Base64.java Source code

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//package org.rsbot.util;
/*
 * 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.
 */

import java.awt.Color;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.math.BigInteger;
import java.util.HashMap;
import java.util.Map;

/**
 * Provides Base64 encoding and decoding as defined by <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>.
 * <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>
 * <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 not thread-safe. Each thread should use its own instance.
 * </p>
 *
 * @author Apache Software Foundation
 * @version $Revision$
 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
 * @since 1.0
 */
public class Base64 {

    /**
     * MIME chunk size per RFC 2045 section 6.8.
     * <p/>
     * <p>
     * The {@value} 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>
     */
    public static final int MIME_CHUNK_SIZE = 76;

    /**
     * PEM chunk size per RFC 1421 section 4.3.2.4.
     * <p/>
     * <p>
     * The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
     * equal signs.
     * </p>
     *
     * @see <a href="http://tools.ietf.org/html/rfc1421">RFC 1421 section 4.3.2.4</a>
     */
    public static final int PEM_CHUNK_SIZE = 64;

    private static final int DEFAULT_BUFFER_RESIZE_FACTOR = 2;

    /**
     * Defines the default buffer size - currently {@value}
     * - must be large enough for at least one encoded block+separator
     */
    private static final int DEFAULT_BUFFER_SIZE = 8192;

    /**
     * Mask used to extract 8 bits, used in decoding bytes
     */
    protected static final int MASK_8BITS = 0xff;

    /**
     * Byte used to pad output.
     */
    protected static final byte PAD_DEFAULT = '='; // Allow static access to default

    protected final byte PAD = PAD_DEFAULT; // instance variable just in case it needs to vary later

    /**
     * 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/>
     * <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.
     * <p/>
     * 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.
     * <p/>
     * 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).
     * <p/>
     * 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;

    /**
     * Number of bytes in each full block of unencoded data, e.g. 4 for Base64 and 5 for Base32
     */
    private final int unencodedBlockSize;

    /**
     * Number of bytes in each full block of encoded data, e.g. 3 for Base64 and 8 for Base32
     */
    private final int encodedBlockSize;

    /**
     * Chunksize for encoding. Not used when decoding.
     * A value of zero or less implies no chunking of the encoded data.
     * Rounded down to nearest multiple of encodedBlockSize.
     */
    protected final int lineLength;

    /**
     * Size of chunk separator. Not used unless {@link #lineLength} > 0.
     */
    private final int chunkSeparatorLength;

    /**
     * Buffer for streaming.
     */
    protected byte[] buffer;

    /**
     * Position where next character should be written in the buffer.
     */
    protected int pos;

    /**
     * Position where next character should be read from the buffer.
     */
    private int readPos;

    /**
     * Boolean flag to indicate the EOF has been reached. Once EOF has been reached, this object becomes useless,
     * and must be thrown away.
     */
    protected boolean eof;

    /**
     * Variable tracks how many characters have been written to the current line. Only used when encoding. We use it to
     * make sure each encoded line never goes beyond lineLength (if lineLength > 0).
     */
    protected int currentLinePos;

    /**
     * Writes to the buffer only occur after every 3/5 reads when encoding, and every 4/8 reads when decoding.
     * This variable helps track that.
     */
    protected int modulus;

    // 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;

    /**
     * Place holder for the bytes we're dealing with for our based logic.
     * Bitwise operations store and extract the encoding or decoding from this variable.
     */
    private int bitWorkArea;

    /**
     * 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/>
     * <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/>
     * <p>
     * When decoding all variants are supported.
     * </p>
     *
     * @param urlSafe if <code>true</code>, URL-safe encoding is used. In most cases this should be set to
     *                <code>false</code>.
     * @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) {
        this.unencodedBlockSize = BYTES_PER_UNENCODED_BLOCK;
        this.encodedBlockSize = BYTES_PER_ENCODED_BLOCK;
        this.lineLength = lineLength;
        this.chunkSeparatorLength = 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 = StringUtil.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 true if this object has buffered data for reading.
     *
     * @return true if there is data still available for reading.
     */
    boolean hasData() { // package protected for access from I/O streams
        return this.buffer != null;
    }

    /**
     * Returns the amount of buffered data available for reading.
     *
     * @return The amount of buffered data available for reading.
     */
    int available() { // package protected for access from I/O streams
        return buffer != null ? pos - readPos : 0;
    }

