Common ArrayDeque
This commit is contained in:
Abduqodiri Qurbonzoda
@@ -0,0 +1,561 @@
|
||||
/*
|
||||
* Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
|
||||
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
|
||||
*/
|
||||
|
||||
package kotlin.collections
|
||||
|
||||
private val emptyElementData = emptyArray<Any?>()
|
||||
private const val maxArraySize = Int.MAX_VALUE - 8
|
||||
private const val defaultMinCapacity = 10
|
||||
|
||||
/**
|
||||
* Resizable-array implementation of the deque data structure.
|
||||
*
|
||||
* The name deque is short for "double ended queue" and is usually pronounced "deck".
|
||||
*
|
||||
* The collection provide methods for convenient access to the both ends.
|
||||
* It also implements [MutableList] interface and supports efficient get/set operations by index.
|
||||
*/
|
||||
@SinceKotlin("1.3")
|
||||
@ExperimentalStdlibApi
|
||||
public class ArrayDeque<E> : AbstractMutableList<E> {
|
||||
private var head: Int = 0
|
||||
private var elementData: Array<Any?>
|
||||
|
||||
override var size: Int = 0
|
||||
private set
|
||||
|
||||
/**
|
||||
* Constructs an empty deque with specified [initialCapacity], or throws [IllegalArgumentException] if [initialCapacity] is negative.
|
||||
*/
|
||||
public constructor(initialCapacity: Int) {
|
||||
elementData = when {
|
||||
initialCapacity == 0 -> emptyElementData
|
||||
initialCapacity > 0 -> arrayOfNulls(initialCapacity)
|
||||
else -> throw IllegalArgumentException("Illegal Capacity: $initialCapacity")
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Constructs an empty deque.
|
||||
*/
|
||||
public constructor() {
|
||||
elementData = emptyElementData
|
||||
}
|
||||
|
||||
/**
|
||||
* Constructs a deque that contains the same elements as the specified [elements] collection in the same order.
|
||||
*/
|
||||
public constructor(elements: Collection<E>) {
|
||||
elementData = elements.toTypedArray()
|
||||
size = elementData.size
|
||||
if (elementData.isEmpty()) elementData = emptyElementData
|
||||
}
|
||||
|
||||
/**
|
||||
* Ensures that the capacity of this deque is at least equal to the specified [minCapacity].
|
||||
*
|
||||
* If the current capacity is less than the [minCapacity], a new backing storage is allocated with greater capacity.
|
||||
* Otherwise, this method takes no action and simply returns.
|
||||
*/
|
||||
private fun ensureCapacity(minCapacity: Int) {
|
||||
if (minCapacity < 0) throw IllegalStateException("Deque is too big.") // overflow
|
||||
if (minCapacity <= elementData.size) return
|
||||
if (elementData === emptyElementData) {
|
||||
elementData = arrayOfNulls(minCapacity.coerceAtLeast(defaultMinCapacity))
|
||||
return
|
||||
}
|
||||
|
||||
val newCapacity = newCapacity(elementData.size, minCapacity)
|
||||
copyElements(newCapacity)
|
||||
}
|
||||
|
||||
// made internal for testing
|
||||
internal fun newCapacity(oldCapacity: Int, minCapacity: Int): Int {
|
||||
// overflow-conscious
|
||||
var newCapacity = oldCapacity + (oldCapacity shr 1)
|
||||
if (newCapacity - minCapacity < 0)
|
||||
newCapacity = minCapacity
|
||||
if (newCapacity - maxArraySize > 0)
|
||||
newCapacity = if (minCapacity > maxArraySize) Int.MAX_VALUE else maxArraySize
|
||||
return newCapacity
|
||||
}
|
||||
|
||||
/**
|
||||
* Creates a new array with the specified [newCapacity] size and copies elements in the [elementData] array to it.
