org.apache.commons.codec.binary
Class Base32

java.lang.Object
  extended by org.apache.commons.codec.binary.BaseNCodec
      extended by org.apache.commons.codec.binary.Base32
All Implemented Interfaces:
BinaryDecoder, BinaryEncoder, Decoder, Encoder

public class Base32
extends BaseNCodec

Provides Base32 encoding and decoding as defined by RFC 4648.

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

This class operates directly on byte streams, and not character streams.

This class is thread-safe.

Since:
1.5
Version:
$Id: Base32.java 1382498 2012-09-09 13:41:55Z sebb $
See Also:
RFC 4648

Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.commons.codec.binary.BaseNCodec
BaseNCodec.Context
 
Field Summary
private static int BITS_PER_ENCODED_BYTE
          BASE32 characters are 5 bits in length.
private static int BYTES_PER_ENCODED_BLOCK
           
private static int BYTES_PER_UNENCODED_BLOCK
           
private static byte[] CHUNK_SEPARATOR
          Chunk separator per RFC 2045 section 2.1.
private static byte[] DECODE_TABLE
          This array is a lookup table that translates Unicode characters drawn from the "Base32 Alphabet" (as specified in Table 3 of RFC 2045) into their 5-bit positive integer equivalents.
private  int decodeSize
          Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
private  byte[] decodeTable
          Decode table to use.
private static byte[] ENCODE_TABLE
          This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Alphabet" equivalents as specified in Table 3 of RFC 2045.
private  int encodeSize
          Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
private  byte[] encodeTable
          Encode table to use.
private static byte[] HEX_DECODE_TABLE
          This array is a lookup table that translates Unicode characters drawn from the "Base32 |Hex Alphabet" (as specified in Table 3 of RFC 2045) into their 5-bit positive integer equivalents.
private static byte[] HEX_ENCODE_TABLE
          This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Hex Alphabet" equivalents as specified in Table 3 of RFC 2045.
private  byte[] lineSeparator
          Line separator for encoding.
private static int MASK_5BITS
          Mask used to extract 5 bits, used when encoding Base32 bytes
 
Fields inherited from class org.apache.commons.codec.binary.BaseNCodec
EOF, lineLength, MASK_8BITS, MIME_CHUNK_SIZE, PAD, PAD_DEFAULT, PEM_CHUNK_SIZE
 
Constructor Summary
Base32()
          Creates a Base32 codec used for decoding and encoding.
Base32(boolean useHex)
          Creates a Base32 codec used for decoding and encoding.
Base32(int lineLength)
          Creates a Base32 codec used for decoding and encoding.
Base32(int lineLength, byte[] lineSeparator)
          Creates a Base32 codec used for decoding and encoding.
Base32(int lineLength, byte[] lineSeparator, boolean useHex)
          Creates a Base32 / Base32 Hex codec used for decoding and encoding.
 
Method Summary
(package private)  void decode(byte[] in, int inPos, int inAvail, BaseNCodec.Context context)
           Decodes all of the provided data, starting at inPos, for inAvail bytes.
(package private)  void encode(byte[] in, int inPos, int inAvail, BaseNCodec.Context context)
           Encodes all of the provided data, starting at inPos, for inAvail bytes.
 boolean isInAlphabet(byte octet)
          Returns whether or not the octet is in the Base32 alphabet.
 
Methods inherited from class org.apache.commons.codec.binary.BaseNCodec
available, containsAlphabetOrPad, decode, decode, decode, encode, encode, encodeAsString, encodeToString, ensureBufferSize, getDefaultBufferSize, getEncodedLength, hasData, isInAlphabet, isInAlphabet, isWhiteSpace, readResults
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

BITS_PER_ENCODED_BYTE

private static final int BITS_PER_ENCODED_BYTE
BASE32 characters are 5 bits in length. They are formed by taking a block of five octets to form a 40-bit string, which is converted into eight BASE32 characters.

See Also:
Constant Field Values

BYTES_PER_ENCODED_BLOCK

private static final int BYTES_PER_ENCODED_BLOCK
See Also:
Constant Field Values

BYTES_PER_UNENCODED_BLOCK

private static final int BYTES_PER_UNENCODED_BLOCK
See Also:
Constant Field Values

CHUNK_SEPARATOR

private static final byte[] CHUNK_SEPARATOR
Chunk separator per RFC 2045 section 2.1.

See Also:
RFC 2045 section 2.1

DECODE_TABLE

private static final byte[] DECODE_TABLE
This array is a lookup table that translates Unicode characters drawn from the "Base32 Alphabet" (as specified in Table 3 of RFC 2045) into their 5-bit positive integer equivalents. Characters that are not in the Base32 alphabet but fall within the bounds of the array are translated to -1.


