package org.sonatype.plexus.components.cipher;
/*
 * $HeadURL: http://juliusdavies.ca/svn/not-yet-commons-ssl/tags/commons-ssl-0.3.10/src/java/org/apache/commons/ssl/Base64.java $
 * $Revision$
 * $Date$
 *
 * ====================================================================
 * 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.
 * ====================================================================
 *
 * 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/>.
 *
 */

Provides Base64 encoding and decoding as defined by RFC 2045.

This class implements section 6.8. Base64 Content-Transfer-Encoding
from RFC 2045 Multipurpose Internet Mail Extensions (MIME) Part One:
Format of Internet Message Bodies by Freed and Borenstein.
Author:
Apache Software Foundation
See Also:
RFC 2045
Version:
$Id$
Since:
1.0-dev/**
 * Provides Base64 encoding and decoding as defined by RFC 2045.
 * <p/>
 * <p>This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite>
 * from RFC 2045 <cite>Multipurpose Internet Mail Extensions (MIME) Part One:
 * Format of Internet Message Bodies</cite> by Freed and Borenstein.</p>
 *
 * @author Apache Software Foundation
 * @version $Id$
 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
 * @since 1.0-dev
 */
public class Base64
{

    
Chunk size per RFC 2045 section 6.8.

The character limit does not count the trailing CRLF, but counts
all other characters, including any equal signs.
See Also:
RFC 2045 section 6.8/**
     * Chunk size per RFC 2045 section 6.8.
     * <p/>
     * <p>The character limit does not count the trailing CRLF, but counts
     * all other characters, including any equal signs.</p>
     *
     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
     */
    static final int CHUNK_SIZE = 76;

    
Chunk separator per RFC 2045 section 2.1.
See Also:
RFC 2045 section 2.1/**
     * Chunk separator per RFC 2045 section 2.1.
     *
     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
     */
    static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();

    
The base length. /** The base length. */
    static final int BASELENGTH = 255;

    
Lookup length. /** Lookup length. */
    static final int LOOKUPLENGTH = 64;

    
Used to calculate the number of bits in a byte. /** Used to calculate the number of bits in a byte. */
    static final int EIGHTBIT = 8;

    
Used when encoding something which has fewer than 24 bits. /** Used when encoding something which has fewer than 24 bits. */
    static final int SIXTEENBIT = 16;

    
Used to determine how many bits data contains. /** Used to determine how many bits data contains. */
    static final int TWENTYFOURBITGROUP = 24;

    
Used to get the number of Quadruples. /** Used to get the number of Quadruples. */
    static final int FOURBYTE = 4;

    
Used to test the sign of a byte. /** Used to test the sign of a byte. */
    static final int SIGN = -128;

    
Byte used to pad output. /** Byte used to pad output. */
    static final byte PAD = (byte) '=';

    
Contains the Base64 values 0 through 63 accessed by using character encodings as
indices.

For example, base64Alphabet['+'] returns 62.


The value of undefined encodings is -1.

/**
     * Contains the Base64 values <code>0</code> through <code>63</code> accessed by using character encodings as
     * indices.
     * <p/>
     * For example, <code>base64Alphabet['+']</code> returns <code>62</code>.
     * </p>
     * <p/>
     * The value of undefined encodings is <code>-1</code>.
     * </p>
     */
    private static byte[] base64Alphabet = new byte[BASELENGTH];

    

Contains the Base64 encodings A through Z, followed by a through
z, followed by 0 through 9, followed by +, and
/.


This array is accessed by using character values as indices.


For example, lookUpBase64Alphabet[62]  returns '+'.

/**
     * <p/>
     * Contains the Base64 encodings <code>A</code> through <code>Z</code>, followed by <code>a</code> through
     * <code>z</code>, followed by <code>0</code> through <code>9</code>, followed by <code>+</code>, and
     * <code>/</code>.
     * </p>
     * <p/>
     * This array is accessed by using character values as indices.
     * </p>
     * <p/>
     * For example, <code>lookUpBase64Alphabet[62] </code> returns <code>'+'</code>.
     * </p>
     */
    private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];

    // Populating the lookup and character arrays
    static {
        for (int i = 0; i < BASELENGTH; i++) {
            base64Alphabet[i] = (byte) -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) '/';
    }

