org.apache.activemq.artemis.shaded.io.netty.util.internal.shaded.org.jctools.queues.MpscChunkedArrayQueue Maven / Gradle / Ivy

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/*
 * 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 org.apache.activemq.artemis.shaded.io.netty.util.internal.shaded.org.jctools.queues;

import org.apache.activemq.artemis.shaded.io.netty.util.internal.shaded.org.jctools.util.Pow2;
import org.apache.activemq.artemis.shaded.io.netty.util.internal.shaded.org.jctools.util.RangeUtil;

import static java.lang.Math.max;
import static java.lang.Math.min;
import static org.apache.activemq.artemis.shaded.io.netty.util.internal.shaded.org.jctools.queues.LinkedArrayQueueUtil.length;
import static org.apache.activemq.artemis.shaded.io.netty.util.internal.shaded.org.jctools.util.Pow2.roundToPowerOfTwo;

abstract class MpscChunkedArrayQueueColdProducerFields extends BaseMpscLinkedArrayQueue
{
    protected final long maxQueueCapacity;

    MpscChunkedArrayQueueColdProducerFields(int initialCapacity, int maxCapacity)
    {
        super(initialCapacity);
        RangeUtil.checkGreaterThanOrEqual(maxCapacity, 4, "maxCapacity");
        RangeUtil.checkLessThan(roundToPowerOfTwo(initialCapacity), roundToPowerOfTwo(maxCapacity),
            "initialCapacity");
        maxQueueCapacity = ((long) Pow2.roundToPowerOfTwo(maxCapacity)) << 1;
    }
}

/**
 * An MPSC array queue which starts at initialCapacity and grows to maxCapacity in linked chunks
 * of the initial size. The queue grows only when the current chunk is full and elements are not copied on
 * resize, instead a link to the new chunk is stored in the old chunk for the consumer to follow.
 */
public class MpscChunkedArrayQueue extends MpscChunkedArrayQueueColdProducerFields
{
    long p0, p1, p2, p3, p4, p5, p6, p7;
    long p10, p11, p12, p13, p14, p15, p16, p17;

    public MpscChunkedArrayQueue(int maxCapacity)
    {
        super(max(2, min(1024, roundToPowerOfTwo(maxCapacity / 8))), maxCapacity);
    }

    /**
     * @param initialCapacity the queue initial capacity. If chunk size is fixed this will be the chunk size.
     *                        Must be 2 or more.
     * @param maxCapacity     the maximum capacity will be rounded up to the closest power of 2 and will be the
     *                        upper limit of number of elements in this queue. Must be 4 or more and round up to a larger
     *                        power of 2 than initialCapacity.
     */
    public MpscChunkedArrayQueue(int initialCapacity, int maxCapacity)
    {
        super(initialCapacity, maxCapacity);
    }

    @Override
    protected long availableInQueue(long pIndex, long cIndex)
    {
        return maxQueueCapacity - (pIndex - cIndex);
    }

    @Override
    public int capacity()
    {
        return (int) (maxQueueCapacity / 2);
    }

    @Override
    protected int getNextBufferSize(E[] buffer)
    {
        return length(buffer);
    }

    @Override
    protected long getCurrentBufferCapacity(long mask)
    {
        return mask;
    }
}