BayernMessenger/vector/src/main/java/im/vector/riotredesign/core/extensions/Iterable.kt

38 lines
1.2 KiB
Kotlin

/*
*
* * Copyright 2019 New Vector Ltd
* *
* * 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 im.vector.riotredesign.core.extensions
/**
* Returns the last element yielding the smallest value of the given function or `null` if there are no elements.
*/
public inline fun <T, R : Comparable<R>> Iterable<T>.lastMinBy(selector: (T) -> R): T? {
val iterator = iterator()
if (!iterator.hasNext()) return null
var minElem = iterator.next()
var minValue = selector(minElem)
while (iterator.hasNext()) {
val e = iterator.next()
val v = selector(e)
if (minValue >= v) {
minElem = e
minValue = v
}
}
return minElem
}