org.refcodes.codec.BaseDecoderImpl Maven / Gradle / Ivy
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Artifact with encoding and decoding (not in terms of encryption/decryption)
implementations (codecs) such as BASE64 encoding / decoding.
// /////////////////////////////////////////////////////////////////////////////
// REFCODES.ORG
// /////////////////////////////////////////////////////////////////////////////
// This code is copyright (c) by Siegfried Steiner, Munich, Germany and licensed
// under the following (see "http://en.wikipedia.org/wiki/Multi-licensing")
// licenses:
// -----------------------------------------------------------------------------
// GNU General Public License, v3.0 ("http://www.gnu.org/licenses/gpl-3.0.html")
// -----------------------------------------------------------------------------
// Apache License, v2.0 ("http://www.apache.org/licenses/LICENSE-2.0")
// -----------------------------------------------------------------------------
// Please contact the copyright holding author(s) of the software artifacts in
// question for licensing issues not being covered by the above listed licenses,
// also regarding commercial licensing models or regarding the compatibility
// with other open source licenses.
// /////////////////////////////////////////////////////////////////////////////
package org.refcodes.codec;
import java.io.IOException;
import org.refcodes.component.AbstractConnectableAutomaton;
import org.refcodes.component.CloseException;
import org.refcodes.component.OpenException;
import org.refcodes.component.Openable;
import org.refcodes.exception.ExceptionUtility;
import org.refcodes.io.ByteProvider;
import org.refcodes.io.ByteReceiver;
import org.refcodes.io.ByteReceiverDecorator;
/**
* Vanilla plain implementation of the {@link BaseDecoder} interface to be used
* with {@link ByteReceiver} instances.
*/
public class BaseDecoderImpl extends AbstractConnectableAutomaton implements BaseDecoder {
// /////////////////////////////////////////////////////////////////////////
// STATICS:
// /////////////////////////////////////////////////////////////////////////
private static final int BYTE_MASK = 0xFF;
private static final int BITS_PER_BYTE = 8;
// /////////////////////////////////////////////////////////////////////////
// CONSTANTS:
// /////////////////////////////////////////////////////////////////////////
// /////////////////////////////////////////////////////////////////////////
// VARIABLES:
// /////////////////////////////////////////////////////////////////////////
private ByteReceiver _byteReceiver;
private BaseMetrics _baseCodecMetrics = BaseConfig.BASE64;
private int _trailingBytes = 0;
int _word = 0;
private byte[] _decodedBytes = new byte[_baseCodecMetrics.getBytesPerInt()];
private int _readIndex = 0;
// /////////////////////////////////////////////////////////////////////////
// CONSTRUCTORS:
// /////////////////////////////////////////////////////////////////////////
/**
* Constructs the {@link BaseDecoder} reading the data to be decoded from
* the provided {@link ByteProvider}.
*
* @param aByteProvider The {@link ByteProvider} from which to read the
* data.
*/
public BaseDecoderImpl( ByteProvider aByteProvider ) {
try {
open( new ByteReceiverDecorator( aByteProvider ) );
}
catch ( OpenException ignore ) {}
}
/**
* Constructs the {@link BaseDecoder} reading the data to be decoded from
* the provided {@link ByteReceiver}.
*
* @param aByteReceiver The {@link ByteReceiver} from which to read the
* data.
*
* @throws OpenException in case opening or accessing an open line
* (connection, junction, link) caused problems.
*/
public BaseDecoderImpl( ByteReceiver aByteReceiver ) throws OpenException {
open( aByteReceiver );
}
/**
* Explicit default constructor.
*/
protected BaseDecoderImpl() {}
// /////////////////////////////////////////////////////////////////////////
// INJECTION:
// /////////////////////////////////////////////////////////////////////////
// /////////////////////////////////////////////////////////////////////////
// METHODS:
// /////////////////////////////////////////////////////////////////////////
/**
* {@inheritDoc}
*/
@Override
public BaseMetrics getBaseMetrics() {
return _baseCodecMetrics;
}
/**
* {@inheritDoc}
*/
@Override
public void setBaseMetrics( BaseMetrics aBaseMetrics ) {
_baseCodecMetrics = aBaseMetrics;
_decodedBytes = new byte[_baseCodecMetrics.getBytesPerInt()];
}
/**
* {@inheritDoc}
*/
@Override
public BaseDecoder withBaseMetrics( BaseMetrics aBaseMetrics ) {
setBaseMetrics( aBaseMetrics );
return this;
}
/**
* {@inheritDoc}
*/
@Override
public boolean hasDatagram() throws OpenException {
return _byteReceiver.hasDatagram();
}
/**
* {@inheritDoc}
*/
@Override
public byte[] readDatagrams() throws OpenException, InterruptedException {
if ( _readIndex > 0 ) {
// TODO: Write test code for BaseDecodeInputStreamReceiverTest!