    /**
     * Get the default buffer size. Can be overridden.
     *
     * @return {@link #DEFAULT_BUFFER_SIZE}
     */
    protected int getDefaultBufferSize() {
        return DEFAULT_BUFFER_SIZE;
    }

    /**
     * Increases our buffer by the {@link #DEFAULT_BUFFER_RESIZE_FACTOR}.
     */
    private void resizeBuffer() {
        if (buffer == null) {
            buffer = new byte[getDefaultBufferSize()];
            pos = 0;
            readPos = 0;
        } else {
            byte[] b = new byte[buffer.length * DEFAULT_BUFFER_RESIZE_FACTOR];
            System.arraycopy(buffer, 0, b, 0, buffer.length);
            buffer = b;
        }
    }

    /**
     * Ensure that the buffer has room for <code>size</code> bytes
     *
     * @param size minimum spare space required
     */
    protected void ensureBufferSize(int size) {
        if ((buffer == null) || (buffer.length < pos + size)) {
            resizeBuffer();
        }
    }

    /**
     * Extracts buffered data into the provided byte[] array, starting at position bPos,
     * up to a maximum of bAvail bytes. Returns how many bytes were actually extracted.
     *
     * @param b      byte[] array to extract the buffered data into.
     * @param bPos   position in byte[] array to start extraction at.
     * @param bAvail amount of bytes we're allowed to extract. We may extract fewer (if fewer are available).
     * @return The number of bytes successfully extracted into the provided byte[] array.
     */
    int readResults(byte[] b, int bPos, int bAvail) { // package protected for access from I/O streams
        if (buffer != null) {
            int len = Math.min(available(), bAvail);
            System.arraycopy(buffer, readPos, b, bPos, len);
            readPos += len;
            if (readPos >= pos) {
                buffer = null; // so hasData() will return false, and this method can return -1
            }
            return len;
        }
        return eof ? -1 : 0;
    }

    /**
     * Checks if a byte value is whitespace or not.
     * Whitespace is taken to mean: space, tab, CR, LF
     *
     * @param byteToCheck the byte to check
     * @return true if byte is whitespace, false otherwise
     */
    protected static boolean isWhiteSpace(byte byteToCheck) {
        switch (byteToCheck) {
        case ' ':
        case '\n':
        case '\r':
        case '\t':
            return true;
        default:
            return false;
        }
    }

    /**
     * Resets this object to its initial newly constructed state.
     */
    private void reset() {
        buffer = null;
        pos = 0;
        readPos = 0;
        currentLinePos = 0;
        modulus = 0;
        eof = false;
    }

    /**
     * Encodes an Object using the Base-N 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 Base-N encoded data which corresponds to the byte[] supplied.
     * @throws IllegalArgumentException if the parameter supplied is not of type byte[]
     */
    public Object encode(Object pObject) {
        if (!(pObject instanceof byte[])) {
            throw new IllegalArgumentException("Parameter supplied to Base-N encode is not a byte[]");
        }
        return encode((byte[]) pObject);
    }

    /**
     * Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet.
     *
     * @param pArray a byte array containing binary data
     * @return A String containing only Base-N character data
     */
    public String encodeToString(byte[] pArray) {
        return StringUtil.newStringUtf8(encode(pArray));
    }

    /**
     * Decodes an Object using the Base-N 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[] or String.
     *
     * @param pObject Object to decode
     * @return An object (of type byte[]) containing the binary data which corresponds to the byte[] or String supplied.
     * @throws IllegalArgumentException if the parameter supplied is not of type byte[]
     */
    public Object decode(Object pObject) throws IllegalArgumentException {
        if (pObject instanceof byte[]) {
            return decode((byte[]) pObject);
        } else if (pObject instanceof String) {
            return decode((String) pObject);
        } else {
            throw new IllegalArgumentException("Parameter supplied to Base-N decode is not a byte[] or a String");
        }
    }

    /**
     * Decodes a String containing characters in the Base-N alphabet.
     *
     * @param pArray A String containing Base-N character data
     * @return a byte array containing binary data
     */
    public byte[] decode(String pArray) {
        return decode(StringUtil.getBytesUtf8(pArray));
    }

