Convert Narya (most of the way) over to a Maven Ant task based build. The

ActionScript bits remain belligerent, but the Java stuff is mostly shipshape.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@6222 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/main/java/com/threerings/io/FramingOutputStream.java

@@ -0,0 +1,93 @@
+//
+// $Id$
+//
+// Narya library - tools for developing networked games
+// Copyright (C) 2002-2010 Three Rings Design, Inc., All Rights Reserved
+// http://code.google.com/p/narya/
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.threerings.io;
+
+import java.nio.ByteBuffer;
+
+/**
+ * The framing output stream accumulates output into a byte array just
+ * like the byte array output stream, but can then be instructed to send
+ * its contents over a channel, prefixed by the length (written as an
+ * integer) of the entire frame (contents plus length prefix). It does
+ * this efficiently so that data is copied as little as possible and so
+ * that the output stream to which the data is written need not be
+ * buffered because the framed output is written in a single call to
+ * <code>write()</code>.
+ *
+ * <p><em>Note:</em> The framing output stream does not synchronize writes
+ * to its internal buffer. It is intended to only be accessed from a
+ * single thread.
+ */
+public class FramingOutputStream extends ByteBufferOutputStream
+{
+    public FramingOutputStream ()
+    {
+        _buffer.put(HEADER_PAD);
+    }
+
+    @Override
+    public ByteBuffer flip ()
+    {
+        throw new UnsupportedOperationException("Use frameAndReturnBuffer() instead.");
+    }
+
+    @Override
+    public void reset ()
+    {
+        throw new UnsupportedOperationException("Use resetFrame() instead.");
+    }
+
+    /**
+     * Writes the frame length to the beginning of our buffer and returns
+     * it for writing to the appropriate channel. This should be followed
+     * by a call to {@link #resetFrame} when the frame has been written.
+     */
+    public ByteBuffer frameAndReturnBuffer ()
+    {
+        // flip the buffer which will limit it to its current position
+        _buffer.flip();
+
+        // then write the frame length and rewind back to the start of the
+        // buffer so that all the data is available
+        int count = _buffer.limit();
+        _buffer.put((byte)((count >>> 24) & 0xFF));
+        _buffer.put((byte)((count >>> 16) & 0xFF));
+        _buffer.put((byte)((count >>>  8) & 0xFF));
+        _buffer.put((byte)((count >>>  0) & 0xFF));
+        _buffer.rewind();
+
+        return _buffer;
+    }
+
+    /**
+     * Resets our internal buffer and prepares to write a new frame.
+     */
+    public void resetFrame ()
+    {
+        _buffer.clear();
+        _buffer.put(HEADER_PAD);
+    }
+
+    /** We pad the beginning of our buffer so that we can write the frame
+     * length when the time comes. */
+    protected static final byte[] HEADER_PAD = new byte[4];
+}