1 //===- llvm/ADT/UniqueVector.h ----------------------------------*- 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 #ifndef LLVM_ADT_UNIQUEVECTOR_H
11 #define LLVM_ADT_UNIQUEVECTOR_H
20 //===----------------------------------------------------------------------===//
21 /// UniqueVector - This class produces a sequential ID number (base 1) for each
22 /// unique entry that is added. T is the type of entries in the vector. This
23 /// class should have an implementation of operator== and of operator<.
24 /// Entries can be fetched using operator[] with the entry ID.
25 template<class T> class UniqueVector {
27 using VectorType = typename std::vector<T>;
28 using iterator = typename VectorType::iterator;
29 using const_iterator = typename VectorType::const_iterator;
32 // Map - Used to handle the correspondence of entry to ID.
33 std::map<T, unsigned> Map;
35 // Vector - ID ordered vector of entries. Entries can be indexed by ID - 1.
39 /// insert - Append entry to the vector if it doesn't already exist. Returns
40 /// the entry's index + 1 to be used as a unique ID.
41 unsigned insert(const T &Entry) {
42 // Check if the entry is already in the map.
43 unsigned &Val = Map[Entry];
45 // See if entry exists, if so return prior ID.
48 // Compute ID for entry.
49 Val = static_cast<unsigned>(Vector.size()) + 1;
52 Vector.push_back(Entry);
56 /// idFor - return the ID for an existing entry. Returns 0 if the entry is
58 unsigned idFor(const T &Entry) const {
59 // Search for entry in the map.
60 typename std::map<T, unsigned>::const_iterator MI = Map.find(Entry);
62 // See if entry exists, if so return ID.
63 if (MI != Map.end()) return MI->second;
69 /// operator[] - Returns a reference to the entry with the specified ID.
70 const T &operator[](unsigned ID) const {
71 assert(ID-1 < size() && "ID is 0 or out of range!");
72 return Vector[ID - 1];
75 /// \brief Return an iterator to the start of the vector.
76 iterator begin() { return Vector.begin(); }
78 /// \brief Return an iterator to the start of the vector.
79 const_iterator begin() const { return Vector.begin(); }
81 /// \brief Return an iterator to the end of the vector.
82 iterator end() { return Vector.end(); }
84 /// \brief Return an iterator to the end of the vector.
85 const_iterator end() const { return Vector.end(); }
87 /// size - Returns the number of entries in the vector.
88 size_t size() const { return Vector.size(); }
90 /// empty - Returns true if the vector is empty.
91 bool empty() const { return Vector.empty(); }
93 /// reset - Clears all the entries.
100 } // end namespace llvm
102 #endif // LLVM_ADT_UNIQUEVECTOR_H