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// Copyright 2020 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)
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{}{}
}
// Join add all elements of `add` to `s`.
func (s StringSet) Join(add StringSet) StringSet {
for elt := range add {
s.Insert(elt)
}
return s
}
// 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
}
// Remove removes `val` from `s`
func (s StringSet) Remove(val string) {
delete(s, val)
}
// Difference returns the difference of two sets
func (s StringSet) Difference(rhs StringSet) StringSet {
newSet := NewStringSet()
for elt := range s {
if !rhs.Exist(elt) {
newSet.Insert(elt)
}
}
return newSet
}
// Slice converts the set to a slice
func (s StringSet) Slice() []string {
res := make([]string, 0)
for val := range s {
res = append(res, val)
}
return res
}
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