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Apache POI - Java API To Access Microsoft Format Files
/* ====================================================================
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.poifs.filesystem;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import org.apache.commons.io.input.UnsynchronizedByteArrayInputStream;
import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
import org.apache.poi.util.IOUtils;
import org.apache.poi.util.LittleEndianByteArrayInputStream;
import org.apache.poi.util.LittleEndianConsts;
import org.apache.poi.util.LittleEndianInput;
import org.apache.poi.util.LittleEndianOutputStream;
import org.apache.poi.util.StringUtil;
/**
* Represents an Ole10Native record which is wrapped around certain binary
* files being embedded in OLE2 documents.
*
* Ole10Native objects come in different shapes:
*
* - unparsed: we can't identify it's structure
* - compact: same as unparsed but with a leading flag
* - parsed - Ole-Class "Package": data + ASCII label,command,filename
* - parsed - Ole-Class "Package2": as above plus UTF16 label,command,filename
*
*/
@SuppressWarnings("unused")
public class Ole10Native {
public static final String OLE10_NATIVE = "\u0001Ole10Native";
private static final Charset UTF8 = StandardCharsets.UTF_8;
// arbitrarily selected; may need to increase
private static final int DEFAULT_MAX_RECORD_LENGTH = 100_000_000;
private static int MAX_RECORD_LENGTH = DEFAULT_MAX_RECORD_LENGTH;
// arbitrarily selected; may need to increase
private static final int DEFAULT_MAX_STRING_LENGTH = 1024;
private static int MAX_STRING_LENGTH = DEFAULT_MAX_STRING_LENGTH;
/**
* Default content of the \u0001Ole entry
*/
private static final byte[] OLE_MARKER_BYTES =
{1, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
private static final String OLE_MARKER_NAME = "\u0001Ole";
// 4 bytes, total size of record not including this field
private int totalSize;
// 2 bytes, unknown, mostly [02 00]
private short flags1 = 2;
// ASCIIZ, stored in this field without the terminating zero
private String label;
// ASCIIZ, stored in this field without the terminating zero
private String fileName;
// 2 bytes, unknown, mostly [00 00]
private short flags2;
// see below
private short unknown1 = 3;
// ASCIIZ, stored in this field without the terminating zero
private String command;
// varying size, the actual native data
private byte[] dataBuffer;
// UTF16-LE String with leading length
private String command2;
// UTF16-LE String with leading length
private String label2;
// UTF16-LE String with leading length
private String fileName2;
/**
* the field encoding mode - merely a try-and-error guess ...
**/
private enum EncodingMode {
/**
* the data is stored in parsed format - including label, command, etc.
*/
parsed,
/**
* the data is stored raw after the length field
*/
unparsed,
/**
* the data is stored raw after the length field and the flags1 field
*/
compact
}
private EncodingMode mode;
/**
* Creates an instance of this class from an embedded OLE Object. The OLE Object is expected
* to include a stream "{01}Ole10Native" which contains the actual
* data relevant for this class.
*
* @param poifs POI Filesystem object
* @return Returns an instance of this class
* @throws IOException on IO error
* @throws Ole10NativeException on invalid or unexcepted data format
*/
public static Ole10Native createFromEmbeddedOleObject(POIFSFileSystem poifs) throws IOException, Ole10NativeException {
return createFromEmbeddedOleObject(poifs.getRoot());
}
/**
* Creates an instance of this class from an embedded OLE Object. The OLE Object is expected
* to include a stream "{01}Ole10Native" which contains the actual
* data relevant for this class.
