Class Base64

java.lang.Object
org.postgresql.util.Base64

public class Base64 extends Object

This code is a stripped down version of Robert Harder's Public Domain Base64 implementation. GZIP support, InputStream and OutputStream stuff and some unneeded encode/decode methods have been removed.

-- Original comments follow --

Encodes and decodes to and from Base64 notation.

Change Log:

  • v2.1 - Cleaned up javadoc comments and unused variables and methods. Added some convenience methods for reading and writing to and from files.
  • v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on systems with other encodings (like EBCDIC).
  • v2.0.1 - Fixed an error when decoding a single byte, that is, when the encoded data was a single byte.
  • v2.0 - I got rid of methods that used booleans to set options. Now everything is more consolidated and cleaner. The code now detects when data that's being decoded is gzip-compressed and will decompress it automatically. Generally things are cleaner. You'll probably have to change some method calls that you were making to support the new options format (ints that you "OR" together).
  • v1.5.1 - Fixed bug when decompressing and decoding to a byte[] using decode( String s, boolean gzipCompressed ). Added the ability to "suspend" encoding in the Output Stream so you can turn on and off the encoding if you need to embed base64 data in an otherwise "normal" stream (like an XML file).
  • v1.5 - Output stream pases on flush() command but doesn't do anything itself. This helps when using GZIP streams. Added the ability to GZip-compress objects before encoding them.
  • v1.4 - Added helper methods to read/write files.
  • v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.
  • v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input stream where last buffer being read, if not completely full, was not returned.
  • v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.
  • v1.3.3 - Fixed I/O streams which were totally messed up.

I am placing this code in the Public Domain. Do with it as you will. This software comes with no guarantees or warranties but with plenty of well-wishing instead! Please visit http://iharder.net/base64 periodically to check for updates or to contribute improvements.

Version:
2.1
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private static final byte[]
     
    private static final byte[]
    The 64 valid Base64 values.
    private static final byte[]
    Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning.
    static final int
    Specify decoding.
    static final int
    Don't break lines when encoding (violates strict Base64 specification).
    static final int
    Specify encoding.
    private static final byte
    The equals sign (=) as a byte.
    private static final byte
     
    private static final int
    Maximum line length (76) of Base64 output.
    private static final byte
    The new line character (\n) as a byte.
    static final int
    No options specified.
    private static final String
    Preferred encoding.
    private static final byte
     
  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    private
    Defeats instantiation.
  • Method Summary

    Modifier and Type
    Method
    Description
    static byte[]
    decode(byte[] source, int off, int len)
    Very low-level access to decoding ASCII characters in the form of a byte array.
    static byte[]
    Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
    private static int
    decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset)
    Decodes four bytes from array source and writes the resulting bytes (up to three of them) to destination.
    private static byte[]
    encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset)
    Encodes up to three bytes of the array source and writes the resulting four Base64 bytes to destination.
    static String
    encodeBytes(byte[] source)
    Encodes a byte array into Base64 notation.
    static String
    encodeBytes(byte[] source, int options)
    Encodes a byte array into Base64 notation.
    static String
    encodeBytes(byte[] source, int off, int len)
    Encodes a byte array into Base64 notation.
    static String
    encodeBytes(byte[] source, int off, int len, int options)
    Encodes a byte array into Base64 notation.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • NO_OPTIONS

      public static final int NO_OPTIONS
      No options specified. Value is zero.
      See Also:
    • ENCODE

      public static final int ENCODE
      Specify encoding.
      See Also:
    • DECODE

      public static final int DECODE
      Specify decoding.
      See Also:
    • DONT_BREAK_LINES

      public static final int DONT_BREAK_LINES
      Don't break lines when encoding (violates strict Base64 specification).
      See Also:
    • MAX_LINE_LENGTH

      private static final int MAX_LINE_LENGTH
      Maximum line length (76) of Base64 output.
      See Also:
    • EQUALS_SIGN

      private static final byte EQUALS_SIGN
      The equals sign (=) as a byte.
      See Also:
    • NEW_LINE

      private static final byte NEW_LINE
      The new line character (\n) as a byte.
      See Also:
    • PREFERRED_ENCODING

      private static final String PREFERRED_ENCODING
      Preferred encoding.
      See Also:
    • ALPHABET

      private static final byte[] ALPHABET
      The 64 valid Base64 values.
    • _NATIVE_ALPHABET

      private static final byte[] _NATIVE_ALPHABET
    • DECODABET

      private static final byte[] DECODABET
      Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning.
    • WHITE_SPACE_ENC

      private static final byte WHITE_SPACE_ENC
      See Also:
    • EQUALS_SIGN_ENC

      private static final byte EQUALS_SIGN_ENC
      See Also:
  • Constructor Details

