org.apache.poi.xssf.streaming.OpcOutputStream Maven / Gradle / Ivy
/* ====================================================================
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You 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 org.apache.poi.xssf.streaming;
import org.apache.poi.xssf.streaming.Zip64Impl.Entry;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.zip.*;
/**
* ZIP64 OutputStream implementation compatible with MS Excel.
* Drop in replacement for `java.util.ZipOutputStream`.
*
* For more information see https://github.com/rzymek/opczip
*/
class OpcOutputStream extends DeflaterOutputStream {
private final Zip64Impl spec;
private final List entries = new ArrayList<>();
private final CRC32 crc = new CRC32();
private Entry current;
private int written = 0;
private boolean finished = false;
/**
* Creates ZIP64 output stream
*
* @param out target stream to write compressed data to
*/
public OpcOutputStream(OutputStream out) {
super(out, new Deflater(Deflater.DEFAULT_COMPRESSION, true));
this.spec = new Zip64Impl(out);
}
/**
* @see Deflater#setLevel(int)
*/
public void setLevel(int level) {
super.def.setLevel(level);
}
/**
* @see ZipOutputStream#putNextEntry(ZipEntry)
*/
public void putNextEntry(String name) throws IOException {
if (current != null) {
closeEntry();
}
current = new Entry(name);
current.offset = written;
written += spec.writeLFH(current);
entries.add(current);
}
/**
* @throws IllegalStateException if no entry found
* @see ZipOutputStream#closeEntry()
*/
public void closeEntry() throws IOException {
if (current == null) {
throw new IllegalStateException("not current zip current");
}
def.finish();
while (!def.finished()) {
deflate();
}
current.size = def.getBytesRead();
current.compressedSize = Math.toIntExact(def.getBytesWritten());
current.crc = crc.getValue();
written += current.compressedSize;
written += spec.writeDAT(current);
current = null;
def.reset();
crc.reset();
}
/**
* @see ZipOutputStream#finish()
*/
@Override
public void finish() throws IOException {
if(finished){
return;
}
if(current != null) {
closeEntry();
}
int offset = written;
for (Entry entry : entries) {
written += spec.writeCEN(entry);
}
written += spec.writeEND(entries.size(), offset, written - offset);
finished = true;
}
/**
* @see ZipOutputStream#write(byte[], int, int)
*/
@Override
public synchronized void write(byte[] b, int off, int len) throws IOException {
if (off < 0 || len < 0 || off > b.length - len) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return;
}
super.write(b, off, len);
crc.update(b, off, len);
}
/**
* @see ZipOutputStream#close()
*/
@Override
public void close() throws IOException {
finish();
out.close();
}
}