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https://issues.apache.org/jira/browse/TIKA-679?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13059623#comment-13059623
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Nick Burch commented on TIKA-679:
---------------------------------
I've committed a first stab at a PRT parser in r1142817, inspired by your work.
It's able to get most view names, and all the text
My hunch is that the file is record based, with e0/e2/e3/f0 3f/bf being the
type marker. This then seems to be followed by the size / 8 mostly zero bytes
then size / 8 mostly zero bytes + another type + size. I can't guess enough to
figure it out though, so I've gone for a largely brute-force pattern matching
approach instead
Can you try with all your files, and report back if the matching rules are too
strict / not strict enough?
> Proposal for PRT Parser
> -----------------------
>
> Key: TIKA-679
> URL: https://issues.apache.org/jira/browse/TIKA-679
> Project: Tika
> Issue Type: Improvement
> Components: mime, parser
> Reporter: Troy Witthoeft
> Priority: Minor
> Labels: CAD, Mime, Parser, Prt, Tika
> Attachments: TikaTest.prt
>
> Original Estimate: 672h
> Remaining Estimate: 672h
>
> It would be nice if Tika had support for prt CAD files.
> A preliminary prt text extractor has been created.
> Any assistance further developing this code is appreciated.
> {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.
> * Searches for specific byte prefix, and outputs text from note entities
> * Does not support special DRAFT-PAK characters.
> */
> 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 {
> XHTMLContentHandler xhtml = new XHTMLContentHandler(handler,
> metadata);
> int[] prefix = new int[] {227, 63};
> //Looking for a prefix set of bytes {E3, 3F}
> int pos = 0;
>
> int read;
> while( (read = stream.read()) > -1) {
> // stream.read() moves to the next byte, and returns an integer value
> of the byte. a value of -1 signals the EOF
> if(read == prefix[pos]) {
> // is the last byte read the same as the
> first byte in the prefix?
> pos++;
>
> if(pos == prefix.length) {
>
> stream.skip(11);
> // skip the 13 bytes
> of the prefix which can vary.
> int length = stream.read();
> // Set the next byte equal to
> the length of text in the user input field, see PRT schema
> stream.skip(1);
>
> byte[] text = new byte[length];
> // a new byte array called text is
> created. It should contain an array of integer values of the user inputted
> text.
> IOUtils.readFully(stream, text);
>
> String str = new String(text, 0,
> text.length, "UTF-8"); // turn it into a string, but does not remove null
> termination, assumes it's found to be utf-8
> xhtml.startElement("p");
> xhtml.characters(str);
> xhtml.endElement("p");
> pos--;
> }
> }
> else {
> //Did not find the prefix. Reset the position
> counter.
> 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}
>
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