    /**
     * Decodes a byte[] containing characters in the Base-N alphabet.
     *
     * @param pArray A byte array containing Base-N character data
     * @return a byte array containing binary data
     */
    public byte[] decode(byte[] pArray) {
        reset();
        if (pArray == null || pArray.length == 0) {
            return pArray;
        }
        decode(pArray, 0, pArray.length);
        decode(pArray, 0, -1); // Notify decoder of EOF.
        byte[] result = new byte[pos];
        readResults(result, 0, result.length);
        return result;
    }

    /**
     * Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
     *
     * @param pArray a byte array containing binary data
     * @return A byte array containing only the basen alphabetic character data
     */
    public byte[] encode(byte[] pArray) {
        reset();
        if (pArray == null || pArray.length == 0) {
            return pArray;
        }
        encode(pArray, 0, pArray.length);
        encode(pArray, 0, -1); // Notify encoder of EOF.
        byte[] buf = new byte[pos - readPos];
        readResults(buf, 0, buf.length);
        return buf;
    }

    /**
     * Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet.
     * Uses UTF8 encoding.
     *
     * @param pArray a byte array containing binary data
     * @return String containing only character data in the appropriate alphabet.
     */
    public String encodeAsString(byte[] pArray) {
        return StringUtil.newStringUtf8(encode(pArray));
    }

    /**
     * Returns whether or not the <code>octet</code> is in the current alphabet.
     * Does not allow whitespace or pad.
     *
     * @param octet The value to test
     * @return <code>true</code> if the value is defined in the current alphabet, <code>false</code> otherwise.
     */
    protected boolean isInAlphabet(byte octet) {
        return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1;
    }

    /**
     * Tests a given byte array to see if it contains only valid characters within the alphabet.
     * The method optionally treats whitespace and pad as valid.
     *
     * @param arrayOctet byte array to test
     * @param allowWSPad if <code>true</code>, then whitespace and PAD are also allowed
     * @return <code>true</code> if all bytes are valid characters in the alphabet or if the byte array is empty;
     *         <code>false</code>, otherwise
     */
    public boolean isInAlphabet(byte[] arrayOctet, boolean allowWSPad) {
        for (int i = 0; i < arrayOctet.length; i++) {
            if (!isInAlphabet(arrayOctet[i])
                    && (!allowWSPad || (arrayOctet[i] != PAD) && !isWhiteSpace(arrayOctet[i]))) {
                return false;
            }
        }
        return true;
    }

    /**
     * Tests a given String to see if it contains only valid characters within the alphabet.
     * The method treats whitespace and PAD as valid.
     *
     * @param basen String to test
     * @return <code>true</code> if all characters in the String are valid characters in the alphabet or if
     *         the String is empty; <code>false</code>, otherwise
     * @see #isInAlphabet(byte[], boolean)
     */
    public boolean isInAlphabet(String basen) {
        return isInAlphabet(StringUtil.getBytesUtf8(basen), true);
    }

    /**
     * Tests a given byte array to see if it contains any characters within the alphabet or PAD.
     * <p/>
     * Intended for use in checking line-ending arrays
     *
     * @param arrayOctet byte array to test
     * @return <code>true</code> if any byte is a valid character in the alphabet or PAD; <code>false</code> otherwise
     */
    protected boolean containsAlphabetOrPad(byte[] arrayOctet) {
        if (arrayOctet == null) {
            return false;
        }
        for (int i = 0; i < arrayOctet.length; i++) {
            if (PAD == arrayOctet[i] || isInAlphabet(arrayOctet[i])) {
                return true;
            }
        }
        return false;
    }

    /**
     * Calculates the amount of space needed to encode the supplied array.
     *
     * @param pArray byte[] array which will later be encoded
     * @return amount of space needed to encoded the supplied array.
     *         Returns a long since a max-len array will require > Integer.MAX_VALUE
     */
    public long getEncodedLength(byte[] pArray) {
        // Calculate non-chunked size - rounded up to allow for padding
        // cast to long is needed to avoid possibility of overflow
        long len = ((pArray.length + unencodedBlockSize - 1) / unencodedBlockSize) * (long) encodedBlockSize;
        if (lineLength > 0) { // We're using chunking
            // Round up to nearest multiple
            len += ((len + lineLength - 1) / lineLength) * chunkSeparatorLength;
        }
        return len;
    }

