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org.apache.commons.codec.binary

Class BaseNCodec

    • Field Summary

      Fields 
      Modifier and TypeField and Description
      protected intlineLength
      Chunksize for encoding.
      protected static intMASK_8BITS
      Mask used to extract 8 bits, used in decoding bytes
      static intMIME_CHUNK_SIZE
      MIME chunk size per RFC 2045 section 6.8.
      protected bytePAD 
      protected static bytePAD_DEFAULT
      Byte used to pad output.
      static intPEM_CHUNK_SIZE
      PEM chunk size per RFC 1421 section 4.3.2.4.
    • Constructor Summary

      Constructors 
      ModifierConstructor and Description
      protected BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength)
      Note lineLength is rounded down to the nearest multiple of encodedBlockSize If chunkSeparatorLength is zero, then chunking is disabled.
    • Method Summary

      Methods 
      Modifier and TypeMethod and Description
      protected booleancontainsAlphabetOrPad(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.
      Objectdecode(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.
      Objectencode(Object obj)
      Encodes an Object using the Base-N algorithm.
      StringencodeAsString(byte[] pArray)
      Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet.
      StringencodeToString(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
      protected intgetDefaultBufferSize()
      Get the default buffer size.
      longgetEncodedLength(byte[] pArray)
      Calculates the amount of space needed to encode the supplied array.
      protected abstract booleanisInAlphabet(byte value)
      Returns whether or not the octet is in the current alphabet.
      booleanisInAlphabet(byte[] arrayOctet, boolean allowWSPad)
      Tests a given byte array to see if it contains only valid characters within the alphabet.
      booleanisInAlphabet(String basen)
      Tests a given String to see if it contains only valid characters within the alphabet.
      protected static booleanisWhiteSpace(byte byteToCheck)
      Checks if a byte value is whitespace or not.
    • 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
      • 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 encodedBlockSize 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
    • Method Detail

      • getDefaultBufferSize

        protected int getDefaultBufferSize()
        Get the default buffer size. Can be overridden.
        Returns:
        DEFAULT_BUFFER_SIZE
      • 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
      • 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
      • 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[]
      • 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
      • 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.
      • 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
      • 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
      • 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 basen alphabetic character data
      • 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)
      • 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
      • 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

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