--- /dev/null
+/*
+ * Jexer - Java Text User Interface
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (C) 2019 Kevin Lamonte
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * @author Kevin Lamonte [kevin.lamonte@gmail.com]
+ * @version 1
+ */
+package jexer.net;
+
+import java.io.OutputStream;
+import java.io.IOException;
+
+import static jexer.net.TelnetSocket.*;
+
+/**
+ * TelnetOutputStream works with TelnetSocket to perform the telnet protocol.
+ */
+public class TelnetOutputStream extends OutputStream {
+
+ // ------------------------------------------------------------------------
+ // Variables --------------------------------------------------------------
+ // ------------------------------------------------------------------------
+
+ /**
+ * The root TelnetSocket that has my telnet protocol state.
+ */
+ private TelnetSocket master;
+
+ /**
+ * The raw socket's OutputStream.
+ */
+ private OutputStream output;
+
+ /**
+ * When true, the last byte the caller passed to write() was a CR.
+ */
+ private boolean writeCR = false;
+
+ // ------------------------------------------------------------------------
+ // Constructors -----------------------------------------------------------
+ // ------------------------------------------------------------------------
+
+ /**
+ * Package private constructor.
+ *
+ * @param master the master TelnetSocket
+ * @param output the underlying socket's OutputStream
+ */
+ TelnetOutputStream(final TelnetSocket master, final OutputStream output) {
+ this.master = master;
+ this.output = output;
+ }
+
+ // ------------------------------------------------------------------------
+ // OutputStrem ------------------------------------------------------------
+ // ------------------------------------------------------------------------
+
+ /**
+ * Closes this output stream and releases any system resources associated
+ * with this stream.
+ *
+ * @throws IOException if an I/O error occurs
+ */
+ @Override
+ public void close() throws IOException {
+ if (output != null) {
+ output.close();
+ output = null;
+ }
+ }
+
+ /**
+ * Flushes this output stream and forces any buffered output bytes to be
+ * written out.
+ *
+ * @throws IOException if an I/O error occurs
+ */
+ @Override
+ public void flush() throws IOException {
+ if ((master.binaryMode == false) && (writeCR == true)) {
+ // The last byte sent to this.write() was a CR, which was never
+ // actually sent. So send the CR in ascii mode, then flush.
+ // CR <anything> -> CR NULL
+ output.write(C_CR);
+ output.write(C_NUL);
+ writeCR = false;
+ }
+ output.flush();
+ }
+
+ /**
+ * Writes b.length bytes from the specified byte array to this output
+ * stream.
+ *
+ * @param b the data.
+ * @throws IOException if an I/O error occurs
+ */
+ @Override
+ public void write(final byte[] b) throws IOException {
+ writeImpl(b, 0, b.length);
+ }
+
+ /**
+ * Writes len bytes from the specified byte array starting at offset off
+ * to this output stream.
+ *
+ * @param b the data.
+ * @param off the start offset in the data.
+ * @param len the number of bytes to write.
+ * @throws IOException if an I/O error occurs
+ */
+ @Override
+ public void write(final byte[] b, final int off,
+ final int len) throws IOException {
+
+ writeImpl(b, off, len);
+ }
+
+ /**
+ * Writes the specified byte to this output stream.
+ *
+ * @param b the byte to write.
+ * @throws IOException if an I/O error occurs
+ */
+ @Override
+ public void write(final int b) throws IOException {
+ byte [] bytes = new byte[1];
+ bytes[0] = (byte) b;
+ writeImpl(bytes, 0, 1);
+ }
+
+ // ------------------------------------------------------------------------
+ // TelnetOutputStrem ------------------------------------------------------
+ // ------------------------------------------------------------------------
+
+ /**
+ * Writes b.length bytes from the specified byte array to this output
+ * stream. Note package private access.
+ *
+ * @param b the data.
+ * @throws IOException if an I/O error occurs
+ */
+ void rawWrite(final byte[] b) throws IOException {
+ output.write(b, 0, b.length);
+ }
+
+ /**
+ * Writes len bytes from the specified byte array starting at offset off
+ * to this output stream.
+ *
+ * @param b the data.
+ * @param off the start offset in the data.
+ * @param len the number of bytes to write.
+ * @throws IOException if an I/O error occurs
+ */
+ private void writeImpl(final byte[] b, final int off,
+ final int len) throws IOException {
+
+ byte [] writeBuffer = new byte[Math.max(len, 4)];
+ int writeBufferI = 0;
+
+ for (int i = 0; i < len; i++) {
+ if (writeBufferI >= writeBuffer.length - 4) {
+ // Flush what we have generated so far and reset the buffer,
+ // because the next byte could generate up to 4 output bytes
+ // (CR <something> <IAC> <IAC>).
+ output.write(writeBuffer, 0, writeBufferI);
+ writeBufferI = 0;
+ }
+
+ // Pull the next byte
+ byte ch = b[i + off];
+
+ if (master.binaryMode == true) {
+
+ if (ch == TELNET_IAC) {
+ // IAC -> IAC IAC
+ writeBuffer[writeBufferI++] = (byte) TELNET_IAC;
+ writeBuffer[writeBufferI++] = (byte) TELNET_IAC;
+ } else {
+ // Anything else -> just send
+ writeBuffer[writeBufferI++] = ch;
+ }
+ continue;
+ }
+
+ // Non-binary mode: more complicated. We use writeCR to handle
+ // the case that the last byte of b was a CR.
+
+ // Bare carriage return -> CR NUL
+ if (ch == C_CR) {
+ if (writeCR == true) {
+ // Flush the previous CR to the stream.
+ // CR <anything> -> CR NULL
+ writeBuffer[writeBufferI++] = (byte) C_CR;
+ writeBuffer[writeBufferI++] = (byte) C_NUL;
+ }
+ writeCR = true;
+ } else if (ch == C_LF) {
+ if (writeCR == true) {
+ // CR LF -> CR LF
+ writeBuffer[writeBufferI++] = (byte) C_CR;
+ writeBuffer[writeBufferI++] = (byte) C_LF;
+ writeCR = false;
+ } else {
+ // Bare LF -> LF
+ writeBuffer[writeBufferI++] = ch;
+ }
+ } else if (ch == TELNET_IAC) {
+ if (writeCR == true) {
+ // CR <anything> -> CR NULL
+ writeBuffer[writeBufferI++] = (byte) C_CR;
+ writeBuffer[writeBufferI++] = (byte) C_NUL;
+ writeCR = false;
+ }
+ // IAC -> IAC IAC
+ writeBuffer[writeBufferI++] = (byte) TELNET_IAC;
+ writeBuffer[writeBufferI++] = (byte) TELNET_IAC;
+ } else {
+ if (writeCR == true) {
+ // CR <anything> -> CR NULL
+ writeBuffer[writeBufferI++] = (byte) C_CR;
+ writeBuffer[writeBufferI++] = (byte) C_NUL;
+ writeCR = false;
+ } else {
+ // Normal character */
+ writeBuffer[writeBufferI++] = ch;
+ }
+ }
+
+ } // while (i < userbuf.length)
+
+ if (writeBufferI > 0) {
+ // Flush what we have generated so far and reset the buffer.
+ output.write(writeBuffer, 0, writeBufferI);
+ }
+ }
+
+}