Class Base64Variant

  • All Implemented Interfaces:
    java.io.Serializable

    public final class Base64Variant
    extends java.lang.Object
    implements java.io.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.
    See Also:
    Serialized Form
    • Field Summary

      Fields 
      Modifier and Type Field Description
      static 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.
      static int BASE64_VALUE_PADDING
      Marker used to denote ascii character (in decoding table) that is the padding character using this variant (if any).
    • Constructor Summary

      Constructors 
      Constructor Description
      Base64Variant​(Base64Variant base, java.lang.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
      Base64Variant​(Base64Variant base, java.lang.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​(java.lang.String name, java.lang.String base64Alphabet, boolean usesPadding, char paddingChar, int maxLineLength)  
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      byte[] decode​(java.lang.String input)
      Convenience method for decoding contents of a Base64-encoded String, using this variant's settings.
      void decode​(java.lang.String str, ByteArrayBuilder builder)
      Convenience method for decoding contents of a Base64-encoded String, using this variant's settings and appending decoded binary data using provided ByteArrayBuilder.
      int decodeBase64Byte​(byte b)  
      int decodeBase64Char​(char c)  
      int decodeBase64Char​(int ch)  
      java.lang.String encode​(byte[] input)
      Convenience method for converting given byte array as base64 encoded String using this variant's settings.
      java.lang.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.
      java.lang.String encode​(byte[] input, boolean addQuotes, java.lang.String linefeed)
      Convenience method for converting given byte array as base64 encoded String using this variant's settings, optionally enclosed in double-quotes.
      byte encodeBase64BitsAsByte​(int value)  
      char encodeBase64BitsAsChar​(int value)  
      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.
      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.
      void encodeBase64Chunk​(java.lang.StringBuilder sb, int b24)  
      int encodeBase64Partial​(int bits, int outputBytes, byte[] buffer, int outPtr)
      Method that outputs partial chunk (which only encodes one or two bytes of data).
      int encodeBase64Partial​(int bits, int outputBytes, char[] buffer, int outPtr)
      Method that outputs partial chunk (which only encodes one or two bytes of data).
      void encodeBase64Partial​(java.lang.StringBuilder sb, int bits, int outputBytes)  
      boolean equals​(java.lang.Object o)  
      int getMaxLineLength()  
      java.lang.String getName()  
      byte getPaddingByte()  
      char getPaddingChar()  
      int hashCode()  
      java.lang.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.
      java.lang.String toString()  
      boolean usesPadding()  
      boolean usesPaddingChar​(char c)  
      boolean usesPaddingChar​(int ch)  
      • Methods inherited from class java.lang.Object

        getClass, notify, notifyAll, wait, wait, wait
    • 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
    • Constructor Detail

      • Base64Variant

        public Base64Variant​(java.lang.String name,
                             java.lang.String base64Alphabet,
                             boolean usesPadding,
                             char paddingChar,
                             int maxLineLength)
      • Base64Variant

        public Base64Variant​(Base64Variant base,
                             java.lang.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,
                             java.lang.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

      • getName

        public java.lang.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​(java.lang.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​(java.lang.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 java.lang.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 java.lang.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
      • encode

        public java.lang.String encode​(byte[] input,
                                       boolean addQuotes,
                                       java.lang.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
        Since:
        2.10
      • decode

        public byte[] decode​(java.lang.String input)
                      throws java.lang.IllegalArgumentException
        Convenience method for decoding contents of a Base64-encoded String, using this variant's settings.
        Parameters:
        input -
        Throws:
        java.lang.IllegalArgumentException - if input is not valid base64 encoded data
        Since:
        2.3
      • decode

        public void decode​(java.lang.String str,
                           ByteArrayBuilder builder)
                    throws java.lang.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:
        java.lang.IllegalArgumentException - if input is not valid base64 encoded data
        Since:
        2.3
      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object
      • equals

        public boolean equals​(java.lang.Object o)
        Overrides:
        equals in class java.lang.Object
      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class java.lang.Object
      • missingPaddingMessage

        public java.lang.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.
        Since:
        2.10