kotlin.collections.ReversedViews.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2015 JetBrains s.r.o.
*
* 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.
*/
@file:kotlin.jvm.JvmMultifileClass
@file:kotlin.jvm.JvmName("CollectionsKt")
package kotlin
import java.util.AbstractList
private open class ReversedListReadOnly(protected open val delegate: List) : AbstractList() {
override val size: Int get() = delegate.size()
override fun get(index: Int): T = delegate[index.flipIndex()]
protected fun Int.flipIndex(): Int = if (this in 0..size() - 1) size() - this - 1 else throw IndexOutOfBoundsException("index $this should be in range [${0..size() - 1}]")
protected fun Int.flipIndexForward(): Int = if (this in 0..size()) size() - this else throw IndexOutOfBoundsException("index $this should be in range [${0..size()}]")
}
private class ReversedList(protected override val delegate: MutableList) : ReversedListReadOnly(delegate) {
override fun clear() = delegate.clear()
override fun removeAt(index: Int): T = delegate.removeAt(index.flipIndex())
override fun set(index: Int, element: T): T = delegate.set(index.flipIndex(), element)
override fun add(index: Int, element: T) {
delegate.add(index.flipIndexForward(), element)
}
}
/**
* Returns a reversed read-only view of the original List.
* All changes made in the original list will be reflected in the reversed one.
*/
public fun List.asReversed(): List = ReversedListReadOnly(this)
/**
* Returns a reversed mutable view of the original mutable List.
* All changes made in the original list will be reflected in the reversed one and vice versa.
*/
@kotlin.jvm.JvmName("asReversedMutable")
public fun MutableList.asReversed(): MutableList = ReversedList(this)