import sun.nio.ch.Util; //导入依赖的package包/类
private int receive(int fd,
                    ByteBuffer dst,
                    ResultContainer resultContainer)
        throws IOException {
    int pos = dst.position();
    int lim = dst.limit();
    assert (pos <= lim);
    int rem = (pos <= lim ? lim - pos : 0);
    if (dst instanceof DirectBuffer && rem > 0)
        return receiveIntoNativeBuffer(fd, resultContainer, dst, rem, pos);

    /* Substitute a native buffer. */
    int newSize = Math.max(rem, 1);
    ByteBuffer bb = Util.getTemporaryDirectBuffer(newSize);
    try {
        int n = receiveIntoNativeBuffer(fd, resultContainer, bb, newSize, 0);
        bb.flip();
        if (n > 0 && rem > 0)
            dst.put(bb);
        return n;
    } finally {
        Util.releaseTemporaryDirectBuffer(bb);
    }
}
 

import sun.nio.ch.Util; //导入依赖的package包/类
/**
 * Constructor for sockets obtained from branching
 */
public SctpChannelImpl(SelectorProvider provider,
                       FileDescriptor fd,
                       Association association)
        throws IOException {
    super(provider);
    this.fd = fd;
    this.fdVal = IOUtil.fdVal(fd);
    this.state = ChannelState.CONNECTED;
    port = (Net.localAddress(fd)).getPort();

    if (association != null) { /* branched */
        this.association = association;
    } else { /* obtained from server channel */
        /* Receive COMM_UP */
        ByteBuffer buf = Util.getTemporaryDirectBuffer(50);
        try {
            receive(buf, null, null, true);
        } finally {
            Util.releaseTemporaryDirectBuffer(buf);
        }
    }
}
 

import sun.nio.ch.Util; //导入依赖的package包/类
private int receive(int fd,
                    ByteBuffer dst,
                    ResultContainer resultContainer,
                    boolean peek)
        throws IOException {
    int pos = dst.position();
    int lim = dst.limit();
    assert (pos <= lim);
    int rem = (pos <= lim ? lim - pos : 0);
    if (dst instanceof DirectBuffer && rem > 0)
        return receiveIntoNativeBuffer(fd, resultContainer, dst, rem, pos, peek);

    /* Substitute a native buffer */
    int newSize = Math.max(rem, 1);
    ByteBuffer bb = Util.getTemporaryDirectBuffer(newSize);
    try {
        int n = receiveIntoNativeBuffer(fd, resultContainer, bb, newSize, 0, peek);
        bb.flip();
        if (n > 0 && rem > 0)
            dst.put(bb);
        return n;
    } finally {
        Util.releaseTemporaryDirectBuffer(bb);
    }
}
 

import sun.nio.ch.Util; //导入依赖的package包/类
private int send(int fd,
                 ByteBuffer src,
                 int assocId,
                 SocketAddress target,
                 MessageInfo messageInfo)
        throws IOException {
    int streamNumber = messageInfo.streamNumber();
    boolean unordered = messageInfo.isUnordered();
    int ppid = messageInfo.payloadProtocolID();

    if (src instanceof DirectBuffer)
        return sendFromNativeBuffer(fd, src, target, assocId,
                streamNumber, unordered, ppid);

    /* Substitute a native buffer */
    int pos = src.position();
    int lim = src.limit();
    assert (pos <= lim && streamNumber >= 0);

    int rem = (pos <= lim ? lim - pos : 0);
    ByteBuffer bb = Util.getTemporaryDirectBuffer(rem);
    try {
        bb.put(src);
        bb.flip();
        /* Do not update src until we see how many bytes were written */
        src.position(pos);

        int n = sendFromNativeBuffer(fd, bb, target, assocId,
                streamNumber, unordered, ppid);
        if (n > 0) {
            /* now update src */
            src.position(pos + n);
        }
        return n;
    } finally {
        Util.releaseTemporaryDirectBuffer(bb);
    }
}
 

import sun.nio.ch.Util; //导入依赖的package包/类
private int send(int fd, ByteBuffer src, MessageInfo messageInfo)
        throws IOException {
    int streamNumber = messageInfo.streamNumber();
    SocketAddress target = messageInfo.address();
    boolean unordered = messageInfo.isUnordered();
    int ppid = messageInfo.payloadProtocolID();

    if (src instanceof DirectBuffer)
        return sendFromNativeBuffer(fd, src, target, streamNumber,
                unordered, ppid);

    /* Substitute a native buffer */
    int pos = src.position();
    int lim = src.limit();
    assert (pos <= lim && streamNumber >= 0);

    int rem = (pos <= lim ? lim - pos : 0);
    ByteBuffer bb = Util.getTemporaryDirectBuffer(rem);
    try {
        bb.put(src);
        bb.flip();
        /* Do not update src until we see how many bytes were written */
        src.position(pos);

        int n = sendFromNativeBuffer(fd, bb, target, streamNumber,
                unordered, ppid);
        if (n > 0) {
            /* now update src */
            src.position(pos + n);
        }
        return n;
    } finally {
        Util.releaseTemporaryDirectBuffer(bb);
    }
}