Package com.helger.commons.base64

Class Base64

  • @Immutable
public final class Base64
extends Object

    Encodes and decodes to and from Base64 notation.

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

    Example:

    String encoded = Base64.encode( myByteArray );
    byte[] myByteArray = Base64.decode( encoded );

    The options parameter, which appears in a few places, is used to pass several pieces of information to the encoder. In the "higher level" methods such as encodeBytes( bytes, options ) the options parameter can be used to indicate such things as first gzipping the bytes before encoding them, not inserting linefeeds, and encoding using the URL-safe and Ordered dialects.

    Note, according to RFC3548, Section 2.1, implementations should not add line feeds unless explicitly told to do so. I've got Base64 set to this behavior now, although earlier versions broke lines by default.

    The constants defined in Base64 can be OR-ed together to combine options, so you might make a call like this:

    String encoded = Base64.encodeBytes( mybytes, Base64.GZIP | Base64.DO_BREAK_LINES );

    to compress the data before encoding it and then making the output have newline characters.

    Also...

    String encoded = Base64.encodeBytes( crazyString.getBytes() );

    Change Log:

    • v2.3.7 - Fixed subtle bug when base 64 input stream contained the value 01111111, which is an invalid base 64 character but should not throw an ArrayIndexOutOfBoundsException either. Led to discovery of mishandling (or potential for better handling) of other bad input characters. You should now get an IOException if you try decoding something that has bad characters in it.
    • v2.3.6 - Fixed bug when breaking lines and the final byte of the encoded string ended in the last column; the buffer was not properly shrunk and contained an extra (null) byte that made it into the string.
    • v2.3.5 - Fixed bug in encodeFromFile(java.lang.String) where estimated buffer size was wrong for files of size 31, 34, and 37 bytes.
    • v2.3.4 - Fixed bug when working with gzipped streams whereby flushing the Base64.OutputStream closed the Base64 encoding (by padding with equals signs) too soon. Also added an option to suppress the automatic decoding of gzipped streams. Also added experimental support for specifying a class loader when using the decodeToObject(java.lang.String, int, java.lang.ClassLoader) method.
    • v2.3.3 - Changed default char encoding to US-ASCII which reduces the internal Java footprint with its CharEncoders and so forth. Fixed some javadocs that were inconsistent. Removed imports and specified things like IOException explicitly inline.
    • v2.3.2 - Reduced memory footprint! Finally refined the "guessing" of how big the final encoded data will be so that the code doesn't have to create two output arrays: an oversized initial one and then a final, exact-sized one. Big win when using the encodeBytesToBytes(byte[]) family of methods (and not using the gzip options which uses a different mechanism with streams and stuff).
    • v2.3.1 - Added encodeBytesToBytes(byte[], int, int, int) and some similar helper methods to be more efficient with memory by not returning a String but just a byte array.
    • v2.3 - This is not a drop-in replacement! This is two years of comments and bug fixes queued up and finally executed. Thanks to everyone who sent me stuff, and I'm sorry I wasn't able to distribute your fixes to everyone else. Much bad coding was cleaned up including throwing exceptions where necessary instead of returning null values or something similar. Here are some changes that may affect you:
      • Does not break lines, by default. This is to keep in compliance with RFC3548.
      • Throws exceptions instead of returning null values. Because some operations (especially those that may permit the GZIP option) use IO streams, there is a possiblity of an IOException being thrown. After some discussion and thought, I've changed the behavior of the methods to throw IOExceptions rather than return null if ever there's an error. I think this is more appropriate, though it will require some changes to your code. Sorry, it should have been done this way to begin with.
      • Removed all references to System.out, System.err, and the like. Shame on me. All I can say is sorry they were ever there.
      • Throws NullPointerExceptions and IllegalArgumentExceptions as needed such as when passed arrays are null or offsets are invalid.
      • Cleaned up as much javadoc as I could to avoid any javadoc warnings. This was especially annoying before for people who were thorough in their own projects and then had gobs of javadoc warnings on this file.
    • 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:
    2.3.7
    Author:
    Robert Harder, Philip Helger