ENCODE_TABLE

private static final byte[] ENCODE_TABLE
This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Alphabet" equivalents as specified in Table 3 of RFC 2045.


HEX_DECODE_TABLE

private static final byte[] HEX_DECODE_TABLE
This array is a lookup table that translates Unicode characters drawn from the "Base32 |Hex Alphabet" (as specified in Table 3 of RFC 2045) into their 5-bit positive integer equivalents. Characters that are not in the Base32 Hex alphabet but fall within the bounds of the array are translated to -1.


HEX_ENCODE_TABLE

private static final byte[] HEX_ENCODE_TABLE
This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Hex Alphabet" equivalents as specified in Table 3 of RFC 2045.


MASK_5BITS

private static final int MASK_5BITS
Mask used to extract 5 bits, used when encoding Base32 bytes

See Also:
Constant Field Values

decodeSize

private final int decodeSize
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. decodeSize = BYTES_PER_ENCODED_BLOCK - 1 + lineSeparator.length;


decodeTable

private final byte[] decodeTable
Decode table to use.


encodeSize

private final int encodeSize
Convenience variable to help us determine when our buffer is going to run out of room and needs resizing. encodeSize = BYTES_PER_ENCODED_BLOCK + lineSeparator.length;


encodeTable

private final byte[] encodeTable
Encode table to use.


lineSeparator

private final byte[] lineSeparator
Line separator for encoding. Not used when decoding. Only used if lineLength > 0.

Constructor Detail

Base32

public Base32()
Creates a Base32 codec used for decoding and encoding.

When encoding the line length is 0 (no chunking).


Base32

public Base32(boolean useHex)
Creates a Base32 codec used for decoding and encoding.

When encoding the line length is 0 (no chunking).

Parameters:
useHex - if true then use Base32 Hex alphabet

Base32

public Base32(int lineLength)
Creates a Base32 codec used for decoding and encoding.

When encoding the line length is given in the constructor, the line separator is CRLF.

Parameters:
lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 8). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.

Base32

public Base32(int lineLength,
              byte[] lineSeparator)
Creates a Base32 codec used for decoding and encoding.

When encoding the line length and line separator are given in the constructor.

Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data.

Parameters:
lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 8). 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.
Throws:
java.lang.IllegalArgumentException - The provided lineSeparator included some Base32 characters. That's not going to work!

Base32

public Base32(int lineLength,
              byte[] lineSeparator,
              boolean useHex)
Creates a Base32 / Base32 Hex codec used for decoding and encoding.

When encoding the line length and line separator are given in the constructor.

Line lengths that aren't multiples of 8 will still essentially end up being multiples of 8 in the encoded data.

Parameters:
lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 8). 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.
useHex - if true, then use Base32 Hex alphabet, otherwise use Base32 alphabet
Throws:
java.lang.IllegalArgumentException - The provided lineSeparator included some Base32 characters. That's not going to work! Or the lineLength > 0 and lineSeparator is null.
Method Detail

decode

void decode(byte[] in,
            int inPos,
            int inAvail,
            BaseNCodec.Context context)

Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once with the data to decode, and once with inAvail set to "-1" to alert decoder that EOF has been reached. The "-1" call is not necessary when decoding, but it doesn't hurt, either.

Ignores all non-Base32 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are silently ignored, but has implications for other bytes, too. This method subscribes to the garbage-in, garbage-out philosophy: it will not check the provided data for validity.

Specified by:
decode in class BaseNCodec
Parameters:
in - byte[] array of ascii data to Base32 decode.
inPos - Position to start reading data from.
inAvail - Amount of bytes available from input for encoding.
context - the context to be used Output is written to Context#buffer as 8-bit octets, using Context#pos as the buffer position

encode

void encode(byte[] in,
            int inPos,
            int inAvail,
            BaseNCodec.Context context)

Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with the data to encode, and once with inAvail set to "-1" to alert encoder that EOF has been reached, so flush last remaining bytes (if not multiple of 5).

Specified by:
encode in class BaseNCodec
Parameters:
in - byte[] array of binary data to Base32 encode.
inPos - Position to start reading data from.
inAvail - Amount of bytes available from input for encoding.
context - the context to be used

isInAlphabet

public boolean isInAlphabet(byte octet)
Returns whether or not the octet is in the Base32 alphabet.

Specified by:
isInAlphabet in class BaseNCodec
Parameters:
octet - The value to test
Returns:
true if the value is defined in the the Base32 alphabet false otherwise.


commons-codec version 1.7-SNAPSHOT - Copyright © 2002-2013 - Apache Software Foundation