com.fasterxml.jackson.core

Class Base64Variant

  • All Implemented Interfaces:
    Serializable


    public final class Base64Variant
    extends Object
    implements Serializable
    Abstract base class used to define specific details of which variant of Base64 encoding/decoding is to be used. Although there is somewhat standard basic version (so-called "MIME Base64"), other variants exists, see Base64 Wikipedia entry for details.
    Author:
    Tatu Saloranta
    See Also:
    Serialized Form
    • Field Detail

      • BASE64_VALUE_INVALID

        public static final int BASE64_VALUE_INVALID
        Marker used to denote ascii characters that do not correspond to a 6-bit value (in this variant), and is not used as a padding character.
        See Also:
        Constant Field Values
      • BASE64_VALUE_PADDING

        public static final int BASE64_VALUE_PADDING
        Marker used to denote ascii character (in decoding table) that is the padding character using this variant (if any).
        See Also:
        Constant Field Values
      • _name

        protected final String _name
        Symbolic name of variant; used for diagnostics/debugging.

        Note that this is the only non-transient field; used when reading back from serialized state

      • _usesPadding

        protected final transient boolean _usesPadding
        Whether this variant uses padding or not.
      • _paddingChar

        protected final transient char _paddingChar
        Characted used for padding, if any (PADDING_CHAR_NONE if not).
      • _maxLineLength

        protected final transient int _maxLineLength
        Maximum number of encoded base64 characters to output during encoding before adding a linefeed, if line length is to be limited (Integer.MAX_VALUE if not limited).

        Note: for some output modes (when writing attributes) linefeeds may need to be avoided, and this value ignored.

    • Constructor Detail

      • Base64Variant

        public Base64Variant(String name,
                             String base64Alphabet,
                             boolean usesPadding,
                             char paddingChar,
                             int maxLineLength)
      • Base64Variant

        public Base64Variant(Base64Variant base,
                             String name,
                             int maxLineLength)
        "Copy constructor" that can be used when the base alphabet is identical to one used by another variant except for the maximum line length (and obviously, name).
      • Base64Variant

        public Base64Variant(Base64Variant base,
                             String name,
                             boolean usesPadding,
                             char paddingChar,
                             int maxLineLength)
        "Copy constructor" that can be used when the base alphabet is identical to one used by another variant, but other details (padding, maximum line length) differ
    • Method Detail

      • readResolve

        protected Object readResolve()
        Method used to "demote" deserialized instances back to canonical ones
      • getName

        public String getName()
      • usesPadding

        public boolean usesPadding()
      • usesPaddingChar

        public boolean usesPaddingChar(char c)
      • usesPaddingChar

        public boolean usesPaddingChar(int ch)
      • getPaddingChar

        public char getPaddingChar()
      • getPaddingByte

        public byte getPaddingByte()
      • getMaxLineLength

        public int getMaxLineLength()
      • decodeBase64Char

        public int decodeBase64Char(char c)
        Returns:
        6-bit decoded value, if valid character;
      • decodeBase64Char

        public int decodeBase64Char(int ch)
      • decodeBase64Byte

        public int decodeBase64Byte(byte b)
      • encodeBase64BitsAsChar

        public char encodeBase64BitsAsChar(int value)
      • encodeBase64Chunk

        public int encodeBase64Chunk(int b24,
                                     char[] buffer,
                                     int ptr)
        Method that encodes given right-aligned (LSB) 24-bit value into 4 base64 characters, stored in given result buffer.
      • encodeBase64Chunk

        public void encodeBase64Chunk(StringBuilder sb,
                                      int b24)
      • encodeBase64Partial

        public int encodeBase64Partial(int bits,
                                       int outputBytes,
                                       char[] buffer,
                                       int outPtr)
        Method that outputs partial chunk (which only encodes one or two bytes of data). Data given is still aligned same as if it as full data; that is, missing data is at the "right end" (LSB) of int.
        Parameters:
        outputBytes - Number of encoded bytes included (either 1 or 2)
      • encodeBase64Partial

        public void encodeBase64Partial(StringBuilder sb,
                                        int bits,
                                        int outputBytes)
      • encodeBase64BitsAsByte

        public byte encodeBase64BitsAsByte(int value)
      • encodeBase64Chunk

        public int encodeBase64Chunk(int b24,
                                     byte[] buffer,
                                     int ptr)
        Method that encodes given right-aligned (LSB) 24-bit value into 4 base64 bytes (ascii), stored in given result buffer.
      • encodeBase64Partial

        public int encodeBase64Partial(int bits,
                                       int outputBytes,
                                       byte[] buffer,
                                       int outPtr)
        Method that outputs partial chunk (which only encodes one or two bytes of data). Data given is still aligned same as if it as full data; that is, missing data is at the "right end" (LSB) of int.
        Parameters:
        outputBytes - Number of encoded bytes included (either 1 or 2)
      • encode

        public String encode(byte[] input)
        Convenience method for converting given byte array as base64 encoded String using this variant's settings. Resulting value is "raw", that is, not enclosed in double-quotes.
        Parameters:
        input - Byte array to encode
      • encode

        public String encode(byte[] input,
                             boolean addQuotes)
        Convenience method for converting given byte array as base64 encoded String using this variant's settings, optionally enclosed in double-quotes.
        Parameters:
        input - Byte array to encode
        addQuotes - Whether to surround resulting value in double quotes or not
      • decode

        public byte[] decode(String input)
                      throws IllegalArgumentException
        Convenience method for decoding contents of a Base64-encoded String, using this variant's settings.
        Parameters:
        input -
        Throws:
        IllegalArgumentException - if input is not valid base64 encoded data
        Since:
        2.2.3
      • decode

        public void decode(String str,
                           ByteArrayBuilder builder)
                    throws IllegalArgumentException
        Convenience method for decoding contents of a Base64-encoded String, using this variant's settings and appending decoded binary data using provided ByteArrayBuilder.

        NOTE: builder will NOT be reset before decoding (nor cleared afterwards); assumption is that caller will ensure it is given in proper state, and used as appropriate afterwards.

        Throws:
        IllegalArgumentException - if input is not valid base64 encoded data
        Since:
        2.2.3
      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object
      • _reportInvalidBase64

        protected void _reportInvalidBase64(char ch,
                                            int bindex,
                                            String msg)
                                     throws IllegalArgumentException
        Parameters:
        bindex - Relative index within base64 character unit; between 0 and 3 (as unit has exactly 4 characters)
        Throws:
        IllegalArgumentException

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