135 template<typename It>
136 void insert(It Start, It End) {
137 for (; Start != End; ++Start)
138 if (set_.insert(*Start).second)
139 vector_.push_back(*Start);
142 /// \brief Remove an item from the set vector.
143 bool remove(const value_type& X) {
145 typename vector_type::iterator I =
146 std::find(vector_.begin(), vector_.end(), X);
147 assert(I != vector_.end() && "Corrupted SetVector instances!");
154 /// \brief Remove items from the set vector based on a predicate function.
156 /// This is intended to be equivalent to the following code, if we could
160 /// V.erase(std::remove_if(V.begin(), V.end(), P), V.end());
163 /// However, SetVector doesn't expose non-const iterators, making any
164 /// algorithm like remove_if impossible to use.
166 /// \returns true if any element is removed.
167 template <typename UnaryPredicate>
168 bool remove_if(UnaryPredicate P) {
169 typename vector_type::iterator I
170 = std::remove_if(vector_.begin(), vector_.end(),
171 TestAndEraseFromSet<UnaryPredicate>(P, set_));
172 if (I == vector_.end())
174 vector_.erase(I, vector_.end());
178 /// \brief Count the number of elements of a given key in the SetVector.
179 /// \returns 0 if the element is not in the SetVector, 1 if it is.
180 size_type count(const key_type &key) const {
181 return set_.count(key);
184 /// \brief Completely clear the SetVector
190 /// \brief Remove the last element of the SetVector.
192 assert(!empty() && "Cannot remove an element from an empty SetVector!");
197 T LLVM_ATTRIBUTE_UNUSED_RESULT pop_back_val() {
203 bool operator==(const SetVector &that) const {
204 return vector_ == that.vector_;
207 bool operator!=(const SetVector &that) const {
208 return vector_ != that.vector_;
212 /// \brief A wrapper predicate designed for use with std::remove_if.
214 /// This predicate wraps a predicate suitable for use with std::remove_if to
215 /// call set_.erase(x) on each element which is slated for removal.
216 template <typename UnaryPredicate>
217 class TestAndEraseFromSet {
222 TestAndEraseFromSet(UnaryPredicate P, set_type &set_) : P(P), set_(set_) {}
224 template <typename ArgumentT>
225 bool operator()(const ArgumentT &Arg) {
234 set_type set_; ///< The set.
235 vector_type vector_; ///< The vector.
238 /// \brief A SetVector that performs no allocations if smaller than
240 template <typename T, unsigned N>
241 class SmallSetVector : public SetVector<T, SmallVector<T, N>, SmallSet<T, N> > {
245 /// \brief Initialize a SmallSetVector with a range of elements
246 template<typename It>
247 SmallSetVector(It Start, It End) {
248 this->insert(Start, End);
252 } // End llvm namespace