    • Field Detail

      • NO_OPTIONS

        public static final int NO_OPTIONS
        No options specified. Value is zero.
        See Also:
        Constant Field Values

      • ENCODE

        public static final int ENCODE
        Specify encoding in first bit. Value is one.
        See Also:
        Constant Field Values

      • DECODE

        public static final int DECODE
        Specify decoding in first bit. Value is zero.
        See Also:
        Constant Field Values

      • GZIP

        public static final int GZIP
        Specify that data should be gzip-compressed in second bit. Value is two.
        See Also:
        Constant Field Values

      • DONT_GUNZIP

        public static final int DONT_GUNZIP
        Specify that gzipped data should not be automatically gunzipped.
        See Also:
        Constant Field Values

      • DO_BREAK_LINES

        public static final int DO_BREAK_LINES
        Do break lines when encoding. Value is 8.
        See Also:
        Constant Field Values

      • 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:
        Constant Field Values

      • DO_NEWLINE_CRLF

        public static final int DO_NEWLINE_CRLF
        Use "\r\n" instead of "\n" as newline separators. Only relevant, if option DO_BREAK_LINES is also used. Value is 64.
        See Also:
        Constant Field Values

      • MAX_LINE_LENGTH

        public static final int MAX_LINE_LENGTH
        Maximum line length (76) of Base64 output.
        See Also:
        Constant Field Values

      • EQUALS_SIGN

        public static final byte EQUALS_SIGN
        The equals sign (=) as a byte.
        See Also:
        Constant Field Values

      • NEW_LINE

        public static final byte NEW_LINE
        The new line character (\n) as a byte.
        See Also:
        Constant Field Values

      • PREFERRED_ENCODING

        public static final Charset PREFERRED_ENCODING
        Preferred encoding: US-ASCII

    • Method Detail

      • encode

        public static void encode​(@Nonnull
                          ByteBuffer raw,
                          @Nonnull
                          ByteBuffer encoded)
        Performs Base64 encoding on the raw ByteBuffer, writing it to the encoded ByteBuffer. This is an experimental feature. Currently it does not pass along any options (such as DO_BREAK_LINES or GZIP.
        Parameters:
        raw - input buffer
        encoded - output buffer
        Since:
        2.3

      • encode

        public static void encode​(@Nonnull
                          ByteBuffer raw,
                          @Nonnull
                          CharBuffer encoded)
        Performs Base64 encoding on the raw ByteBuffer, writing it to the encoded CharBuffer. This is an experimental feature. Currently it does not pass along any options (such as DO_BREAK_LINES or GZIP.
        Parameters:
        raw - input buffer
        encoded - output buffer
        Since:
        2.3

      • encodeBytes

        @Nonnull
public static String encodeBytes​(@Nonnull
                                 byte[] source)
        Encodes a byte array into Base64 notation. Does not GZip-compress data.
        Parameters:
        source - The data to convert
        Returns:
        The data in Base64-encoded form
        Throws:
        NullPointerException - if source array is null
        Since:
        1.4

      • encodeBytes

        @Nonnull
public static String encodeBytes​(@Nonnull
                                 byte[] source,
                                 int options)
                          throws IOException
        Encodes a byte array into Base64 notation.

        Example options: 

           GZIP: gzip-compresses object before encoding it.
   DO_BREAK_LINES: 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.DO_BREAK_LINES )

        As of v 2.3, if there is an error with the GZIP stream, the method will throw an IOException. This is new to v2.3! In earlier versions, it just returned a null value, but in retrospect that's a pretty poor way to handle it.

