--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/com/trilead/ssh2/StreamGobbler.java	Thu May 22 10:41:19 2014 -0700
@@ -0,0 +1,194 @@
+
+package com.trilead.ssh2;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * A <code>StreamGobbler</code> is an InputStream that uses an internal worker
+ * thread to constantly consume input from another InputStream. It uses a buffer
+ * to store the consumed data. The buffer size is automatically adjusted, if needed.
+ * <p>
+ * This class is sometimes very convenient - if you wrap a session's STDOUT and STDERR
+ * InputStreams with instances of this class, then you don't have to bother about
+ * the shared window of STDOUT and STDERR in the low level SSH-2 protocol,
+ * since all arriving data will be immediatelly consumed by the worker threads.
+ * Also, as a side effect, the streams will be buffered (e.g., single byte
+ * read() operations are faster).
+ * <p>
+ * Other SSH for Java libraries include this functionality by default in
+ * their STDOUT and STDERR InputStream implementations, however, please be aware
+ * that this approach has also a downside:
+ * <p>
+ * If you do not call the StreamGobbler's <code>read()</code> method often enough
+ * and the peer is constantly sending huge amounts of data, then you will sooner or later
+ * encounter a low memory situation due to the aggregated data (well, it also depends on the Java heap size).
+ * Joe Average will like this class anyway - a paranoid programmer would never use such an approach.
+ * <p>
+ * The term "StreamGobbler" was taken from an article called "When Runtime.exec() won't",
+ * see http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html.
+ *
+ * @author Christian Plattner, plattner@trilead.com
+ * @version $Id: StreamGobbler.java,v 1.1 2007/10/15 12:49:56 cplattne Exp $
+ */
+
+public class StreamGobbler extends InputStream {
+    class GobblerThread extends Thread {
+        public void run() {
+            byte[] buff = new byte[8192];
+
+            while (true) {
+                try {
+                    int avail = is.read(buff);
+
+                    synchronized (synchronizer) {
+                        if (avail <= 0) {
+                            isEOF = true;
+                            synchronizer.notifyAll();
+                            break;
+                        }
+
+                        int space_available = buffer.length - write_pos;
+
+                        if (space_available < avail) {
+                            /* compact/resize buffer */
+                            int unread_size = write_pos - read_pos;
+                            int need_space = unread_size + avail;
+                            byte[] new_buffer = buffer;
+
+                            if (need_space > buffer.length) {
+                                int inc = need_space / 3;
+                                inc = (inc < 256) ? 256 : inc;
+                                inc = (inc > 8192) ? 8192 : inc;
+                                new_buffer = new byte[need_space + inc];
+                            }
+
+                            if (unread_size > 0)
+                                System.arraycopy(buffer, read_pos, new_buffer, 0, unread_size);
+
+                            buffer = new_buffer;
+                            read_pos = 0;
+                            write_pos = unread_size;
+                        }
+
+                        System.arraycopy(buff, 0, buffer, write_pos, avail);
+                        write_pos += avail;
+                        synchronizer.notifyAll();
+                    }
+                }
+                catch (IOException e) {
+                    synchronized (synchronizer) {
+                        exception = e;
+                        synchronizer.notifyAll();
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
+    private InputStream is;
+    private GobblerThread t;
+
+    private Object synchronizer = new Object();
+
+    private boolean isEOF = false;
+    private boolean isClosed = false;
+    private IOException exception = null;
+
+    private byte[] buffer = new byte[2048];
+    private int read_pos = 0;
+    private int write_pos = 0;
+
+    public StreamGobbler(InputStream is) {
+        this.is = is;
+        t = new GobblerThread();
+        t.setDaemon(true);
+        t.start();
+    }
+
+    public int read() throws IOException {
+        synchronized (synchronizer) {
+            if (isClosed)
+                throw new IOException("This StreamGobbler is closed.");
+
+            while (read_pos == write_pos) {
+                if (exception != null)
+                    throw exception;
+
+                if (isEOF)
+                    return -1;
+
+                try {
+                    synchronizer.wait();
+                }
+                catch (InterruptedException e) {
+                }
+            }
+
+            int b = buffer[read_pos++] & 0xff;
+            return b;
+        }
+    }
+
+    public int available() throws IOException {
+        synchronized (synchronizer) {
+            if (isClosed)
+                throw new IOException("This StreamGobbler is closed.");
+
+            return write_pos - read_pos;
+        }
+    }
+
+    public int read(byte[] b) throws IOException {
+        return read(b, 0, b.length);
+    }
+
+    public void close() throws IOException {
+        synchronized (synchronizer) {
+            if (isClosed)
+                return;
+
+            isClosed = true;
+            isEOF = true;
+            synchronizer.notifyAll();
+            is.close();
+        }
+    }
+
+    public int read(byte[] b, int off, int len) throws IOException {
+        if (b == null)
+            throw new NullPointerException();
+
+        if ((off < 0) || (len < 0) || ((off + len) > b.length) || ((off + len) < 0) || (off > b.length))
+            throw new IndexOutOfBoundsException();
+
+        if (len == 0)
+            return 0;
+
+        synchronized (synchronizer) {
+            if (isClosed)
+                throw new IOException("This StreamGobbler is closed.");
+
+            while (read_pos == write_pos) {
+                if (exception != null)
+                    throw exception;
+
+                if (isEOF)
+                    return -1;
+
+                try {
+                    synchronizer.wait();
+                }
+                catch (InterruptedException e) {
+                }
+            }
+
+            int avail = write_pos - read_pos;
+            avail = (avail > len) ? len : avail;
+            System.arraycopy(buffer, read_pos, b, off, avail);
+            read_pos += avail;
+            return avail;
+        }
+    }
+}