*
* @param directory POI Filesystem object
* @return Returns an instance of this class
* @throws IOException on IO error
* @throws Ole10NativeException on invalid or unexcepted data format
*/
public static Ole10Native createFromEmbeddedOleObject(DirectoryNode directory) throws IOException, Ole10NativeException {
DocumentEntry nativeEntry = (DocumentEntry) directory.getEntry(OLE10_NATIVE);
try (DocumentInputStream dis = directory.createDocumentInputStream(nativeEntry)) {
byte[] data = IOUtils.toByteArray(dis, nativeEntry.getSize(), MAX_RECORD_LENGTH);
return new Ole10Native(data, 0);
}
}
/**
* @param length the max record length allowed for Ole10Native
*/
public static void setMaxRecordLength(int length) {
MAX_RECORD_LENGTH = length;
}
/**
* @return the max record length allowed for Ole10Native
*/
public static int getMaxRecordLength() {
return MAX_RECORD_LENGTH;
}
/**
* @param length the max string length allowed for Ole10Native
*/
public static void setMaxStringLength(int length) {
MAX_STRING_LENGTH = length;
}
/**
* @return the max string length allowed for Ole10Native
*/
public static int getMaxStringLength() {
return MAX_STRING_LENGTH;
}
/**
* Creates an instance and fills the fields based on ... the fields
*/
public Ole10Native(String label, String filename, String command, byte[] data) {
setLabel(label);
setFileName(filename);
setCommand(command);
command2 = command;
setDataBuffer(data);
mode = EncodingMode.parsed;
}
/**
* Creates an instance and fills the fields based on the data in the given buffer.
*
* @param data The buffer containing the Ole10Native record
* @param offset The start offset of the record in the buffer
* @throws Ole10NativeException on invalid or unexcepted data format
*/
public Ole10Native(final byte[] data, final int offset) throws Ole10NativeException {
LittleEndianByteArrayInputStream leis = new LittleEndianByteArrayInputStream(data, offset);
totalSize = leis.readInt();
leis.limit(totalSize + LittleEndianConsts.INT_SIZE);
leis.mark(0);
try {
flags1 = leis.readShort();
if (flags1 == 2) {
leis.mark(0);
// some files like equations don't have a valid filename,
// but somehow encode the formula right away in the ole10 header
boolean validFileName = !Character.isISOControl(leis.readByte());
leis.reset();
if (validFileName) {
readParsed(leis);
} else {
readCompact(leis);
}
} else {
leis.reset();
readUnparsed(leis);
}
} catch (IOException e) {
throw new Ole10NativeException("Invalid Ole10Native", e);
}
}
private void readParsed(LittleEndianByteArrayInputStream leis) throws Ole10NativeException, IOException {
mode = EncodingMode.parsed;
label = readAsciiZ(leis);
fileName = readAsciiZ(leis);
flags2 = leis.readShort();
unknown1 = leis.readShort();
command = readAsciiLen(leis);
dataBuffer = IOUtils.toByteArray(leis, leis.readInt(), MAX_RECORD_LENGTH);
leis.mark(0);
short lowSize = leis.readShort();
if (lowSize != 0) {
leis.reset();
command2 = readUtf16(leis);
label2 = readUtf16(leis);
fileName2 = readUtf16(leis);
}
}
private void readCompact(LittleEndianByteArrayInputStream leis) throws IOException {
mode = EncodingMode.compact;
dataBuffer = IOUtils.toByteArray(leis, totalSize - LittleEndianConsts.SHORT_SIZE, MAX_RECORD_LENGTH);
}
private void readUnparsed(LittleEndianByteArrayInputStream leis) throws IOException {
mode = EncodingMode.unparsed;
dataBuffer = IOUtils.toByteArray(leis, totalSize, MAX_RECORD_LENGTH);
}
/**
* Add the \1OLE marker entry, which is not the Ole10Native entry.
* Beside this "\u0001Ole" record there were several other records, e.g. CompObj,
* OlePresXXX, but it seems, that they aren't necessary
*/
public static void createOleMarkerEntry(final DirectoryEntry parent) throws IOException {
if (!parent.hasEntry(OLE_MARKER_NAME)) {
parent.createDocument(OLE_MARKER_NAME, new UnsynchronizedByteArrayInputStream(OLE_MARKER_BYTES));
}
}
/**
* Add the \1OLE marker entry, which is not the Ole10Native entry.
* Beside this "\u0001Ole" record there were several other records, e.g. CompObj,
* OlePresXXX, but it seems, that they aren't necessary
*/
public static void createOleMarkerEntry(final POIFSFileSystem poifs) throws IOException {
createOleMarkerEntry(poifs.getRoot());
}
/**
* Read zero terminated string (ASCIIZ).
*/
private static String readAsciiZ(LittleEndianInput is) throws Ole10NativeException {
// arbitrary sized buffer - not sure how big strings can get in an Ole10 record
byte[] buf = new byte[MAX_STRING_LENGTH];
for (int i=0; i