1 //===-- llvm/ADT/SetOperations.h - Generic Set Operations -------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines generic set operations that may be used on set's of
10 // different types, and different element types.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #ifndef LLVM_ADT_SETOPERATIONS_H
15 #define LLVM_ADT_SETOPERATIONS_H
16
17 namespace llvm {
18
19 /// set_union(A, B) - Compute A := A u B, return whether A changed.
20 ///
21 template <class S1Ty, class S2Ty>
set_union(S1Ty & S1,const S2Ty & S2)22 bool set_union(S1Ty &S1, const S2Ty &S2) {
23 bool Changed = false;
24
25 for (typename S2Ty::const_iterator SI = S2.begin(), SE = S2.end();
26 SI != SE; ++SI)
27 if (S1.insert(*SI).second)
28 Changed = true;
29
30 return Changed;
31 }
32
33 /// set_intersect(A, B) - Compute A := A ^ B
34 /// Identical to set_intersection, except that it works on set<>'s and
35 /// is nicer to use. Functionally, this iterates through S1, removing
36 /// elements that are not contained in S2.
37 ///
38 template <class S1Ty, class S2Ty>
set_intersect(S1Ty & S1,const S2Ty & S2)39 void set_intersect(S1Ty &S1, const S2Ty &S2) {
40 for (typename S1Ty::iterator I = S1.begin(); I != S1.end();) {
41 const auto &E = *I;
42 ++I;
43 if (!S2.count(E)) S1.erase(E); // Erase element if not in S2
44 }
45 }
46
47 /// set_difference(A, B) - Return A - B
48 ///
49 template <class S1Ty, class S2Ty>
set_difference(const S1Ty & S1,const S2Ty & S2)50 S1Ty set_difference(const S1Ty &S1, const S2Ty &S2) {
51 S1Ty Result;
52 for (typename S1Ty::const_iterator SI = S1.begin(), SE = S1.end();
53 SI != SE; ++SI)
54 if (!S2.count(*SI)) // if the element is not in set2
55 Result.insert(*SI);
56 return Result;
57 }
58
59 /// set_subtract(A, B) - Compute A := A - B
60 ///
61 template <class S1Ty, class S2Ty>
set_subtract(S1Ty & S1,const S2Ty & S2)62 void set_subtract(S1Ty &S1, const S2Ty &S2) {
63 for (typename S2Ty::const_iterator SI = S2.begin(), SE = S2.end();
64 SI != SE; ++SI)
65 S1.erase(*SI);
66 }
67
68 /// set_is_subset(A, B) - Return true iff A in B
69 ///
70 template <class S1Ty, class S2Ty>
set_is_subset(const S1Ty & S1,const S2Ty & S2)71 bool set_is_subset(const S1Ty &S1, const S2Ty &S2) {
72 if (S1.size() > S2.size())
73 return false;
74 for (const auto It : S1)
75 if (!S2.count(It))
76 return false;
77 return true;
78 }
79
80 /// set_is_strict_subset(A, B) - Return true iff A in B and and A != B
81 ///
82 template <class S1Ty, class S2Ty>
set_is_strict_subset(const S1Ty & S1,const S2Ty & S2)83 bool set_is_strict_subset(const S1Ty &S1, const S2Ty &S2) {
84 if (S1.size() >= S2.size())
85 return false;
86 return set_is_subset(S1, S2);
87 }
88
89 } // End llvm namespace
90
91 #endif
92