Class Base64


  • abstract class Base64
    extends java.lang.Object
    A very fast and memory efficient class to encode and decode to and from BASE64 in full accordance with RFC 2045.

    On Windows XP sp1 with 1.4.2_04 and later ;), this encoder and decoder is about 10 times faster on small arrays (10 - 1000 bytes) and 2-3 times as fast on larger arrays (10000 - 1000000 bytes) compared to sun.misc.Encoder()/Decoder().

    On byte arrays the encoder is about 20% faster than Jakarta Commons Base64 Codec for encode and about 50% faster for decoding large arrays. This implementation is about twice as fast on very small arrays (< 30 bytes). If source/destination is a String this version is about three times as fast due to the fact that the Commons Codec result has to be recoded to a String from byte[], which is very expensive.

    This encode/decode algorithm doesn't create any temporary arrays as many other codecs do, it only allocates the resulting array. This produces less garbage and it is possible to handle arrays twice as large as algorithms that create a temporary array. (E.g. Jakarta Commons Codec). It is unknown whether Sun's sun.misc.Encoder()/Decoder() produce temporary arrays but since performance is quite low it probably does.

    The encoder produces the same output as the Sun one except that the Sun's encoder appends a trailing line separator if the last character isn't a pad. Unclear why but it only adds to the length and is probably a side effect. Both are in conformance with RFC 2045 though.
    Commons codec seem to always att a trailing line separator.

    Note! The encode/decode method pairs (types) come in three versions with the exact same algorithm and thus a lot of code redundancy. This is to not create any temporary arrays for transcoding to/from different format types. The methods not used can simply be commented out.

    There is also a "fast" version of all decode methods that works the same way as the normal ones, but har a few demands on the decoded input. Normally though, these fast verions should be used if the source if the input is known and it hasn't bee tampered with.

    If you find the code useful or you find a bug, please send me a note at base64 @ miginfocom . com. Licence (BSD): ============== Copyright (c) 2004, Mikael Grev, MiG InfoCom AB. (base64 @ miginfocom . com) All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of the MiG InfoCom AB nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    Version:
    2.2
    • Field Summary

      Fields 
      Modifier and Type Field Description
      (package private) static byte[] BA  
      private static char[] CA  
      private static byte[] EMPTY_ARRAY  
      (package private) static int[] IA  
    • Constructor Summary

      Constructors 
      Constructor Description
      Base64()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      (package private) static byte[] decodeFast​(byte[] sArr, int start, int end)  
      (package private) static long decodeLongBits​(JsonIterator iter)  
      (package private) static void encodeLongBits​(long bits, JsonStream stream)  
      (package private) static int encodeToBytes​(byte[] sArr, JsonStream stream)  
      (package private) static int encodeToChar​(byte[] sArr, char[] dArr, int start)  
      (package private) static int findEnd​(byte[] sArr, int start)  
      • Methods inherited from class java.lang.Object

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

      • CA

        private static final char[] CA
      • BA

        static final byte[] BA
      • IA

        static final int[] IA
      • EMPTY_ARRAY

        private static final byte[] EMPTY_ARRAY
    • Constructor Detail

      • Base64

        Base64()
    • Method Detail

      • encodeToChar

        static int encodeToChar​(byte[] sArr,
                                char[] dArr,
                                int start)
      • encodeToBytes

        static int encodeToBytes​(byte[] sArr,
                                 JsonStream stream)
                          throws java.io.IOException
        Throws:
        java.io.IOException
      • encodeLongBits

        static void encodeLongBits​(long bits,
                                   JsonStream stream)
                            throws java.io.IOException
        Throws:
        java.io.IOException
      • decodeLongBits

        static long decodeLongBits​(JsonIterator iter)
                            throws java.io.IOException
        Throws:
        java.io.IOException
      • findEnd

        static int findEnd​(byte[] sArr,
                           int start)
      • decodeFast

        static byte[] decodeFast​(byte[] sArr,
                                 int start,
                                 int end)