2 //===-- llvm/ADT/UniqueVector.h ---------------------------------*- C++ -*-===//
4 // The LLVM Compiler Infrastructure
6 // This file was developed by James M. Laskey and is distributed under
7 // the University of Illinois Open Source License. See LICENSE.TXT for details.
9 //===----------------------------------------------------------------------===//
11 #ifndef LLVM_ADT_UNIQUEVECTOR_H
12 #define LLVM_ADT_UNIQUEVECTOR_H
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 {
26 // Map - Used to handle the correspondence of entry to ID.
27 std::map<T, unsigned> Map;
29 // Vector - ID ordered vector of entries. Entries can be indexed by ID - 1.
31 std::vector<const T *> Vector;
34 /// insert - Append entry to the vector if it doesn't already exist. Returns
35 /// the entry's index + 1 to be used as a unique ID.
36 unsigned insert(const T &Entry) {
37 // Check if the entry is already in the map.
38 typename std::map<T, unsigned>::iterator MI = Map.lower_bound(Entry);
40 // See if entry exists, if so return prior ID.
41 if (MI != Map.end() && MI->first == Entry) return MI->second;
43 // Compute ID for entry.
44 unsigned ID = Vector.size() + 1;
47 MI = Map.insert(MI, std::make_pair(Entry, ID));
50 Vector.push_back(&MI->first);
55 /// idFor - return the ID for an existing entry. Returns 0 if the entry is
57 unsigned idFor(const T &Entry) const {
58 // Search for entry in the map.
59 typename std::map<T, unsigned>::iterator MI = Map.find(Entry);
61 // See if entry exists, if so return ID.
62 if (MI != Map.end()) return MI->second;
68 /// operator[] - Returns a reference to the entry with the specified ID.
70 const T &operator[](unsigned ID) const { return *Vector[ID - 1]; }
72 /// size - Returns the number of entries in the vector.
74 size_t size() const { return Vector.size(); }
76 /// empty - Returns true if the vector is empty.
78 bool empty() const { return Vector.empty(); }
80 /// reset - Clears all the entries.
88 } // End of namespace llvm
90 #endif // LLVM_ADT_UNIQUEVECTOR_H