/
set.go
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/
set.go
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// Copyright 2019 Authors of Cilium
//
// 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,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package set
// SliceSubsetOf checks whether the first slice is a subset of the second slice. If
// not, it also returns slice of elements which are the difference of both
// input slices.
func SliceSubsetOf(sub, main []string) (bool, []string) {
var diff []string
occurrences := make(map[string]int, len(main))
result := true
for _, element := range main {
occurrences[element]++
}
for _, element := range sub {
if count, ok := occurrences[element]; !ok {
// Element was not found in the main slice.
result = false
diff = append(diff, element)
} else if count < 1 {
// The element is in both slices, but the sub slice
// has more duplicates.
result = false
} else {
occurrences[element]--
}
}
return result, diff
}