/*

 *  Licensed to the Apache Software Foundation (ASF) under one or more

 *  contributor license agreements.  See the NOTICE file distributed with

 *  this work for additional information regarding copyright ownership.

 *  The ASF licenses this file to You under the Apache License, Version 2.0

 *  (the "License"); you may not use this file except in compliance with

 *  the License.  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 *  Unless required by applicable law or agreed to in writing, software

 *  distributed under the License is distributed on an "AS IS" BASIS,

 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 *  See the License for the specific language governing permissions and

 *  limitations under the License.

 */

package org.apache.tomcat.util.buf;

/**

 * This class provides encode/decode for RFC 2045 Base64 as

 * defined by RFC 2045, N. Freed and N. Borenstein.

 * RFC 2045: Multipurpose Internet Mail Extensions (MIME)

 * Part One: Format of Internet Message Bodies. Reference

 * 1996 Available at: http://www.ietf.org/rfc/rfc2045.txt

 * This class is used by XML Schema binary format validation

 *

 * @author Jeffrey Rodriguez

 */

public final class Base64 {

    private static org.apache.juli.logging.Log log=

        org.apache.juli.logging.LogFactory.getLog( Base64.class );

    static private final int  BASELENGTH         = 255;

    static private final int  LOOKUPLENGTH       = 63;

    static private final int  TWENTYFOURBITGROUP = 24;

    static private final int  EIGHTBIT           = 8;

    static private final int  SIXTEENBIT         = 16;

    static private final int  FOURBYTE           = 4;

    static private final byte PAD               = ( byte ) '=';

    static private byte [] base64Alphabet       = new byte[BASELENGTH];

    static private byte [] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];

    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 );

    }

    static boolean isBase64( byte octect ) {

        //shall we ignore white space? JEFF??

        return(octect == PAD || base64Alphabet[octect] != -1 );

    }

    static boolean isArrayByteBase64( byte[] arrayOctect ) {

        int length = arrayOctect.length;

        if ( length == 0 )

            return false;

        for ( int i=0; i < length; i++ ) {

            if ( Base64.isBase64( arrayOctect[i] ) == false)

                return false;

        }

        return true;

    }

    /**

     * Encodes hex octects into Base64

     *

     * @param binaryData Array containing binaryData

     * @return Encoded Base64 array

     */

    public static byte[] encode( byte[] binaryData ) {

        int      lengthDataBits    = binaryData.length*EIGHTBIT;

        int      fewerThan24bits   = lengthDataBits%TWENTYFOURBITGROUP;

        int      numberTriplets    = lengthDataBits/TWENTYFOURBITGROUP;

        byte     encodedData[]     = null;

        if ( fewerThan24bits != 0 ) //data not divisible by 24 bit

            encodedData = new byte[ (numberTriplets + 1 )*4  ];

        else // 16 or 8 bit

            encodedData = new byte[ numberTriplets*4 ];

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

        int encodedIndex = 0;

        int dataIndex   = 0;

        int i           = 0;

        for ( i = 0; i<numberTriplets; i++ ) {

            dataIndex = i*3;

            b1 = binaryData[dataIndex];

            b2 = binaryData[dataIndex + 1];

            b3 = binaryData[dataIndex + 2];

            l  = (byte)(b2 & 0x0f);

            k  = (byte)(b1 & 0x03);

            encodedIndex = i*4;

            encodedData[encodedIndex]   = lookUpBase64Alphabet[ b1 >>2 ];

            encodedData[encodedIndex+1] = lookUpBase64Alphabet[(b2 >>4 ) |

( k<<4 )];

            encodedData[encodedIndex+2] = lookUpBase64Alphabet[ (l <<2 ) |

( b3>>6)];

            encodedData[encodedIndex+3] = lookUpBase64Alphabet[ b3 & 0x3f ];

        }

        // form integral number of 6-bit groups

        dataIndex    = i*3;

        encodedIndex = i*4;

        if (fewerThan24bits == EIGHTBIT ) {

            b1 = binaryData[dataIndex];

            k = (byte) ( b1 &0x03 );

            encodedData[encodedIndex]     = lookUpBase64Alphabet[ b1 >>2 ];

            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 );

            encodedData[encodedIndex]     = lookUpBase64Alphabet[ b1 >>2 ];

            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[ (b2 >>4 )

| ( k<<4 )];

            encodedData[encodedIndex + 2] = lookUpBase64Alphabet[ l<<2 ];

            encodedData[encodedIndex + 3] = PAD;

        }

        return encodedData;

    }

    /**

     * Decodes Base64 data into octects

     *

     * @param base64Data Byte array containing Base64 data

     * @return Array containind decoded data.

     */

    public byte[] decode( byte[] base64Data ) {

        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

        // Adjust size

        int encodedIndex = 0;

        int dataIndex    = 0;

        decodedData      = new byte[ numberQuadruple*3 + 1 ];

        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 ) ;

                decodedData[encodedIndex+1] = (byte)((b2 & 0xf)<<4 );

                decodedData[encodedIndex+2] = (byte) 0;

            } 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) );

                decodedData[encodedIndex+2] = (byte)( b3<<6);

            }

            encodedIndex += 3;

        }

        return decodedData;

    }

    static final int base64[]= {

	64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,

	    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,

	    64,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,

	    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,

	    64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,

	    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,

	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64

    };

    public static String base64Decode( String orig ) {

	char chars[]=orig.toCharArray();

	StringBuffer sb=new StringBuffer();

	int i=0;

	int shift = 0;   // # of excess bits stored in accum

	int acc = 0;

	for (i=0; i<chars.length; i++) {

	    int v = base64[ chars[i] & 0xFF ];

	    if ( v >= 64 ) {

		if( chars[i] != '=' )

                    if (log.isDebugEnabled())

                        log.debug("Wrong char in base64: " + chars[i]);

	    } else {

		acc= ( acc << 6 ) | v;

		shift += 6;

		if ( shift >= 8 ) {

		    shift -= 8;

		    sb.append( (char) ((acc >> shift) & 0xff));

		}

	    }

	}

	return sb.toString();

    }

}