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Xodus is pure Java transactional schema-less embedded database
/**
* Copyright 2010 - 2018 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.
*/
package jetbrains.exodus.query
import jetbrains.exodus.entitystore.Selector
import java.util.*
private val noQueue = arrayOf()
private val noData = arrayOf?>()
private val maxArraySize = Integer.MAX_VALUE - 8
private fun hugeCapacity(minCapacity: Int): Int {
if (minCapacity < 0) {
throw OutOfMemoryError()
}
return if (minCapacity > maxArraySize) {
Integer.MAX_VALUE
} else {
maxArraySize
}
}
class PriorityMap(initialCapacity: Int, private val comparator: Comparator>, private val valueGettter: Selector) : AbstractQueue() {
private var queue = if (initialCapacity <= 0) {
noQueue
} else {
arrayOfNulls(initialCapacity)
}
private var data = if (initialCapacity <= 0) {
noData
} else {
arrayOfNulls(initialCapacity)
}
override var size: Int = 0
private set
private var modCount = 0
private fun grow(minCapacity: Int) {
val oldCapacity = queue.size
var newCapacity = oldCapacity + if (oldCapacity < 64) {
oldCapacity + 2
} else {
oldCapacity shr 1
}
if (newCapacity - maxArraySize > 0) {
newCapacity = hugeCapacity(minCapacity)
}
queue = Arrays.copyOf(queue, newCapacity)
data = Arrays.copyOf(data, newCapacity)
}
override fun add(element: E) = offer(element)
override fun offer(e: E?): Boolean {
if (e == null)
throw NullPointerException()
modCount++
val i = size
if (i >= queue.size) {
grow(i + 1)
}
size = i + 1
if (i == 0) {
queue[0] = e
data[0] = valueGettter.select(e)
} else {
up(i, e, valueGettter.select(e))
}
return true
}
@Suppress("UNCHECKED_CAST")
override fun peek(): E? {
return if (size == 0) {
null
} else {
queue[0] as E
}
}
override fun clear() {
modCount++
for (i in 0 until size) {
queue[i] = null
}
for (i in 0 until size) {
data[i] = null
}
size = 0
}
@Suppress("UNCHECKED_CAST")
override fun poll(): E? {
if (size == 0) {
return null
}
val s = --size
modCount++
val result = queue[0] as E
val x = queue[s] as E
queue[s] = null
val v = data[s]
data[s] = null
if (s != 0) {
down(0, x, v!!)
}
return result
}
override fun iterator(): MutableIterator = Itr()
@Suppress("UNCHECKED_CAST")
private fun up(key: Int, x: E, v: Comparable) {
var k = key
while (k > 0) {
val parent = (k - 1).ushr(1)
val ev = data[parent]
if (comparator.compare(v, ev) >= 0) {
break
}
queue[k] = queue[parent]
data[k] = ev
k = parent
}
queue[k] = x
data[k] = v
}
@Suppress("UNCHECKED_CAST")
private fun down(key: Int, x: E, v: Comparable) {
var k = key
val half = size.ushr(1)
while (k < half) {
var child = (k shl 1) + 1
var cv = data[child]
val right = child + 1
if (right < size && comparator.compare(cv, data[right]) > 0) {
child = right
cv = data[child]
}
if (comparator.compare(v, cv) <= 0) {
break
}
data[k] = cv
queue[k] = queue[child]
k = child
}
queue[k] = x
data[k] = v
}
/*@Suppress("UNCHECKED_CAST")
private fun removeAt(i: Int): E? {
modCount++
val s = --size
if (s == i) {
queue[i] = null
data[i] = null
} else {
val moved = queue[s] as E
queue[s] = null
val v = data[s]
down(i, moved, v!!)
if (queue[i] === moved) {
up(i, moved, v)
if (queue[i] !== moved) {
return moved
}
}
}
return null
}
private fun removeEq(o: Any): Boolean {
for (i in 0 until size) {
if (o === queue[i]) {
removeAt(i)
return true
}
}
return false
}*/
private inner class Itr : MutableIterator {
private var cursor = 0
private var lastRet = -1
private var forgetMeNot: ArrayDeque? = null
private var lastRetElt: E? = null
private var expectedModCount = modCount
override fun hasNext(): Boolean {
return cursor < size || forgetMeNot != null && !forgetMeNot!!.isEmpty()
}
@Suppress("UNCHECKED_CAST")
override fun next(): E {
if (expectedModCount != modCount) {
throw ConcurrentModificationException()
}
if (cursor < size) {
val index = cursor++
lastRet = index
return queue[index] as E
}
if (forgetMeNot != null) {
lastRet = -1
lastRetElt = forgetMeNot!!.poll()
lastRetElt?.let { return it }
}
throw NoSuchElementException()
}
override fun remove() {
TODO()
/* if (expectedModCount != modCount) {
throw ConcurrentModificationException()
}
if (lastRet != -1) {
val moved = removeAt(lastRet)
lastRet = -1
if (moved == null) {
cursor--
} else {
if (forgetMeNot == null) {
forgetMeNot = ArrayDeque()
}
forgetMeNot!!.add(moved)
}
} else {
lastRetElt?.let {
removeEq(it)
lastRetElt = null
} ?: throw IllegalStateException()
}
expectedModCount = modCount*/
}
}
}