    
Returns whether or not the octect is in the base 64 alphabet.
Params:
b – The value to test
Returns:
true if the value is defined in the the base 64 alphabet, false otherwise./**
     * Returns whether or not the <code>octect</code> is in the base 64 alphabet.
     *
     * @param b The value to test
     * @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise.
     */
    public static boolean isBase64(byte b) {
        return (b == PAD) || (b >= 0 && base64Alphabet[b] >= 0);
    }

    
Tests a given byte array to see if it contains
only valid characters within the Base64 alphabet.
Params:
arrayOctect – byte array to test
Returns:
true if all bytes are valid characters in the Base64
        alphabet or if the byte array is empty; false, otherwise/**
     * Tests a given byte array to see if it contains
     * only valid characters within the Base64 alphabet.
     *
     * @param arrayOctect byte array to test
     * @return <code>true</code> if all bytes are valid characters in the Base64
     *         alphabet or if the byte array is empty; false, otherwise
     */
    public static boolean isArrayByteBase64(byte[] arrayOctect) {

        arrayOctect = discardWhitespace(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 (!isBase64(arrayOctect[i])) {
                return false;
            }
        }
        return true;
    }

    
Encodes binary data using the base64 algorithm but
does not chunk the output.
Params:
binaryData – binary data to encode
Returns:
Base64 characters/**
     * Encodes binary data using the base64 algorithm but
     * does not chunk the output.
     *
     * @param binaryData binary data to encode
     * @return Base64 characters
     */
    public static byte[] encodeBase64(byte[] binaryData) {
        return encodeBase64(binaryData, false);
    }

    
Encodes binary data using the base64 algorithm and chunks
the encoded output into 76 character blocks
Params:
binaryData – binary data to encode
Returns:
Base64 characters chunked in 76 character blocks/**
     * Encodes binary data using the base64 algorithm and chunks
     * the encoded output into 76 character blocks
     *
     * @param binaryData binary data to encode
     * @return Base64 characters chunked in 76 character blocks
     */
    public static byte[] encodeBase64Chunked(byte[] binaryData) {
        return encodeBase64(binaryData, true);
    }


    
Decodes an Object using the base64 algorithm.  This method
is provided in order to satisfy the requirements of the
Decoder interface, and will throw a DecoderException if the
supplied object is not of type byte[].
Params:
pObject – Object to decode
Throws:
IllegalArgumentException – if the parameter supplied is not
                                 of type byte[]
Returns:
An object (of type byte[]) containing the
        binary data which corresponds to the byte[] supplied./**
     * Decodes an Object using the base64 algorithm.  This method
     * is provided in order to satisfy the requirements of the
     * Decoder interface, and will throw a DecoderException if the
     * supplied object is not of type byte[].
     *
     * @param pObject Object to decode
     * @return An object (of type byte[]) containing the
     *         binary data which corresponds to the byte[] supplied.
     * @throws IllegalArgumentException if the parameter supplied is not
     *                                  of type byte[]
     */
    public Object decode(Object pObject) throws IllegalArgumentException {
        if (!(pObject instanceof byte[])) {
            throw new IllegalArgumentException("Parameter supplied to Base64 decode is not a byte[]");
        }
        return decode((byte[]) pObject);
    }

    
Decodes a byte[] containing containing
characters in the Base64 alphabet.
Params:
pArray – A byte array containing Base64 character data
Returns:
a byte array containing binary data/**
     * Decodes a byte[] containing containing
     * characters in the Base64 alphabet.
     *
     * @param pArray A byte array containing Base64 character data
     * @return a byte array containing binary data
     */
    public byte[] decode(byte[] pArray) {
        return decodeBase64(pArray);
    }

    
Encodes binary data using the base64 algorithm, optionally
chunking the output into 76 character blocks.
Params:
binaryData – Array containing binary data to encode.
isChunked –  if true this encoder will chunk
                  the base64 output into 76 character blocks
Returns:
Base64-encoded data./**
     * Encodes binary data using the base64 algorithm, optionally
     * chunking the output into 76 character blocks.
     *
     * @param binaryData Array containing binary data to encode.
     * @param isChunked  if <code>true</code> this encoder will chunk
     *                   the base64 output into 76 character blocks
     * @return Base64-encoded data.
     */
    public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {
        int lengthDataBits = binaryData.length * EIGHTBIT;
        int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
        int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
        byte encodedData[];
        int encodedDataLength;
        int nbrChunks = 0;

