/*
* Copyright (c) 2011 Tamas Cservenak. All rights reserved.
*
* <tamas@cservenak.com>
* http://www.cservenak.com/
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package lzma.streams;
import lzma.sdk.lzma.Encoder;
import org.cservenak.streams.Coder;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import static lzma.sdk.lzma.Encoder.EMatchFinderTypeBT2;
import static lzma.sdk.lzma.Encoder.EMatchFinderTypeBT4;
public class LzmaEncoderWrapper
implements Coder
{
private final static byte[] MINUS_ONE = new byte[8];
static {
for (int i = 0; i < MINUS_ONE.length; ++i) {
MINUS_ONE[i] = (byte) -1;
}
}
private final Encoder encoder;
public LzmaEncoderWrapper(final Encoder encoder)
{
this.encoder = encoder;
}
@Override
public void code(final InputStream in, final OutputStream out)
throws IOException
{
encoder.writeCoderProperties(out);
// write -1 as "unknown" for file size
out.write(MINUS_ONE);
encoder.code(in, out, -1, -1, null);
}
/**
* A convenient builder that makes it easier to configure the LZMA encoder. Default values:
* <ul>
* <li>dictionary size: 23 (almost max, so is memory hungry)</li>
* <li>end marker mode: true</li>
* <li>match finder: BT4</li>
* <li>number of fast bytes: 0x20</li>
* </ul>
*/
public static class Builder
{
private int dictionnarySize = 1 << 23;
private boolean endMarkerMode = true;
private int matchFinder = EMatchFinderTypeBT4;
private int numFastBytes = 0x20;
public Builder useMaximalDictionarySize()
{
dictionnarySize = 1 << 28;
return this;
}
public Builder useMediumDictionarySize()
{
dictionnarySize = 1 << 15;
return this;
}
public Builder useMinimalDictionarySize()
{
dictionnarySize = 1;
return this;
}
public Builder useEndMarkerMode(boolean endMarkerMode)
{
this.endMarkerMode = endMarkerMode;
return this;
}
public Builder useBT4MatchFinder()
{
matchFinder = EMatchFinderTypeBT4;
return this;
}
public Builder useBT2MatchFinder()
{
matchFinder = EMatchFinderTypeBT2;
return this;
}
public Builder useMinimalFastBytes()
{
numFastBytes = 5;
return this;
}
public Builder useMediumFastBytes()
{
numFastBytes = 0x20;
return this;
}
public Builder useMaximalFastBytes()
{
numFastBytes = 273;
return this;
}
public LzmaEncoderWrapper build()
{
Encoder encoder = new Encoder();
encoder.setDictionarySize(dictionnarySize);
encoder.setEndMarkerMode(endMarkerMode);
encoder.setMatchFinder(matchFinder);
encoder.setNumFastBytes(numFastBytes);
return new LzmaEncoderWrapper(encoder);
}
}
}