1193323Sed//===-- llvm/ADT/SetOperations.h - Generic Set Operations -------*- C++ -*-===// 2193323Sed// 3353358Sdim// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4353358Sdim// See https://llvm.org/LICENSE.txt for license information. 5353358Sdim// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6193323Sed// 7193323Sed//===----------------------------------------------------------------------===// 8193323Sed// 9193323Sed// This file defines generic set operations that may be used on set's of 10193323Sed// different types, and different element types. 11193323Sed// 12193323Sed//===----------------------------------------------------------------------===// 13193323Sed 14193323Sed#ifndef LLVM_ADT_SETOPERATIONS_H 15193323Sed#define LLVM_ADT_SETOPERATIONS_H 16193323Sed 17193323Sednamespace llvm { 18193323Sed 19193323Sed/// set_union(A, B) - Compute A := A u B, return whether A changed. 20193323Sed/// 21193323Sedtemplate <class S1Ty, class S2Ty> 22193323Sedbool set_union(S1Ty &S1, const S2Ty &S2) { 23193323Sed bool Changed = false; 24193323Sed 25193323Sed for (typename S2Ty::const_iterator SI = S2.begin(), SE = S2.end(); 26193323Sed SI != SE; ++SI) 27193323Sed if (S1.insert(*SI).second) 28193323Sed Changed = true; 29193323Sed 30193323Sed return Changed; 31193323Sed} 32193323Sed 33193323Sed/// set_intersect(A, B) - Compute A := A ^ B 34193323Sed/// Identical to set_intersection, except that it works on set<>'s and 35193323Sed/// is nicer to use. Functionally, this iterates through S1, removing 36193323Sed/// elements that are not contained in S2. 37193323Sed/// 38193323Sedtemplate <class S1Ty, class S2Ty> 39193323Sedvoid set_intersect(S1Ty &S1, const S2Ty &S2) { 40193323Sed for (typename S1Ty::iterator I = S1.begin(); I != S1.end();) { 41296417Sdim const auto &E = *I; 42193323Sed ++I; 43193323Sed if (!S2.count(E)) S1.erase(E); // Erase element if not in S2 44193323Sed } 45193323Sed} 46193323Sed 47193323Sed/// set_difference(A, B) - Return A - B 48193323Sed/// 49193323Sedtemplate <class S1Ty, class S2Ty> 50193323SedS1Ty set_difference(const S1Ty &S1, const S2Ty &S2) { 51193323Sed S1Ty Result; 52193323Sed for (typename S1Ty::const_iterator SI = S1.begin(), SE = S1.end(); 53193323Sed SI != SE; ++SI) 54193323Sed if (!S2.count(*SI)) // if the element is not in set2 55193323Sed Result.insert(*SI); 56193323Sed return Result; 57193323Sed} 58193323Sed 59193323Sed/// set_subtract(A, B) - Compute A := A - B 60193323Sed/// 61193323Sedtemplate <class S1Ty, class S2Ty> 62193323Sedvoid set_subtract(S1Ty &S1, const S2Ty &S2) { 63193323Sed for (typename S2Ty::const_iterator SI = S2.begin(), SE = S2.end(); 64193323Sed SI != SE; ++SI) 65193323Sed S1.erase(*SI); 66193323Sed} 67193323Sed 68193323Sed} // End llvm namespace 69193323Sed 70193323Sed#endif 71