package org.apache.xmlrpc;

/*
 * $Header: /home/cvs/xml-rpc/src/java/org/apache/xmlrpc/Base64.java,v 1.4.2.3 2003/02/04 03:47:42 rhoegg Exp $
 * $Revision: 1.4.2.3 $
 * $Date: 2003/02/04 03:47:42 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
 * ITS 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * [Additional notices, if required by prior licensing conditions]
 *
 */

import java.util.Enumeration;
import java.util.Vector;

/**
 * This class provides encode/decode for RFC 2045 Base64 as defined by
 * RFC 2045, N. Freed and N. Borenstein.  <a
 * href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>:
 * Multipurpose Internet Mail Extensions (MIME) Part One: Format of
 * Internet Message Bodies. Reference 1996
 *
 * @author Jeffrey Rodriguez
 * @author Daniel Rall
 * @since 1.2
 */
public final class  Base64
{
    static final int CHUNK_SIZE = 76;
    static final byte[] CHUNK_SEPARATOR = "\n".getBytes();

    static private final int  BASELENGTH         = 255;
    static private final int  LOOKUPLENGTH       = 64;
    static private final int  TWENTYFOURBITGROUP = 24;
    static private final int  EIGHTBIT           = 8;
    static private final int  SIXTEENBIT         = 16;
    static private final int  SIXBIT             = 6;
    static private final int  FOURBYTE           = 4;
    static private final int  SIGN               = -128;
    static private final byte PAD                = (byte) '=';
    static private byte [] base64Alphabet       = new byte[BASELENGTH];
    static private byte [] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
    //static private final Log log = LogSource.getInstance("org.apache.commons.util.Base64");

    static
    {
        for (int i = 0; i < BASELENGTH; i++ )
        {
            base64Alphabet[i] = -1;
        }
        for (int i = 'Z'; i >= 'A'; i--)
        {
            base64Alphabet[i] = (byte) (i - 'A');
        }
        for (int i = 'z'; i>= 'a'; i--)
        {
            base64Alphabet[i] = (byte) (i - 'a' + 26);
        }
        for (int i = '9'; i >= '0'; i--)
        {
            base64Alphabet[i] = (byte) (i - '0' + 52);
        }

        base64Alphabet['+']  = 62;
        base64Alphabet['/']  = 63;

        for (int i = 0; i <= 25; i++ )
            lookUpBase64Alphabet[i] = (byte) ('A' + i);

        for (int i = 26,  j = 0; i <= 51; i++, j++ )
            lookUpBase64Alphabet[i] = (byte) ('a'+ j);

        for (int i = 52,  j = 0; i <= 61; i++, j++ )
            lookUpBase64Alphabet[i] = (byte) ('0' + j);

        lookUpBase64Alphabet[62] = (byte) '+';
        lookUpBase64Alphabet[63] = (byte) '/';
    }

    public static boolean isBase64( String isValidString )
    {
        return isArrayByteBase64(isValidString.getBytes());
    }

    public static boolean isBase64( byte octect )
    {
        //shall we ignore white space? JEFF??
        return (octect == PAD || base64Alphabet[octect] != -1);
    }

    public static boolean isArrayByteBase64( byte[] arrayOctect )
    {
        int length = arrayOctect.length;
        if (length == 0)
        {
            // shouldn't a 0 length array be valid base64 data?
            // return false;
            return true;
        }
        for (int i=0; i < length; i++)
        {
            if ( !Base64.isBase64(arrayOctect[i]) )
                return false;
        }
        return true;
    }

    /**
     * Encodes hex octects into Base64.
     *
     * @param binaryData Array containing binary data to encode.
     * @return Base64-encoded data.
     */
    public static byte[] encode( byte[] binaryData )
    {
        int      lengthDataBits    = binaryData.length*EIGHTBIT;
        int      fewerThan24bits   = lengthDataBits%TWENTYFOURBITGROUP;
        int      numberTriplets    = lengthDataBits/TWENTYFOURBITGROUP;
        byte     encodedData[]     = null;
        int      encodedDataLength = 0;

        if (fewerThan24bits != 0)
        {
            //data not divisible by 24 bit
            encodedDataLength = (numberTriplets + 1 ) * 4;
        }
        else
        {
            // 16 or 8 bit
            encodedDataLength = numberTriplets * 4;
        }

