Package com.fasterxml.jackson.core

Class Base64Variant

java.lang.Object
com.fasterxml.jackson.core.Base64Variant
All Implemented Interfaces:
Serializable
public final class Base64Variant extends Object implements Serializable
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:

  • Field Details

    • PADDING_CHAR_NONE

      protected static final char PADDING_CHAR_NONE
      Placeholder used by "no padding" variant, to be used when a character value is needed.
      See Also:

    • 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:

    • 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:

  • Constructor Details

    • Base64Variant

      public Base64Variant(String name, String base64Alphabet, boolean writePadding, 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).
      Parameters:
      base - Variant to use for settings not specific by other parameters
      name - Name of this variant
      maxLineLength - Maximum length (in characters) of lines to output before using linefeed

    • Base64Variant

      public Base64Variant(Base64Variant base, String name, boolean writePadding, 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
      Parameters:
      base - Variant to use for settings not specific by other parameters
      name - Name of this variant
      writePadding - Whether variant will use padding when encoding
      paddingChar - Padding character used for encoding, excepted on reading, if any
      maxLineLength - Maximum length (in characters) of lines to output before using linefeed

  • Method Details

    • withPaddingAllowed

      public Base64Variant withPaddingAllowed()
      Returns:
      Base64Variant which does not require padding on read
      Since:
      2.12

    • withPaddingRequired

      public Base64Variant withPaddingRequired()
      Returns:
      Base64Variant which requires padding on read
      Since:
      2.12

    • withPaddingForbidden

      public Base64Variant withPaddingForbidden()
      Returns:
      Base64Variant which does not accept padding on read
      Since:
      2.12

    • withReadPadding

      public Base64Variant withReadPadding(Base64Variant.PaddingReadBehaviour readPadding)
      Parameters:
      readPadding - Padding read behavior desired
      Returns:
      Instance with desired padding read behavior setting (this if already has setting; new instance otherwise)
      Since:
      2.12

    • withWritePadding

      public Base64Variant withWritePadding(boolean writePadding)
      Parameters:
      writePadding - Determines if padding is output on write or not
      Returns:
      Base64Variant which writes padding or not depending on writePadding
      Since:
      2.12

    • readResolve

      protected Object readResolve()

    • getName

      public String getName()

    • usesPadding

      public boolean usesPadding()
      Returns:
      True if this Base64 encoding will write padding on output (note: before Jackson 2.12 also dictated whether padding was accepted on read)

    • requiresPaddingOnRead

      public boolean requiresPaddingOnRead()
      Returns:
      True if this variant requires padding on content decoded; false if not.
      Since:
      2.12

    • acceptsPaddingOnRead

      public boolean acceptsPaddingOnRead()
      Returns:
      True if this variant accepts padding on content decoded; false if not.
      Since:
      2.12

    • usesPaddingChar

      public boolean usesPaddingChar(char c)

    • usesPaddingChar

      public boolean usesPaddingChar(int ch)

    • paddingReadBehaviour

      public Base64Variant.PaddingReadBehaviour paddingReadBehaviour()
      Returns:
      Indicator on how this Base64 encoding will handle possible padding in content when reading.
      Since:
      2.12

    • getPaddingChar

      public char getPaddingChar()

    • getPaddingByte

      public byte getPaddingByte()

    • getMaxLineLength

      public int getMaxLineLength()

    • decodeBase64Char

      public int decodeBase64Char(char c)
      Parameters:
      c - Character to decode
      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 outPtr)
      Method that encodes given right-aligned (LSB) 24-bit value into 4 base64 characters, stored in given result buffer. Caller must ensure there is sufficient space for 4 encoded characters at specified position.
      Parameters:
      b24 - 3-byte value to encode
      buffer - Output buffer to append characters to
      outPtr - Starting position within buffer to append encoded characters
      Returns:
      Pointer in output buffer after appending 4 encoded characters

    • 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:
      bits - 24-bit chunk containing 1 or 2 bytes to encode
      outputBytes - Number of input bytes to encode (either 1 or 2)
      buffer - Output buffer to append characters to
      outPtr - Starting position within buffer to append encoded characters
      Returns:
      Pointer in output buffer after appending encoded characters (2, 3 or 4)

    • 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 outPtr)
      Method that encodes given right-aligned (LSB) 24-bit value into 4 base64 bytes (ascii), stored in given result buffer.
      Parameters:
      b24 - 3-byte value to encode
      buffer - Output buffer to append characters (as bytes) to
      outPtr - Starting position within buffer to append encoded characters
      Returns:
      Pointer in output buffer after appending 4 encoded characters

    • 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:
      bits - 24-bit chunk containing 1 or 2 bytes to encode
      outputBytes - Number of input bytes to encode (either 1 or 2)
      buffer - Output buffer to append characters to
      outPtr - Starting position within buffer to append encoded characters
      Returns:
      Pointer in output buffer after appending encoded characters (2, 3 or 4)

    • 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
      Returns:
      Base64 encoded String of encoded input bytes, not surrounded by quotes

    • 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. Linefeeds added, if needed, are expressed as 2-character JSON (and Java source) escape sequence of backslash + `n`.
      Parameters:
      input - Byte array to encode
      addQuotes - Whether to surround resulting value in double quotes or not
      Returns:
      Base64 encoded String of encoded input bytes, possibly surrounded by quotes (if addQuotes enabled)

    • encode

      public String encode(byte[] input, boolean addQuotes, String linefeed)
      Convenience method for converting given byte array as base64 encoded String using this variant's settings, optionally enclosed in double-quotes. Linefeed character to use is passed explicitly.
      Parameters:
      input - Byte array to encode
      addQuotes - Whether to surround resulting value in double quotes or not
      linefeed - Linefeed to use for encoded content
      Returns:
      Base64 encoded String of encoded input bytes
      Since:
      2.10

    • 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 - Base64-encoded input String to decode
      Returns:
      Byte array of decoded contents
      Throws:
      IllegalArgumentException - if input is not valid base64 encoded data
      Since:
      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.

      Parameters:
      str - Input to decode
      builder - Builder used for assembling decoded content
      Throws:
      IllegalArgumentException - if input is not valid base64 encoded data
      Since:
      2.3

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • _reportInvalidBase64

      protected void _reportInvalidBase64(char ch, int bindex, String msg) throws IllegalArgumentException
      Parameters:
      ch - Character to report on
      bindex - Relative index within base64 character unit; between 0 and 3 (as unit has exactly 4 characters)
      msg - Base message to use for exception
      Throws:
      IllegalArgumentException

    • _reportBase64EOF

      protected void _reportBase64EOF() throws IllegalArgumentException
      Throws:
      IllegalArgumentException

    • _reportBase64UnexpectedPadding

      protected void _reportBase64UnexpectedPadding() throws IllegalArgumentException
      Throws:
      IllegalArgumentException

    • unexpectedPaddingMessage

      protected String unexpectedPaddingMessage()
      Helper method that will construct a message to use in exceptions for cases where input ends prematurely in place where padding is not expected.
      Returns:
      Exception message for indicating "unexpected padding" case
      Since:
      2.12

    • missingPaddingMessage

      public String missingPaddingMessage()
      Helper method that will construct a message to use in exceptions for cases where input ends prematurely in place where padding would be expected.
      Returns:
      Exception message for indicating "missing padding" case
      Since:
      2.10