BaseNCodec (Apache Commons Codec 1.15 API)

java.lang.Object
- org.apache.commons.codec.binary.BaseNCodec

All Implemented Interfaces:

BinaryDecoder, BinaryEncoder, Decoder, Encoder

Direct Known Subclasses:

Base16, Base32, Base64
```
public abstract class BaseNCodec
extends Object
implements BinaryEncoder, BinaryDecoder
```
Abstract superclass for Base-N encoders and decoders.
This class is thread-safe.
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.

Field Summary

Fields
Modifier and Type	Field and Description
`protected static CodecPolicy`	`DECODING_POLICY_DEFAULT` The default decoding policy.
`protected int`	`lineLength` Chunksize for encoding.
`protected static int`	`MASK_8BITS` Mask used to extract 8 bits, used in decoding bytes
`static int`	`MIME_CHUNK_SIZE` MIME chunk size per RFC 2045 section 6.8.
`protected byte`	`pad`
`protected byte`	`PAD` Deprecated. Use `pad`. Will be removed in 2.0.
`protected static byte`	`PAD_DEFAULT` Byte used to pad output.
`static int`	`PEM_CHUNK_SIZE` PEM chunk size per RFC 1421 section 4.3.2.4.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength)` Note `lineLength` is rounded down to the nearest multiple of the encoded block size.
`protected`	`BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength, byte pad)` Note `lineLength` is rounded down to the nearest multiple of the encoded block size.
`protected`	`BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength, byte pad, CodecPolicy decodingPolicy)` Note `lineLength` is rounded down to the nearest multiple of the encoded block size.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`protected boolean`	`containsAlphabetOrPad(byte[] arrayOctet)` Tests a given byte array to see if it contains any characters within the alphabet or PAD.
`byte[]`	`decode(byte[] pArray)` Decodes a byte[] containing characters in the Base-N alphabet.
`Object`	`decode(Object obj)` Decodes an Object using the Base-N algorithm.
`byte[]`	`decode(String pArray)` Decodes a String containing characters in the Base-N alphabet.
`byte[]`	`encode(byte[] pArray)` Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
`byte[]`	`encode(byte[] pArray, int offset, int length)` Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
`Object`	`encode(Object obj)` Encodes an Object using the Base-N algorithm.
`String`	`encodeAsString(byte[] pArray)` Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet.
`String`	`encodeToString(byte[] pArray)` Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet.
`protected byte[]`	`ensureBufferSize(int size, org.apache.commons.codec.binary.BaseNCodec.Context context)` Ensure that the buffer has room for `size` bytes
`static byte[]`	`getChunkSeparator()` Gets a copy of the chunk separator per RFC 2045 section 2.1.
`CodecPolicy`	`getCodecPolicy()` Returns the decoding behavior policy.
`protected int`	`getDefaultBufferSize()` Get the default buffer size.
`long`	`getEncodedLength(byte[] pArray)` Calculates the amount of space needed to encode the supplied array.
`protected abstract boolean`	`isInAlphabet(byte value)` Returns whether or not the `octet` is in the current alphabet.
`boolean`	`isInAlphabet(byte[] arrayOctet, boolean allowWSPad)` Tests a given byte array to see if it contains only valid characters within the alphabet.
`boolean`	`isInAlphabet(String basen)` Tests a given String to see if it contains only valid characters within the alphabet.
`boolean`	`isStrictDecoding()` Returns true if decoding behavior is strict.
`protected static boolean`	`isWhiteSpace(byte byteToCheck)` Checks if a byte value is whitespace or not.

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

- Field Detail
  - MIME_CHUNK_SIZE
```
public static final int MIME_CHUNK_SIZE
```
    MIME chunk size per RFC 2045 section 6.8.
    The 76 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.
    
    See Also:
    
    RFC 2045 section 6.8, Constant Field Values
  - PEM_CHUNK_SIZE
```
public static final int PEM_CHUNK_SIZE
```
    PEM chunk size per RFC 1421 section 4.3.2.4.
    The 64 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.
    
    See Also:
    
    RFC 1421 section 4.3.2.4, Constant Field Values
  - MASK_8BITS
```
protected static final int MASK_8BITS
```
    Mask used to extract 8 bits, used in decoding bytes
    
    See Also:
    
    Constant Field Values
  - PAD_DEFAULT
```
protected static final byte PAD_DEFAULT
```
    Byte used to pad output.
    
    See Also:
    
    Constant Field Values
  - DECODING_POLICY_DEFAULT
```
protected static final CodecPolicy DECODING_POLICY_DEFAULT
```
    The default decoding policy.
    
    Since:
    
    1.15
  - PAD
```
@Deprecated
protected final byte PAD
```
    Deprecated. Use pad. Will be removed in 2.0.
    