    /**
     * 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.
     */
    void encode(byte[] in, int inPos, int inAvail) {
        if (eof) {
            return;
        }
        // inAvail < 0 is how we're informed of EOF in the underlying data we're
        // encoding.
        if (inAvail < 0) {
            eof = true;
            if (0 == modulus && lineLength == 0) {
                return; // no leftovers to process and not using chunking
            }
            ensureBufferSize(encodeSize);
            int savedPos = pos;
            switch (modulus) { // 0-2
            case 1: // 8 bits = 6 + 2
                buffer[pos++] = encodeTable[(bitWorkArea >> 2) & MASK_6BITS]; // top 6 bits
                buffer[pos++] = encodeTable[(bitWorkArea << 4) & MASK_6BITS]; // remaining 2
                // URL-SAFE skips the padding to further reduce size.
                if (encodeTable == STANDARD_ENCODE_TABLE) {
                    buffer[pos++] = PAD;
                    buffer[pos++] = PAD;
                }
                break;

            case 2: // 16 bits = 6 + 6 + 4
                buffer[pos++] = encodeTable[(bitWorkArea >> 10) & MASK_6BITS];
                buffer[pos++] = encodeTable[(bitWorkArea >> 4) & MASK_6BITS];
                buffer[pos++] = encodeTable[(bitWorkArea << 2) & MASK_6BITS];
                // URL-SAFE skips the padding to further reduce size.
                if (encodeTable == STANDARD_ENCODE_TABLE) {
                    buffer[pos++] = PAD;
                }
                break;
            }
            currentLinePos += 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 && currentLinePos > 0) {
                System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
                pos += lineSeparator.length;
            }
        } else {
            for (int i = 0; i < inAvail; i++) {
                ensureBufferSize(encodeSize);
                modulus = (modulus + 1) % BYTES_PER_UNENCODED_BLOCK;
                int b = in[inPos++];
                if (b < 0) {
                    b += 256;
                }
                bitWorkArea = (bitWorkArea << 8) + b; //  BITS_PER_BYTE
                if (0 == modulus) { // 3 bytes = 24 bits = 4 * 6 bits to extract
                    buffer[pos++] = encodeTable[(bitWorkArea >> 18) & MASK_6BITS];
                    buffer[pos++] = encodeTable[(bitWorkArea >> 12) & MASK_6BITS];
                    buffer[pos++] = encodeTable[(bitWorkArea >> 6) & MASK_6BITS];
                    buffer[pos++] = encodeTable[bitWorkArea & MASK_6BITS];
                    currentLinePos += BYTES_PER_ENCODED_BLOCK;
                    if (lineLength > 0 && lineLength <= currentLinePos) {
                        System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
                        pos += lineSeparator.length;
                        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.
     */
    void decode(byte[] in, int inPos, int inAvail) {
        if (eof) {
            return;
        }
        if (inAvail < 0) {
            eof = true;
        }
        for (int i = 0; i < inAvail; i++) {
            ensureBufferSize(decodeSize);
            byte b = in[inPos++];
            if (b == PAD) {
                // We're done.
                eof = true;
                break;
            } else {
                if (b >= 0 && b < DECODE_TABLE.length) {
                    int result = DECODE_TABLE[b];
                    if (result >= 0) {
                        modulus = (modulus + 1) % BYTES_PER_ENCODED_BLOCK;
                        bitWorkArea = (bitWorkArea << BITS_PER_ENCODED_BYTE) + result;
                        if (modulus == 0) {
                            buffer[pos++] = (byte) ((bitWorkArea >> 16) & MASK_8BITS);
                            buffer[pos++] = (byte) ((bitWorkArea >> 8) & MASK_8BITS);
                            buffer[pos++] = (byte) (bitWorkArea & 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 (eof && modulus != 0) {
            ensureBufferSize(decodeSize);

            // We have some spare bits remaining
            // Output all whole multiples of 8 bits and ignore the rest
            switch (modulus) {
            //   case 1: // 6 bits - ignore entirely
            //       break;
            case 2: // 12 bits = 8 + 4
                bitWorkArea = bitWorkArea >> 4; // dump the extra 4 bits
                buffer[pos++] = (byte) ((bitWorkArea) & MASK_8BITS);
                break;
            case 3: // 18 bits = 8 + 8 + 2
                bitWorkArea = bitWorkArea >> 2; // dump 2 bits
                buffer[pos++] = (byte) ((bitWorkArea >> 8) & MASK_8BITS);
                buffer[pos++] = (byte) ((bitWorkArea) & MASK_8BITS);
                break;
            }
        }
    }

