org.refcodes.codec.BaseDecoder 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/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.EOFException;
import java.io.IOException;
import java.io.InputStream;
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.exception.ExceptionUtility;
import org.refcodes.io.BytesDestination;
import org.refcodes.io.BytesReceiver;
import org.refcodes.io.BytesReceiverDecorator;
import org.refcodes.io.InputStreamByteReceiver;
/**
* The {@link BaseDecoder} implements the {@link BaseBuilder} functionality in
* terms of a {@link BytesReceiver}. It implements the {@link Decoder} interface
* attaching to the "refcodes-io" artifact via the {@link BytesReceiver}
* interface. This increases the scope of usage scenarios.
*/
public class BaseDecoder extends AbstractConnectableAutomaton implements BaseMetricsProperty, BaseMetricsBuilder, Decoder {
// /////////////////////////////////////////////////////////////////////////
// STATICS:
// /////////////////////////////////////////////////////////////////////////
private static final int BYTE_MASK = 0xFF;
private static final int BITS_PER_BYTE = 8;
// /////////////////////////////////////////////////////////////////////////
// CONSTANTS:
// /////////////////////////////////////////////////////////////////////////
// /////////////////////////////////////////////////////////////////////////
// VARIABLES:
// /////////////////////////////////////////////////////////////////////////
private BytesReceiver _byteReceiver;
private BaseMetrics _baseMetrics = BaseMetricsConfig.BASE64;
private int _trailingBytes = 0;
int _word = 0;
private byte[] _decodedBytes = new byte[_baseMetrics.getBytesPerInt()];
private int _readIndex = 0;
// /////////////////////////////////////////////////////////////////////////
// CONSTRUCTORS:
// /////////////////////////////////////////////////////////////////////////
/**
* Constructs the {@link BaseDecoder} reading the data to be decoded from
* the provided {@link InputStream}.
*
* @param aInputStream the input stream
*
* @throws IOException throw in case using the {@link InputStream} caused
* I/O related problems.
*/
public BaseDecoder( InputStream aInputStream ) throws IOException {
this( new InputStreamByteReceiver( aInputStream ) );
}
/**
* Constructs the {@link BaseDecoder} reading the data to be decoded from
* the provided {@link InputStream}.
*
* @param aInputStream the input stream
* @param aBaseMetrics The {@link BaseMetrics} to use.
*
* @throws IOException throw in case using the {@link InputStream} caused
* I/O related problems.
*/
public BaseDecoder( InputStream aInputStream, BaseMetrics aBaseMetrics ) throws IOException {
this( new InputStreamByteReceiver( aInputStream ), aBaseMetrics );
}
/**
* Constructs the {@link BaseDecoder} reading the data to be decoded from
* the provided {@link BytesDestination}.
*
* @param aByteProvider The {@link BytesDestination} from which to read the
* data.
*/
public BaseDecoder( BytesDestination aByteProvider ) {
try {
open( new BytesReceiverDecorator( aByteProvider ) );
}
catch ( IOException ignore ) {}
}
/**
* Constructs the {@link BaseDecoder} reading the data to be decoded from
* the provided {@link BytesReceiver}.
*
* @param aByteReceiver The {@link BytesReceiver} from which to read the
* data.
*
* @throws IOException in case opening or accessing an open line
* (connection, junction, link) caused problems.
*/
public BaseDecoder( BytesReceiver aByteReceiver ) throws IOException {
open( aByteReceiver );
}
/**
* Constructs the {@link BaseDecoder} reading the data to be decoded from
* the provided {@link InputStreamByteReceiver}.
*
* @param aInputStreamByteReceiver The {@link InputStreamByteReceiver} 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 BaseDecoder( InputStreamByteReceiver aInputStreamByteReceiver, BaseMetrics aBaseMetrics ) throws IOException {
this( aInputStreamByteReceiver );
setBaseMetrics( aBaseMetrics );
}
/**
* Explicit default constructor.
