/**
* sends data from buffer.
*
* <p>precondition: sendbb is in put mode post condition: sendbb is in put mode
*/
private void sendFromBuffer() {
aa(this, isSender(), "nonsender can't write");
aa(this, isConnected() || isClosurePending(), "needs to be established can't write");
// switch sendbb to get mode
sendbb.flip();
p(this, 3, "Sending from buffer. bb flipped.");
int payloadLength = Math.min(Transport.MAX_PAYLOAD_SIZE, sendbb.limit());
p(this, 4, "Max Payload size: " + Transport.MAX_PAYLOAD_SIZE);
p(this, 4, "payloadlen: " + payloadLength);
dumpState(4);
if (roomForPacket(payloadLength) && payloadLength > 0) {
byte[] payload = new byte[payloadLength];
sendbb.get(payload);
Transport t = makeTransport(Transport.DATA, seqNum, payload);
tcpMan.sendData(this.tsid, t);
p(this, 3, "Write: converting to packet: " + TCPManager.bytesToString(payload));
// only increment the seqNum if a packet is sent
seqNum += payloadLength;
}
// switch back to put mode
sendbb.compact();
dumpState(4);
if (isClosurePending() && sendbb.position() == 0) release();
}
/**
* Read from the socket up to len bytes into the buffer buf starting at position pos.
*
* @param buf byte[] the buffer
* @param pos int starting position in buffer
* @param len int number of bytes to read
* @return int on success, the number of bytes read, which may be smaller than len; on failure, -1
*/
public int read(byte[] buf, int pos, int len) {
aa(this, isReceiver(), "nonreceiver socket reading");
aa(this, state == State.ESTABLISHED, "attempting to read from closed socket");
recvbb.flip();
int bytesCopied = Math.min(recvbb.limit(), len);
recvbb.get(buf, pos, bytesCopied);
recvbb.compact();
return bytesCopied;
}
private void initSender() {
aa(this, sockType == SocketType.SENDER, "");
sendWindow = 3 * Transport.MAX_PAYLOAD_SIZE;
sendBase = 0;
seqNum = 0;
sendbb = ByteBuffer.allocate(SEND_BUFFER_SIZE);
}
private void deliverToBuffer() {
while (transportBuffer.containsKey(recvBase)) {
p(this, 4, "coalescing at recvBase: " + recvBase);
dumpState(6);
byte[] payload = transportBuffer.get(recvBase).getPayload();
if (recvbb.remaining() >= payload.length) {
recvbb.put(payload);
recvBase += payload.length;
p(this, 5, "coalesced: recvBase incremented to " + recvBase);
} else {
p(this, 5, "coalesce ending: buffer full");
break;
}
}
}
/**
* Write to the socket up to len bytes from the buffer buf starting at position pos.
*
* @param buf byte[] the buffer to write from
* @param pos int starting position in buffer
* @param len int number of bytes to write
* @return int on success, the number of bytes written, which may be smaller than len; on failure,
* -1
*/
public int write(byte[] buf, int pos, int len) {
aa(this, isSender(), "nonsender can't write");
aa(this, isConnected(), "nonsender can't write");
// fill buffer
p(
this,
3,
"write called"); // \n\t buf = " + TCPManager.bytesToString(buf)); p(this, 4, "sendbb
// position: " + sendbb.position());
dumpState(4);
// p(this, 4, "sendbb limit: " + sendbb.limit());
// p(this, 4, "sendbb remaining: " + sendbb.remaining());
// p(this, 4, "sendbb size: " + sendbb.capacity());
int bytesCopied = Math.min(sendbb.remaining(), len);
sendbb.put(buf, pos, bytesCopied);
p(this, 3, "bytes copied: " + bytesCopied);
// try to send as much as possible
sendFromBuffer();
return bytesCopied;
}
/** Initiate closure of a connection (graceful shutdown) */
public void close() {
p(this, 3, "Close()");
switch (sockType) {
case SENDER:
state = State.SHUTDOWN;
if (sendbb.position() == 0) release();
break;
case RECEIVER:
release();
break;
case WELCOME:
release();
}
}
private void initReceiver() {
aa(this, sockType == SocketType.RECEIVER, "");
recvBase = 0;
recvbb = ByteBuffer.allocate(RECV_BUFFER_SIZE);
transportBuffer = new HashMap<Integer, Transport>();
}