org.apache.commons.net.telnet.TelnetOutputStream Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.commons.net.telnet;
import java.io.IOException;
import java.io.OutputStream;
/**
* Wraps an output stream.
*
* In binary mode, the only conversion is to double IAC.
*
* In ASCII mode, if convertCRtoCRLF is true (currently always true), any CR is converted to CRLF.
* IACs are doubled.
* Also a bare LF is converted to CRLF and a bare CR is converted to CR\0
*
***/
final class TelnetOutputStream extends OutputStream
{
private final TelnetClient __client;
// TODO there does not appear to be any way to change this value - should it be a ctor parameter?
private final boolean __convertCRtoCRLF = true;
private boolean __lastWasCR = false;
TelnetOutputStream(TelnetClient client)
{
__client = client;
}
/***
* Writes a byte to the stream.
*
* @param ch The byte to write.
* @exception IOException If an error occurs while writing to the underlying
* stream.
***/
@Override
public void write(int ch) throws IOException
{
synchronized (__client)
{
ch &= 0xff;
if (__client._requestedWont(TelnetOption.BINARY)) // i.e. ASCII
{
if (__lastWasCR)
{
if (__convertCRtoCRLF)
{
__client._sendByte('\n');
if (ch == '\n') // i.e. was CRLF anyway
{
__lastWasCR = false;
return ;
}
} // __convertCRtoCRLF
else if (ch != '\n')
{
__client._sendByte('\0'); // RFC854 requires CR NUL for bare CR
}
}
switch (ch)
{
case '\r':
__client._sendByte('\r');
__lastWasCR = true;
break;
case '\n':
if (!__lastWasCR) { // convert LF to CRLF
__client._sendByte('\r');
}
__client._sendByte(ch);
__lastWasCR = false;
break;
case TelnetCommand.IAC:
__client._sendByte(TelnetCommand.IAC);
__client._sendByte(TelnetCommand.IAC);
__lastWasCR = false;
break;
default:
__client._sendByte(ch);
__lastWasCR = false;
break;
}
} // end ASCII
else if (ch == TelnetCommand.IAC)
{
__client._sendByte(ch);
__client._sendByte(TelnetCommand.IAC);
} else {
__client._sendByte(ch);
}
}
}
/***
* Writes a byte array to the stream.
*
* @param buffer The byte array to write.
* @exception IOException If an error occurs while writing to the underlying
* stream.
***/
@Override
public void write(byte buffer[]) throws IOException
{
write(buffer, 0, buffer.length);
}
/***
* Writes a number of bytes from a byte array to the stream starting from
* a given offset.
*
* @param buffer The byte array to write.
* @param offset The offset into the array at which to start copying data.
* @param length The number of bytes to write.
* @exception IOException If an error occurs while writing to the underlying
* stream.
***/
@Override
public void write(byte buffer[], int offset, int length) throws IOException
{
synchronized (__client)
{
while (length-- > 0) {
write(buffer[offset++]);
}
}
}
/*** Flushes the stream. ***/
@Override
public void flush() throws IOException
{
__client._flushOutputStream();
}
/*** Closes the stream. ***/
@Override
public void close() throws IOException
{
__client._closeOutputStream();
}
}