        Parameters:
        source - The data to convert
        options - Specified options
        Returns:
        The Base64-encoded data as a String
        Throws:
        IOException - if there is an error
        NullPointerException - if source array is null
        Since:
        2.0
        See Also:
        GZIP, DO_BREAK_LINES

      • encodeBytes

        @Nonnull
public static String encodeBytes​(@Nonnull
                                 byte[] source,
                                 int off,
                                 int len)
        Encodes a byte array into Base64 notation. Does not GZip-compress data.

        As of v 2.3, if there is an error, the method will throw an IOException. This is new to v2.3! In earlier versions, it just returned a null value, but in retrospect that's a pretty poor way to handle it.

        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 as a String
        Throws:
        NullPointerException - if source array is null
        IllegalArgumentException - if source array, offset, or length are invalid
        Since:
        1.4

      • encodeBytes

        @Nonnull
public static String encodeBytes​(@Nonnull
                                 byte[] source,
                                 @Nonnegative
                                 int off,
                                 @Nonnegative
                                 int len,
                                 int nOptions)
                          throws IOException
        Encodes a byte array into Base64 notation.

        Example options: 

           GZIP: gzip-compresses object before encoding it.
   DO_BREAK_LINES: 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.DO_BREAK_LINES )

        As of v 2.3, if there is an error with the GZIP stream, the method will throw an IOException. This is new to v2.3! In earlier versions, it just returned a null value, but in retrospect that's a pretty poor way to handle it.

        Parameters:
        source - The data to convert
        off - Offset in array where conversion should begin
        len - Length of data to convert
        nOptions - Specified options
        Returns:
        The Base64-encoded data as a String
        Throws:
        IOException - if there is an error
        NullPointerException - if source array is null
        IllegalArgumentException - if source array, offset, or length are invalid
        Since:
        2.0
        See Also:
        GZIP, DO_BREAK_LINES

      • encodeBytesToBytes

        @Nonnull
@ReturnsMutableCopy
public static byte[] encodeBytesToBytes​(@Nonnull
                                        byte[] source)
        Similar to encodeBytes(byte[]) but returns a byte array instead of instantiating a String. This is more efficient if you're working with I/O streams and have large data sets to encode.
        Parameters:
        source - The data to convert
        Returns:
        The Base64-encoded data as a byte[] (of ASCII characters)
        Throws:
        NullPointerException - if source array is null
        Since:
        2.3.1

      • decode

        @Nonnull
@ReturnsMutableCopy
public static byte[] decode​(@Nonnull
                            byte[] source)
                     throws IOException
        Low-level access to decoding ASCII characters in the form of a byte array. Ignores GUNZIP option, if it's set. This is not generally a recommended method, although it is used internally as part of the decoding process. Special case: if len = 0, an empty array is returned. Still, if you need more speed and reduced memory footprint (and aren't gzipping), consider this method.
        Parameters:
        source - The Base64 encoded data
        Returns:
        decoded data
        Throws:
        IOException - In case of error
        Since:
        2.3.1

      • decode

        @Nonnull
@ReturnsMutableCopy
public static byte[] decode​(@Nonnull
                            byte[] source,
                            int options)
                     throws IOException
        Low-level access to decoding ASCII characters in the form of a byte array. Ignores GUNZIP option, if it's set. This is not generally a recommended method, although it is used internally as part of the decoding process. Special case: if len = 0, an empty array is returned. Still, if you need more speed and reduced memory footprint (and aren't gzipping), consider this method.
        Parameters:
        source - The Base64 encoded data
        options - Can specify options such as alphabet type to use
        Returns:
        decoded data
        Throws:
        IOException - In case of error
        Since:
        2.3.1

