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14 | pmbaty | 1 | //===- llvm/ADT/UniqueVector.h ----------------------------------*- C++ -*-===// |
2 | // |
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3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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4 | // See https://llvm.org/LICENSE.txt for license information. |
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5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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6 | // |
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7 | //===----------------------------------------------------------------------===// |
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8 | |||
9 | #ifndef LLVM_ADT_UNIQUEVECTOR_H |
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10 | #define LLVM_ADT_UNIQUEVECTOR_H |
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11 | |||
12 | #include <cassert> |
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13 | #include <cstddef> |
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14 | #include <map> |
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15 | #include <vector> |
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16 | |||
17 | namespace llvm { |
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18 | |||
19 | //===----------------------------------------------------------------------===// |
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20 | /// UniqueVector - This class produces a sequential ID number (base 1) for each |
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21 | /// unique entry that is added. T is the type of entries in the vector. This |
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22 | /// class should have an implementation of operator== and of operator<. |
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23 | /// Entries can be fetched using operator[] with the entry ID. |
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24 | template<class T> class UniqueVector { |
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25 | public: |
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26 | using VectorType = typename std::vector<T>; |
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27 | using iterator = typename VectorType::iterator; |
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28 | using const_iterator = typename VectorType::const_iterator; |
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29 | |||
30 | private: |
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31 | // Map - Used to handle the correspondence of entry to ID. |
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32 | std::map<T, unsigned> Map; |
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33 | |||
34 | // Vector - ID ordered vector of entries. Entries can be indexed by ID - 1. |
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35 | VectorType Vector; |
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36 | |||
37 | public: |
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38 | /// insert - Append entry to the vector if it doesn't already exist. Returns |
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39 | /// the entry's index + 1 to be used as a unique ID. |
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40 | unsigned insert(const T &Entry) { |
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41 | // Check if the entry is already in the map. |
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42 | unsigned &Val = Map[Entry]; |
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43 | |||
44 | // See if entry exists, if so return prior ID. |
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45 | if (Val) return Val; |
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46 | |||
47 | // Compute ID for entry. |
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48 | Val = static_cast<unsigned>(Vector.size()) + 1; |
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49 | |||
50 | // Insert in vector. |
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51 | Vector.push_back(Entry); |
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52 | return Val; |
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53 | } |
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54 | |||
55 | /// idFor - return the ID for an existing entry. Returns 0 if the entry is |
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56 | /// not found. |
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57 | unsigned idFor(const T &Entry) const { |
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58 | // Search for entry in the map. |
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59 | typename std::map<T, unsigned>::const_iterator MI = Map.find(Entry); |
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60 | |||
61 | // See if entry exists, if so return ID. |
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62 | if (MI != Map.end()) return MI->second; |
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63 | |||
64 | // No luck. |
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65 | return 0; |
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66 | } |
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67 | |||
68 | /// operator[] - Returns a reference to the entry with the specified ID. |
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69 | const T &operator[](unsigned ID) const { |
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70 | assert(ID-1 < size() && "ID is 0 or out of range!"); |
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71 | return Vector[ID - 1]; |
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72 | } |
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73 | |||
74 | /// Return an iterator to the start of the vector. |
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75 | iterator begin() { return Vector.begin(); } |
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76 | |||
77 | /// Return an iterator to the start of the vector. |
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78 | const_iterator begin() const { return Vector.begin(); } |
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79 | |||
80 | /// Return an iterator to the end of the vector. |
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81 | iterator end() { return Vector.end(); } |
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82 | |||
83 | /// Return an iterator to the end of the vector. |
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84 | const_iterator end() const { return Vector.end(); } |
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85 | |||
86 | /// size - Returns the number of entries in the vector. |
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87 | size_t size() const { return Vector.size(); } |
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88 | |||
89 | /// empty - Returns true if the vector is empty. |
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90 | bool empty() const { return Vector.empty(); } |
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91 | |||
92 | /// reset - Clears all the entries. |
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93 | void reset() { |
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94 | Map.clear(); |
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95 | Vector.resize(0, 0); |
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96 | } |
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97 | }; |
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98 | |||
99 | } // end namespace llvm |
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100 | |||
101 | #endif // LLVM_ADT_UNIQUEVECTOR_H |