org.refcodes.codec.BaseEncoder 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, distributed
// on an "AS IS" BASIS WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, and licen-
// sed 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/TEXT-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 java.io.OutputStream;
import org.refcodes.codec.BaseMetricsAccessor.BaseMetricsBuilder;
import org.refcodes.codec.BaseMetricsAccessor.BaseMetricsProperty;
import org.refcodes.component.AbstractConnectableAutomaton;
import org.refcodes.component.ConnectionComponent;
import org.refcodes.component.Openable;
import org.refcodes.io.ByteTransmitterDecorator;
import org.refcodes.io.BytesReceiver;
import org.refcodes.io.BytesSource;
import org.refcodes.io.BytesTransmitter;
import org.refcodes.io.OutputStreamBytesTransmitter;
/**
* The {@link BaseEncoder} implements the {@link BaseBuilder} functionality in
* terms of a {@link BytesTransmitter}.
*
* Make sure to call {@link #close()} when done as the final padding bytes are
* appended to the end!
*/
public class BaseEncoder extends AbstractConnectableAutomaton implements BaseMetricsProperty, BaseMetricsBuilder, Encoder {
// /////////////////////////////////////////////////////////////////////////
// CONSTANTS:
// /////////////////////////////////////////////////////////////////////////
private static final int BYTE_MASK = 0xFF;
private static final int BYTES_PER_INT = 4;
private static final int BITS_PER_BYTE = 8;
private static final int BITS_PER_INT = BITS_PER_BYTE * BYTES_PER_INT;
// /////////////////////////////////////////////////////////////////////////
// VARIABLES:
// /////////////////////////////////////////////////////////////////////////
private BytesTransmitter _byteSender;
private BaseMetrics _baseMetrics = BaseMetricsConfig.BASE64;
private byte[] _buffer = new byte[_baseMetrics.getBytesPerInt()];
private int _index = 0;
// /////////////////////////////////////////////////////////////////////////
// CONSTRUCTORS:
// /////////////////////////////////////////////////////////////////////////
/**
* Constructs the {@link BaseEncoder} instance using the provided
* {@link OutputStream} to receive the encoded data.
*
* @param aOutputStream the output stream
*
* @throws IOException throw in case using the {@link OutputStream} caused
* I/O related problems.
*/
public BaseEncoder( OutputStream aOutputStream ) throws IOException {
this( new OutputStreamBytesTransmitter( aOutputStream ) );
}
/**
* Constructs the {@link BaseEncoder} instance using the provided
* {@link OutputStream} to receive the encoded data.
*
* @param aOutputStream the output stream
* @param aBaseMetrics The {@link BaseMetrics} to use.
*
* @throws IOException throw in case using the {@link OutputStream} caused
* I/O related problems.
*/
public BaseEncoder( OutputStream aOutputStream, BaseMetrics aBaseMetrics ) throws IOException {
this( new OutputStreamBytesTransmitter( aOutputStream ), aBaseMetrics );
}
/**
* Constructs the {@link BaseEncoder} instance using the provided
* {@link BytesSource} to receive the encoded data.
*
* @param aByteConsumer The {@link BytesSource} to be fed with the encoded
* data.
*/
public BaseEncoder( BytesSource aByteConsumer ) {
try {
open( new ByteTransmitterDecorator( aByteConsumer ) );
}
catch ( IOException ignore ) {}
}
/**
* Constructs the {@link BaseEncoder} instance using the provided
* {@link BytesTransmitter} to receive the encoded data.
*
* @param aByteSender The {@link BytesTransmitter} to be fed with the
* encoded data.
*
* @throws IOException in case opening or accessing an open line
* (connection, junction, link) caused problems.
*/
public BaseEncoder( BytesTransmitter aByteSender ) throws IOException {
open( aByteSender );
}
/**
* Constructs the {@link BaseEncoder} instance using the provided
* {@link OutputStreamBytesTransmitter} to receive the encoded data.
*
* @param aOutputStreamBytesTransmitter The
* {@link OutputStreamBytesTransmitter} to use.
* @param aBaseMetrics The {@link BaseMetrics} to use.
*
* @throws IOException in case opening or accessing an open line
* (connection, junction, link) caused problems.
*/
public BaseEncoder( OutputStreamBytesTransmitter aOutputStreamBytesTransmitter, BaseMetrics aBaseMetrics ) throws IOException {
this( aOutputStreamBytesTransmitter );
setBaseMetrics( aBaseMetrics );
}
/**
* Explicit default constructor.
