Package org.openpdf.renderer.decode

Class PDFDecoder

java.lang.Object

org.openpdf.renderer.decode.PDFDecoder

public class PDFDecoder
extends Object

A PDF Decoder encapsulates all the methods of decoding a stream of bytes based on all the various encoding methods.

You should use the decodeStream() method of this object rather than using any of the decoders directly.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	PDFDecoder.FilterSpec	Utility class for reading and storing the specification of Filters on a stream

Field Summary

Fields

Modifier and Type	Field	Description
static final Set<String>	DCT_FILTERS

Constructor Summary

Constructors

Modifier	Constructor	Description
private	PDFDecoder()	Creates a new instance of PDFDecoder

Method Summary

Modifier and Type	Method	Description
static ByteBuffer	decodeStream(PDFObject dict, ByteBuffer streamBuf, Set<String> filterLimits)	decode a byte[] stream using the filters specified in the object's dictionary (passed as argument 1).
private static String	getCryptFilterName(PDFObject param)	The name of the Crypt filter to apply
static boolean	isEncrypted(PDFObject dict)	Determines whether a stream is encrypted or not; note that encodings (e.g., Flate, LZW) are not considered encryptions.
static boolean	isLastFilter(PDFObject dict, Set<String> filters)

Methods inherited from class java.lang.Object

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

Field Details

DCT_FILTERS

public static final Set<String> DCT_FILTERS

Constructor Details

PDFDecoder

private PDFDecoder()

Creates a new instance of PDFDecoder

Method Details

isLastFilter

public static boolean isLastFilter(PDFObject dict,
 Set<String> filters)
                            throws IOException

Throws:

IOException

decodeStream

public static ByteBuffer decodeStream(PDFObject dict,
 ByteBuffer streamBuf,
 Set<String> filterLimits)
                               throws IOException

decode a byte[] stream using the filters specified in the object's dictionary (passed as argument 1).

Parameters:

dict - the dictionary associated with the stream

streamBuf - the data in the stream, as a byte buffer

Throws:

IOException

getCryptFilterName

private static String getCryptFilterName(PDFObject param)
                                  throws IOException

The name of the Crypt filter to apply

Parameters:

param - the parameters to the Crypt filter

Returns:

the name of the crypt filter to apply

Throws:

IOException - if there's a problem reading the objects

isEncrypted

public static boolean isEncrypted(PDFObject dict)
                           throws IOException

Determines whether a stream is encrypted or not; note that encodings (e.g., Flate, LZW) are not considered encryptions.

Parameters:

dict - the stream dictionary

Returns:

whether the stream is encrypted

Throws:

IOException - if the stream dictionary can't be read