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
17namespace llvm {
18
19/// set_union(A, B) - Compute A := A u B, return whether A changed.
20///
21template <class S1Ty, class S2Ty>
22bool 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///
38template <class S1Ty, class S2Ty>
39void 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///
49template <class S1Ty, class S2Ty>
50S1Ty 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///
61template <class S1Ty, class S2Ty>
62void 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///
70template <class S1Ty, class S2Ty>
71bool 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///
82template <class S1Ty, class S2Ty>
83bool 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