Add 'src/jexer/' from commit 'cf01c92f5809a0732409e280fb0f32f27393618d'
[fanfix.git] / src / jexer / net / TelnetOutputStream.java
diff --git a/src/jexer/net/TelnetOutputStream.java b/src/jexer/net/TelnetOutputStream.java
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+/*
+ * 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);
+        }
+    }
+
+}