io.jsonwebtoken.impl.io

Class Base64InputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

io.jsonwebtoken.impl.io.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 behavior of the Base64InputStream is to DECODE, whereas the default behavior of the Base64OutputStream is to ENCODE, but this behavior 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).

You can set the decoding behavior when the input bytes contain leftover trailing bits that cannot be created by a valid encoding. These can be bits that are unused from the final character or entire characters. The default mode is lenient decoding.

• Lenient: Any trailing bits are composed into 8-bit bytes where possible. The remainder are discarded.
• Strict: The decoding will raise an IllegalArgumentException if trailing bits are not part of a valid encoding. Any unused bits from the final character must be zero. Impossible counts of entire final characters are not allowed.

When strict decoding is enabled it is expected that the decoded bytes will be re-encoded to a byte array that matches the original, i.e. no changes occur on the final character. This requires that the input bytes use the same padding and alphabet as the encoder.

Since:

0.12.0, copied from commons-codec 585497f09b026f6602daf986723a554e051bdfe6

See Also:

RFC 2045

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
Base64InputStream(InputStream inputStream) Creates a Base64InputStream such that all data read is Base64-decoded from the original provided InputStream.

Method Summary

Methods

Modifier and Type	Method and Description
int	available()
boolean	isStrictDecoding() Returns true if decoding behavior is strict.
void	mark(int readLimit) Marks the current position in this input stream.
boolean	markSupported()
int	read() Reads one byte from this input stream.
int	read(byte[] array, int offset, int len) Attempts to read len bytes into the specified b array starting at offset from this InputStream.
void	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n)

Methods inherited from class java.io.FilterInputStream

close, read

Methods inherited from class java.lang.Object

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

Constructor Detail

Base64InputStream

public Base64InputStream(InputStream inputStream)

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

Parameters:

inputStream - InputStream to wrap.

Method Detail

available

public int available()
              throws IOException

Overrides:

available in class FilterInputStream

Returns:

0 if the InputStream has reached EOF, 1 otherwise

Throws:

IOException

Since:

1.7

isStrictDecoding

public boolean isStrictDecoding()

Returns true if decoding behavior is strict. Decoding will raise an IllegalArgumentException if trailing bits are not part of a valid encoding.

The default is false for lenient encoding. Decoding will compose trailing bits into 8-bit bytes and discard the remainder.

Returns:

true if using strict decoding

Since:

1.15

mark

public void mark(int readLimit)

Marks the current position in this input stream.

The mark(int) method of BaseNCodecInputStream does nothing.

Overrides:

mark in class FilterInputStream

Parameters:

readLimit - the maximum limit of bytes that can be read before the mark position becomes invalid.

Since:

1.7

See Also:

markSupported()

markSupported

public boolean markSupported()

Overrides:

markSupported in class FilterInputStream

Returns:

Always returns false

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[] array,
       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:

array - 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

reset

public void reset()
           throws IOException

Repositions this stream to the position at the time the mark method was last called on this input stream.

The reset() method of BaseNCodecInputStream does nothing except throw an IOException.

Overrides:

reset in class FilterInputStream

Throws:

IOException - if this method is invoked

Since:

1.7

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class FilterInputStream

Throws:

IllegalArgumentException - if the provided skip length is negative

IOException

Since:

1.7