Class Base64

java.lang.Object
com.itextpdf.commons.utils.Base64

public class Base64 extends Object
Encodes and decodes to and from Base64 notation.

Homepage: http://iharder.net/base64.
Change Log:

  • v2.2.1 - Fixed bug using URL_SAFE and ORDERED encodings. Fixed bug when using very small files (~< 40 bytes).
  • v2.2 - Added some helper methods for encoding/decoding directly from one file to the next. Also added a main() method to support command line encoding/decoding from one file to the next. Also added these Base64 dialects:
    1. The default is RFC3548 format.
    2. Calling Base64.setFormat(Base64.BASE64_FORMAT.URLSAFE_FORMAT) generates URL and file name friendly format as described in Section 4 of RFC3548. http://www.faqs.org/rfcs/rfc3548.html
    3. Calling Base64.setFormat(Base64.BASE64_FORMAT.ORDERED_FORMAT) generates URL and file name friendly format that preserves lexical ordering as described in http://www.faqs.org/qa/rfcc-1940.html
    Special thanks to Jim Kellerman at http://www.powerset.com/ for contributing the new Base64 dialects.
  • 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:
2.2.1
Author:
Robert Harder, rob@iharder.net
  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    A Base64.InputStream will read data from another java.io.InputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly.
    static class 
    A Base64.OutputStream will write data to another java.io.OutputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly.
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    Specify decoding.
    static final int
    Don't break lines when encoding (violates strict Base64 specification)
    static final int
    Specify encoding.
    static final int
    Specify that data should be gzip-compressed.
    static final int
    No options specified.
    static final int
    Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.
    static final int
    Encode using Base64-like encoding that is URL- and Filename-safe as described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html.
  • Method Summary

    Modifier and Type
    Method
    Description
    static byte[]
    decode(byte[] source, int off, int len, int options)
    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.
    static byte[]
    decode(String s, int options)
    Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
    static void
    decodeFileToFile(String infile, String outfile)
    Reads infile and decodes it to outfile.
    static byte[]
    decodeFromFile(String filename)
    Convenience method for reading a base64-encoded file and decoding it.
    static boolean
    decodeToFile(String dataToDecode, String filename)
    Convenience method for decoding data to a file.
    static Object
    decodeToObject(String encodedObject)
    Attempts to decode Base64 data and deserialize a Java Object within.
    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.
    static void
    encodeFileToFile(String infile, String outfile)
    Reads infile and encodes it to outfile.
    static String
    encodeFromFile(String filename)
    Convenience method for reading a binary file and base64-encoding it.
    static String
    encodeObject(Serializable serializableObject)
    Serializes an object and returns the Base64-encoded version of that serialized object.
    static String
    encodeObject(Serializable serializableObject, int options)
    Serializes an object and returns the Base64-encoded version of that serialized object.
    static boolean
    encodeToFile(byte[] dataToEncode, String filename)
    Convenience method for encoding data to a file.

    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:
    • GZIP

      public static final int GZIP
      Specify that data should be gzip-compressed.
      See Also:
    • DONT_BREAK_LINES

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

      public static final int URL_SAFE
      Encode using Base64-like encoding that is URL- and Filename-safe as described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html. It is important to note that data encoded this way is not officially valid Base64, or at the very least should not be called Base64 without also specifying that is was encoded using the URL- and Filename-safe dialect.
      See Also:
    • ORDERED

      public static final int ORDERED
      Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.
      See Also:
  • Method Details

    • encodeObject

      public static String encodeObject (Serializable serializableObject)
      Serializes an object and returns the Base64-encoded version of that serialized object. If the object cannot be serialized or there is another error, the method will return null. The object is not GZip-compressed before being encoded.
      Parameters:
      serializableObject - The object to encode
      Returns:
      The Base64-encoded object
      Since:
      1.4
    • encodeObject

      public static String encodeObject (Serializable serializableObject, int options)
      Serializes an object and returns the Base64-encoded version of that serialized object. If the object cannot be serialized or there is another error, the method will return null.
      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: encodeObject( myObj, Base64.GZIP ) or
      Example: encodeObject( myObj, Base64.GZIP | Base64.DONT_BREAK_LINES )
      Parameters:
      serializableObject - The object to encode
      options - Specified options
      Returns:
      The Base64-encoded object
      Since:
      2.0
      See Also:
    • 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:
      The Base64-encoded 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:
      The Base64-encoded data
      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:
      The Base64-encoded data
      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 alphabet type is pulled from this (standard, url-safe, ordered)
      Returns:
      The Base64-encoded data
      Since:
      2.0
      See Also:
    • decode

      public static byte[] decode (byte[] source, int off, int len, int options)
      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
      options - The options when decoding
      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
    • decode

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

      public static Object decodeToObject (String encodedObject)
      Attempts to decode Base64 data and deserialize a Java Object within. Returns null if there was an error.
      Parameters:
      encodedObject - The Base64 data to decode
      Returns:
      The decoded and deserialized object
      Since:
      1.5
    • encodeToFile

      public static boolean encodeToFile (byte[] dataToEncode, String filename)
      Convenience method for encoding data to a file.
      Parameters:
      dataToEncode - byte array of data to encode in base64 form
      filename - Filename for saving encoded data
      Returns:
      true if successful, false otherwise
      Since:
      2.1
    • decodeToFile

      public static boolean decodeToFile (String dataToDecode, String filename)
      Convenience method for decoding data to a file.
      Parameters:
      dataToDecode - Base64-encoded data as a string
      filename - Filename for saving decoded data
      Returns:
      true if successful, false otherwise
      Since:
      2.1
    • decodeFromFile

      public static byte[] decodeFromFile (String filename)
      Convenience method for reading a base64-encoded file and decoding it.
      Parameters:
      filename - Filename for reading encoded data
      Returns:
      decoded byte array or null if unsuccessful
      Since:
      2.1
    • encodeFromFile

      public static String encodeFromFile (String filename)
      Convenience method for reading a binary file and base64-encoding it.
      Parameters:
      filename - Filename for reading binary data
      Returns:
      base64-encoded string or null if unsuccessful
      Since:
      2.1
    • encodeFileToFile

      public static void encodeFileToFile (String infile, String outfile)
      Reads infile and encodes it to outfile.
      Parameters:
      infile - Input file
      outfile - Output file
      Since:
      2.2
    • decodeFileToFile

      public static void decodeFileToFile (String infile, String outfile)
      Reads infile and decodes it to outfile.
      Parameters:
      infile - Input file
      outfile - Output file
      Since:
      2.2