uk.co.real_logic.aeron.driver.UnicastFlowControl Maven / Gradle / Ivy

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/*
 * Copyright 2014 - 2015 Real Logic Ltd.
 *
 * 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 uk.co.real_logic.aeron.driver;

import java.net.InetSocketAddress;

import static uk.co.real_logic.aeron.logbuffer.LogBufferDescriptor.computePosition;

/**
 * Default unicast sender flow control strategy.
 *
 * Max of right edges.
 * No tracking of receivers.
 */
public class UnicastFlowControl implements FlowControl
{
    private long positionLimit = 0;
    private int positionBitsToShift;
    private int initialTermId;

    /**
     * {@inheritDoc}
     */
    public long onStatusMessage(
        final int termId, final int termOffset, final int receiverWindowLength, final InetSocketAddress address)
    {
        final long position = computePosition(termId, termOffset, positionBitsToShift, initialTermId);
        final long newPositionLimit = position + receiverWindowLength;
        positionLimit = Math.max(positionLimit, newPositionLimit);

        return positionLimit;
    }

    /**
     * {@inheritDoc}
     */
    public void initialize(final int initialTermId, final int termBufferCapacity)
    {
        this.initialTermId = initialTermId;
        positionBitsToShift = Long.numberOfTrailingZeros(termBufferCapacity);
        positionLimit = computePosition(initialTermId, 0, positionBitsToShift, initialTermId);
    }

    /**
     * {@inheritDoc}
     */
    public long onIdle(final long now)
    {
        return positionLimit;
    }
}