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* Copyright (c) 2003-2006, www.pdfbox.org
* All rights reserved.
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* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of pdfbox; nor the names of its
* contributors may be used to endorse or promote products derived from this
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*
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package org.pdfbox.pdfparser;
import java.io.File;
import java.io.InputStream;
import java.io.IOException;
import java.util.Iterator;
import org.pdfbox.cos.COSBase;
import org.pdfbox.cos.COSDictionary;
import org.pdfbox.cos.COSDocument;
import org.pdfbox.cos.COSObject;
import org.pdfbox.cos.COSStream;
import org.pdfbox.exceptions.WrappedIOException;
import org.pdfbox.io.RandomAccess;
import org.pdfbox.pdmodel.PDDocument;
import org.pdfbox.pdmodel.fdf.FDFDocument;
import org.pdfbox.persistence.util.COSObjectKey;
/**
* This class will handle the parsing of the PDF document.
*
* @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
* @version $Revision: 1.53 $
*/
public class PDFParser extends BaseParser
{
private static final int SPACE_BYTE = 32;
private static final String PDF_HEADER = "%PDF-";
private COSDocument document;
/**
* Temp file directory.
*/
private File tempDirectory = null;
private RandomAccess raf = null;
/**
* Constructor.
*
* @param input The input stream that contains the PDF document.
*
* @throws IOException If there is an error initializing the stream.
*/
public PDFParser( InputStream input ) throws IOException
{
this(input, null);
}
/**
* Constructor to allow control over RandomAccessFile.
* @param input The input stream that contains the PDF document.
* @param rafi The RandomAccessFile to be used in internal COSDocument
*
* @throws IOException If there is an error initializing the stream.
*/
public PDFParser(InputStream input, RandomAccess rafi)
throws IOException
{
super(input);
this.raf = rafi;
}
/**
* This is the directory where pdfbox will create a temporary file
* for storing pdf document stream in. By default this directory will
* be the value of the system property java.io.tmpdir.
*
* @param tmpDir The directory to create scratch files needed to store
* pdf document streams.
*/
public void setTempDirectory( File tmpDir )
{
tempDirectory = tmpDir;
}
/**
* This will prase the stream and create the PDF document. This will close
* the stream when it is done parsing.
*
* @throws IOException If there is an error reading from the stream.
*/
public void parse() throws IOException
{
try
{
if ( raf == null )
{
if( tempDirectory != null )
{
document = new COSDocument( tempDirectory );
}
else
{
document = new COSDocument();
}
}
else
{
document = new COSDocument( raf );
}
setDocument( document );
String header = readLine();
document.setHeaderString( header );
if( header.length() < PDF_HEADER.length()+1 )
{
throw new IOException( "Error: Header is corrupt '" + header + "'" );
}
//sometimes there are some garbage bytes in the header before the header
//actually starts, so lets try to find the header first.
int headerStart = header.indexOf( PDF_HEADER );
//greater than zero because if it is zero then
//there is no point of trimming
if( headerStart > 0 )
{
//trim off any leading characters
header = header.substring( headerStart, header.length() );
}
try
{
float pdfVersion = Float.parseFloat(
header.substring( PDF_HEADER.length(), Math.min( header.length(), PDF_HEADER.length()+3) ) );
document.setVersion( pdfVersion );
}
catch( NumberFormatException e )
{
throw new IOException( "Error getting pdf version:" + e );
}
skipHeaderFillBytes();
Object nextObject;
boolean wasLastParsedObjectAnXref = false;
try
{
while( (nextObject = parseObject()) != null )
{
if( nextObject instanceof PDFXref )
{
PDFXref xref = (PDFXref)nextObject;
addXref(xref);
wasLastParsedObjectAnXref = true;
}
else
{
wasLastParsedObjectAnXref = false;
}
skipSpaces();
}
if( document.getTrailer() == null )
{
COSDictionary trailer = new COSDictionary();
Iterator xrefIter = document.getObjectsByType( "XRef" ).iterator();
while( xrefIter.hasNext() )
{
COSStream next = (COSStream)((COSObject)xrefIter.next()).getObject();
trailer.addAll( next );
}
document.setTrailer( trailer );
}
if( !document.isEncrypted() )
{
document.dereferenceObjectStreams();
}
}
catch( IOException e )
{
if( wasLastParsedObjectAnXref )
{
//Then we assume that there is just random garbage after
//the xref, not sure why the PDF spec allows this but it does.