|
||||
*/
|
||||
private fun copyElements(newCapacity: Int) {
|
||||
val newElements = arrayOfNulls<Any?>(newCapacity)
|
||||
elementData.copyInto(newElements, 0, head, elementData.size)
|
||||
elementData.copyInto(newElements, elementData.size - head, 0, head)
|
||||
head = 0
|
||||
elementData = newElements
|
||||
}
|
||||
|
||||
@kotlin.internal.InlineOnly
|
||||
private inline fun internalGet(internalIndex: Int): E {
|
||||
@Suppress("UNCHECKED_CAST")
|
||||
return elementData[internalIndex] as E
|
||||
}
|
||||
|
||||
private fun positiveMod(index: Int): Int = if (index >= elementData.size) index - elementData.size else index
|
||||
|
||||
private fun negativeMod(index: Int): Int = if (index < 0) index + elementData.size else index
|
||||
|
||||
@kotlin.internal.InlineOnly
|
||||
private inline fun internalIndex(index: Int): Int = positiveMod(head + index)
|
||||
|
||||
private fun incremented(index: Int): Int = if (index == elementData.lastIndex) 0 else index + 1
|
||||
|
||||
private fun decremented(index: Int): Int = if (index == 0) elementData.lastIndex else index - 1
|
||||
|
||||
override fun isEmpty(): Boolean = size == 0
|
||||
|
||||
/**
|
||||
* Returns the first element, or throws [NoSuchElementException] if this deque is empty.
|
||||
*/
|
||||
public fun first(): E = if (isEmpty()) throw NoSuchElementException("ArrayDeque is empty.") else internalGet(head)
|
||||
|
||||
/**
|
||||
* Returns the first element, or `null` if this deque is empty.
|
||||
*/
|
||||
public fun firstOrNull(): E? = if (isEmpty()) null else internalGet(head)
|
||||
|
||||
/**
|
||||
* Returns the last element, or throws [NoSuchElementException] if this deque is empty.
|
||||
*/
|
||||
public fun last(): E = if (isEmpty()) throw NoSuchElementException("ArrayDeque is empty.") else internalGet(internalIndex(lastIndex))
|
||||
|
||||
/**
|
||||
* Returns the last element, or `null` if this deque is empty.
|
||||
*/
|
||||
public fun lastOrNull(): E? = if (isEmpty()) null else internalGet(internalIndex(lastIndex))
|
||||
|
||||
/**
|
||||
* Prepends the specified [element] to this deque.
|
||||
*/
|
||||
public fun addFirst(element: E) {
|
||||
ensureCapacity(size + 1)
|
||||
|
||||
head = decremented(head)
|
||||
elementData[head] = element
|
||||
size += 1
|
||||
}
|
||||
|
||||
/**
|
||||
* Appends the specified [element] to this deque.
|
||||
*/
|
||||
public fun addLast(element: E) {
|
||||
ensureCapacity(size + 1)
|
||||
|
||||
elementData[internalIndex(size)] = element
|
||||
size += 1
|
||||
}
|
||||
|
||||
/**
|
||||
* Removes the first element from this deque and returns that removed element, or throws [NoSuchElementException] if this deque is empty.
|
||||
*/
|
||||
public fun removeFirst(): E {
|
||||
if (isEmpty()) throw NoSuchElementException("ArrayDeque is empty.")
|
||||
|
||||
val element = internalGet(head)
|
||||
elementData[head] = null
|
||||
head = incremented(head)
|
||||
size -= 1
|
||||
return element
|
||||
}
|
||||
|
||||
/**
|
||||
* Removes the first element from this deque and returns that removed element, or returns `null` if this deque is empty.
|
||||
*/
|
||||
public fun removeFirstOrNull(): E? = if (isEmpty()) null else removeFirst()
|
||||
|
||||
/**
|
||||
* Removes the last element from this deque and returns that removed element, or throws [NoSuchElementException] if this deque is empty.
|
||||
*/
|
||||
public fun removeLast(): E {
|
||||
if (isEmpty()) throw NoSuchElementException("ArrayDeque is empty.")