        // allow extra length for the separator
        int nbrChunks = (CHUNK_SEPARATOR.length == 0 ? 0 :
                         (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE));

        encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length;
        encodedData = new byte[encodedDataLength];

        byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;

        int encodedIndex = 0;
        int dataIndex   = 0;
        int i           = 0;
        int nextSeparatorIndex = CHUNK_SIZE;
        int chunksSoFar = 0;

        //log.debug("number of triplets = " + numberTriplets);
        for ( i = 0; i<numberTriplets; i++ )
        {
            dataIndex = i*3;
            b1 = binaryData[dataIndex];
            b2 = binaryData[dataIndex + 1];
            b3 = binaryData[dataIndex + 2];

            //log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3);

            l  = (byte)(b2 & 0x0f);
            k  = (byte)(b1 & 0x03);

            byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
            byte val2 = ((b2 & SIGN)==0)?(byte)(b2>>4):(byte)((b2)>>4^0xf0);
            byte val3 = ((b3 & SIGN)==0)?(byte)(b3>>6):(byte)((b3)>>6^0xfc);

            encodedData[encodedIndex]   = lookUpBase64Alphabet[ val1 ];
            //log.debug( "val2 = " + val2 );
            //log.debug( "k4   = " + (k<<4) );
            //log.debug(  "vak  = " + (val2 | (k<<4)) );
            encodedData[encodedIndex+1] =
                lookUpBase64Alphabet[ val2 | ( k<<4 )];
            encodedData[encodedIndex+2] =
                lookUpBase64Alphabet[ (l <<2 ) | val3 ];
            encodedData[encodedIndex+3] = lookUpBase64Alphabet[ b3 & 0x3f ];

            encodedIndex += 4;

            // this assumes that CHUNK_SIZE % 4 == 0
            if(encodedIndex == nextSeparatorIndex){
                System.arraycopy(CHUNK_SEPARATOR, 0, encodedData,
                                 encodedIndex, CHUNK_SEPARATOR.length);
                chunksSoFar++;
                nextSeparatorIndex = (CHUNK_SIZE * (chunksSoFar + 1)) +
                                     (chunksSoFar * CHUNK_SEPARATOR.length);
                encodedIndex += CHUNK_SEPARATOR.length;
            }
        }

        // form integral number of 6-bit groups
        dataIndex    = i*3;

        if (fewerThan24bits == EIGHTBIT )
        {
            b1 = binaryData[dataIndex];
            k = (byte) ( b1 &0x03 );
            //log.debug("b1=" + b1);
            //log.debug("b1<<2 = " + (b1>>2) );
            byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
            encodedData[encodedIndex]     = lookUpBase64Alphabet[ val1 ];
            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[ k<<4 ];
            encodedData[encodedIndex + 2] = PAD;
            encodedData[encodedIndex + 3] = PAD;
        }
        else if (fewerThan24bits == SIXTEENBIT)
        {

            b1 = binaryData[dataIndex];
            b2 = binaryData[dataIndex +1 ];
            l = (byte) (b2 & 0x0f);
            k = (byte) (b1 & 0x03);

            byte val1 = ((b1 & SIGN) == 0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
            byte val2 = ((b2 & SIGN) == 0)?(byte)(b2>>4):(byte)((b2)>>4^0xf0);

            encodedData[encodedIndex]     = lookUpBase64Alphabet[ val1 ];
            encodedData[encodedIndex + 1] =
                lookUpBase64Alphabet[ val2 | ( k<<4 )];
            encodedData[encodedIndex + 2] = lookUpBase64Alphabet[ l<<2 ];
            encodedData[encodedIndex + 3] = PAD;
        }

