//===-- llvm/ADT/SetOperations.h - Generic Set Operations -------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file defines generic set operations that may be used on set's of // different types, and different element types. // //===----------------------------------------------------------------------===// #ifndef LLVM_ADT_SETOPERATIONS_H #define LLVM_ADT_SETOPERATIONS_H namespace llvm { /// set_union(A, B) - Compute A := A u B, return whether A changed. /// template <class S1Ty, class S2Ty> bool set_union(S1Ty &S1, const S2Ty &S2) { bool Changed = false; for (typename S2Ty::const_iterator SI = S2.begin(), SE = S2.end(); SI != SE; ++SI) if (S1.insert(*SI).second) Changed = true; return Changed; } /// set_intersect(A, B) - Compute A := A ^ B /// Identical to set_intersection, except that it works on set<>'s and /// is nicer to use. Functionally, this iterates through S1, removing /// elements that are not contained in S2. /// template <class S1Ty, class S2Ty> void set_intersect(S1Ty &S1, const S2Ty &S2) { for (typename S1Ty::iterator I = S1.begin(); I != S1.end();) { const auto &E = *I; ++I; if (!S2.count(E)) S1.erase(E); // Erase element if not in S2 } } /// set_difference(A, B) - Return A - B /// template <class S1Ty, class S2Ty> S1Ty set_difference(const S1Ty &S1, const S2Ty &S2) { S1Ty Result; for (typename S1Ty::const_iterator SI = S1.begin(), SE = S1.end(); SI != SE; ++SI) if (!S2.count(*SI)) // if the element is not in set2 Result.insert(*SI); return Result; } /// set_subtract(A, B) - Compute A := A - B /// template <class S1Ty, class S2Ty> void set_subtract(S1Ty &S1, const S2Ty &S2) { for (typename S2Ty::const_iterator SI = S2.begin(), SE = S2.end(); SI != SE; ++SI) S1.erase(*SI); } } // End llvm namespace #endif |