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/*
* Copyright (C) 2018 The Android Open Source Project
*
* 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 com.android.net.module.util;
import static java.lang.Math.max;
import android.os.Handler;
import android.system.Os;
import java.io.FileDescriptor;
/**
* Specialization of {@link FdEventsReader} that reads packets into a byte array.
*
* TODO: rename this class to something more correctly descriptive (something
* like [or less horrible than] FdReadEventsHandler?).
*/
public abstract class PacketReader extends FdEventsReader<byte[]> {
public static final int DEFAULT_RECV_BUF_SIZE = 2 * 1024;
protected PacketReader(Handler h) {
this(h, DEFAULT_RECV_BUF_SIZE);
}
protected PacketReader(Handler h, int recvBufSize) {
super(h, new byte[max(recvBufSize, DEFAULT_RECV_BUF_SIZE)]);
}
@Override
protected final int recvBufSize(byte[] buffer) {
return buffer.length;
}
/**
* Subclasses MAY override this to change the default read() implementation
* in favour of, say, recvfrom().
*
* Implementations MUST return the bytes read or throw an Exception.
*/
@Override
protected int readPacket(FileDescriptor fd, byte[] packetBuffer) throws Exception {
return Os.read(fd, packetBuffer, 0, packetBuffer.length);
}
}
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