    See Also:
    
    Constant Field Values
  - pad
```
protected final byte pad
```
  - lineLength
```
protected final int lineLength
```
    Chunksize for encoding. Not used when decoding. A value of zero or less implies no chunking of the encoded data. Rounded down to nearest multiple of encodedBlockSize.
- Constructor Detail
  - BaseNCodec
```
protected BaseNCodec(int unencodedBlockSize,
                     int encodedBlockSize,
                     int lineLength,
                     int chunkSeparatorLength)
```
    Note lineLength is rounded down to the nearest multiple of the encoded block size. If chunkSeparatorLength is zero, then chunking is disabled.
    
    Parameters:
    
    unencodedBlockSize - the size of an unencoded block (e.g. Base64 = 3)
    
    encodedBlockSize - the size of an encoded block (e.g. Base64 = 4)
    
    lineLength - if > 0, use chunking with a length lineLength
    
    chunkSeparatorLength - the chunk separator length, if relevant
  - BaseNCodec
```
protected BaseNCodec(int unencodedBlockSize,
                     int encodedBlockSize,
                     int lineLength,
                     int chunkSeparatorLength,
                     byte pad)
```
    Note lineLength is rounded down to the nearest multiple of the encoded block size. If chunkSeparatorLength is zero, then chunking is disabled.
    
    Parameters:
    
    unencodedBlockSize - the size of an unencoded block (e.g. Base64 = 3)
    
    encodedBlockSize - the size of an encoded block (e.g. Base64 = 4)
    
    lineLength - if > 0, use chunking with a length lineLength
    
    chunkSeparatorLength - the chunk separator length, if relevant
    
    pad - byte used as padding byte.
  - BaseNCodec
```
protected BaseNCodec(int unencodedBlockSize,
                     int encodedBlockSize,
                     int lineLength,
                     int chunkSeparatorLength,
                     byte pad,
                     CodecPolicy decodingPolicy)
```
    Note lineLength is rounded down to the nearest multiple of the encoded block size. If chunkSeparatorLength is zero, then chunking is disabled.
    
    Parameters:
    
    unencodedBlockSize - the size of an unencoded block (e.g. Base64 = 3)
    
    encodedBlockSize - the size of an encoded block (e.g. Base64 = 4)
    
    lineLength - if > 0, use chunking with a length lineLength
    
    chunkSeparatorLength - the chunk separator length, if relevant
    
    pad - byte used as padding byte.
    
    decodingPolicy - Decoding policy.
    
    Since:
    
    1.15
- Method Detail
  - getChunkSeparator
```
public static byte[] getChunkSeparator()
```
    Gets a copy of the chunk separator per RFC 2045 section 2.1.
    
    Returns:
    
    the chunk separator
    
    Since:
    
    1.15
    
    See Also:
    
    RFC 2045 section 2.1
  - isWhiteSpace
```
protected static boolean isWhiteSpace(byte byteToCheck)
```
    Checks if a byte value is whitespace or not. Whitespace is taken to mean: space, tab, CR, LF
    
    Parameters:
    
    byteToCheck - the byte to check
    
    Returns:
    
    true if byte is whitespace, false otherwise
  - containsAlphabetOrPad
```
protected boolean containsAlphabetOrPad(byte[] arrayOctet)
```
    Tests a given byte array to see if it contains any characters within the alphabet or PAD. Intended for use in checking line-ending arrays
    
    Parameters:
    
    arrayOctet - byte array to test
    
    Returns:
    
    true if any byte is a valid character in the alphabet or PAD; false otherwise
  - decode
```
public byte[] decode(byte[] pArray)
```
    Decodes a byte[] containing characters in the Base-N alphabet.
    
    Specified by:
    
    decode in interface BinaryDecoder
    
    Parameters:
    
    pArray - A byte array containing Base-N character data
    
    Returns:
    
    a byte array containing binary data
  - decode
```
public Object decode(Object obj)
              throws DecoderException
```
    Decodes an Object using the Base-N algorithm. This method is provided in order to satisfy the requirements of the Decoder interface, and will throw a DecoderException if the supplied object is not of type byte[] or String.
    
    Specified by:
    
    decode in interface Decoder
    
    Parameters:
    
    obj - Object to decode
    
    Returns:
    
    An object (of type byte[]) containing the binary data which corresponds to the byte[] or String supplied.
    
    Throws:
    
    DecoderException - if the parameter supplied is not of type byte[]
  - decode
```
public byte[] decode(String pArray)
```
    Decodes a String containing characters in the Base-N alphabet.
    
    Parameters:
    
    pArray - A String containing Base-N character data
    
    Returns:
    
    a byte array containing binary data
  - encode
```
public byte[] encode(byte[] pArray)
```
    Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
    
    Specified by:
    
    encode in interface BinaryEncoder
    
    Parameters:
    
    pArray - a byte array containing binary data
    
    Returns:
    
    A byte array containing only the base N alphabetic character data
  - encode
```
public byte[] encode(byte[] pArray,
                     int offset,
                     int length)
```
    Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
    
    Parameters:
    
    pArray - a byte array containing binary data
    
    offset - initial offset of the subarray.
    
    length - length of the subarray.
    
