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The runtime environment for ONC/RPC programs, both client and server side.
/*
* $Header: /home/harald/repos/remotetea.sf.net/remotetea/src/org/acplt/oncrpc/XdrBufferEncodingStream.java,v 1.2 2003/08/14 11:26:50 haraldalbrecht Exp $
*
* Copyright (c) 1999, 2000
* Lehrstuhl fuer Prozessleittechnik (PLT), RWTH Aachen
* D-52064 Aachen, Germany.
* All rights reserved.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 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 Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this program (see the file LICENSE.txt for more
* details); if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
package org.acplt.oncrpc;
import java.io.*;
import java.net.*;
/**
* The XdrBufferEncodingStream class provides a buffer-based
* XDR stream.
*
* @version $Revision: 1.2 $ $Date: 2003/08/14 11:26:50 $ $State: Exp $ $Locker: $
* @author Harald Albrecht
*/
public class XdrBufferEncodingStream extends XdrEncodingStream {
/**
* Constructs a new XdrBufferEncodingStream with a buffer
* to encode data into of the given size.
*
* @param bufferSize Size of buffer to store encoded data in.
*/
public XdrBufferEncodingStream(int bufferSize) {
if ( (bufferSize < 0)
|| (bufferSize & 3) != 0 ) {
throw(new IllegalArgumentException("size of buffer must be a multiple of four and must not be negative"));
}
this.buffer = new byte[bufferSize];
bufferIndex = 0;
bufferHighmark = buffer.length - 4;
}
/**
* Constructs a new XdrBufferEncodingStream with a given
* buffer.
*
* @param buffer Buffer to store encoded information in.
*
* @throws IllegalArgumentException if encodedLength is not
* a multiple of four.
*/
public XdrBufferEncodingStream(byte [] buffer) {
//
// Make sure that the buffer size is a multiple of four, otherwise
// throw an exception.
//
if ( (buffer.length & 3) != 0 ) {
throw(new IllegalArgumentException("size of buffer must be a multiple of four"));
}
this.buffer = buffer;
bufferIndex = 0;
bufferHighmark = buffer.length - 4;
}
/**
* Returns the amount of encoded data in the buffer.
*
* @return length of data encoded in buffer.
*/
public int getXdrLength() {
return bufferIndex;
}
/**
* Returns the buffer holding encoded data.
*
* @return Buffer with encoded data.
*/
public byte [] getXdrData() {
return buffer;
}
/**
* Begins encoding a new XDR record. This involves resetting this
* encoding XDR stream back into a known state.
*
* @param receiverAddress Indicates the receiver of the XDR data. This can be
* null for XDR streams connected permanently to a
* receiver (like in case of TCP/IP based XDR streams).
* @param receiverPort Port number of the receiver.
*
* @throws OncRpcException if an ONC/RPC error occurs.
* @throws IOException if an I/O error occurs.
*/
public void beginEncoding(InetAddress receiverAddress, int receiverPort)
throws OncRpcException, IOException {
bufferIndex = 0;
}
/**
* Flushes this encoding XDR stream and forces any buffered output bytes
* to be written out. The general contract of endEncoding is that
* calling it is an indication that the current record is finished and any
* bytes previously encoded should immediately be written to their intended
* destination.
*
* @throws OncRpcException if an ONC/RPC error occurs.
* @throws IOException if an I/O error occurs.
*/
public void endEncoding()
throws OncRpcException, IOException {
}
/**
* Closes this encoding XDR stream and releases any system resources
* associated with this stream. The general contract of close
* is that it closes the encoding XDR stream. A closed XDR stream cannot
* perform encoding operations and cannot be reopened.
*
* @throws OncRpcException if an ONC/RPC error occurs.
* @throws IOException if an I/O error occurs.
*/
public void close()
throws OncRpcException, IOException {
buffer = null;
}
/**
* Encodes (aka "serializes") a "XDR int" value and writes it down a
* XDR stream. A XDR int is 32 bits wide -- the same width Java's "int"
* data type has. This method is one of the basic methods all other
* methods can rely on.
*
* @throws OncRpcException if an ONC/RPC error occurs.
* @throws IOException if an I/O error occurs.
*/
public void xdrEncodeInt(int value)
throws OncRpcException, IOException {
if ( bufferIndex <= bufferHighmark ) {
//
// There's enough space in the buffer, so encode this int as
// four bytes (french octets) in big endian order (that is, the
// most significant byte comes first.
//
buffer[bufferIndex++] = (byte)(value >>> 24);
buffer[bufferIndex++] = (byte)(value >>> 16);
buffer[bufferIndex++] = (byte)(value >>> 8);
buffer[bufferIndex++] = (byte) value;
} else {
throw(new OncRpcException(OncRpcException.RPC_BUFFEROVERFLOW));
}
}
/**
* Encodes (aka "serializes") a XDR opaque value, which is represented
* by a vector of byte values, and starts at offset with a
* length of length. Only the opaque value is encoded, but
* no length indication is preceeding the opaque value, so the receiver
* has to know how long the opaque value will be. The encoded data is
* always padded to be a multiple of four. If the given length is not a
* multiple of four, zero bytes will be used for padding.
*
* @throws OncRpcException if an ONC/RPC error occurs.
* @throws IOException if an I/O error occurs.
*/
public void xdrEncodeOpaque(byte [] value, int offset, int length)
throws OncRpcException, IOException {
//
// First calculate the number of bytes needed for padding.
//
int padding = (4 - (length & 3)) & 3;
if ( bufferIndex <= bufferHighmark - (length + padding) ) {
System.arraycopy(value, offset, buffer, bufferIndex, length);
bufferIndex += length;
if ( padding != 0 ) {
//
// If the length of the opaque data was not a multiple, then
// pad with zeros, so the write pointer (argh! how comes Java
// has a pointer...?!) points to a byte, which has an index
// of a multiple of four.
//
System.arraycopy(paddingZeros, 0, buffer, bufferIndex, padding);
bufferIndex += padding;
}
} else {
throw(new OncRpcException(OncRpcException.RPC_BUFFEROVERFLOW));
}
}
/**
* The buffer which will receive the encoded information, before it
* is sent via a datagram socket.
*/
private byte [] buffer;
/**
* The write pointer is an index into the buffer.
*/
private int bufferIndex;
/**
* Index of the last four byte word in the buffer.
*/
private int bufferHighmark;
/**
* Some zeros, only needed for padding -- like in real life.
*/
private static final byte [] paddingZeros = { 0, 0, 0, 0 };
}
// End of XdrBufferEncodingStream.java