com.knowgate.misc

Class Base64Decoder

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

com.knowgate.misc.Base64Decoder

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class Base64Decoder
extends java.io.FilterInputStream

A class to decode Base64 streams and strings.

See RFC 1521 section 5.2 for details of the Base64 algorithm.

This class can be used for decoding strings:

 String encoded = "d2VibWFzdGVyOnRyeTJndWVTUw";
 String decoded = Base64Decoder.decode(encoded);
 

or for decoding streams:

 InputStream in = new Base64Decoder(System.in);
 

Version:

1.1, 2002/11/01, added decodeToBytes() to better handle binary data (thanks to Sean Graham), 1.0, 2000/06/11

Constructor Summary

Constructors

Constructor and Description
Base64Decoder(java.io.InputStream in) Constructs a new Base64 decoder that reads input from the given InputStream.

Method Summary

Methods

Modifier and Type	Method and Description
static java.lang.String	decode(java.lang.String encoded) Returns the decoded form of the given encoded string, as a String.
static byte[]	decodeToBytes(java.lang.String encoded) Returns the decoded form of the given encoded string, as bytes.
static void	main(java.lang.String[] args)
int	read() Returns the next decoded character from the stream, or -1 if end of stream was reached.
int	read(byte[] buf, int off, int len) Reads decoded data into an array of bytes and returns the actual number of bytes read, or -1 if end of stream was reached.

Methods inherited from class java.io.FilterInputStream

available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

Base64Decoder

public Base64Decoder(java.io.InputStream in)

Constructs a new Base64 decoder that reads input from the given InputStream.

Parameters:

in - the input stream

Method Detail

read

public int read()
         throws java.io.IOException

Returns the next decoded character from the stream, or -1 if end of stream was reached.

Overrides:

read in class java.io.FilterInputStream

Returns:

the decoded character, or -1 if the end of the input stream is reached

Throws:

java.io.IOException - if an I/O error occurs

read

public int read(byte[] buf,
       int off,
       int len)
         throws java.io.IOException

Reads decoded data into an array of bytes and returns the actual number of bytes read, or -1 if end of stream was reached.

Overrides:

read in class java.io.FilterInputStream

Parameters:

buf - the buffer into which the data is read

off - the start offset of the data

len - the maximum number of bytes to read

Returns:

the actual number of bytes read, or -1 if the end of the input stream is reached

Throws:

java.io.IOException - if an I/O error occurs

decode

public static java.lang.String decode(java.lang.String encoded)

Returns the decoded form of the given encoded string, as a String. Note that not all binary data can be represented as a String, so this method should only be used for encoded String data. Use decodeToBytes() otherwise.

Parameters:

encoded - the string to decode

Returns:

the decoded form of the encoded string

decodeToBytes

public static byte[] decodeToBytes(java.lang.String encoded)

Returns the decoded form of the given encoded string, as bytes.

Parameters:

encoded - the string to decode

Returns:

the decoded form of the encoded string

main

public static void main(java.lang.String[] args)
                 throws java.lang.Exception

Throws:

java.lang.Exception