|
||||
|
||||
val internalLastIndex = internalIndex(lastIndex)
|
||||
val element = internalGet(internalLastIndex)
|
||||
elementData[internalLastIndex] = null
|
||||
size -= 1
|
||||
return element
|
||||
}
|
||||
|
||||
/**
|
||||
* Removes the last element from this deque and returns that removed element, or returns `null` if this deque is empty.
|
||||
*/
|
||||
public fun removeLastOrNull(): E? = if (isEmpty()) null else removeLast()
|
||||
|
||||
// MutableList, MutableCollection
|
||||
public override fun add(element: E): Boolean {
|
||||
addLast(element)
|
||||
return true
|
||||
}
|
||||
|
||||
public override fun add(index: Int, element: E) {
|
||||
AbstractList.checkPositionIndex(index, size)
|
||||
|
||||
if (index == size) {
|
||||
addLast(element)
|
||||
return
|
||||
} else if (index == 0) {
|
||||
addFirst(element)
|
||||
return
|
||||
}
|
||||
|
||||
ensureCapacity(size + 1)
|
||||
|
||||
// Elements in circular array lay in 2 ways:
|
||||
// 1. `head` is less than `tail`: [#, #, e1, e2, e3, #]
|
||||
// 2. `head` is greater than `tail`: [e3, #, #, #, e1, e2]
|
||||
// where head is the index of the first element in the circular array,
|
||||
// and tail is the index following the last element.
|
||||
//
|
||||
// At this point the insertion index is not equal to head or tail.
|
||||
// Also the circular array can store at least one more element.
|
||||
//
|
||||
// Depending on where the given element must be inserted the preceding or the succeeding
|
||||
// elements will be shifted to make room for the element to be inserted.
|
||||
//
|
||||
// In case the preceding elements are shifted:
|
||||
// * if the insertion index is greater than the head (regardless of circular array form)
|
||||
// -> shift the preceding elements
|
||||
// * otherwise, the circular array has (2) form and the insertion index is less than tail
|
||||
// -> shift all elements in the back of the array
|
||||
// -> shift preceding elements in the front of the array
|
||||
// In case the succeeding elements are shifted:
|
||||
// * if the insertion index is less than the tail (regardless of circular array form)
|
||||
// -> shift the succeeding elements
|
||||
// * otherwise, the circular array has (2) form and the insertion index is greater than head
|
||||
// -> shift all elements in the front of the array
|
||||
// -> shift succeeding elements in the back of the array
|
||||
|
||||
val internalIndex = internalIndex(index)
|
||||
|
||||
if (index < (size + 1) shr 1) {
|
||||
// closer to the first element -> shift preceding elements
|
||||
val decrementedInternalIndex = decremented(internalIndex)
|
||||
val decrementedHead = decremented(head)
|
||||
|
||||
if (decrementedInternalIndex >= head) {
|
||||
elementData[decrementedHead] = elementData[head] // head can be zero
|
||||
elementData.copyInto(elementData, head, head + 1, decrementedInternalIndex + 1)
|
||||
} else { // head > tail
|
||||
elementData.copyInto(elementData, head - 1, head, elementData.size) // head can't be zero
|
||||
elementData[elementData.size - 1] = elementData[0]
|
||||
elementData.copyInto(elementData, 0, 1, decrementedInternalIndex + 1)
|
||||
}
|
||||
|
||||
elementData[decrementedInternalIndex] = element
|
||||
head = decrementedHead
|
||||
} else {
|
||||
// closer to the last element -> shift succeeding elements
|
||||
val tail = internalIndex(size)
|
||||
|
||||
if (internalIndex < tail) {
|
||||
elementData.copyInto(elementData, internalIndex + 1, internalIndex, tail)
