io.netty.buffer.IntPriorityQueue Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
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/*
* Copyright 2020 The Netty Project
*
* The Netty Project licenses this file to you 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:
*
* https://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 io.netty.buffer;
import java.util.Arrays;
/**
* Internal primitive priority queue, used by {@link PoolChunk}.
* The implementation is based on the binary heap, as described in Algorithms by Sedgewick and Wayne.
*/
final class IntPriorityQueue {
public static final int NO_VALUE = -1;
private int[] array = new int[9];
private int size;
public void offer(int handle) {
if (handle == NO_VALUE) {
throw new IllegalArgumentException("The NO_VALUE (" + NO_VALUE + ") cannot be added to the queue.");
}
size++;
if (size == array.length) {
// Grow queue capacity.
array = Arrays.copyOf(array, 1 + (array.length - 1) * 2);
}
array[size] = handle;
lift(size);
}
public void remove(int value) {
for (int i = 1; i <= size; i++) {
if (array[i] == value) {
array[i] = array[size--];
lift(i);
sink(i);
return;
}
}
}
public int peek() {
if (size == 0) {
return NO_VALUE;
}
return array[1];
}
public int poll() {
if (size == 0) {
return NO_VALUE;
}
int val = array[1];
array[1] = array[size];
array[size] = 0;
size--;
sink(1);
return val;
}
public boolean isEmpty() {
return size == 0;
}
private void lift(int index) {
int parentIndex;
while (index > 1 && subord(parentIndex = index >> 1, index)) {
swap(index, parentIndex);
index = parentIndex;
}
}
private void sink(int index) {
int child;
while ((child = index << 1) <= size) {
if (child < size && subord(child, child + 1)) {
child++;
}
if (!subord(index, child)) {
break;
}
swap(index, child);
index = child;
}
}
private boolean subord(int a, int b) {
return array[a] > array[b];
}
private void swap(int a, int b) {
int value = array[a];
array[a] = array[b];
array[b] = value;
}
}