Base64 (common_tools 3.8.7 API)

java.lang.Object
- net.sergeych.utils.Base64

Direct Known Subclasses:

Base64u
```
public class Base64
extends java.lang.Object
```
Encode arbitrary binary into printable ASCII using BASE64 encoding.
Base64 is a way of encoding 8-bit characters using only ASCII printable characters similar to UUENCODE. UUENCODE includes a filename where BASE64 does not. The spec is described in RFC 2045. Base64 is a scheme where 3 bytes are concatenated, then split to form 4 groups of 6-bits each; and each 6-bits gets translated to an encoded printable ASCII character, via a table lookup. An encoded string is therefore longer than the original by about 1/3. The "=" character is used to pad the end. Base64 is used, among other things, to encode the user:password string in an Authorization: header for HTTP. Don't confuse Base64 with x-www-form-urlencoded which is handled by Java.net.URLEncoder.encode/decode
If you don't like this code, there is another implementation at http://www.ruffboy .com/download.htm Sun has an undocumented method called sun.misc.Base64Encoder.encode. You could use hex, simpler to code, but not as compact.
If you wanted to encode a giant file, you could do it in large chunks that are even multiples of 3 bytes, except for the last chunk, and append the outputs.
To encode a string, rather than binary data java.net.URLEncoder may be better. See printable characters in the Java glossary for a discussion of the differences.
Base 64 armouring uses only the characters A-Z \\p{Lower} 0-9 +/=. This makes it suitable for encoding binary data as SQL strings, that will work no matter what the encoding. Unfortunately + / and = all have special meaning in URLs.
```
 Works exactly like Base64 except avoids using the characters
 + / and =.  This means Base64u-encoded data can be used either
 URLCoded or plain in
 URL-Encoded contexts such as GET, PUT or URLs. You can treat the
 output either as
 not needing encoding or already URLEncoded.

 
```
Base64 ASCII armouring. Encode arbitrary binary into printable ASCII using BASE64 encoding. very loosely based on the Base64 Reader by: Dr. Mark Thornton
Optrak Distribution Software Ltd. http://www.optrak.co.uk and Kevin Kelley's http://www.ruralnet.net/~kelley/java/Base64.java

real.sergeych@gmail.com: Added some utility functions to simplify its usage.
Since:

1999-12-03

Field Summary

Fields
Modifier and Type	Field and Description
`protected int[]`	`charToValue` binary value encoded by a given letter of the alphabet 0..63, overridden in Base64u.
`protected static int[]`	`cv` binary value encoded by a given letter of the alphabet 0..63.
`protected static boolean`	`DEBUGGING` used to disable test driver.
`protected static int`	`IGNORE` Marker value for chars we just ignore, e.g.
`protected int`	`lineLength` max chars per line, excluding lineSeparator.
`protected java.lang.String`	`lineSeparator` how we separate lines, e.g.
`protected static int`	`PAD` Marker for = trailing pad.
`protected char`	`spec1` special character 1, will be - in Base64u.
`protected char`	`spec2` special character 2, will be in in Base64u.
`protected char`	`spec3` special character 3, will be * in Base64u.
`protected char[]`	`valueToChar` letter of the alphabet used to encode binary values 0..63, overridden in Base64u.
`protected static char[]`	`vc` letter of the alphabet used to encode binary values 0..63

Constructor Summary

Constructors
Constructor and Description

Base64()
constructor.

Constructors
Constructor and Description
`Base64()` constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`byte[]`	`decode(java.lang.String s)` decode a well-formed complete Base64 string back into an array of bytes.
`static byte[]`	`decodeCompactString(java.lang.String s)`
`static byte[]`	`decodeLines(java.lang.String s)` Decodes a byte array from Base64 format and ignores line separators, tabs and blanks.
`java.lang.String`	`encode(byte[] b)` Encode an arbitrary array of bytes as Base64 printable ASCII.
`static java.lang.String`	`encodeCompactString(byte[] data)`
`static java.lang.String`	`encodeLines(byte[] data)`
`static java.lang.String`	`encodeString(byte[] data)`
`static void`	`main(java.lang.String[] args)` test driver.
`void`	`setLineLength(int length)` determines how long the lines are that are generated by encode.
`void`	`setLineSeparator(java.lang.String lineSeparator)` How lines are separated.
`static void`	`show(byte[] b)` debug display array as hex.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - DEBUGGING
```
protected static final boolean DEBUGGING
```
    used to disable test driver.
    
