1193323Sed//===-- llvm/ADT/UniqueVector.h ---------------------------------*- C++ -*-===//
2193323Sed//
3193323Sed//                     The LLVM Compiler Infrastructure
4193323Sed//
5193323Sed// This file is distributed under the University of Illinois Open Source
6193323Sed// License. See LICENSE.TXT for details.
7193323Sed//
8193323Sed//===----------------------------------------------------------------------===//
9193323Sed
10193323Sed#ifndef LLVM_ADT_UNIQUEVECTOR_H
11193323Sed#define LLVM_ADT_UNIQUEVECTOR_H
12193323Sed
13193323Sed#include <cassert>
14193323Sed#include <map>
15193323Sed#include <vector>
16193323Sed
17193323Sednamespace llvm {
18193323Sed
19193323Sed//===----------------------------------------------------------------------===//
20193323Sed/// UniqueVector - This class produces a sequential ID number (base 1) for each
21193323Sed/// unique entry that is added.  T is the type of entries in the vector. This
22193323Sed/// class should have an implementation of operator== and of operator<.
23193323Sed/// Entries can be fetched using operator[] with the entry ID.
24193323Sedtemplate<class T> class UniqueVector {
25193323Sedprivate:
26193323Sed  // Map - Used to handle the correspondence of entry to ID.
27193323Sed  std::map<T, unsigned> Map;
28193323Sed
29193323Sed  // Vector - ID ordered vector of entries. Entries can be indexed by ID - 1.
30193323Sed  //
31193323Sed  std::vector<T> Vector;
32193323Sed
33193323Sedpublic:
34193323Sed  /// insert - Append entry to the vector if it doesn't already exist.  Returns
35193323Sed  /// the entry's index + 1 to be used as a unique ID.
36193323Sed  unsigned insert(const T &Entry) {
37193323Sed    // Check if the entry is already in the map.
38193323Sed    unsigned &Val = Map[Entry];
39193323Sed
40193323Sed    // See if entry exists, if so return prior ID.
41193323Sed    if (Val) return Val;
42193323Sed
43193323Sed    // Compute ID for entry.
44193323Sed    Val = static_cast<unsigned>(Vector.size()) + 1;
45193323Sed
46193323Sed    // Insert in vector.
47193323Sed    Vector.push_back(Entry);
48193323Sed    return Val;
49193323Sed  }
50193323Sed
51193323Sed  /// idFor - return the ID for an existing entry.  Returns 0 if the entry is
52193323Sed  /// not found.
53193323Sed  unsigned idFor(const T &Entry) const {
54193323Sed    // Search for entry in the map.
55193323Sed    typename std::map<T, unsigned>::const_iterator MI = Map.find(Entry);
56193323Sed
57193323Sed    // See if entry exists, if so return ID.
58193323Sed    if (MI != Map.end()) return MI->second;
59193323Sed
60193323Sed    // No luck.
61193323Sed    return 0;
62193323Sed  }
63193323Sed
64193323Sed  /// operator[] - Returns a reference to the entry with the specified ID.
65193323Sed  ///
66193323Sed  const T &operator[](unsigned ID) const {
67193323Sed    assert(ID-1 < size() && "ID is 0 or out of range!");
68193323Sed    return Vector[ID - 1];
69193323Sed  }
70193323Sed
71193323Sed  /// size - Returns the number of entries in the vector.
72193323Sed  ///
73193323Sed  size_t size() const { return Vector.size(); }
74193323Sed
75193323Sed  /// empty - Returns true if the vector is empty.
76193323Sed  ///
77193323Sed  bool empty() const { return Vector.empty(); }
78193323Sed
79193323Sed  /// reset - Clears all the entries.
80193323Sed  ///
81193323Sed  void reset() {
82193323Sed    Map.clear();
83193323Sed    Vector.resize(0, 0);
84193323Sed  }
85193323Sed};
86193323Sed
87193323Sed} // End of namespace llvm
88193323Sed
89193323Sed#endif // LLVM_ADT_UNIQUEVECTOR_H
90