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 /// \brief Determine if the SetVector is empty or not.
63 return vector_.empty();
66 /// \brief Determine the number of elements in the SetVector.
67 size_type size() const {
68 return vector_.size();
71 /// \brief Get an iterator to the beginning of the SetVector.
73 return vector_.begin();
76 /// \brief Get a const_iterator to the beginning of the SetVector.
77 const_iterator begin() const {
78 return vector_.begin();
81 /// \brief Get an iterator to the end of the SetVector.
86 /// \brief Get a const_iterator to the end of the SetVector.
87 const_iterator end() const {
91 /// \brief Get an reverse_iterator to the end of the SetVector.
92 reverse_iterator rbegin() {
93 return vector_.rbegin();
96 /// \brief Get a const_reverse_iterator to the end of the SetVector.
97 const_reverse_iterator rbegin() const {
98 return vector_.rbegin();
101 /// \brief Get a reverse_iterator to the beginning of the SetVector.
102 reverse_iterator rend() {
103 return vector_.rend();
106 /// \brief Get a const_reverse_iterator to the beginning of the SetVector.
107 const_reverse_iterator rend() const {
108 return vector_.rend();
111 /// \brief Return the last element of the SetVector.
112 const T &back() const {
113 assert(!empty() && "Cannot call back() on empty SetVector!");
114 return vector_.back();
117 /// \brief Index into the SetVector.
118 const_reference operator[](size_type n) const {
119 assert(n < vector_.size() && "SetVector access out of range!");
123 /// \brief Insert a new element into the SetVector.
124 /// \returns true iff the element was inserted into the SetVector.
125 bool insert(const value_type &X) {
126 bool result = set_.insert(X).second;
128 vector_.push_back(X);
132 /// \brief Insert a range of elements into the SetVector.
133 template<typename It>
134 void insert(It Start, It End) {
135 for (; Start != End; ++Start)
136 if (set_.insert(*Start).second)
137 vector_.push_back(*Start);
140 /// \brief Remove an item from the set vector.
141 bool remove(const value_type& X) {
143 typename vector_type::iterator I =
144 std::find(vector_.begin(), vector_.end(), X);
145 assert(I != vector_.end() && "Corrupted SetVector instances!");
152 /// \brief Remove items from the set vector based on a predicate function.
154 /// This is intended to be equivalent to the following code, if we could
158 /// V.erase(std::remove_if(V.begin(), V.end(), P), V.end());
161 /// However, SetVector doesn't expose non-const iterators, making any
162 /// algorithm like remove_if impossible to use.
164 /// \returns true if any element is removed.
165 template <typename UnaryPredicate>
166 bool remove_if(UnaryPredicate P) {
167 typename vector_type::iterator I
168 = std::remove_if(vector_.begin(), vector_.end(),
169 TestAndEraseFromSet<UnaryPredicate>(P, set_));
170 if (I == vector_.end())
172 vector_.erase(I, vector_.end());
176 /// \brief Count the number of elements of a given key in the SetVector.
177 /// \returns 0 if the element is not in the SetVector, 1 if it is.
178 size_type count(const key_type &key) const {
179 return set_.count(key);
182 /// \brief Completely clear the SetVector
188 /// \brief Remove the last element of the SetVector.
190 assert(!empty() && "Cannot remove an element from an empty SetVector!");
195 T LLVM_ATTRIBUTE_UNUSED_RESULT pop_back_val() {
201 bool operator==(const SetVector &that) const {
202 return vector_ == that.vector_;
205 bool operator!=(const SetVector &that) const {
206 return vector_ != that.vector_;
210 /// \brief A wrapper predicate designed for use with std::remove_if.
212 /// This predicate wraps a predicate suitable for use with std::remove_if to
213 /// call set_.erase(x) on each element which is slated for removal.
214 template <typename UnaryPredicate>
215 class TestAndEraseFromSet {
220 TestAndEraseFromSet(UnaryPredicate P, set_type &set_) : P(P), set_(set_) {}
222 template <typename ArgumentT>
223 bool operator()(const ArgumentT &Arg) {
232 set_type set_; ///< The set.
233 vector_type vector_; ///< The vector.
236 /// \brief A SetVector that performs no allocations if smaller than
238 template <typename T, unsigned N>
239 class SmallSetVector : public SetVector<T, SmallVector<T, N>, SmallSet<T, N> > {
243 /// \brief Initialize a SmallSetVector with a range of elements
244 template<typename It>
245 SmallSetVector(It Start, It End) {
246 this->insert(Start, End);
250 } // End llvm namespace