org.apache.kerby.util

Class Base64InputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

org.apache.kerby.util.Base64InputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class Base64InputStream
extends FilterInputStream

Provides Base64 encoding and decoding in a streaming fashion (unlimited size). When encoding the default lineLength is 76 characters and the default lineEnding is CRLF, but these can be overridden by using the appropriate constructor.

The default behaviour of the Base64InputStream is to DECODE, whereas the default behaviour of the Base64OutputStream is to ENCODE, but this behaviour can be overridden by using a different constructor.

This class implements section 6.8. Base64 Content-Transfer-Encoding from RFC 2045 Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies by Freed and Borenstein.

Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).

Since:

1.4

Version:

$Id: Base64InputStream.java 155 2009-09-17 21:00:58Z julius $

Author:

Apache Software Foundation

See Also:

RFC 2045

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
Base64InputStream(InputStream in) Creates a Base64InputStream such that all data read is Base64-decoded from the original provided InputStream.
Base64InputStream(InputStream in, boolean doEncode) Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original provided InputStream.
Base64InputStream(InputStream in, boolean doEncode, int lineLength, byte[] lineSeparator) Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original provided InputStream.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	markSupported()
int	read() Reads one byte from this input stream.
int	read(byte[] b, int offset, int len) Attempts to read len bytes into the specified b array starting at offset from this InputStream.

Methods inherited from class java.io.FilterInputStream

available, close, mark, read, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

Base64InputStream

public Base64InputStream(InputStream in)

Creates a Base64InputStream such that all data read is Base64-decoded from the original provided InputStream.

Parameters:

in - InputStream to wrap.

Base64InputStream

public Base64InputStream(InputStream in,
                 boolean doEncode)

Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original provided InputStream.

Parameters:

in - InputStream to wrap.

doEncode - true if we should encode all data read from us, false if we should decode.

Base64InputStream

public Base64InputStream(InputStream in,
                 boolean doEncode,
                 int lineLength,
                 byte[] lineSeparator)

Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original provided InputStream.

Parameters:

in - InputStream to wrap.

doEncode - true if we should encode all data read from us, false if we should decode.

lineLength - If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to nearest multiple of 4). If lineLength <=0, the encoded data is not divided into lines. If doEncode is false, lineLength is ignored.

lineSeparator - If doEncode is true, each line of encoded data will be terminated with this byte sequence (e.g. \r\n). If lineLength <= 0, the lineSeparator is not used. If doEncode is false lineSeparator is ignored.

Method Detail

read

public int read()
         throws IOException

Reads one byte from this input stream.

Overrides:

read in class FilterInputStream

Returns:

the byte as an integer in the range 0 to 255. Returns -1 if EOF has been reached.

Throws:

IOException - if an I/O error occurs.

read

public int read(byte[] b,
       int offset,
       int len)
         throws IOException

Attempts to read len bytes into the specified b array starting at offset from this InputStream.

Overrides:

read in class FilterInputStream

Parameters:

b - destination byte array

offset - where to start writing the bytes

len - maximum number of bytes to read

Returns:

number of bytes read

Throws:

IOException - if an I/O error occurs.

NullPointerException - if the byte array parameter is null

IndexOutOfBoundsException - if offset, len or buffer size are invalid

markSupported

public boolean markSupported()

Overrides:

markSupported in class FilterInputStream

Returns:

false