}
else
{
//some other error so just pass it along
throw e;
}
}
}
catch( Throwable t )
{
//so if the PDF is corrupt then close the document and clear
//all resources to it
if( document != null )
{
document.close();
}
if( t instanceof IOException )
{
throw (IOException)t;
}
else
{
throw new WrappedIOException( t );
}
}
finally
{
pdfSource.close();
}
}
/**
* This will skip a header's binary fill bytes. This is in accordance to
* PDF Specification 1.5 pg 68 section 3.4.1 "Syntax.File Structure.File Header"
*
* @throws IOException If there is an error reading from the stream.
*/
protected void skipHeaderFillBytes() throws IOException
{
skipSpaces();
int c = pdfSource.peek();
if( !Character.isDigit( (char)c ) )
{
// Fill bytes conform with PDF reference (but without comment sign)
// => skip until EOL
readLine();
}
// else: no fill bytes
}
/**
* This will get the document that was parsed. parse() must be called before this is called.
* When you are done with this document you must call close() on it to release
* resources.
*
* @return The document that was parsed.
*
* @throws IOException If there is an error getting the document.
*/
public COSDocument getDocument() throws IOException
{
if( document == null )
{
throw new IOException( "You must call parse() before calling getDocument()" );
}
return document;
}
/**
* This will get the PD document that was parsed. When you are done with
* this document you must call close() on it to release resources.
*
* @return The document at the PD layer.
*
* @throws IOException If there is an error getting the document.
*/
public PDDocument getPDDocument() throws IOException
{
return new PDDocument( getDocument() );
}
/**
* This will get the FDF document that was parsed. When you are done with
* this document you must call close() on it to release resources.
*
* @return The document at the PD layer.
*
* @throws IOException If there is an error getting the document.
*/
public FDFDocument getFDFDocument() throws IOException
{
return new FDFDocument( getDocument() );
}
/**
* This will parse a document object from the stream.
*
* @return The parsed object.
*
* @throws IOException If an IO error occurs.
*/
private Object parseObject() throws IOException
{
Object object = null;
skipSpaces();
char peekedChar = (char)pdfSource.peek();
while( peekedChar == 'e' )
{
//there are times when there are multiple endobj, so lets
//just read them and move on.
readString();
skipSpaces();
peekedChar = (char)pdfSource.peek();
}
if( pdfSource.isEOF() )
{
//"Skipping because of EOF" );
//end of file we will return a null object and call it a day.
}
else if( peekedChar == 'x' ||
peekedChar == 't' ||
peekedChar == 's')
{
//System.out.println( "parseObject() parsing xref" );
//FDF documents do not always have the xref
if( peekedChar == 'x' || peekedChar == 't' )
{
object = parseXrefSection();
}
//if peeked char is xref or startxref
if( peekedChar == 'x' || peekedChar == 's')
{
skipSpaces();
while( pdfSource.peek() == 'x' )
{
parseXrefSection();
}
String startxref = readString();
if( !startxref.equals( "startxref" ) )
{
throw new IOException( "expected='startxref' actual='" + startxref + "' " + pdfSource );
}
skipSpaces();
//read some integer that is in the stream but PDFBox doesn't use
readInt();
}
//This MUST be readLine because readString strips out comments
//and it will think that %% is a comment in from of the EOF
String eof = readExpectedString( "%%EOF" );
if( eof.indexOf( "%%EOF" )== -1 && !pdfSource.isEOF() )
{
throw new IOException( "expected='%%EOF' actual='" + eof + "' next=" + readString() +
" next=" +readString() );
}
else if( !pdfSource.isEOF() )
{
//we might really be at the end of the file, there might just be some crap at the
//end of the file.
pdfSource.fillBuffer();
if( pdfSource.available() < 1000 )
{
//We need to determine if we are at the end of the file.
byte[] data = new byte[ 1000 ];
int amountRead = pdfSource.read( data );
if( amountRead != -1 )
{
pdfSource.unread( data, 0, amountRead );
}
boolean atEndOfFile = true;//we assume yes unless we find another.
for( int i=0; i<amountRead-3 && atEndOfFile; i++ )
{
atEndOfFile = !(data[i] == 'E' &&
data[i+1] == 'O' &&
data[i+2] == 'F' );
}
if( atEndOfFile )
{
while( pdfSource.read( data, 0, data.length ) != -1 )
{
//read until done.