byte[] theDecodedBytes = new byte[_decodedBytes.length - _readIndex];
int l = 0;
for ( int i = _readIndex; i < _decodedBytes.length; i++ ) {
theDecodedBytes[l++] = _decodedBytes[i];
}
_readIndex = 0;
return theDecodedBytes;
}
try {
char eRead;
for ( int l = 0; l < _baseCodecMetrics.getDigitsPerInt(); l++ ) {
_word <<= _baseCodecMetrics.getBitsPerDigit();
eRead = (char) _byteReceiver.readDatagram();
if ( eRead != _baseCodecMetrics.getPaddingChar() ) {
_word |= (int) _baseCodecMetrics.toValue( eRead ) & BYTE_MASK;
}
else {
_trailingBytes++;
}
}
for ( int i = 0; i < _baseCodecMetrics.getBytesPerInt(); i++ ) {
int theIndex = _baseCodecMetrics.getBytesPerInt() - i - 1;
_decodedBytes[theIndex] = (byte) _word;
_word >>= BITS_PER_BYTE;
}
_word = 0;
}
catch ( IOException e ) {
throw new OpenException( "Unable to read from the provided receiver <" + _byteReceiver + ">: " + ExceptionUtility.toMessage( e ), e );
}
if ( _trailingBytes != 0 ) {
int theLastBlockSize = _baseCodecMetrics.getBytesPerInt() - _trailingBytes;
byte[] theDecodedBytes = new byte[theLastBlockSize];
for ( int i = 0; i < theLastBlockSize; i++ ) {
theDecodedBytes[i] = _decodedBytes[i];
}
return theDecodedBytes;
}
return _decodedBytes;
}
/**
* {@inheritDoc}
*/
@Override
public byte readDatagram() throws OpenException, InterruptedException {
// TODO: Write test code for BaseDecodeInputStreamReceiverTest!
if ( _readIndex == 0 ) {
readDatagrams();
}
byte theDecodedByte = _decodedBytes[_readIndex++];
if ( _readIndex >= _decodedBytes.length ) _readIndex = 0;
return theDecodedByte;
}
/**
* {@inheritDoc}
*/
@Override
public void releaseAll() {
synchronized ( this ) {
notifyAll();
}
}
/**
* {@inheritDoc}
*/
@Override
public synchronized void close() throws CloseException {
try {
_byteReceiver.close();
}
catch ( IOException e ) {
throw new CloseException( "Unable to close the receiver <" + _byteReceiver + ">", e );
}
super.close();
}
// /////////////////////////////////////////////////////////////////////////
// HOOKS:
// /////////////////////////////////////////////////////////////////////////
/**
* Open.
*
* @param aConnection the connection
* @throws OpenException the open exception
*/
protected void open( ByteProvider aConnection ) throws OpenException {
if ( aConnection instanceof ByteReceiver ) {
_byteReceiver = (ByteReceiver) aConnection;
}
else {
_byteReceiver = new ByteReceiverDecorator( aConnection );
}
if ( !_byteReceiver.isOpened() ) {
if ( _byteReceiver instanceof Openable ) {
((Openable) _byteReceiver).open();
}
else {
throw new OpenException( "The provided connection is in status <" + _byteReceiver.getConnectionStatus() + "> but does not provide the <" + Openable.class.getName() + "> interface." );
}
}
open();
}
// /////////////////////////////////////////////////////////////////////////
// HELPER:
// /////////////////////////////////////////////////////////////////////////
// /////////////////////////////////////////////////////////////////////////
// INNER CLASSES:
// /////////////////////////////////////////////////////////////////////////
/**
* Vanilla plain implementation of the {@link BaseDecoderProvider} interface
* to be used with {@link ByteProvider} ({@link ByteReceiver}) instances.
*/
public static class BaseDecoderProviderImpl extends BaseDecoderImpl implements BaseDecoderProvider {
// /////////////////////////////////////////////////////////////////////
// METHODS:
// /////////////////////////////////////////////////////////////////////
/**
* {@inheritDoc}
*/
@Override
public void open( ByteProvider aConnection ) throws OpenException {
super.open( aConnection );
}
}
}