|
||||
} else { // head > tail
|
||||
elementData.copyInto(elementData, 1, 0, tail)
|
||||
elementData[0] = elementData[elementData.size - 1]
|
||||
elementData.copyInto(elementData, internalIndex + 1, internalIndex, elementData.size - 1)
|
||||
}
|
||||
|
||||
elementData[internalIndex] = element
|
||||
}
|
||||
size += 1
|
||||
}
|
||||
|
||||
private fun copyCollectionElements(internalIndex: Int, elements: Collection<E>) {
|
||||
val iterator = elements.iterator()
|
||||
|
||||
for (index in internalIndex until elementData.size) {
|
||||
if (!iterator.hasNext()) break
|
||||
elementData[index] = iterator.next()
|
||||
}
|
||||
for (index in 0 until head) {
|
||||
if (!iterator.hasNext()) break
|
||||
elementData[index] = iterator.next()
|
||||
}
|
||||
|
||||
size += elements.size
|
||||
}
|
||||
|
||||
public override fun addAll(elements: Collection<E>): Boolean {
|
||||
if (elements.isEmpty()) return false
|
||||
ensureCapacity(this.size + elements.size)
|
||||
copyCollectionElements(internalIndex(size), elements)
|
||||
return true
|
||||
}
|
||||
|
||||
public override fun addAll(index: Int, elements: Collection<E>): Boolean {
|
||||
AbstractList.checkPositionIndex(index, size)
|
||||
|
||||
if (elements.isEmpty()) {
|
||||
return false
|
||||
} else if (index == size) {
|
||||
return addAll(elements)
|
||||
}
|
||||
|
||||
ensureCapacity(this.size + elements.size)
|
||||
|
||||
val tail = internalIndex(size)
|
||||
val internalIndex = internalIndex(index)
|
||||
val elementsSize = elements.size
|
||||
|
||||
if (index < (size + 1) shr 1) {
|
||||
// closer to the first element -> shift preceding elements
|
||||
|
||||
var shiftedHead = head - elementsSize
|
||||
|
||||
if (internalIndex >= head) {
|
||||
if (shiftedHead >= 0) {
|
||||
elementData.copyInto(elementData, shiftedHead, head, internalIndex)
|
||||
} else { // head < tail, insertion leads to head >= tail
|
||||
shiftedHead += elementData.size
|
||||
val elementsToShift = internalIndex - head
|
||||
val shiftToBack = elementData.size - shiftedHead
|
||||
|
||||
if (shiftToBack >= elementsToShift) {
|
||||
elementData.copyInto(elementData, shiftedHead, head, internalIndex)
|
||||
} else {
|
||||
elementData.copyInto(elementData, shiftedHead, head, head + shiftToBack)
|
||||
elementData.copyInto(elementData, 0, head + shiftToBack, internalIndex)
|
||||
}
|
||||
}
|
||||
} else { // head > tail, internalIndex < tail
|
||||
elementData.copyInto(elementData, shiftedHead, head, elementData.size)
|
||||
if (elementsSize >= internalIndex) {
|
||||
elementData.copyInto(elementData, elementData.size - elementsSize, 0, internalIndex)
|
||||
} else {
|
||||
elementData.copyInto(elementData, elementData.size - elementsSize, 0, elementsSize)
|
||||
elementData.copyInto(elementData, 0, elementsSize, internalIndex)
|
||||
}
|
||||
}
|
||||
head = shiftedHead
|
||||
copyCollectionElements(negativeMod(internalIndex - elementsSize), elements)
|
||||
} else {
|
||||
// closer to the last element -> shift succeeding elements
|
||||
|
||||
val shiftedInternalIndex = internalIndex + elementsSize
|
||||
|
||||
if (internalIndex < tail) {
|
||||
if (tail + elementsSize <= elementData.size) {
|
||||
elementData.copyInto(elementData, shiftedInternalIndex, internalIndex, tail)
|
||||
} else { // head < tail, insertion leads to head >= tail
|
||||
if (shiftedInternalIndex >= elementData.size) {
|
||||
elementData.copyInto(elementData, shiftedInternalIndex - elementData.size, internalIndex, tail)