}
}
}
}
}
else
{
int number = -1;
int genNum = -1;
String objectKey = null;
boolean missingObjectNumber = false;
try
{
char peeked = (char)pdfSource.peek();
if( peeked == '<' )
{
missingObjectNumber = true;
}
else
{
number = readInt();
}
}
catch( IOException e )
{
//ok for some reason "GNU Ghostscript 5.10" puts two endobj
//statements after an object, of course this is nonsense
//but because we want to support as many PDFs as possible
//we will simply try again
number = readInt();
}
if( !missingObjectNumber )
{
skipSpaces();
genNum = readInt();
objectKey = readString( 3 );
//System.out.println( "parseObject() num=" + number +
//" genNumber=" + genNum + " key='" + objectKey + "'" );
if( !objectKey.equals( "obj" ) )
{
throw new IOException("expected='obj' actual='" + objectKey + "' " + pdfSource );
}
}
else
{
number = -1;
genNum = -1;
}
skipSpaces();
COSBase pb = parseDirObject();
String endObjectKey = readString();
if( endObjectKey.equals( "stream" ) )
{
pdfSource.unread( endObjectKey.getBytes() );
pdfSource.unread( ' ' );
if( pb instanceof COSDictionary )
{
pb = parseCOSStream( (COSDictionary)pb, getDocument().getScratchFile() );
}
else
{
// this is not legal
// the combination of a dict and the stream/endstream forms a complete stream object
throw new IOException("stream not preceded by dictionary");
}
endObjectKey = readString();
}
COSObjectKey key = new COSObjectKey( number, genNum );
COSObject pdfObject = document.getObjectFromPool( key );
object = pdfObject;
pdfObject.setObject(pb);
if( !endObjectKey.equals( "endobj" ) )
{
if( !pdfSource.isEOF() )
{
try
{
//It is possible that the endobj is missing, there
//are several PDFs out there that do that so skip it and move on.
Float.parseFloat( endObjectKey );
pdfSource.unread( SPACE_BYTE );
pdfSource.unread( endObjectKey.getBytes() );
}
catch( NumberFormatException e )
{
//we will try again incase there was some garbage which
//some writers will leave behind.
String secondEndObjectKey = readString();
if( !secondEndObjectKey.equals( "endobj" ) )
{
if( isClosing() )
{
//found a case with 17506.pdf object 41 that was like this
//41 0 obj [/Pattern /DeviceGray] ] endobj
//notice the second array close, here we are reading it
//and ignoring and attempting to continue
pdfSource.read();
}
skipSpaces();
String thirdPossibleEndObj = readString();
if( !thirdPossibleEndObj.equals( "endobj" ) )
{
throw new IOException("expected='endobj' firstReadAttempt='" + endObjectKey + "' " +
"secondReadAttempt='" + secondEndObjectKey + "' " + pdfSource);
}
}
}
}
}
skipSpaces();
}
//System.out.println( "parsed=" + object );
return object;
}
/**
* This will parse the xref table and trailers from the stream.
*
* @return a new PDFXref
*
* @throws IOException If an IO error occurs.
*/
protected PDFXref parseXrefSection() throws IOException
{
int[] params = new int[2];
parseXrefTable(params);
parseTrailer();
return new PDFXref(params[0], params[1]);
}
/**
* This will parse the xref table from the stream.
*
* It stores the starting object number and the count
*
* @param params The start and count parameters
*
* @throws IOException If an IO error occurs.
*/
protected void parseXrefTable(int[] params) throws IOException
{
String nextLine = null;
nextLine = readLine();
if( nextLine.equals( "xref" ) )
{
params[0] = readInt();
params[1] = readInt();
nextLine = readString();
}
skipSpaces();
while( !nextLine.equals( "trailer" ) && !pdfSource.isEOF() && !isEndOfName((char)pdfSource.peek()))
{
//skip past all the xref entries.
nextLine = readString();
skipSpaces();
}
skipSpaces();
}
private void parseTrailer() throws IOException
{
COSDictionary parsedTrailer = parseCOSDictionary();
COSDictionary docTrailer = document.getTrailer();
if( docTrailer == null )
{
document.setTrailer( parsedTrailer );
}
else
{
docTrailer.addAll( parsedTrailer );
}
}
}