// Copyright 2018 PingCAP, Inc. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // See the License for the specific language governing permissions and // limitations under the License. package set // StringSet is a string set. type StringSet map[string]struct{} // NewStringSet builds a string set. func NewStringSet(ss ...string) StringSet { set := make(StringSet, len(ss)) for _, s := range ss { set.Insert(s) } return set } // Exist checks whether `val` exists in `s`. func (s StringSet) Exist(val string) bool { _, ok := s[val] return ok } // Insert inserts `val` into `s`. func (s StringSet) Insert(val string) { s[val] = struct{}{} } // Intersection returns the intersection of two sets func (s StringSet) Intersection(rhs StringSet) StringSet { newSet := NewStringSet() for elt := range s { if rhs.Exist(elt) { newSet.Insert(elt) } } return newSet } // Count returns the number in Set s. func (s StringSet) Count() int { return len(s) }