LLVM  3.7.0
UniqueVector.h
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1 //===-- llvm/ADT/UniqueVector.h ---------------------------------*- 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_UNIQUEVECTOR_H
11 #define LLVM_ADT_UNIQUEVECTOR_H
12 
13 #include <cassert>
14 #include <map>
15 #include <vector>
16 
17 namespace llvm {
18 
19 //===----------------------------------------------------------------------===//
20 /// UniqueVector - This class produces a sequential ID number (base 1) for each
21 /// unique entry that is added. T is the type of entries in the vector. This
22 /// class should have an implementation of operator== and of operator<.
23 /// Entries can be fetched using operator[] with the entry ID.
24 template<class T> class UniqueVector {
25 public:
26  typedef typename std::vector<T> VectorType;
27  typedef typename VectorType::iterator iterator;
28  typedef typename VectorType::const_iterator const_iterator;
29 
30 private:
31  // Map - Used to handle the correspondence of entry to ID.
32  std::map<T, unsigned> Map;
33 
34  // Vector - ID ordered vector of entries. Entries can be indexed by ID - 1.
35  //
36  VectorType Vector;
37 
38 public:
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];
44 
45  // See if entry exists, if so return prior ID.
46  if (Val) return Val;
47 
48  // Compute ID for entry.
49  Val = static_cast<unsigned>(Vector.size()) + 1;
50 
51  // Insert in vector.
52  Vector.push_back(Entry);
53  return Val;
54  }
55 
56  /// idFor - return the ID for an existing entry. Returns 0 if the entry is
57  /// not found.
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);
61 
62  // See if entry exists, if so return ID.
63  if (MI != Map.end()) return MI->second;
64 
65  // No luck.
66  return 0;
67  }
68 
69  /// operator[] - Returns a reference to the entry with the specified ID.
70  ///
71  const T &operator[](unsigned ID) const {
72  assert(ID-1 < size() && "ID is 0 or out of range!");
73  return Vector[ID - 1];
74  }
75 
76  /// \brief Return an iterator to the start of the vector.
77  iterator begin() { return Vector.begin(); }
78 
79  /// \brief Return an iterator to the start of the vector.
80  const_iterator begin() const { return Vector.begin(); }
81 
82  /// \brief Return an iterator to the end of the vector.
83  iterator end() { return Vector.end(); }
84 
85  /// \brief Return an iterator to the end of the vector.
86  const_iterator end() const { return Vector.end(); }
87 
88  /// size - Returns the number of entries in the vector.
89  ///
90  size_t size() const { return Vector.size(); }
91 
92  /// empty - Returns true if the vector is empty.
93  ///
94  bool empty() const { return Vector.empty(); }
95 
96  /// reset - Clears all the entries.
97  ///
98  void reset() {
99  Map.clear();
100  Vector.resize(0, 0);
101  }
102 };
103 
104 } // End of namespace llvm
105 
106 #endif // LLVM_ADT_UNIQUEVECTOR_H
const T & operator[](unsigned ID) const
operator[] - Returns a reference to the entry with the specified ID.
Definition: UniqueVector.h:71
const_iterator begin() const
Return an iterator to the start of the vector.
Definition: UniqueVector.h:80
VectorType::iterator iterator
Definition: UniqueVector.h:27
VectorType::const_iterator const_iterator
Definition: UniqueVector.h:28
const_iterator end() const
Return an iterator to the end of the vector.
Definition: UniqueVector.h:86
unsigned idFor(const T &Entry) const
idFor - return the ID for an existing entry.
Definition: UniqueVector.h:58
std::vector< T > VectorType
Definition: UniqueVector.h:26
bool empty() const
empty - Returns true if the vector is empty.
Definition: UniqueVector.h:94
void reset()
reset - Clears all the entries.
Definition: UniqueVector.h:98
iterator begin()
Return an iterator to the start of the vector.
Definition: UniqueVector.h:77
iterator end()
Return an iterator to the end of the vector.
Definition: UniqueVector.h:83
unsigned insert(const T &Entry)
insert - Append entry to the vector if it doesn't already exist.
Definition: UniqueVector.h:41
size_t size() const
size - Returns the number of entries in the vector.
Definition: UniqueVector.h:90
UniqueVector - This class produces a sequential ID number (base 1) for each unique entry that is adde...
Definition: UniqueVector.h:24