      • decode

        @Nonnull
@ReturnsMutableCopy
public static byte[] decode​(@Nonnull
                            byte[] aSource,
                            int nOfs,
                            int nLen,
                            int nOptions)
                     throws IOException
        Low-level access to decoding ASCII characters in the form of a byte array. Ignores GUNZIP option, if it's set. This is not generally a recommended method, although it is used internally as part of the decoding process. Special case: if len = 0, an empty array is returned. Still, if you need more speed and reduced memory footprint (and aren't gzipping), consider this method.
        Parameters:
        aSource - The Base64 encoded data
        nOfs - The offset of where to begin decoding
        nLen - The length of characters to decode
        nOptions - Can specify options such as alphabet type to use
        Returns:
        decoded data
        Throws:
        IOException - If bogus characters exist in source data
        Since:
        1.3

      • decode

        @Nonnull
@ReturnsMutableCopy
public static byte[] decode​(@Nonnull
                            String s)
                     throws IOException
        Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
        Parameters:
        s - the string to decode
        Returns:
        the decoded data
        Throws:
        IOException - If there is a problem
        Since:
        1.4

      • decode

        @Nonnull
@ReturnsMutableCopy
public static byte[] decode​(@Nonnull
                            String s,
                            int options)
                     throws IOException
        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
        Throws:
        IOException - if there is an error
        NullPointerException - if s is null
        Since:
        1.4

      • encodeToFile

        @Nonnull
public static ESuccess encodeToFile​(@Nonnull
                                    byte[] aDataToEncode,
                                    @Nonnull
                                    File aFile)
                             throws IOException
        Convenience method for encoding data to a file.

        As of v 2.3, if there is a error, the method will throw an IOException. This is new to v2.3! In earlier versions, it just returned false, but in retrospect that's a pretty poor way to handle it.

        Parameters:
        aDataToEncode - byte array of data to encode in base64 form
        aFile - File for saving encoded data
        Returns:
        ESuccess
        Throws:
        IOException - if there is an error
        NullPointerException - if dataToEncode is null
        Since:
        2.1

      • decodeToFile

        @Nonnull
public static ESuccess decodeToFile​(@Nonnull
                                    String sDataToDecode,
                                    @Nonnull
                                    File aFile)
                             throws IOException
        Convenience method for decoding data to a file.

        As of v 2.3, if there is a error, the method will throw an IOException. This is new to v2.3! In earlier versions, it just returned false, but in retrospect that's a pretty poor way to handle it.

        Parameters:
        sDataToDecode - Base64-encoded data as a string
        aFile - File for saving decoded data
        Returns:
        ESuccess
        Throws:
        IOException - if there is an error
        Since:
        2.1

      • decodeFromFile

        @Nonnull
@ReturnsMutableCopy
public static byte[] decodeFromFile​(@Nonnull
                                    String sFilename)
                             throws IOException
        Convenience method for reading a base64-encoded file and decoding it.

        As of v 2.3, if there is a error, the method will throw an IOException. This is new to v2.3! In earlier versions, it just returned false, but in retrospect that's a pretty poor way to handle it.

        Parameters:
        sFilename - Filename for reading encoded data
        Returns:
        decoded byte array
        Throws:
        IOException - if there is an error
        Since:
        2.1

      • encodeFromFile

        @Nonnull
public static String encodeFromFile​(@Nonnull
                                    String sFilename)
                             throws IOException
        Convenience method for reading a binary file and base64-encoding it.

        As of v 2.3, if there is a error, the method will throw an IOException. This is new to v2.3! In earlier versions, it just returned false, but in retrospect that's a pretty poor way to handle it.

