org.apache.pdfbox.pdfparser

Class NonSequentialPDFParser

java.lang.Object

org.apache.pdfbox.pdfparser.BaseParser

org.apache.pdfbox.pdfparser.PDFParser

org.apache.pdfbox.pdfparser.NonSequentialPDFParser

public class NonSequentialPDFParser
extends PDFParser

PDFParser which first reads startxref and xref tables in order to know valid objects and parse only these objects. Thus it is closer to a conforming parser than the sequential reading of PDFParser. This class can be used as a PDFParser replacement. First parse() must be called before page objects can be retrieved, e.g. getPDDocument(). This class is a much enhanced version of QuickParser presented in PDFBOX-1104 by Jeremy Villalobos.

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	DEFAULT_TRAIL_BYTECOUNT
protected static char[]	EOF_MARKER
protected static char[]	OBJ_MARKER
protected SecurityHandler	securityHandler
protected static char[]	STARTXREF_MARKER
static String	SYSPROP_EOFLOOKUPRANGE
static String	SYSPROP_PARSEMINIMAL
static String	TMP_FILE_PREFIX

Fields inherited from class org.apache.pdfbox.pdfparser.PDFParser

xrefTrailerResolver

Fields inherited from class org.apache.pdfbox.pdfparser.BaseParser

DEF, document, ENDOBJ, ENDSTREAM, FORCE_PARSING, forceParsing, pdfSource, PROP_PUSHBACK_SIZE

Constructor Summary

Constructors

Constructor and Description
NonSequentialPDFParser(File file, RandomAccess raBuf) Constructs parser for given file using given buffer for temporary storage.
NonSequentialPDFParser(File file, RandomAccess raBuf, String decryptionPassword) Constructs parser for given file using given buffer for temporary storage.
NonSequentialPDFParser(InputStream input)
NonSequentialPDFParser(String filename) Constructs parser for given file using memory buffer.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	decrypt(COSString str, long objNr, long objGenNr) Decrypts given COSString.
protected void	deleteTempFile() Remove the temporary file.
PDPage	getPage(int pageNr) Returns the page requested with all the objects loaded into it.
int	getPageNumber() Returns the number of pages in a document.
PDDocument	getPDDocument() This will get the PD document that was parsed.
protected File	getPdfFile()
SecurityHandler	getSecurityHandler() Returns security handler of the document or null if document is not encrypted or parse() wasn't called before.
protected long	getStartxrefOffset() Looks for and parses startxref.
protected void	initialParse() The initial parse will first parse only the trailer, the xrefstart and all xref tables to have a pointer (offset) to all the pdf's objects.
protected int	lastIndexOf(char[] pattern, byte[] buf, int endOff) Searches last appearance of pattern within buffer.
void	parse() This will parse the stream and populate the COSDocument object.
protected COSStream	parseCOSStream(COSDictionary dic, RandomAccess file) This will read a COSStream from the input stream using length attribute within dictionary.
protected COSBase	parseObjectDynamically(COSObject obj, boolean requireExistingNotCompressedObj) This will parse the next object from the stream and add it to the local state.
protected COSBase	parseObjectDynamically(int objNr, int objGenNr, boolean requireExistingNotCompressedObj) This will parse the next object from the stream and add it to the local state.
protected void	readPattern(char[] pattern) Reads given pattern from BaseParser.pdfSource.
protected void	releasePdfSourceInputStream() Enable handling of alternative pdfSource implementation.
void	setEOFLookupRange(int byteCount) Sets how many trailing bytes of PDF file are searched for EOF marker and 'startxref' marker.
protected void	setPdfSource(long fileOffset) Sets BaseParser.pdfSource to start next parsing at given file offset.

