/**
* Read data from the input buffer up to len bytes long. Block until there is data available.
*
* @param dst
* @param off
* @param len
* @return The number of bytes read
*/
public synchronized int read(byte[] dst, int off, int len) throws SocketException {
while ((dataBuffer.getUsed() == 0) && !controlBlock.isReset() && !isEOF()) {
try {
wait();
} catch (InterruptedException ex) {
// Ignore
}
}
if (controlBlock.isReset()) {
throw new SocketException("Connection reset");
} else if (isEOF()) {
return -1;
} else {
return dataBuffer.read(dst, off, len);
}
}
/**
* Process the given segment (that must be the next expected segment). The data will be send to
* the input data buffer, if there is enough space left in the buffer.
*
* @param hdr
* @param skbuf
* @return True if the segment has been fully processed, false otherwise.
* @throws SocketException
*/
private synchronized boolean processNextSegment(TCPHeader hdr, SocketBuffer skbuf)
throws SocketException {
final int seqNr = hdr.getSequenceNr();
if (seqNr != rcv_next) {
throw new IllegalArgumentException("hdr.seqNr != rcv_next");
}
// This segment is the first expected segment
// Sent it to the application if there is enough space
final int dataLength = hdr.getDataLength();
if (dataLength > dataBuffer.getFreeSize()) {
// Not enough free space, ignore this segment, it will be retransmitted.
log.debug("nextSegment dropped due to lack of space");
return false;
} else {
// Enough space, save
if (dataLength > 0) {
dataBuffer.add(skbuf, 0, dataLength);
// Update rcv_next
rcv_next += dataLength;
}
final boolean fin = hdr.isFlagFinishedSet();
final boolean syn = hdr.isFlagSynchronizeSet();
if (syn || fin) {
// SYN & FIN take up 1 seq-nr
rcv_next++;
}
if ((dataLength > 0) || fin) {
// And ACK it
controlBlock.sendACK(0, rcv_next);
}
// Notify threads blocked in read
notifyAll();
// We've processed it fully
return true;
}
}
/**
* Has the End of the InputChannel been reached?
*
* @return True if EOF has been reached, false otherwise
*/
protected final boolean isEOF() {
if (!finReceived) {
// Other site has not closed
return false;
}
if (dataBuffer.getUsed() > 0) {
// Still data in databuffer
return false;
}
if (!futureSegments.isEmpty()) {
// Still future segments
return false;
}
// TODO No other requirements here?????
return true;
}
public int getBufferSize() {
return dataBuffer.getLength();
}
/** Return the number of available bytes in the input buffer. */
public int available() {
return dataBuffer.getUsed();
}