/*

  * 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.commons.codec.binary;

 import java.math.BigInteger;

 /**

  * Provides Base64 encoding and decoding as defined by <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>.

  *

  * <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>

  * <p>

  * The class can be parameterized in the following manner with various constructors:

  * <ul>

  * <li>URL-safe mode: Default off.</li>

  * <li>Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of

  * 4 in the encoded data.

  * <li>Line separator: Default is CRLF ("\r\n")</li>

  * </ul>

  * </p>

  * <p>

  * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only

  * encode/decode character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252,

  * UTF-8, etc).

  * </p>

  * <p>

  * This class is thread-safe.

  * </p>

  *

  * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>

  * @since 1.0

  * @version $Id$

  */

 public class Base64 extends BaseNCodec {

     /**

      * BASE32 characters are 6 bits in length.

      * They are formed by taking a block of 3 octets to form a 24-bit string,

      * which is converted into 4 BASE64 characters.

      */

     private static final int BITS_PER_ENCODED_BYTE = 6;

     private static final int BYTES_PER_UNENCODED_BLOCK = 3;

     private static final int BYTES_PER_ENCODED_BLOCK = 4;

     /**

      * Chunk separator per RFC 2045 section 2.1.

      *

      * <p>

      * N.B. The next major release may break compatibility and make this field private.

      * </p>

      *

      * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>

      */

     static final byte[] CHUNK_SEPARATOR = {'\r', '\n'};

     /**

      * This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet"

      * equivalents as specified in Table 1 of RFC 2045.

      *

      * Thanks to "commons" project in ws.apache.org for this code.

      * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/

      */

     private static final byte[] STANDARD_ENCODE_TABLE = {

             'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',

             'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',

             'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',

             'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',

             '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'

     };

     /**

      * This is a copy of the STANDARD_ENCODE_TABLE above, but with + and /

      * changed to - and _ to make the encoded Base64 results more URL-SAFE.

      * This table is only used when the Base64's mode is set to URL-SAFE.

      */

     private static final byte[] URL_SAFE_ENCODE_TABLE = {

             'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',

             'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',

             'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',

             'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',

             '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'

     };

     /**

      * This array is a lookup table that translates Unicode characters drawn from the "Base64 Alphabet" (as specified

      * in Table 1 of RFC 2045) into their 6-bit positive integer equivalents. Characters that are not in the Base64

      * alphabet but fall within the bounds of the array are translated to -1.

      *

      * Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both

      * URL_SAFE and STANDARD base64. (The encoder, on the other hand, needs to know ahead of time what to emit).

      *

      * Thanks to "commons" project in ws.apache.org for this code.

      * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/

      */

     private static final byte[] DECODE_TABLE = {

             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

             -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, 52, 53, 54,

             55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 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, -1, -1, -1, -1, 63, -1, 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

     };

     /**

      * Base64 uses 6-bit fields.

      */

     /** Mask used to extract 6 bits, used when encoding */

     private static final int MASK_6BITS = 0x3f;

     // The static final fields above are used for the original static byte[] methods on Base64.

     // The private member fields below are used with the new streaming approach, which requires

     // some state be preserved between calls of encode() and decode().

     /**

      * Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able

      * to decode both STANDARD and URL_SAFE streams, but the encodeTable must be a member variable so we can switch

      * between the two modes.

      */

     private final byte[] encodeTable;

     // Only one decode table currently; keep for consistency with Base32 code

     private final byte[] decodeTable = DECODE_TABLE;

     /**

      * Line separator for encoding. Not used when decoding. Only used if lineLength > 0.

      */

     private final byte[] lineSeparator;

     /**

      * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.

      * <code>decodeSize = 3 + lineSeparator.length;</code>

      */

     private final int decodeSize;

     /**

      * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.

      * <code>encodeSize = 4 + lineSeparator.length;</code>

      */

     private final int encodeSize;

     /**

      * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

      * <p>

      * When encoding the line length is 0 (no chunking), and the encoding table is STANDARD_ENCODE_TABLE.

      * </p>

      *

      * <p>

      * When decoding all variants are supported.

      * </p>

      */

     public Base64() {

         this(0);

     }

     /**

      * Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.

      * <p>

      * When encoding the line length is 76, the line separator is CRLF, and the encoding table is

      * STANDARD_ENCODE_TABLE.

      * </p>

      *

      * <p>

      * When decoding all variants are supported.