    Returns:
    
    A byte array containing only the base N alphabetic character data
    
    Since:
    
    1.11
  - encode
```
public Object encode(Object obj)
              throws EncoderException
```
    Encodes an Object using the Base-N algorithm. This method is provided in order to satisfy the requirements of the Encoder interface, and will throw an EncoderException if the supplied object is not of type byte[].
    
    Specified by:
    
    encode in interface Encoder
    
    Parameters:
    
    obj - Object to encode
    
    Returns:
    
    An object (of type byte[]) containing the Base-N encoded data which corresponds to the byte[] supplied.
    
    Throws:
    
    EncoderException - if the parameter supplied is not of type byte[]
  - encodeAsString
```
public String encodeAsString(byte[] pArray)
```
    Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet. Uses UTF8 encoding.
    
    Parameters:
    
    pArray - a byte array containing binary data
    
    Returns:
    
    String containing only character data in the appropriate alphabet.
    
    Since:
    
    1.5 This is a duplicate of encodeToString(byte[]); it was merged during refactoring.
  - encodeToString
```
public String encodeToString(byte[] pArray)
```
    Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet. Uses UTF8 encoding.
    
    Parameters:
    
    pArray - a byte array containing binary data
    
    Returns:
    
    A String containing only Base-N character data
  - ensureBufferSize
```
protected byte[] ensureBufferSize(int size,
                                  org.apache.commons.codec.binary.BaseNCodec.Context context)
```
    Ensure that the buffer has room for size bytes
    
    Parameters:
    
    size - minimum spare space required
    
    context - the context to be used
    
    Returns:
    
    the buffer
  - getCodecPolicy
```
public CodecPolicy getCodecPolicy()
```
    Returns the decoding behavior policy.
    The default is lenient. If the decoding policy is strict, then decoding will raise an IllegalArgumentException if trailing bits are not part of a valid encoding. Decoding will compose trailing bits into 8-bit bytes and discard the remainder.
    
    Returns:
    
    true if using strict decoding
    
    Since:
    
    1.15
  - getDefaultBufferSize
```
protected int getDefaultBufferSize()
```
    Get the default buffer size. Can be overridden.
    
    Returns:
    
    the default buffer size.
  - getEncodedLength
```
public long getEncodedLength(byte[] pArray)
```
    Calculates the amount of space needed to encode the supplied array.
    
    Parameters:
    
    pArray - byte[] array which will later be encoded
    
    Returns:
    
    amount of space needed to encoded the supplied array. Returns a long since a max-len array will require > Integer.MAX_VALUE
  - isInAlphabet
```
protected abstract boolean isInAlphabet(byte value)
```
    Returns whether or not the octet is in the current alphabet. Does not allow whitespace or pad.
    
    Parameters:
    
    value - The value to test
    
    Returns:
    
    true if the value is defined in the current alphabet, false otherwise.
  - isInAlphabet
```
public boolean isInAlphabet(byte[] arrayOctet,
                            boolean allowWSPad)
```
    Tests a given byte array to see if it contains only valid characters within the alphabet. The method optionally treats whitespace and pad as valid.
    
    Parameters:
    
    arrayOctet - byte array to test
    
    allowWSPad - if true, then whitespace and PAD are also allowed
    
    Returns:
    
    true if all bytes are valid characters in the alphabet or if the byte array is empty; false, otherwise
  - isInAlphabet
```
public boolean isInAlphabet(String basen)
```
    Tests a given String to see if it contains only valid characters within the alphabet. The method treats whitespace and PAD as valid.
    
    Parameters:
    
    basen - String to test
    
    Returns:
    
    true if all characters in the String are valid characters in the alphabet or if the String is empty; false, otherwise
    
    See Also:
    
    isInAlphabet(byte[], boolean)
  - 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 decoding. Decoding will compose trailing bits into 8-bit bytes and discard the remainder.
    
    Returns:
    
    true if using strict decoding
    
    Since:
    
    1.15

Class BaseNCodec

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MIME_CHUNK_SIZE

PEM_CHUNK_SIZE

MASK_8BITS

PAD_DEFAULT

DECODING_POLICY_DEFAULT

PAD

pad

lineLength

Constructor Detail

BaseNCodec

BaseNCodec

BaseNCodec

Method Detail

getChunkSeparator

isWhiteSpace

containsAlphabetOrPad

decode

decode

decode

encode

encode

encode

encodeAsString

encodeToString

ensureBufferSize

getCodecPolicy

getDefaultBufferSize

getEncodedLength

isInAlphabet

isInAlphabet

isInAlphabet

isStrictDecoding