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

        // If the output is to be "chunked" into 76 character sections,
        // for compliance with RFC 2045 MIME, then it is important to
        // allow for extra length to account for the separator(s)
        if (isChunked) {

            nbrChunks =
                (CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE));
            encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length;
        }

        encodedData = new byte[encodedDataLength];

        byte k, l, b1, b2, b3;
        int dataIndex;
        int i;
        int encodedIndex = 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;

            // If we are chunking, let's put a chunk separator down.
            if (isChunked) {
                // 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;
        }

        if (isChunked) {
            // 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
Params:
base64Data – Byte array containing Base64 data
Returns:
Array containing decoded data./**
     * Decodes Base64 data into octects
     *
     * @param base64Data Byte array containing Base64 data
     * @return Array containing decoded data.
     */
    public static byte[] decodeBase64(byte[] base64Data) {
        // RFC 2045 requires that we discard ALL non-Base64 characters
        base64Data = discardNonBase64(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[];
        byte b1, b2, b3, b4, marker0, marker1;

        // Throw away anything not in base64Data
        int dataIndex;
        int encodedIndex = 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 ) (always true at this point)
            {
                //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.
Params:
data – The base-64 encoded data to discard the whitespace
            from.
Returns:
The data, less whitespace (see RFC 2045)./**
     * Discards any whitespace from a base-64 encoded block.
     *
     * @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:
                    groomedData[bytesCopied++] = data[i];
            }
        }

        byte packedData[] = new byte[bytesCopied];

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

        return packedData;
    }

    
Discards any characters outside of the base64 alphabet, per
the requirements on page 25 of RFC 2045 - "Any characters
outside of the base64 alphabet are to be ignored in base64
encoded data."
Params:
data – The base-64 encoded data to groom
Returns:
The data, less non-base64 characters (see RFC 2045)./**
     * Discards any characters outside of the base64 alphabet, per
     * the requirements on page 25 of RFC 2045 - "Any characters
     * outside of the base64 alphabet are to be ignored in base64
     * encoded data."
     *
     * @param data The base-64 encoded data to groom
     * @return The data, less non-base64 characters (see RFC 2045).
     */
    static byte[] discardNonBase64(byte[] data) {
        byte groomedData[] = new byte[data.length];
        int bytesCopied = 0;

        for (int i = 0; i < data.length; i++) {
            if (isBase64(data[i])) {
                groomedData[bytesCopied++] = data[i];
            }
        }

        byte packedData[] = new byte[bytesCopied];

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

        return packedData;
    }

    // Implementation of the Encoder Interface

    
Encodes an Object using the base64 algorithm.  This method
is provided in order to satisfy the requirements of the
Encoder interface, and will throw an EncoderException if the
supplied object is not of type byte[].
Params:
pObject – Object to encode
Throws:
IllegalArgumentException – if the parameter supplied is not
                                 of type byte[]
Returns:
An object (of type byte[]) containing the
        base64 encoded data which corresponds to the byte[] supplied./**
     * Encodes an Object using the base64 algorithm.  This method
     * is provided in order to satisfy the requirements of the
     * Encoder interface, and will throw an EncoderException if the
     * supplied object is not of type byte[].
     *
     * @param pObject Object to encode
     * @return An object (of type byte[]) containing the
     *         base64 encoded data which corresponds to the byte[] supplied.
     * @throws IllegalArgumentException if the parameter supplied is not
     *                                  of type byte[]
     */
    public Object encode(Object pObject) throws IllegalArgumentException {
        if (!(pObject instanceof byte[])) {
            throw new IllegalArgumentException("Parameter supplied to Base64 encode is not a byte[]");
        }
        return encode((byte[]) pObject);
    }

    
Encodes a byte[] containing binary data, into a byte[] containing
characters in the Base64 alphabet.
Params:
pArray – a byte array containing binary data
Returns:
A byte array containing only Base64 character data/**
     * Encodes a byte[] containing binary data, into a byte[] containing
     * characters in the Base64 alphabet.
     *
     * @param pArray a byte array containing binary data
     * @return A byte array containing only Base64 character data
     */
    public byte[] encode(byte[] pArray) {
        return encodeBase64(pArray, false);
    }

}