      * </p>

      *

      * @param urlSafe

      *            if {@code true}, URL-safe encoding is used. In most cases this should be set to {@code false}.

      * @since 1.4

      */

     public Base64(boolean urlSafe) {

         this(MIME_CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe);

     }

     /**

      * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

      * <p>

      * When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is

      * STANDARD_ENCODE_TABLE.

      * </p>

      * <p>

      * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

      * </p>

      * <p>

      * When decoding all variants are supported.

      * </p>

      *

      * @param lineLength

      *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of

      *            4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when

      *            decoding.

      * @since 1.4

      */

     public Base64(int lineLength) {

         this(lineLength, CHUNK_SEPARATOR);

     }

     /**

      * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

      * <p>

      * When encoding the line length and line separator are given in the constructor, and the encoding table is

      * STANDARD_ENCODE_TABLE.

      * </p>

      * <p>

      * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

      * </p>

      * <p>

      * When decoding all variants are supported.

      * </p>

      *

      * @param lineLength

      *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of

      *            4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when

      *            decoding.

      * @param lineSeparator

      *            Each line of encoded data will end with this sequence of bytes.

      * @throws IllegalArgumentException

      *             Thrown when the provided lineSeparator included some base64 characters.

      * @since 1.4

      */

     public Base64(int lineLength, byte[] lineSeparator) {

         this(lineLength, lineSeparator, false);

     }

     /**

      * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

      * <p>

      * When encoding the line length and line separator are given in the constructor, and the encoding table is

      * STANDARD_ENCODE_TABLE.

      * </p>

      * <p>

      * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

      * </p>

      * <p>

      * When decoding all variants are supported.

      * </p>

      *

      * @param lineLength

      *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of

      *            4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when

      *            decoding.

      * @param lineSeparator

      *            Each line of encoded data will end with this sequence of bytes.

      * @param urlSafe

      *            Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode

      *            operations. Decoding seamlessly handles both modes.

      * @throws IllegalArgumentException

      *             The provided lineSeparator included some base64 characters. That's not going to work!

      * @since 1.4

      */

     public Base64(int lineLength, byte[] lineSeparator, boolean urlSafe) {

         super(BYTES_PER_UNENCODED_BLOCK, BYTES_PER_ENCODED_BLOCK,

                 lineLength,

                 lineSeparator == null ? 0 : lineSeparator.length);

         // TODO could be simplified if there is no requirement to reject invalid line sep when length <=0

         // @see test case Base64Test.testConstructors()

         if (lineSeparator != null) {

             if (containsAlphabetOrPad(lineSeparator)) {

                 String sep = StringUtils.newStringUtf8(lineSeparator);

                 throw new IllegalArgumentException("lineSeparator must not contain base64 characters: [" + sep + "]");

             }

             if (lineLength > 0){ // null line-sep forces no chunking rather than throwing IAE

                 this.encodeSize = BYTES_PER_ENCODED_BLOCK + lineSeparator.length;

                 this.lineSeparator = new byte[lineSeparator.length];

                 System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);

             } else {

                 this.encodeSize = BYTES_PER_ENCODED_BLOCK;

                 this.lineSeparator = null;

             }

         } else {

             this.encodeSize = BYTES_PER_ENCODED_BLOCK;

             this.lineSeparator = null;

         }

         this.decodeSize = this.encodeSize - 1;

         this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE;

     }

     /**

      * Returns our current encode mode. True if we're URL-SAFE, false otherwise.

      *

      * @return true if we're in URL-SAFE mode, false otherwise.

      * @since 1.4

      */

     public boolean isUrlSafe() {

         return this.encodeTable == URL_SAFE_ENCODE_TABLE;

     }

     /**

      * <p>

      * Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with

      * the data to encode, and once with inAvail set to "-1" to alert encoder that EOF has been reached, so flush last

      * remaining bytes (if not multiple of 3).

      * </p>

      * <p>

      * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.

      * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/

      * </p>

      *

      * @param in

      *            byte[] array of binary data to base64 encode.

      * @param inPos

      *            Position to start reading data from.

      * @param inAvail

      *            Amount of bytes available from input for encoding.