*/
protected BaseEncoder() {}
// /////////////////////////////////////////////////////////////////////////
// INJECTION:
// /////////////////////////////////////////////////////////////////////////
/**
* {@inheritDoc}
*/
@Override
public BaseMetrics getBaseMetrics() {
return _baseMetrics;
}
/**
* {@inheritDoc}
*/
@Override
public void setBaseMetrics( BaseMetrics aBaseMetrics ) {
_baseMetrics = aBaseMetrics;
_buffer = new byte[_baseMetrics.getBytesPerInt()];
}
/**
* {@inheritDoc}
*/
@Override
public BaseEncoder withBaseMetrics( BaseMetrics aBaseMetrics ) {
setBaseMetrics( aBaseMetrics );
return this;
}
/**
* {@inheritDoc}
*/
@Override
public void transmitByte( byte aByte ) throws IOException {
_buffer[_index % _baseMetrics.getBytesPerInt()] = aByte;
_index++;
if ( _index % _baseMetrics.getBytesPerInt() == 0 ) {
toEncodedText( 0 );
}
}
/**
* {@inheritDoc}
*/
@Override
public void transmitBytes( byte[] aDatagram ) throws IOException {
for ( byte eData : aDatagram ) {
transmitByte( eData );
}
}
/**
* {@inheritDoc}
*/
@Override
public void transmitBytes( byte[] aDatagram, int aOffset, int aLength ) throws IOException {
for ( int i = aOffset; i < aOffset + aLength; i++ ) {
transmitByte( aDatagram[i] );
}
}
/**
* {@inheritDoc}
*/
@Override
public void flush() throws IOException {
_byteSender.flush();
}
/**
* {@inheritDoc}
*
* Make sure to call {@link #close()} when done as the final padding bytes
* are appended to the end!
*/
@Override
public synchronized void close() throws IOException {
// int theMod = _index % _baseCodecMetrics.getBytesPerInt();
// int theTrailingBytes = (theMod == 0) ? 0 : _baseCodecMetrics.getBytesPerInt() - theMod;
final int theTrailingBytes = _baseMetrics.toPaddingCharsNumber( _index );
try {
if ( theTrailingBytes != 0 ) {
while ( _index % _baseMetrics.getBytesPerInt() != 0 ) {
_buffer[_index % _baseMetrics.getBytesPerInt()] = 0;
_index++;
}
toEncodedText( theTrailingBytes );
for ( int i = 0; i < theTrailingBytes; i++ ) {
_byteSender.transmitByte( (byte) ( _baseMetrics.getPaddingChar() & 0xFF ) );
}
}
}
catch ( IOException e ) {
throw new IOException( "Unable to finish off encoding.", e );
}
try {
_byteSender.flush();
_byteSender.close();
}
catch ( IOException e ) {
throw new IOException( "Unable to close the output stream <" + _byteSender + ">.", e );
}
super.close();
}
// /////////////////////////////////////////////////////////////////////////
// HOOKS:
// /////////////////////////////////////////////////////////////////////////
/**
* Open.
*
* @param aConnection the connection
*
* @throws IOException the open exception
*/
protected void open( BytesSource aConnection ) throws IOException {
if ( aConnection instanceof BytesReceiver ) {
_byteSender = (BytesTransmitter) aConnection;
}
else {
_byteSender = new ByteTransmitterDecorator( aConnection );
}
if ( !_byteSender.isOpened() ) {
if ( _byteSender instanceof Openable ) {
( (Openable) _byteSender ).open();
}
else {
throw new IOException( "The provided connection is in status <" + _byteSender.getConnectionStatus() + "> but does not provide the <" + Openable.class.getName() + "> interface." );
}
}
open();
}
// /////////////////////////////////////////////////////////////////////////
// HELPER:
// /////////////////////////////////////////////////////////////////////////
/**
* To encoded text.
*
* @param aTrailingBytes the trailing bytes
*
* @throws IOException the open exception
*/
private void toEncodedText( int aTrailingBytes ) throws IOException {
int theWord = toWord( _buffer, 0, _baseMetrics );
theWord <<= ( BITS_PER_BYTE * ( BYTES_PER_INT - _baseMetrics.getBytesPerInt() ) );
for ( int i = 0; i < _baseMetrics.getDigitsPerInt() - aTrailingBytes; i++ ) {
final int eByte = ( theWord >> ( BITS_PER_INT - _baseMetrics.getBitsPerDigit() ) ) & _baseMetrics.getDigitMask();
_byteSender.transmitByte( (byte) ( _baseMetrics.toChar( eByte ) & 0xFF ) );
theWord <<= _baseMetrics.getBitsPerDigit();
}
}
/**
* To word.
*
* @param aDecodedData the decoded data
* @param aOffset the offset
* @param aBaseMetrics the base metrics
*
* @return the int
*/
private static int toWord( byte[] aDecodedData, int aOffset, BaseMetrics aBaseMetrics ) {
int eWord = 0;
for ( int i = 0; i < aBaseMetrics.getBytesPerInt(); i++ ) {
eWord <<= BITS_PER_BYTE;
if ( aOffset + i < aDecodedData.length ) {
eWord |= (int) aDecodedData[aOffset + i] & BYTE_MASK;
}
}
return eWord;
}
// /////////////////////////////////////////////////////////////////////////
// INNER CLASSES:
// /////////////////////////////////////////////////////////////////////////
/**
* The {@link BaseEncoderConnection} implements the {@link BaseEncoder}
* functionality in terms of a {@link ConnectionComponent}. In addition to
* the {@link BaseEncoder} it provides means to open a dedicated
* {@link BytesSource} connection.
*/
public static class BaseEncoderConnection extends BaseEncoder implements ConnectionComponent {
// /////////////////////////////////////////////////////////////////////
// METHODS:
// /////////////////////////////////////////////////////////////////////
/**
* {@inheritDoc}
*/
@Override
public void open( BytesSource aConnection ) throws IOException {
super.open( aConnection );
}
}
}
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