    /**
     * Returns whether or not the <code>octet</code> is in the base 64 alphabet.
     *
     * @param octet The value to test
     * @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> 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</code> if all characters in the String are valid characters in the Base64 alphabet or if
     *         the String is empty; <code>false</code>, otherwise
     * @since 1.5
     */
    public static boolean isBase64(String base64) {
        return isBase64(StringUtil.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</code> if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
     *         <code>false</code>, 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.
     * <p/>
     * 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 StringUtil.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 StringUtil.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</code> 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</code> this encoder will chunk the base64 output into 76 character blocks
     * @param urlSafe    if <code>true</code> 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</code> this encoder will chunk the base64 output into 76 character blocks
     * @param urlSafe       if <code>true</code> 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;
    }

}

class StringUtil {

    private static final String[] COLOURS_STR = new String[] { "red", "green", "cyan", "purple", "white" };
    private static final Map<String, Color> COLOR_MAP = new HashMap<String, Color>();

    public static String join(final String[] s) {
        final int l = s.length;
        switch (l) {
        case 0:
            return "";
        case 1:
            return s[0];
        }
        final String d = ", ";
        final int x = d.length();
        int n = 0, i;
        for (i = 0; i < l; i++) {
            n += s[i].length() + x;
        }
        final StringBuffer buf = new StringBuffer(n - x);
        i = 0;
        boolean c = true;
        while (c) {
            buf.append(s[i]);
            i++;
            c = i < l;
            if (c) {
                buf.append(d);
            }
        }
        return buf.toString();
    }

    /**
     * Draws a line on the screen at the specified index. Default is green.
     * <p/>
     * Available colours: red, green, cyan, purple, white.
     *
     * @param render The Graphics object to be used.
     * @param row    The index where you want the text.
     * @param text   The text you want to render. Colours can be set like [red].
     */
    public static void drawLine(Graphics render, int row, String text) {
        FontMetrics metrics = render.getFontMetrics();
        int height = metrics.getHeight() + 4; // height + gap
        int y = row * height + 15 + 19;
        String[] texts = text.split("\\[");
        int xIdx = 7;
        Color cur = Color.GREEN;
        for (String t : texts) {
            for (@SuppressWarnings("unused")
            String element : COLOURS_STR) {
                // String element = COLOURS_STR[i];
                // Don't search for a starting '[' cause it they don't exists.
                // we split on that.
                int endIdx = t.indexOf(']');
                if (endIdx != -1) {
                    String colorName = t.substring(0, endIdx);
                    if (COLOR_MAP.containsKey(colorName)) {
                        cur = COLOR_MAP.get(colorName);
                    } else {
                        try {
                            Field f = Color.class.getField(colorName);
                            int mods = f.getModifiers();
                            if (Modifier.isPublic(mods) && Modifier.isStatic(mods) && Modifier.isFinal(mods)) {
                                cur = (Color) f.get(null);
                                COLOR_MAP.put(colorName, cur);
                            }
                        } catch (Exception ignored) {
                        }
                    }
                    t = t.replace(colorName + "]", "");
                }
            }
            render.setColor(Color.BLACK);
            render.drawString(t, xIdx, y + 1);
            render.setColor(cur);
            render.drawString(t, xIdx, y);
            xIdx += metrics.stringWidth(t);
        }
    }

    public static String throwableToString(Throwable t) {
        if (t != null) {
            Writer exception = new StringWriter();
            PrintWriter printWriter = new PrintWriter(exception);
            t.printStackTrace(printWriter);
            return exception.toString();
        }
        return "";
    }

    public static byte[] getBytesUtf8(String string) {
        try {
            return string.getBytes("UTF-8");
        } catch (UnsupportedEncodingException e) {
            throw new IllegalStateException(e);
        }
    }

    public static String newStringUtf8(byte[] bytes) {
        if (bytes == null) {
            return null;
        }
        try {
            return new String(bytes, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            throw new IllegalStateException(e);
        }
    }

}