      * @param context

      *            the context to be used

      */

     @Override

     void encode(byte[] in, int inPos, int inAvail, Context context) {

         if (context.eof) {

             return;

         }

         // inAvail < 0 is how we're informed of EOF in the underlying data we're

         // encoding.

         if (inAvail < 0) {

             context.eof = true;

             if (0 == context.modulus && lineLength == 0) {

                 return; // no leftovers to process and not using chunking

             }

             final byte[] buffer = ensureBufferSize(encodeSize, context);

             final int savedPos = context.pos;

             switch (context.modulus) { // 0-2

                 case 0 : // nothing to do here

                     break;

                 case 1 : // 8 bits = 6 + 2

                     // top 6 bits:

                     buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 2) & MASK_6BITS];

                     // remaining 2:

                     buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 4) & MASK_6BITS];

                     // URL-SAFE skips the padding to further reduce size.

                     if (encodeTable == STANDARD_ENCODE_TABLE) {

                         buffer[context.pos++] = PAD;

                         buffer[context.pos++] = PAD;

                     }

                     break;

                 case 2 : // 16 bits = 6 + 6 + 4

                     buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 10) & MASK_6BITS];

                     buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 4) & MASK_6BITS];

                     buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 2) & MASK_6BITS];

                     // URL-SAFE skips the padding to further reduce size.

                     if (encodeTable == STANDARD_ENCODE_TABLE) {

                         buffer[context.pos++] = PAD;

                     }

                     break;

                 default:

                     throw new IllegalStateException("Impossible modulus "+context.modulus);

             }

             context.currentLinePos += context.pos - savedPos; // keep track of current line position

             // if currentPos == 0 we are at the start of a line, so don't add CRLF

             if (lineLength > 0 && context.currentLinePos > 0) {

                 System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length);

                 context.pos += lineSeparator.length;

             }

         } else {

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

                 final byte[] buffer = ensureBufferSize(encodeSize, context);

                 context.modulus = (context.modulus+1) % BYTES_PER_UNENCODED_BLOCK;

                 int b = in[inPos++];

                 if (b < 0) {

                     b += 256;

                 }

                 context.ibitWorkArea = (context.ibitWorkArea << 8) + b; //  BITS_PER_BYTE

                 if (0 == context.modulus) { // 3 bytes = 24 bits = 4 * 6 bits to extract

                     buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 18) & MASK_6BITS];

                     buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 12) & MASK_6BITS];

                     buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 6) & MASK_6BITS];

                     buffer[context.pos++] = encodeTable[context.ibitWorkArea & MASK_6BITS];

                     context.currentLinePos += BYTES_PER_ENCODED_BLOCK;

                     if (lineLength > 0 && lineLength <= context.currentLinePos) {

                         System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length);

                         context.pos += lineSeparator.length;

                         context.currentLinePos = 0;

                     }

                 }

             }

         }

     }

     /**

      * <p>

      * Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once

      * with the data to decode, and once with inAvail set to "-1" to alert decoder that EOF has been reached. The "-1"

      * call is not necessary when decoding, but it doesn't hurt, either.

      * </p>

      * <p>

      * Ignores all non-base64 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are

      * silently ignored, but has implications for other bytes, too. This method subscribes to the garbage-in,

      * garbage-out philosophy: it will not check the provided data for validity.

      * </p>

      * <p>

      * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.

      * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/

      * </p>

      *

      * @param in

      *            byte[] array of ascii data to base64 decode.

      * @param inPos

      *            Position to start reading data from.

      * @param inAvail

      *            Amount of bytes available from input for encoding.

      * @param context

      *            the context to be used

      */

     @Override

     void decode(byte[] in, int inPos, int inAvail, Context context) {

         if (context.eof) {

             return;

         }

         if (inAvail < 0) {

             context.eof = true;

         }

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

             final byte[] buffer = ensureBufferSize(decodeSize, context);

             final byte b = in[inPos++];

             if (b == PAD) {

                 // We're done.

                 context.eof = true;

                 break;

             } else {

                 if (b >= 0 && b < DECODE_TABLE.length) {

                     final int result = DECODE_TABLE[b];

                     if (result >= 0) {

                         context.modulus = (context.modulus+1) % BYTES_PER_ENCODED_BLOCK;

                         context.ibitWorkArea = (context.ibitWorkArea << BITS_PER_ENCODED_BYTE) + result;

                         if (context.modulus == 0) {

                             buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 16) & MASK_8BITS);

                             buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);

                             buffer[context.pos++] = (byte) (context.ibitWorkArea & MASK_8BITS);

                         }

                     }

                 }

             }

         }

         // Two forms of EOF as far as base64 decoder is concerned: actual

         // EOF (-1) and first time '=' character is encountered in stream.