Methods inherited from class org.apache.pdfbox.pdfparser.PDFParser

getDocument, getFDFDocument, isContinueOnError, parseStartXref, parseTrailer, parseXrefStream, parseXrefTable, setTempDirectory

Methods inherited from class org.apache.pdfbox.pdfparser.BaseParser

isClosing, isClosing, isEndOfName, isEOL, isEOL, isWhitespace, isWhitespace, parseBoolean, parseCOSArray, parseCOSDictionary, parseCOSName, parseCOSString, parseDirObject, readExpectedString, readInt, readLine, readString, readString, setDocument, skipSpaces

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SYSPROP_PARSEMINIMAL

public static final String SYSPROP_PARSEMINIMAL

See Also:

Constant Field Values

SYSPROP_EOFLOOKUPRANGE

public static final String SYSPROP_EOFLOOKUPRANGE

See Also:

Constant Field Values

DEFAULT_TRAIL_BYTECOUNT

protected static final int DEFAULT_TRAIL_BYTECOUNT

See Also:

Constant Field Values

EOF_MARKER

protected static final char[] EOF_MARKER

STARTXREF_MARKER

protected static final char[] STARTXREF_MARKER

OBJ_MARKER

protected static final char[] OBJ_MARKER

securityHandler

protected SecurityHandler securityHandler

TMP_FILE_PREFIX

public static final String TMP_FILE_PREFIX

See Also:

Constant Field Values

Constructor Detail

NonSequentialPDFParser

public NonSequentialPDFParser(String filename)
                       throws IOException

Constructs parser for given file using memory buffer.

Parameters:

filename - the filename of the pdf to be parsed

Throws:

IOException - If something went wrong.

NonSequentialPDFParser

public NonSequentialPDFParser(File file,
                      RandomAccess raBuf)
                       throws IOException

Constructs parser for given file using given buffer for temporary storage.

Parameters:

file - the pdf to be parsed

raBuf - the buffer to be used for parsing

Throws:

IOException - If something went wrong.

NonSequentialPDFParser

public NonSequentialPDFParser(File file,
                      RandomAccess raBuf,
                      String decryptionPassword)
                       throws IOException

Constructs parser for given file using given buffer for temporary storage.

Parameters:

file - the pdf to be parsed

raBuf - the buffer to be used for parsing

decryptionPassword - password to be used for decryption

Throws:

IOException - If something went wrong.

NonSequentialPDFParser

public NonSequentialPDFParser(InputStream input)
                       throws IOException

Throws:

IOException

Method Detail

setEOFLookupRange

public void setEOFLookupRange(int byteCount)

Sets how many trailing bytes of PDF file are searched for EOF marker and 'startxref' marker. If not set we use default value DEFAULT_TRAIL_BYTECOUNT.

In case system property SYSPROP_EOFLOOKUPRANGE is defined this value will be set on initialization but can be overwritten later.

Parameters:

byteCount - number of trailing bytes

initialParse

protected void initialParse()
                     throws IOException

The initial parse will first parse only the trailer, the xrefstart and all xref tables to have a pointer (offset) to all the pdf's objects. It can handle linearized pdfs, which will have an xref at the end pointing to an xref at the beginning of the file. Last the root object is parsed.

Throws:

IOException

setPdfSource

protected final void setPdfSource(long fileOffset)
                           throws IOException

Sets BaseParser.pdfSource to start next parsing at given file offset.

Throws:

IOException

releasePdfSourceInputStream

protected final void releasePdfSourceInputStream()
                                          throws IOException

Enable handling of alternative pdfSource implementation.

Throws:

IOException

getStartxrefOffset

protected final long getStartxrefOffset()
                                 throws IOException

Looks for and parses startxref. We first look for last '%%EOF' marker (within last DEFAULT_TRAIL_BYTECOUNT bytes (or range set via setEOFLookupRange(int)) and go back to find startxref.

Throws:

IOException

lastIndexOf

protected int lastIndexOf(char[] pattern,
              byte[] buf,
              int endOff)

Searches last appearance of pattern within buffer. Lookup before _lastOff and goes back until 0.