        // we also add a separator to the end of the final chunk.
        if(chunksSoFar < nbrChunks)
            System.arraycopy(CHUNK_SEPARATOR, 0, encodedData,
                             encodedDataLength - CHUNK_SEPARATOR.length, CHUNK_SEPARATOR.length);

        return encodedData;
    }

    /**
     * Decodes Base64 data into octects
     *
     * @param binaryData Byte array containing Base64 data
     * @return Array containing decoded data.
     */
    public static byte[] decode( byte[] base64Data )
    {
        // RFC 2045 suggests line wrapping at (no more than) 76
        // characters -- we may have embedded whitespace.
        base64Data = discardWhitespace(base64Data);

        // handle the edge case, so we don't have to worry about it later
        if(base64Data.length == 0) { return new byte[0]; }

        int      numberQuadruple    = base64Data.length/FOURBYTE;
        byte     decodedData[]      = null;
        byte     b1=0,b2=0,b3=0, b4=0, marker0=0, marker1=0;

        // Throw away anything not in base64Data

        int encodedIndex = 0;
        int dataIndex    = 0;
        {
            // this sizes the output array properly - rlw
            int lastData = base64Data.length;
            // ignore the '=' padding
            while (base64Data[lastData-1] == PAD)
            {
                if (--lastData == 0)
                {
                    return new byte[0];
                }
            }
            decodedData = new byte[ lastData - numberQuadruple ];
        }

        for (int i = 0; i < numberQuadruple; i++)
        {
            dataIndex = i * 4;
            marker0   = base64Data[dataIndex + 2];
            marker1   = base64Data[dataIndex + 3];

            b1 = base64Alphabet[base64Data[dataIndex]];
            b2 = base64Alphabet[base64Data[dataIndex +1]];

            if (marker0 != PAD && marker1 != PAD)
            {
                //No PAD e.g 3cQl
                b3 = base64Alphabet[ marker0 ];
                b4 = base64Alphabet[ marker1 ];

                decodedData[encodedIndex]   = (byte)(  b1 <<2 | b2>>4 ) ;
                decodedData[encodedIndex + 1] =
                    (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
                decodedData[encodedIndex + 2] = (byte)( b3<<6 | b4 );
            }
            else if (marker0 == PAD)
            {
                //Two PAD e.g. 3c[Pad][Pad]
                decodedData[encodedIndex]   = (byte)(  b1 <<2 | b2>>4 ) ;
            }
            else if (marker1 == PAD)
            {
                //One PAD e.g. 3cQ[Pad]
                b3 = base64Alphabet[ marker0 ];

                decodedData[encodedIndex]   = (byte)(  b1 <<2 | b2>>4 );
                decodedData[encodedIndex + 1] =
                    (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
            }
            encodedIndex += 3;
        }
        return decodedData;
    }

    /**
     * Discards any whitespace from a base-64 encoded block.
     *
     * Any other non-base-64 characters will be silently
     * discarded. This complies with the RFC, although a warning or
     * exception would also be RFC compliant (and is actually
     * recommended).
     *
     * @param data The base-64 encoded data to discard the whitespace
     * from.
     * @return The data, less whitespace (see RFC 2045).
     */
    static byte[] discardWhitespace(byte[] data)
    {
        byte groomedData[] = new byte[data.length];
        int bytesCopied = 0;

        for (int i = 0; i < data.length; i++)
        {
            switch (data[i])
            {
            case (byte) ' ':
            case (byte) '\n':
            case (byte) '\r':
            case (byte) '\t':
                break;
            default:
                if(isBase64(data[i])){
                   groomedData[bytesCopied++] = data[i];
                }
                else{
                    // according to the RFC, we could raise a warning
                    // or exception here
                }
            }
        }

        byte packedData[] = new byte[bytesCopied];

        System.arraycopy(groomedData, 0, packedData,
                             0, bytesCopied);

        return packedData;
    }
}
