com.orsonpdf.filter

Class Ascii85OutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

com.orsonpdf.filter.Ascii85OutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

public class Ascii85OutputStream
extends java.io.FilterOutputStream

An ascii85 encoder, implemented as an OutputStream.

Call flush() or close() to properly close the ascii85 block. The block must be closed for the encoded data to be valid. Do not call flush() before you intend to end the ascii85 block. Multiple ascii85 blocks may be encoded by calling flush() and then writing more bytes to the stream.

Note that if you use the constructor with the useSpaceCompression option, the encoded text will be shorter when there are many consecutive space characters in the encoded data, but it will not be compatible with Adobe's ascii85 implementation. It makes sense to use this option if interoperability with other ascii85 implementations is not a requirement.

Author:

Ben Upsavs

Field Summary

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

Constructors

Constructor and Description
Ascii85OutputStream(java.io.OutputStream out) Creates an output stream to encode ascii85 data, using a default line with of 72 characters and not using the space character compression option.
Ascii85OutputStream(java.io.OutputStream out, boolean useSpaceCompression) Creates an output stream to encode ascii85 data, using a default line width of 72 characters.
Ascii85OutputStream(java.io.OutputStream out, int width, boolean useSpaceCompression) Creates an output stream to encode ascii85 data.

Method Summary

Modifier and Type	Method and Description
void	flush() Adds the closing block and flushes the underlying output stream.
void	write(int b) Writes a single byte to the stream.
void	writeUnencoded(byte[] b) Writes bytes to the underlying output stream, unencoded.
void	writeUnencoded(byte[] b, int off, int len) Writes bytes to the underlying output stream, unencoded.
void	writeUnencoded(int b) Writes a single byte to the underlying output stream, unencoded.

Methods inherited from class java.io.FilterOutputStream

close, write, write

Methods inherited from class java.lang.Object

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

Constructor Detail

Ascii85OutputStream

public Ascii85OutputStream(java.io.OutputStream out)

Creates an output stream to encode ascii85 data, using a default line with of 72 characters and not using the space character compression option. Call flush() to add the padding and end the ascii85 block.

Parameters:

out - the output stream.

Ascii85OutputStream

public Ascii85OutputStream(java.io.OutputStream out,
                           boolean useSpaceCompression)

Creates an output stream to encode ascii85 data, using a default line width of 72 characters. Call flush() to end the ascii85 block.

Parameters:

out - the output stream.

useSpaceCompression - Whether to use space character compression in the output.

Ascii85OutputStream

public Ascii85OutputStream(java.io.OutputStream out,
                           int width,
                           boolean useSpaceCompression)

Creates an output stream to encode ascii85 data. Call flush() to end the ascii85 block.

Parameters:

out - the output stream.

width - The maximum line width of the encoded output text. Whitespace characters are ignored when decoding.

useSpaceCompression - Whether to use space character compression in the output.

Method Detail

write

public void write(int b)
           throws java.io.IOException

Writes a single byte to the stream. See OutputStream.write(int b) for details.

Overrides:

write in class java.io.FilterOutputStream

Parameters:

b - The byte to encode.

Throws:

java.io.IOException - If an I/O error occurs in the underlying output stream.

writeUnencoded

public void writeUnencoded(int b)
                    throws java.io.IOException

Writes a single byte to the underlying output stream, unencoded. If done improperly, this may corrupt the ascii85 data stream. Writing a byte using this method may cause the line length to increase since the line length counter will not be updated by this method.

Parameters:

b - The byte to write.

Throws:

java.io.IOException - If the underlying output stream has an I/O error.

writeUnencoded

public void writeUnencoded(byte[] b)
                    throws java.io.IOException

Writes bytes to the underlying output stream, unencoded. If done improperly, this may corrupt the ascii85 data stream. Writing bytes using this method may cause the line length to increase since the line length counter will not be updated by this method.

Parameters:

b - The bytes to write.

Throws:

java.io.IOException - If the underlying output stream has an I/O error.

writeUnencoded

public void writeUnencoded(byte[] b,
                           int off,
                           int len)
                    throws java.io.IOException

Writes bytes to the underlying output stream, unencoded. If done improperly, this may corrupt the ascii85 data stream. Writing bytes using this method may cause the line length to increase since the line length counter will not be updated by this method.

Parameters:

b - The bytes to write.

off - The offset of b to start reading from.

len - The amount of bytes to read from b.

Throws:

java.io.IOException - If the underlying output stream has an I/O error.

flush

public void flush()
           throws java.io.IOException

Adds the closing block and flushes the underlying output stream. This method should only be called if it is intended that the ascii85 block should be closed.

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.FilterOutputStream

Throws:

java.io.IOException