| /* |
| * Copyright 2016-2017 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 kotlinx.coroutines.experimental.internal |
| |
| import java.util.* |
| |
| /** |
| * @suppress **This is unstable API and it is subject to change.** |
| */ |
| public interface ThreadSafeHeapNode { |
| public var index: Int |
| } |
| |
| /** |
| * Synchronized binary heap. |
| * |
| * @suppress **This is unstable API and it is subject to change.** |
| */ |
| public class ThreadSafeHeap<T> where T: ThreadSafeHeapNode, T: Comparable<T> { |
| private var a: Array<T?>? = null |
| |
| @JvmField @PublishedApi @Volatile |
| internal var size = 0 |
| |
| public val isEmpty: Boolean get() = size == 0 |
| |
| public fun clear() = synchronized(this) { |
| Arrays.fill(a, 0, size, null) |
| size = 0 |
| } |
| |
| public fun peek(): T? = synchronized(this) { firstImpl() } |
| |
| public fun removeFirstOrNull(): T? = synchronized(this) { |
| if (size > 0) { |
| removeAtImpl(0) |
| } else |
| null |
| } |
| |
| public inline fun removeFirstIf(predicate: (T) -> Boolean): T? = synchronized(this) { |
| val first = firstImpl() ?: return@synchronized null |
| if (predicate(first)) { |
| removeAtImpl(0) |
| } else |
| null |
| } |
| |
| public fun addLast(node: T) = synchronized(this) { |
| addImpl(node) |
| } |
| |
| public fun addLastIf(node: T, cond: () -> Boolean): Boolean = synchronized(this) { |
| if (cond()) { |
| addImpl(node) |
| true |
| } else |
| false |
| } |
| |
| public fun remove(node: T): Boolean = synchronized(this) { |
| if (node.index < 0) { |
| false |
| } else { |
| removeAtImpl(node.index) |
| true |
| } |
| } |
| |
| @PublishedApi |
| internal fun firstImpl(): T? = a?.get(0) |
| |
| @PublishedApi |
| internal fun removeAtImpl(index: Int): T { |
| check(size > 0) |
| val a = this.a!! |
| size-- |
| if (index < size) { |
| swap(index, size) |
| val j = (index - 1) / 2 |
| if (index > 0 && a[index]!! < a[j]!!) { |
| swap(index, j) |
| siftUpFrom(j) |
| } else { |
| siftDownFrom(index) |
| } |
| } |
| val result = a[size]!! |
| result.index = -1 |
| a[size] = null |
| return result |
| } |
| |
| @PublishedApi |
| internal fun addImpl(node: T) { |
| val a = realloc() |
| var i = size++ |
| a[i] = node |
| node.index = i |
| siftUpFrom(i) |
| } |
| |
| private tailrec fun siftUpFrom(i: Int) { |
| if (i <= 0) return |
| val a = a!! |
| val j = (i - 1) / 2 |
| if (a[j]!! <= a[i]!!) return |
| swap(i, j) |
| siftUpFrom(j) |
| } |
| |
| private tailrec fun siftDownFrom(i: Int) { |
| var j = 2 * i + 1 |
| if (j >= size) return |
| val a = a!! |
| if (j + 1 < size && a[j + 1]!! < a[j]!!) j++ |
| if (a[i]!! <= a[j]!!) return |
| swap(i, j) |
| siftDownFrom(j) |
| } |
| |
| @Suppress("UNCHECKED_CAST") |
| private fun realloc(): Array<T?> { |
| val a = this.a |
| return when { |
| a == null -> (arrayOfNulls<ThreadSafeHeapNode>(4) as Array<T?>).also { this.a = it } |
| size >= a.size -> a.copyOf(size * 2).also { this.a = it } |
| else -> a |
| } |
| } |
| |
| private fun swap(i: Int, j: Int) { |
| val a = a!! |
| val ni = a[j]!! |
| val nj = a[i]!! |
| a[i] = ni |
| a[j] = nj |
| ni.index = i |
| nj.index = j |
| } |
| } |