io.netty.buffer.LongLongHashMap 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).
/*
* 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;
/**
* Internal primitive map implementation that is specifically optimised for the runs availability map use case in {@link
* PoolChunk}.
*/
final class LongLongHashMap {
private static final int MASK_TEMPLATE = ~1;
private int mask;
private long[] array;
private int maxProbe;
private long zeroVal;
private final long emptyVal;
LongLongHashMap(long emptyVal) {
this.emptyVal = emptyVal;
zeroVal = emptyVal;
int initialSize = 32;
array = new long[initialSize];
mask = initialSize - 1;
computeMaskAndProbe();
}
public long put(long key, long value) {
if (key == 0) {
long prev = zeroVal;
zeroVal = value;
return prev;
}
for (;;) {
int index = index(key);
for (int i = 0; i < maxProbe; i++) {
long existing = array[index];
if (existing == key || existing == 0) {
long prev = existing == 0? emptyVal : array[index + 1];
array[index] = key;
array[index + 1] = value;
for (; i < maxProbe; i++) { // Nerf any existing misplaced entries.
index = index + 2 & mask;
if (array[index] == key) {
array[index] = 0;
prev = array[index + 1];
break;
}
}
return prev;
}
index = index + 2 & mask;
}
expand(); // Grow array and re-hash.
}
}
public void remove(long key) {
if (key == 0) {
zeroVal = emptyVal;
return;
}
int index = index(key);
for (int i = 0; i < maxProbe; i++) {
long existing = array[index];
if (existing == key) {
array[index] = 0;
break;
}
index = index + 2 & mask;
}
}
public long get(long key) {
if (key == 0) {
return zeroVal;
}
int index = index(key);
for (int i = 0; i < maxProbe; i++) {
long existing = array[index];
if (existing == key) {
return array[index + 1];
}
index = index + 2 & mask;
}
return emptyVal;
}
private int index(long key) {
// Hash with murmur64, and mask.
key ^= key >>> 33;
key *= 0xff51afd7ed558ccdL;
key ^= key >>> 33;
key *= 0xc4ceb9fe1a85ec53L;
key ^= key >>> 33;
return (int) key & mask;
}
private void expand() {
long[] prev = array;
array = new long[prev.length * 2];
computeMaskAndProbe();
for (int i = 0; i < prev.length; i += 2) {
long key = prev[i];
if (key != 0) {
long val = prev[i + 1];
put(key, val);
}
}
}
private void computeMaskAndProbe() {
int length = array.length;
mask = length - 1 & MASK_TEMPLATE;
maxProbe = (int) Math.log(length);
}
}