*/
protected BaseDecoder() {}
// /////////////////////////////////////////////////////////////////////////
// INJECTION:
// /////////////////////////////////////////////////////////////////////////
// /////////////////////////////////////////////////////////////////////////
// METHODS:
// /////////////////////////////////////////////////////////////////////////
/**
* {@inheritDoc}
*/
@Override
public BaseMetrics getBaseMetrics() {
return _baseMetrics;
}
/**
* {@inheritDoc}
*/
@Override
public void setBaseMetrics( BaseMetrics aBaseMetrics ) {
_baseMetrics = aBaseMetrics;
_decodedBytes = new byte[_baseMetrics.getBytesPerInt()];
}
/**
* {@inheritDoc}
*/
@Override
public BaseDecoder withBaseMetrics( BaseMetrics aBaseMetrics ) {
setBaseMetrics( aBaseMetrics );
return this;
}
/**
* {@inheritDoc}
*/
@Override
public int available() throws IOException {
return _byteReceiver.available();
}
/**
* {@inheritDoc}
*/
@Override
public byte[] receiveAllBytes() throws IOException, EOFException {
if ( _readIndex > 0 ) {
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;
}
if ( !_byteReceiver.hasAvailable() ) {
throw new EOFException( "Reached end of file (stream), no more data avaialble!" );
}
try {
char eRead;
for ( int l = 0; l < _baseMetrics.getDigitsPerInt(); l++ ) {
eRead = (char) _byteReceiver.receiveByte();
while ( eRead == '\n' || eRead == '\r' ) { // Skip any line breaks!
eRead = (char) _byteReceiver.receiveByte();
}
_word <<= _baseMetrics.getBitsPerDigit();
if ( eRead != _baseMetrics.getPaddingChar() ) {
_word |= (int) _baseMetrics.toValue( eRead ) & BYTE_MASK;
}
else {
_trailingBytes++;
}
}
for ( int i = 0; i < _baseMetrics.getBytesPerInt(); i++ ) {
int theIndex = _baseMetrics.getBytesPerInt() - i - 1;
_decodedBytes[theIndex] = (byte) _word;
_word >>= BITS_PER_BYTE;
}
_word = 0;
}
catch ( IOException e ) {
throw new IOException( "Unable to read from the provided receiver <" + _byteReceiver + ">: " + ExceptionUtility.toMessage( e ), e );
}
if ( _trailingBytes != 0 ) {
int theLastBlockSize = _baseMetrics.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 receiveByte() throws IOException, EOFException {
if ( _readIndex >= _baseMetrics.getBytesPerInt() - _trailingBytes ) {
if ( !_byteReceiver.hasAvailable() ) {
throw new EOFException( "Reached end of file (stream), no more data avaialble!" );
}
_trailingBytes = 0;
_readIndex = 0;
}
if ( _readIndex == 0 ) {
receiveAllBytes();
}
byte theDecodedByte = _decodedBytes[_readIndex++];
if ( _readIndex >= _decodedBytes.length ) _readIndex = 0;
return theDecodedByte;
}
/**
* {@inheritDoc}
*/
@Override
public synchronized void close() throws IOException {
try {
_byteReceiver.close();
}
catch ( IOException e ) {
throw new IOException( "Unable to close the receiver <" + _byteReceiver + ">", e );
}
super.close();
}
// /////////////////////////////////////////////////////////////////////////
// HOOKS:
// /////////////////////////////////////////////////////////////////////////
/**
* Open.
*
* @param aConnection the connection
*
* @throws IOException the open exception
*/
protected void open( BytesDestination aConnection ) throws IOException {
if ( aConnection instanceof BytesReceiver ) {
_byteReceiver = (BytesReceiver) aConnection;
}
else {
_byteReceiver = new BytesReceiverDecorator( aConnection );
}
if ( !_byteReceiver.isOpened() ) {
if ( _byteReceiver instanceof Openable ) {
((Openable) _byteReceiver).open();
}
else {
throw new IOException( "The provided connection is in status <" + _byteReceiver.getConnectionStatus() + "> but does not provide the <" + Openable.class.getName() + "> interface." );
}
}
open();
}
// /////////////////////////////////////////////////////////////////////////
// HELPER:
// /////////////////////////////////////////////////////////////////////////
// /////////////////////////////////////////////////////////////////////////
// INNER CLASSES:
// /////////////////////////////////////////////////////////////////////////
/**
* The {@link BaseDecoderConnection} implements the {@link BaseDecoder}
* functionality in terms of a {@link ConnectionComponent}. In addition to
* the {@link BaseDecoder} it provides means to open a dedicated
* {@link BytesDestination} connection.
*/
public static class BaseDecoderConnection extends BaseDecoder implements ConnectionComponent {
// /////////////////////////////////////////////////////////////////////
// METHODS:
// /////////////////////////////////////////////////////////////////////
/**
* {@inheritDoc}
*/
@Override
public void open( BytesDestination aConnection ) throws IOException {
super.open( aConnection );
}
}
}
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