|
||||
} else {
|
||||
val shiftToFront = tail + elementsSize - elementData.size
|
||||
elementData.copyInto(elementData, 0, tail - shiftToFront, tail)
|
||||
elementData.copyInto(elementData, shiftedInternalIndex, internalIndex, tail - shiftToFront)
|
||||
}
|
||||
}
|
||||
} else { // head > tail, internalIndex > head
|
||||
elementData.copyInto(elementData, elementsSize, 0, tail)
|
||||
if (shiftedInternalIndex >= elementData.size) {
|
||||
elementData.copyInto(elementData, shiftedInternalIndex - elementData.size, internalIndex, elementData.size)
|
||||
} else {
|
||||
elementData.copyInto(elementData, 0, elementData.size - elementsSize, elementData.size)
|
||||
elementData.copyInto(elementData, shiftedInternalIndex, internalIndex, elementData.size - elementsSize)
|
||||
}
|
||||
}
|
||||
copyCollectionElements(internalIndex, elements)
|
||||
}
|
||||
|
||||
return true
|
||||
}
|
||||
|
||||
public override fun get(index: Int): E {
|
||||
AbstractList.checkElementIndex(index, size)
|
||||
|
||||
return internalGet(internalIndex(index))
|
||||
}
|
||||
|
||||
public override fun set(index: Int, element: E): E {
|
||||
AbstractList.checkElementIndex(index, size)
|
||||
|
||||
val internalIndex = internalIndex(index)
|
||||
val oldElement = internalGet(internalIndex)
|
||||
elementData[internalIndex] = element
|
||||
|
||||
return oldElement
|
||||
}
|
||||
|
||||
public override fun contains(element: E): Boolean = indexOf(element) != -1
|
||||
|
||||
public override fun indexOf(element: E): Int {
|
||||
val tail = internalIndex(size)
|
||||
|
||||
if (head < tail) {
|
||||
for (index in head until tail) {
|
||||
if (element == elementData[index]) return index - head
|
||||
}
|
||||
} else if (head >= tail) {
|
||||
for (index in head until elementData.size) {
|
||||
if (element == elementData[index]) return index - head
|
||||
}
|
||||
for (index in 0 until tail) {
|
||||
if (element == elementData[index]) return index + elementData.size - head
|
||||
}
|
||||
}
|
||||
|
||||
return -1
|
||||
}
|
||||
|
||||
public override fun lastIndexOf(element: E): Int {
|
||||
val tail = internalIndex(size)
|
||||
|
||||
if (head < tail) {
|
||||
for (index in tail - 1 downTo head) {
|
||||
if (element == elementData[index]) return index - head
|
||||
}
|
||||
} else if (head > tail) {
|
||||
for (index in tail - 1 downTo 0) {
|
||||
if (element == elementData[index]) return index + elementData.size - head
|
||||
}
|
||||
for (index in elementData.lastIndex downTo head) {
|
||||
if (element == elementData[index]) return index - head
|
||||
}
|
||||
}
|
||||
|
||||
return -1
|
||||
}
|
||||
|
||||
public override fun remove(element: E): Boolean {
|
||||
val index = indexOf(element)
|
||||
if (index == -1) return false
|
||||
removeAt(index)
|
||||
return true
|
||||
}
|
||||
|
||||
public override fun removeAt(index: Int): E {
|
||||
AbstractList.checkElementIndex(index, size)
|
||||
|
||||
if (index == lastIndex) {
|
||||
return removeLast()
|
||||
} else if (index == 0) {
|
||||
return removeFirst()
|
||||
}
|
||||
|
||||
val internalIndex = internalIndex(index)
|
||||
val element = internalGet(internalIndex)
|
||||
|
||||
if (index < size shr 1) {
|
||||
// closer to the first element -> shift preceding elements
|
||||
if (internalIndex >= head) {
|
||||
elementData.copyInto(elementData, head + 1, head, internalIndex)
|
||||
} else { // head > tail, internalIndex < head
|
||||
elementData.copyInto(elementData, 1, 0, internalIndex)