Parameters:

pattern - pattern to search for

buf - buffer to search pattern in

endOff - offset (exclusive) where lookup starts at

Returns:

start offset of pattern within buffer or -1 if pattern could not be found

readPattern

protected final void readPattern(char[] pattern)
                          throws IOException

Reads given pattern from BaseParser.pdfSource. Skipping whitespace at start and end.

Throws:

IOException - if pattern could not be read

parse

public void parse()
           throws IOException

This will parse the stream and populate the COSDocument object. This will close the stream when it is done parsing.

Overrides:

parse in class PDFParser

Throws:

IOException - If there is an error reading from the stream or corrupt data is found.

getPdfFile

protected File getPdfFile()

deleteTempFile

protected void deleteTempFile()

Remove the temporary file. A temporary file is created if this class is instantiated with an InputStream

getSecurityHandler

public SecurityHandler getSecurityHandler()

Returns security handler of the document or null if document is not encrypted or parse() wasn't called before.

Returns:

the security handler.

getPDDocument

public PDDocument getPDDocument()
                         throws IOException

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. Overwriting super method was necessary in order to set security handler.

Overrides:

getPDDocument in class PDFParser

Returns:

The document at the PD layer.

Throws:

IOException - If there is an error getting the document.

getPageNumber

public int getPageNumber()
                  throws IOException

Returns the number of pages in a document.

Returns:

the number of pages.

Throws:

IOException - if PAGES or other needed object is missing

getPage

public PDPage getPage(int pageNr)
               throws IOException

Returns the page requested with all the objects loaded into it.

Parameters:

pageNr - starts from 0 to the number of pages.

Returns:

the page with the given pagenumber.

Throws:

IOException - If something went wrong.

parseObjectDynamically

protected final COSBase parseObjectDynamically(COSObject obj,
                             boolean requireExistingNotCompressedObj)
                                        throws IOException

This will parse the next object from the stream and add it to the local state. This is taken from PDFParser and reduced to parsing an indirect object.

Parameters:

obj - object to be parsed (we only take object number and generation number for lookup start offset)

requireExistingNotCompressedObj - if true object to be parsed must not be contained within compressed stream

Returns:

the parsed object (which is also added to document object)

Throws:

IOException - If an IO error occurs.

parseObjectDynamically

protected COSBase parseObjectDynamically(int objNr,
                             int objGenNr,
                             boolean requireExistingNotCompressedObj)
                                  throws IOException

This will parse the next object from the stream and add it to the local state. This is taken from PDFParser and reduced to parsing an indirect object.

Parameters:

objNr - object number of object to be parsed

objGenNr - object generation number of object to be parsed

requireExistingNotCompressedObj - if true the object to be parsed must be defined in xref (comment: null objects may be missing from xref) and it must not be a compressed object within object stream (this is used to circumvent being stuck in a loop in a malicious PDF)

Returns:

the parsed object (which is also added to document object)

Throws:

IOException - If an IO error occurs.

decrypt

protected final void decrypt(COSString str,
           long objNr,
           long objGenNr)
                      throws IOException

Decrypts given COSString.

Throws:

IOException

parseCOSStream

protected COSStream parseCOSStream(COSDictionary dic,
                       RandomAccess file)
                            throws IOException

This will read a COSStream from the input stream using length attribute within dictionary. If length attribute is a indirect reference it is first resolved to get the stream length. This means we copy stream data without testing for 'endstream' or 'endobj' and thus it is no problem if these keywords occur within stream. We require 'endstream' to be found after stream data is read.

Overrides:

parseCOSStream in class BaseParser

Parameters:

dic - dictionary that goes with this stream.

file - file to write the stream to when reading.

Returns:

parsed pdf stream.

Throws:

IOException - if an error occurred reading the stream, like problems with reading length attribute, stream does not end with 'endstream' after data read, stream too short etc.