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/*
* 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.tika.parser.dwg;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.Set;
import org.apache.poi.util.IOUtils;
import org.apache.poi.util.LittleEndian;
import org.apache.poi.util.StringUtil;
import org.apache.tika.exception.TikaException;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.parser.Parser;
import org.apache.tika.sax.XHTMLContentHandler;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
/**
* DWG (CAD Drawing) parser. This is a very basic parser, which just
* looks for bits of the headers.
* Note that we use Apache POI for various parts of the processing, as
* lots of the low level string/int/short concepts are the same.
*/
public class DWGParser implements Parser {
private static MediaType TYPE = MediaType.image("vnd.dwg");
public Set getSupportedTypes(ParseContext context) {
return Collections.singleton(TYPE);
}
/** The order of the fields in the header */
private static String[] HEADER_PROPERTIES_ENTRIES = {
Metadata.TITLE,
Metadata.SUBJECT,
Metadata.AUTHOR,
Metadata.KEYWORDS,
Metadata.COMMENTS,
Metadata.LAST_AUTHOR,
null, // Unknown?
Metadata.RELATION, // Hyperlink
};
public void parse(
InputStream stream, ContentHandler handler,
Metadata metadata, ParseContext context)
throws IOException, TikaException, SAXException {
// First up, which version of the format are we handling?
byte[] header = new byte[128];
IOUtils.readFully(stream, header);
String version = new String(header, 0, 6, "US-ASCII");
XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata);
xhtml.startDocument();
if (version.equals("AC1018")) {
metadata.set(Metadata.CONTENT_TYPE, TYPE.toString());
if(skipToPropertyInfoSection(stream, header)){
get2004Props(stream,metadata,xhtml);
}
} else if (version.equals("AC1021") || version.equals("AC1024")) {
metadata.set(Metadata.CONTENT_TYPE, TYPE.toString());
skipToPropertyInfoSection(stream, header);
get2007and2010Props(stream,metadata,xhtml);
} else {
throw new TikaException(
"Unsupported AutoCAD drawing version: " + version);
}
xhtml.endDocument();
}
/**
* Stored as US-ASCII
*/
private void get2004Props(
InputStream stream, Metadata metadata, XHTMLContentHandler xhtml)
throws IOException, SAXException {
for (int i = 0; i < HEADER_PROPERTIES_ENTRIES.length; i++) {
int stringLen = LittleEndian.readUShort(stream);
byte[] stringData = new byte[stringLen];
IOUtils.readFully(stream, stringData);
// Often but not always null terminated
if (stringData[stringLen-1] == 0) {
stringLen--;
}
String headerValue =
StringUtil.getFromCompressedUnicode(stringData, 0, stringLen);
handleHeader(i, headerValue, metadata, xhtml);
}
}
/**
* Stored as UCS2, so 16 bit "unicode"
*/
private void get2007and2010Props(
InputStream stream, Metadata metadata, XHTMLContentHandler xhtml)
throws IOException, SAXException {
for (int i = 0; i < HEADER_PROPERTIES_ENTRIES.length; i++) {
int stringLen = LittleEndian.readUShort(stream);
byte[] stringData = new byte[stringLen * 2];
IOUtils.readFully(stream, stringData);
String headerValue = StringUtil.getFromUnicodeLE(stringData);
handleHeader(i, headerValue, metadata, xhtml);
}
}
private void handleHeader(
int headerNumber, String value, Metadata metadata,
XHTMLContentHandler xhtml) throws SAXException {
if(value == null || value.length() == 0) {
return;
}
// Some strings are null terminated
if(value.charAt(value.length()-1) == 0) {
value = value.substring(0, value.length()-1);
}
String headerProp = HEADER_PROPERTIES_ENTRIES[headerNumber];
if(headerProp != null) {
metadata.set(headerProp, value);
}
xhtml.element("p", value);
}
private boolean skipToPropertyInfoSection(InputStream stream, byte[] header)
throws IOException {
// The offset is stored in the header from 0x20 onwards
long offsetToSection = LittleEndian.getLong(header, 0x20);
long toSkip = offsetToSection - header.length;
if(offsetToSection == 0){
return false;
}
while (toSkip > 0) {
byte[] skip = new byte[Math.min((int) toSkip, 0x4000)];
IOUtils.readFully(stream, skip);
toSkip -= skip.length;
}
return true;
}
public void parse(
InputStream stream, ContentHandler handler, Metadata metadata)
throws IOException, SAXException, TikaException {
parse(stream, handler, metadata, new ParseContext());
}
}
