Proposal for PRT Parser
-----------------------
Key: TIKA-679
URL: https://issues.apache.org/jira/browse/TIKA-679
Project: Tika
Issue Type: Improvement
Components: mime, parser
Affects Versions: 0.9
Reporter: Troy Witthoeft
Priority: Minor
It would be nice if Tika had support for prt CAD files.
A preliminary prt text extractor has been created.
{code:title=PRTParser.java|borderStyle=solid}
package org.apache.tika.parser.prt;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.Collections;
import java.util.Set;
import org.apache.poi.util.IOUtils;
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;
/**
* Description: PRT (CAD Drawing) parser. This is a very basic parser.
* It also currently sets some dummy metadata.
*/
public class PRTParser implements Parser {
private static final Set<MediaType> SUPPORTED_TYPES =
Collections.singleton(MediaType.application("prt"));
public static final String PRT_MIME_TYPE = "application/prt";
public Set<MediaType> getSupportedTypes(ParseContext context) {
return SUPPORTED_TYPES;
}
public void parse(
InputStream stream, ContentHandler handler,
Metadata metadata, ParseContext context)
throws IOException, SAXException, TikaException {
byte[] prefix = new byte[]
{0x01, 0x1F}; //
int pos = 0;
int read;
while( (read = stream.read()) >
-1) { // Reads the next single byte of data (returns byte pos) until you hit
the EOF
if(read == prefix[pos]) {
// If the byte being read is
pos++;
if(pos ==
prefix.length) {
// found it!
int length =
stream.read();
int unknown =
stream.read();
byte[] text = new
byte[length];
IOUtils.readFully(stream, text); //reads a selected byte array from the
InputStream
// turn it into a
string, removing null termination
// assumes it's found
to be utf-8
String str = new
String(text, 0, text.length, "UTF-8");
XHTMLContentHandler
xhtml = new XHTMLContentHandler(handler, metadata);
xhtml.startElement("p");
xhtml.characters(str);
xhtml.endElement("p");
pos--;
}
} else {
pos = 0;
}
}
}
/**
* @deprecated This method will be removed in Apache Tika 1.0.
*/
public void parse(
InputStream stream, ContentHandler handler, Metadata
metadata)
throws IOException, SAXException, TikaException {
parse(stream, handler, metadata, new ParseContext());
}
}
{code}
I am looking for assistance in improving this code. I am in the process of
picking apart the prt file structure.
Here are my findings.
The file header contains, a magic mime type, file creation date, and file
description.
The magic mime type can be identified with <match value="0M3C" type="string"
offset="8" />
If present, the file creation date is after the identifier. It is in format
YYYYMMDDhhmm. It is always in the same address, 0x001Eh-0x002Ah OR the
31st-43rd bytes.
If present, the user entered file description IMMEDIATELY follows date. Max
chars is 498. It is always at the same address, 0x002Bh-0x021Ch OR the
43rd-540th bytes. Terminated with [00][01][C8]
The goal is to extract the user entered text. User text is marked by a prefix
of 42 bytes. Newest entries are at the top of the file.
The prefix is always marked by the presence of six 3's and [E3][3F], that is
followed by 10 variable bytes, then a byte signifying the length of the user
input text + 1, and a null.
GUIDE
[33][33][33][33][33][33][E3][3F][0#][00][00][0#][00][00][0#][0#][0#][1F][ln][00][USERINPUT
TEXT][00][xx]
EXAMPLE
[33][33][33][33][33][33][E3][3F][00][00][00][00][00][00][00][02][01][1F][05][00][54][49][4B][41][00][0B]
= TIKA
Any pointers on how to improve the code is appreciated.
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