        Parameters:
        sFilename - Filename for reading binary data
        Returns:
        base64-encoded string
        Throws:
        IOException - if there is an error
        Since:
        2.1

      • encodeFileToFile

        public static void encodeFileToFile​(@Nonnull
                                    String infile,
                                    @Nonnull
                                    File aFile)
                             throws IOException
        Reads infile and encodes it to outfile.
        Parameters:
        infile - Input file
        aFile - Output file
        Throws:
        IOException - if there is an error
        Since:
        2.2

      • decodeFileToFile

        public static void decodeFileToFile​(@Nonnull
                                    String aInFile,
                                    @Nonnull
                                    File aOutFile)
                             throws IOException
        Reads infile and decodes it to outfile.
        Parameters:
        aInFile - Input file
        aOutFile - Output file
        Throws:
        IOException - if there is an error
        Since:
        2.2

      • safeDecode

        @Nullable
@ReturnsMutableCopy
public static byte[] safeDecode​(@Nullable
                                String sEncoded)
        Decode the string with the default encoding (US-ASCII is the preferred one).
        Parameters:
        sEncoded - The encoded string.
        Returns:
        null if decoding failed.

      • safeDecode

        @Nullable
@ReturnsMutableCopy
public static byte[] safeDecode​(@Nullable
                                String sEncoded,
                                int nOptions)
        Decode the string with the default encoding (US-ASCII is the preferred one).
        Parameters:
        sEncoded - The encoded string.
        nOptions - Decoding options.
        Returns:
        null if decoding failed.

      • safeDecode

        @Nullable
@ReturnsMutableCopy
public static byte[] safeDecode​(@Nullable
                                byte[] aEncodedBytes)
        Decode the byte array.
        Parameters:
        aEncodedBytes - The encoded byte array.
        Returns:
        null if decoding failed.

      • safeDecode

        @Nullable
@ReturnsMutableCopy
public static byte[] safeDecode​(@Nullable
                                byte[] aEncodedBytes,
                                int nOptions)
        Decode the byte array.
        Parameters:
        aEncodedBytes - The encoded byte array.
        nOptions - Decoding options.
        Returns:
        null if decoding failed.

      • safeDecode

        @Nullable
@ReturnsMutableCopy
public static byte[] safeDecode​(@Nullable
                                byte[] aEncodedBytes,
                                @Nonnegative
                                int nOfs,
                                @Nonnegative
                                int nLen)
        Decode the byte array.
        Parameters:
        aEncodedBytes - The encoded byte array.
        nOfs - The offset of where to begin decoding
        nLen - The number of characters to decode
        Returns:
        null if decoding failed.

      • safeDecode

        @Nullable
@ReturnsMutableCopy
public static byte[] safeDecode​(@Nullable
                                byte[] aEncodedBytes,
                                @Nonnegative
                                int nOfs,
                                @Nonnegative
                                int nLen,
                                int nOptions)
        Decode the byte array.
        Parameters:
        aEncodedBytes - The encoded byte array.
        nOfs - The offset of where to begin decoding
        nLen - The number of characters to decode
        nOptions - Decoding options.
        Returns:
        null if decoding failed.

      • safeDecodeAsString

        @Nullable
public static String safeDecodeAsString​(@Nullable
                                        String sEncoded,
                                        @Nonnull
                                        Charset aCharset)
        Decode the string and convert it back to a string.
        Parameters:
        sEncoded - The encoded string.
        aCharset - The character set to be used.
        Returns:
        null if decoding failed.

      • safeDecodeAsString

        @Nullable
public static String safeDecodeAsString​(@Nullable
                                        byte[] aEncodedBytes,
                                        @Nonnull
                                        Charset aCharset)
        Decode the byte array and convert it to a string.
        Parameters:
        aEncodedBytes - The encoded byte array.
        aCharset - The character set to be used.
        Returns:
        null if decoding failed.

      • safeDecodeAsString

        @Nullable
public static String safeDecodeAsString​(@Nullable
                                        byte[] aEncodedBytes,
                                        @Nonnegative
                                        int nOfs,
                                        @Nonnegative
                                        int nLength,
                                        @Nonnull
                                        Charset aCharset)
        Decode the byte array and convert it to a string.
        Parameters:
        aEncodedBytes - The encoded byte array.
        nOfs - Offset into array
        nLength - Number of bytes to decode.
        aCharset - The character set to be used.
        Returns:
        null if decoding failed.