|
||||
elementData[0] = elementData[elementData.size - 1]
|
||||
elementData.copyInto(elementData, head + 1, head, elementData.size - 1)
|
||||
}
|
||||
|
||||
elementData[head] = null
|
||||
head = incremented(head)
|
||||
} else {
|
||||
// closer to the last element -> shift succeeding elements
|
||||
val internalLastIndex = internalIndex(lastIndex)
|
||||
|
||||
if (internalIndex <= internalLastIndex) {
|
||||
elementData.copyInto(elementData, internalIndex, internalIndex + 1, internalLastIndex + 1)
|
||||
} else { // head > tail, internalIndex > head
|
||||
elementData.copyInto(elementData, internalIndex, internalIndex + 1, elementData.size)
|
||||
elementData[elementData.size - 1] = elementData[0]
|
||||
elementData.copyInto(elementData, 0, 1, internalLastIndex + 1)
|
||||
}
|
||||
|
||||
elementData[internalLastIndex] = null
|
||||
}
|
||||
size -= 1
|
||||
|
||||
return element
|
||||
}
|
||||
|
||||
public override fun removeAll(elements: Collection<E>): Boolean = filterInPlace { !elements.contains(it) }
|
||||
|
||||
public override fun retainAll(elements: Collection<E>): Boolean = filterInPlace { elements.contains(it) }
|
||||
|
||||
private inline fun filterInPlace(predicate: (E) -> Boolean): Boolean {
|
||||
if (this.isEmpty() || elementData.isEmpty())
|
||||
return false
|
||||
|
||||
val tail = internalIndex(size)
|
||||
var newTail = head
|
||||
var modified = false
|
||||
|
||||
if (head < tail) {
|
||||
for (index in head until tail) {
|
||||
val element = elementData[index]
|
||||
|
||||
@Suppress("UNCHECKED_CAST")
|
||||
if (predicate(element as E))
|
||||
elementData[newTail++] = element
|
||||
else
|
||||
modified = true
|
||||
}
|
||||
|
||||
elementData.fill(null, newTail, tail)
|
||||
|
||||
} else {
|
||||
for (index in head until elementData.size) {
|
||||
val element = elementData[index]
|
||||
elementData[index] = null
|
||||
|
||||
@Suppress("UNCHECKED_CAST")
|
||||
if (predicate(element as E))
|
||||
elementData[newTail++] = element
|
||||
else
|
||||
modified = true
|
||||
}
|
||||
|
||||
newTail = positiveMod(newTail)
|
||||
|
||||
for (index in 0 until tail) {
|
||||
val element = elementData[index]
|
||||
elementData[index] = null
|
||||
|
||||
@Suppress("UNCHECKED_CAST")
|
||||
if (predicate(element as E)) {
|
||||
elementData[newTail] = element
|
||||
newTail = incremented(newTail)
|
||||
} else {
|
||||
modified = true
|
||||
}
|
||||
}
|
||||
}
|
||||
if (modified)
|
||||
size = negativeMod(newTail - head)
|
||||
|
||||
return modified
|
||||
}
|
||||
|
||||
public override fun clear() {
|
||||
val tail = internalIndex(size)
|
||||
if (head < tail) {
|
||||
elementData.fill(null, head, tail)
|
||||
} else if (isNotEmpty()) {
|
||||
elementData.fill(null, head, elementData.size)
|
||||
elementData.fill(null, 0, tail)
|
||||
}
|
||||
head = 0
|
||||
size = 0
|
||||
}
|
||||
|
||||
// For testing only
|
||||
internal fun internalStructure(structure: (head: Int, elements: Array<Any?>) -> Unit) {
|
||||
val tail = internalIndex(size)
|
||||
|
||||
if (isEmpty()) {
|
||||
structure(head, emptyArray())
|
||||
} else if (head < tail) {
|
||||
@Suppress("UNCHECKED_CAST")
|
||||
structure(head, elementData.sliceArray(head until tail))
|
||||
} else {
|
||||
@Suppress("UNCHECKED_CAST")
|
||||
structure(head - elementData.size, elementData.sliceArray(head until elementData.size).plus(elements = elementData.sliceArray(0 until tail)))
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user