[util/slice] Add util slice.

pkg/util/slice/slice.go

@@ -0,0 +1,38 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+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 slice
+
+// ToMap create a map[K]V out of the provided slice s using key() to create the map keys and
+// val() to create the values.
+//
+// The caller can compare the length of the map to the one of the slice in order to detect
+// potential key conflicts.
+func ToMap[K comparable, V any, S ~[]E, E any](s S, key func(int) K, val func(int) V) map[K]V {
+	ret := make(map[K]V, len(s))
+	for i := range s {
+		ret[key(i)] = val(i)
+	}
+	return ret
+}
+
+// ToRefMap create a map[K]*S out of the provided slice s []S using key() to create the map keys.
+//
+// The caller can compare the length of the map to the one of the slice in order to detect
+// potential key conflicts.
+func ToRefMap[K comparable, S ~[]E, E any](s S, key func(*E) K) map[K]*E {
+	return ToMap(s, func(i int) K { return key(&s[i]) }, func(i int) *E { return &s[i] })
+}