         // This approach makes the '=' padding characters completely optional.

         if (context.eof && context.modulus != 0) {

             final byte[] buffer = ensureBufferSize(decodeSize, context);

             // We have some spare bits remaining

             // Output all whole multiples of 8 bits and ignore the rest

             switch (context.modulus) {

 //              case 0 : // impossible, as excluded above

                 case 1 : // 6 bits - ignore entirely

                     // TODO not currently tested; perhaps it is impossible?

                     break;

                 case 2 : // 12 bits = 8 + 4

                     context.ibitWorkArea = context.ibitWorkArea >> 4; // dump the extra 4 bits

                     buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);

                     break;

                 case 3 : // 18 bits = 8 + 8 + 2

                     context.ibitWorkArea = context.ibitWorkArea >> 2; // dump 2 bits

                     buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);

                     buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);

                     break;

                 default:

                     throw new IllegalStateException("Impossible modulus "+context.modulus);

             }

         }

     }

     /**

      * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the

      * method treats whitespace as valid.

      *

      * @param arrayOctet

      *            byte array to test

      * @return {@code true} if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;

      *         {@code false}, otherwise

      * @deprecated 1.5 Use {@link #isBase64(byte[])}, will be removed in 2.0.

      */

     @Deprecated

     public static boolean isArrayByteBase64(byte[] arrayOctet) {

         return isBase64(arrayOctet);

     }

     /**

      * Returns whether or not the <code>octet</code> is in the base 64 alphabet.

      *

      * @param octet

      *            The value to test

      * @return {@code true} if the value is defined in the the base 64 alphabet, {@code false} otherwise.

      * @since 1.4

      */

     public static boolean isBase64(byte octet) {

         return octet == PAD_DEFAULT || (octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1);

     }

     /**

      * Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the

      * method treats whitespace as valid.

      *

      * @param base64

      *            String to test

      * @return {@code true} if all characters in the String are valid characters in the Base64 alphabet or if

      *         the String is empty; {@code false}, otherwise

      *  @since 1.5

      */

     public static boolean isBase64(String base64) {

         return isBase64(StringUtils.getBytesUtf8(base64));

     }

     /**

      * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the

      * method treats whitespace as valid.

      *

      * @param arrayOctet

      *            byte array to test

      * @return {@code true} if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;

      *         {@code false}, otherwise

      * @since 1.5

      */

     public static boolean isBase64(byte[] arrayOctet) {

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

             if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[i])) {

                 return false;

             }

         }

         return true;

     }

     /**

      * Encodes binary data using the base64 algorithm but does not chunk the output.

      *

      * @param binaryData

      *            binary data to encode

      * @return byte[] containing Base64 characters in their UTF-8 representation.

      */

     public static byte[] encodeBase64(byte[] binaryData) {

         return encodeBase64(binaryData, false);

     }

     /**

      * Encodes binary data using the base64 algorithm but does not chunk the output.

      *

      * NOTE:  We changed the behaviour of this method from multi-line chunking (commons-codec-1.4) to

      * single-line non-chunking (commons-codec-1.5).

      *

      * @param binaryData

      *            binary data to encode

      * @return String containing Base64 characters.

      * @since 1.4 (NOTE:  1.4 chunked the output, whereas 1.5 does not).

      */

     public static String encodeBase64String(byte[] binaryData) {

         return StringUtils.newStringUtf8(encodeBase64(binaryData, false));

     }

     /**

      * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The

      * url-safe variation emits - and _ instead of + and / characters.

      *

      * @param binaryData

      *            binary data to encode

      * @return byte[] containing Base64 characters in their UTF-8 representation.

      * @since 1.4

      */

     public static byte[] encodeBase64URLSafe(byte[] binaryData) {

         return encodeBase64(binaryData, false, true);

     }

     /**

      * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The

      * url-safe variation emits - and _ instead of + and / characters.

      *

      * @param binaryData

      *            binary data to encode

      * @return String containing Base64 characters

      * @since 1.4

      */

     public static String encodeBase64URLSafeString(byte[] binaryData) {

         return StringUtils.newStringUtf8(encodeBase64(binaryData, false, true));

     }

     /**

      * 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);

     }

     /**

      * 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} this encoder will chunk the base64 output into 76 character blocks

      * @return Base64-encoded data.

