com.alibaba.nacos.client.identify

Class Base64

java.lang.Object

com.alibaba.nacos.client.identify.Base64

public class Base64
extends Object

Provides Base64 encoding and decoding as defined by RFC 2045.

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.

The class can be parameterized in the following manner with various constructors:

• URL-safe mode: Default off.
• Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
• Line separator: Default is CRLF ("\r\n")

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).

This class is not thread-safe. Each thread should use its own instance.

Since:

1.0

Version:

$Revision: 1080712 $

Author:

Apache Software Foundation

See Also:

RFC 2045

Constructor Summary

Constructors

Constructor and Description
Base64() Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
Base64(int lineLength, byte[] lineSeparator, boolean urlSafe) Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

Method Summary

Modifier and Type	Method and Description
static byte[]	decodeBase64(byte[] base64Data) Decodes Base64 data into octets
static byte[]	encodeBase64(byte[] binaryData) Encodes binary data using the base64 algorithm but does not chunk the output.
static byte[]	encodeBase64(byte[] binaryData, boolean isChunked, boolean urlSafe, int maxResultSize) Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
protected boolean	isInAlphabet(byte octet) Returns whether or not the octet is in the Base32 alphabet.

Methods inherited from class java.lang.Object

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

Constructor Detail

Base64

public Base64()

Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

When encoding the line length is 0 (no chunking), and the encoding table is STANDARD_ENCODE_TABLE.

When decoding all variants are supported.

Base64

public Base64(int lineLength,
              byte[] lineSeparator,
              boolean urlSafe)

Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

When encoding the line length and line separator are given in the constructor, and the encoding table is STANDARD_ENCODE_TABLE.

Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

When decoding all variants are supported.

Parameters:

lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.

lineSeparator - Each line of encoded data will end with this sequence of bytes.

urlSafe - Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode operations. Decoding seamlessly handles both modes.

Throws:

IllegalArgumentException - The provided lineSeparator included some base64 characters. That's not going to work!

Since:

1.4

Method Detail

encodeBase64

public static byte[] encodeBase64(byte[] binaryData)

Encodes binary data using the base64 algorithm but does not chunk the output.

Parameters:

binaryData - binary data to encode

Returns:

byte[] containing Base64 characters in their UTF-8 representation.

encodeBase64

public static byte[] encodeBase64(byte[] binaryData,
                                  boolean isChunked,
                                  boolean urlSafe,
                                  int maxResultSize)

Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.

Parameters:

binaryData - Array containing binary data to encode.

isChunked - if true this encoder will chunk the base64 output into 76 character blocks

urlSafe - if true this encoder will emit - and _ instead of the usual + and / characters.

maxResultSize - The maximum result size to accept.

Returns:

Base64-encoded data.

Throws:

IllegalArgumentException - Thrown when the input array needs an output array bigger than maxResultSize

Since:

1.4

decodeBase64

public static byte[] decodeBase64(byte[] base64Data)

Decodes Base64 data into octets

Parameters:

base64Data - Byte array containing Base64 data

Returns:

Array containing decoded data.

isInAlphabet

protected boolean isInAlphabet(byte octet)

Returns whether or not the octet is in the Base32 alphabet.

Parameters:

octet - The value to test

Returns:

true if the value is defined in the the Base32 alphabet false otherwise.