    See Also:
    
    Constant Field Values
  - IGNORE
```
protected static final int IGNORE
```
    Marker value for chars we just ignore, e.g. \n \r high ascii.
    
    See Also:
    
    Constant Field Values
  - PAD
```
protected static final int PAD
```
    Marker for = trailing pad.
    
    See Also:
    
    Constant Field Values
  - cv
```
protected static int[] cv
```
    binary value encoded by a given letter of the alphabet 0..63.
  - vc
```
protected static char[] vc
```
    letter of the alphabet used to encode binary values 0..63
  - lineSeparator
```
protected java.lang.String lineSeparator
```
    how we separate lines, e.g. \n, \r\n, \r etc.
  - valueToChar
```
protected char[] valueToChar
```
    letter of the alphabet used to encode binary values 0..63, overridden in Base64u.
  - spec1
```
protected char spec1
```
    special character 1, will be - in Base64u.
  - spec2
```
protected char spec2
```
    special character 2, will be in in Base64u.
  - spec3
```
protected char spec3
```
    special character 3, will be * in Base64u.
  - charToValue
```
protected int[] charToValue
```
    binary value encoded by a given letter of the alphabet 0..63, overridden in Base64u.
  - lineLength
```
protected int lineLength
```
    max chars per line, excluding lineSeparator. A multiple of 4.
- Constructor Detail
  - Base64
```
public Base64()
```
    constructor.
- Method Detail
  - decodeLines
```
public static byte[] decodeLines(java.lang.String s)
```
    Decodes a byte array from Base64 format and ignores line separators, tabs and blanks. CR, LF, Tab and Space characters are ignored in the input data.
    
    Parameters:
    
    s - A Base64 String to be decoded.
    
    Returns:
    
    An array containing the decoded data bytes.
    
    Throws:
    
    java.lang.IllegalArgumentException - If the input is not valid Base64 encoded data.
  - encodeString
```
public static java.lang.String encodeString(byte[] data)
```
  - encodeCompactString
```
public static java.lang.String encodeCompactString(byte[] data)
```
  - encodeLines
```
public static java.lang.String encodeLines(byte[] data)
```
  - show
```
public static void show(byte[] b)
```
    debug display array as hex.
    
    Parameters:
    
    b - byte array to display.
  - main
```
public static void main(java.lang.String[] args)
```
    test driver.
    
    Parameters:
    
    args - not used
  - decode
```
public byte[] decode(java.lang.String s)
```
    decode a well-formed complete Base64 string back into an array of bytes. It must have an even multiple of 4 data characters (not counting \n), padded out with = as needed.
    
    Parameters:
    
    s - base64-encoded string
    
    Returns:
    
    plaintext as a byte array.
  - encode
```
public java.lang.String encode(byte[] b)
```
    Encode an arbitrary array of bytes as Base64 printable ASCII. It will be broken into lines of 72 chars each. The last line is not terminated with a line separator. The output will always have an even multiple of data characters, exclusive of \n. It is padded out with =.
    
    Parameters:
    
    b - byte array to encode, typically produced by a ByteArrayOutputStream.
    
    Returns:
    
    base-64 encoded String, not char[] or byte[].
  - setLineLength
```
public final void setLineLength(int length)
```
    determines how long the lines are that are generated by encode. Ignored by decode.
    
    Parameters:
    
    length - 0 means no newlines inserted. Must be a multiple of 4.
  - setLineSeparator
```
public final void setLineSeparator(java.lang.String lineSeparator)
```
    How lines are separated. Ignored by decode.
    
    Parameters:
    
    lineSeparator - may be "" but not null. Usually contains only a combination of chars \n and \r. Could be any chars not in set A-Z \\p{Lower} 0-9 + /.
  - decodeCompactString
```
public static byte[] decodeCompactString(java.lang.String s)
```

Class Base64

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEBUGGING

IGNORE

PAD

cv

vc

lineSeparator

valueToChar

spec1

spec2

spec3

charToValue

lineLength

Constructor Detail

Base64

Method Detail

decodeLines

encodeString

encodeCompactString

encodeLines

show

main

decode

encode

setLineLength

setLineSeparator

decodeCompactString