      * @throws IllegalArgumentException

      *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}

      */

     public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {

         return encodeBase64(binaryData, isChunked, false);

     }

     /**

      * 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} this encoder will chunk the base64 output into 76 character blocks

      * @param urlSafe

      *            if {@code true} this encoder will emit - and _ instead of the usual + and / characters.

      * @return Base64-encoded data.

      * @throws IllegalArgumentException

      *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}

      * @since 1.4

      */

     public static byte[] encodeBase64(byte[] binaryData, boolean isChunked, boolean urlSafe) {

         return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE);

     }

     /**

      * 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} this encoder will chunk the base64 output into 76 character blocks

      * @param urlSafe

      *            if {@code true} this encoder will emit - and _ instead of the usual + and / characters.

      * @param maxResultSize

      *            The maximum result size to accept.

      * @return Base64-encoded data.

      * @throws IllegalArgumentException

      *             Thrown when the input array needs an output array bigger than maxResultSize

      * @since 1.4

      */

     public static byte[] encodeBase64(byte[] binaryData, boolean isChunked, boolean urlSafe, int maxResultSize) {

         if (binaryData == null || binaryData.length == 0) {

             return binaryData;

         }

         // Create this so can use the super-class method

         // Also ensures that the same roundings are performed by the ctor and the code

         Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe);

         long len = b64.getEncodedLength(binaryData);

         if (len > maxResultSize) {

             throw new IllegalArgumentException("Input array too big, the output array would be bigger (" +

                 len +

                 ") than the specified maximum size of " +

                 maxResultSize);

         }

         return b64.encode(binaryData);

     }

     /**

      * Decodes a Base64 String into octets

      *

      * @param base64String

      *            String containing Base64 data

      * @return Array containing decoded data.

      * @since 1.4

      */

     public static byte[] decodeBase64(String base64String) {

         return new Base64().decode(base64String);

     }

     /**

      * Decodes Base64 data into octets

      *

      * @param base64Data

      *            Byte array containing Base64 data

      * @return Array containing decoded data.

      */

     public static byte[] decodeBase64(byte[] base64Data) {

         return new Base64().decode(base64Data);

     }

     // Implementation of the Encoder Interface

     // Implementation of integer encoding used for crypto

     /**

      * Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature

      *

      * @param pArray

      *            a byte array containing base64 character data

      * @return A BigInteger

      * @since 1.4

      */

     public static BigInteger decodeInteger(byte[] pArray) {

         return new BigInteger(1, decodeBase64(pArray));

     }

     /**

      * Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature

      *

      * @param bigInt

      *            a BigInteger

      * @return A byte array containing base64 character data

      * @throws NullPointerException

      *             if null is passed in

      * @since 1.4

      */

     public static byte[] encodeInteger(BigInteger bigInt) {

         if (bigInt == null) {

             throw new NullPointerException("encodeInteger called with null parameter");

         }

         return encodeBase64(toIntegerBytes(bigInt), false);

     }

     /**

      * Returns a byte-array representation of a <code>BigInteger</code> without sign bit.

      *

      * @param bigInt

      *            <code>BigInteger</code> to be converted

      * @return a byte array representation of the BigInteger parameter

      */

     static byte[] toIntegerBytes(BigInteger bigInt) {

         int bitlen = bigInt.bitLength();

         // round bitlen

         bitlen = ((bitlen + 7) >> 3) << 3;

         byte[] bigBytes = bigInt.toByteArray();

         if (((bigInt.bitLength() % 8) != 0) && (((bigInt.bitLength() / 8) + 1) == (bitlen / 8))) {

             return bigBytes;

         }

         // set up params for copying everything but sign bit

         int startSrc = 0;

         int len = bigBytes.length;

         // if bigInt is exactly byte-aligned, just skip signbit in copy

         if ((bigInt.bitLength() % 8) == 0) {

             startSrc = 1;

             len--;

         }

         int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec

         byte[] resizedBytes = new byte[bitlen / 8];

         System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);

         return resizedBytes;

     }

     /**

      * Returns whether or not the <code>octet</code> is in the Base32 alphabet.

      *

      * @param octet

      *            The value to test

      * @return {@code true} if the value is defined in the the Base32 alphabet {@code false} otherwise.

      */

     @Override

     protected boolean isInAlphabet(byte octet) {

         return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1;

     }

 }