    • Base64

      private Base64()
      Defeats instantiation.
  • Method Details

    • encode3to4

      private static byte[] encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset)
      Encodes up to three bytes of the array source and writes the resulting four Base64 bytes to destination. The source and destination arrays can be manipulated anywhere along their length by specifying srcOffset and destOffset. This method does not check to make sure your arrays are large enough to accommodate srcOffset + 3 for the source array or destOffset + 4 for the destination array. The actual number of significant bytes in your array is given by numSigBytes.
      Parameters:
      source - the array to convert
      srcOffset - the index where conversion begins
      numSigBytes - the number of significant bytes in your array
      destination - the array to hold the conversion
      destOffset - the index where output will be put
      Returns:
      the destination array
      Since:
      1.3
    • encodeBytes

      public static String encodeBytes(byte[] source)
      Encodes a byte array into Base64 notation. Does not GZip-compress data.
      Parameters:
      source - The data to convert
      Returns:
      Base64 notation of input data
      Since:
      1.4
    • encodeBytes

      public static String encodeBytes(byte[] source, int options)

      Encodes a byte array into Base64 notation.

      Valid options:

         GZIP: gzip-compresses object before encoding it.
         DONT_BREAK_LINES: don't break lines at 76 characters
           Note: Technically, this makes your encoding non-compliant.
       

      Example: encodeBytes( myData, Base64.GZIP ) or

      Example: encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )

      Parameters:
      source - The data to convert
      options - Specified options
      Returns:
      Base64 notation
      Since:
      2.0
      See Also:
    • encodeBytes

      public static String encodeBytes(byte[] source, int off, int len)
      Encodes a byte array into Base64 notation. Does not GZip-compress data.
      Parameters:
      source - The data to convert
      off - Offset in array where conversion should begin
      len - Length of data to convert
      Returns:
      Base64 notation
      Since:
      1.4
    • encodeBytes

      public static String encodeBytes(byte[] source, int off, int len, int options)

      Encodes a byte array into Base64 notation.

      Valid options:

         GZIP: gzip-compresses object before encoding it.
         DONT_BREAK_LINES: don't break lines at 76 characters
           Note: Technically, this makes your encoding non-compliant.
       

      Example: encodeBytes( myData, Base64.GZIP ) or

      Example: encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )

      Parameters:
      source - The data to convert
      off - Offset in array where conversion should begin
      len - Length of data to convert
      options - Specified options
      Returns:
      Base64 notation
      Since:
      2.0
      See Also:
    • decode4to3

      private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset)
      Decodes four bytes from array source and writes the resulting bytes (up to three of them) to destination. The source and destination arrays can be manipulated anywhere along their length by specifying srcOffset and destOffset. This method does not check to make sure your arrays are large enough to accommodate srcOffset + 4 for the source array or destOffset + 3 for the destination array. This method returns the actual number of bytes that were converted from the Base64 encoding.
      Parameters:
      source - the array to convert
      srcOffset - the index where conversion begins
      destination - the array to hold the conversion
      destOffset - the index where output will be put
      Returns:
      the number of decoded bytes converted
      Since:
      1.3
    • decode

      public static byte[] decode(byte[] source, int off, int len)
      Very low-level access to decoding ASCII characters in the form of a byte array. Does not support automatically gunzipping or any other "fancy" features.
      Parameters:
      source - The Base64 encoded data
      off - The offset of where to begin decoding
      len - The length of characters to decode
      Returns:
      decoded data
      Since:
      1.3
    • decode

      public static byte[] decode(String s)
      Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
      Parameters:
      s - the string to decode
      Returns:
      the decoded data
      Since:
      1.4