Class Base16

  • All Implemented Interfaces:
    BinaryDecoder, BinaryEncoder, Decoder, Encoder

    public class Base16
    extends BaseNCodec
    Provides Base16 encoding and decoding.

    This class is thread-safe.

    This implementation strictly follows RFC 4648, and as such unlike the Base32 and Base64 implementations, it does not ignore invalid alphabet characters or whitespace, neither does it offer chunking or padding characters.

    The only additional feature above those specified in RFC 4648 is support for working with a lower-case alphabet in addition to the default upper-case alphabet.

    Since:
    1.15
    See Also:
    RFC 4648 - 8. Base 16 Encoding
    • Field Detail

      • BITS_PER_ENCODED_BYTE

        private static final int BITS_PER_ENCODED_BYTE
        BASE16 characters are 4 bits in length. They are formed by taking an 8-bit group, which is converted into two BASE16 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
      • UPPER_CASE_DECODE_TABLE

        private static final byte[] UPPER_CASE_DECODE_TABLE
        This array is a lookup table that translates Unicode characters drawn from the "Base16 Alphabet" (as specified in Table 5 of RFC 4648) into their 4-bit positive integer equivalents. Characters that are not in the Base16 alphabet but fall within the bounds of the array are translated to -1.
      • UPPER_CASE_ENCODE_TABLE

        private static final byte[] UPPER_CASE_ENCODE_TABLE
        This array is a lookup table that translates 4-bit positive integer index values into their "Base16 Alphabet" equivalents as specified in Table 5 of RFC 4648.
      • LOWER_CASE_DECODE_TABLE

        private static final byte[] LOWER_CASE_DECODE_TABLE
        This array is a lookup table that translates Unicode characters drawn from the a lower-case "Base16 Alphabet" into their 4-bit positive integer equivalents. Characters that are not in the Base16 alphabet but fall within the bounds of the array are translated to -1.
      • LOWER_CASE_ENCODE_TABLE

        private static final byte[] LOWER_CASE_ENCODE_TABLE
        This array is a lookup table that translates 4-bit positive integer index values into their "Base16 Alphabet" lower-case equivalents.
      • MASK_4BITS

        private static final int MASK_4BITS
        Mask used to extract 4 bits, used when decoding character.
        See Also:
        Constant Field Values
      • decodeTable

        private final byte[] decodeTable
        Decode table to use.
      • encodeTable

        private final byte[] encodeTable
        Encode table to use.
    • Constructor Detail

      • Base16

        public Base16()
        Creates a Base16 codec used for decoding and encoding.
      • Base16

        public Base16​(boolean lowerCase)
        Creates a Base16 codec used for decoding and encoding.
        Parameters:
        lowerCase - if true then use a lower-case Base16 alphabet.
      • Base16

        public Base16​(boolean lowerCase,
                      CodecPolicy decodingPolicy)
        Creates a Base16 codec used for decoding and encoding.
        Parameters:
        lowerCase - if true then use a lower-case Base16 alphabet.
        decodingPolicy - Decoding policy.
    • Method Detail

      • decodeOctet

        private int decodeOctet​(byte octet)
      • isInAlphabet

        public boolean isInAlphabet​(byte octet)
        Returns whether or not the octet is in the Base16 alphabet.
        Specified by:
        isInAlphabet in class BaseNCodec
        Parameters:
        octet - The value to test.
        Returns:
        true if the value is defined in the the Base16 alphabet false otherwise.
      • validateTrailingCharacter

        private void validateTrailingCharacter()
        Validates whether decoding allows an entire final trailing character that cannot be used for a complete byte.
        Throws:
        java.lang.IllegalArgumentException - if strict decoding is enabled