/*
* Copyright (c) 2015 Villu Ruusmann
*
* This file is part of JPMML-SkLearn
*
* JPMML-SkLearn is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* JPMML-SkLearn 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with JPMML-SkLearn. If not, see <http://www.gnu.org/licenses/>.
*/
package org.jpmml.sklearn;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.util.zip.InflaterInputStream;
import com.google.common.io.ByteStreams;
import com.google.common.io.CountingInputStream;
public class CompressedInputStreamStorage extends InputStreamStorage {
public CompressedInputStreamStorage(InputStream is) throws IOException {
super(init(new PushbackInputStream(is, 2)));
}
static
private InputStream init(PushbackInputStream is) throws IOException {
byte[] magic = new byte[2];
ByteStreams.readFully(is, magic);
is.unread(magic);
// Joblib 0.10.0 and newer
if(magic[0] == 'x'){
return initZlib(is);
} else
// Joblib 0.9.4 and earlier
if(magic[0] == 'Z' && magic[1] == 'F'){
return initCompat(is);
} else
{
throw new IOException();
}
}
static
private InputStream initZlib(PushbackInputStream is){
InflaterInputStream zlibIs = new InflaterInputStream(is);
return zlibIs;
}
static
private InputStream initCompat(PushbackInputStream is) throws IOException {
byte[] headerBytes = new byte[2 + 19];
ByteStreams.readFully(is, headerBytes);
String header = new String(headerBytes);
if(!header.startsWith("ZF0x")){
throw new IOException();
}
// Remove trailing whitespace
header = header.trim();
final
long expectedSize = Long.parseLong(header.substring(4), 16);
// Consume the first byte
int firstByte = is.read();
if(firstByte < 0){
return is;
} // End if
// If the first byte is not a space character, then make it available for reading again
if(firstByte != '\u0020'){
is.unread(firstByte);
}
InflaterInputStream zlibIs = new InflaterInputStream(is);
InputStream result = new FilterInputStream(new CountingInputStream(zlibIs)){
private boolean closed = false;
@Override
public void close() throws IOException {
if(this.closed){
return;
}
this.closed = true;
long size = ((CountingInputStream)super.in).getCount();
super.close();
if(size != expectedSize){
throw new IOException("Expected " + expectedSize + " byte(s) of uncompressed data, got " + size + " byte(s)");
}
}
};
return result;
}
}