    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017
    018    package org.apache.commons.net.util;
    019
    020    import java.io.UnsupportedEncodingException;
    021    import java.math.BigInteger;
    022
    023
    024
    025    /**
    026     * Provides Base64 encoding and decoding as defined by RFC 2045.
    027     *
    028     * <p>
    029     * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
    030     * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
    031     * </p>
    032     * <p>
    033     * The class can be parameterized in the following manner with various constructors:
    034     * <ul>
    035     * <li>URL-safe mode: Default off.</li>
    036     * <li>Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of
    037     * 4 in the encoded data.
    038     * <li>Line separator: Default is CRLF ("\r\n")</li>
    039     * </ul>
    040     * </p>
    041     * <p>
    042     * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode
    043     * character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
    044     * </p>
    045     *
    046     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
    047     * @author Apache Software Foundation
    048     * @since 2.2
    049     * @version $Id$
    050     */
    051    public class Base64 {
    052        private static final int DEFAULT_BUFFER_RESIZE_FACTOR = 2;
    053
    054        private static final int DEFAULT_BUFFER_SIZE = 8192;
    055
    056        /**
    057         * Chunk size per RFC 2045 section 6.8.
    058         *
    059         * <p>
    060         * The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
    061         * equal signs.
    062         * </p>
    063         *
    064         * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
    065         */
    066        static final int CHUNK_SIZE = 76;
    067
    068        /**
    069         * Chunk separator per RFC 2045 section 2.1.
    070         *
    071         * <p>
    072         * N.B. The next major release may break compatibility and make this field private.
    073         * </p>
    074         *
    075         * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
    076         */
    077        static final byte[] CHUNK_SEPARATOR = {'\r', '\n'};
    078
    079        /**
    080         * This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet"
    081         * equivalents as specified in Table 1 of RFC 2045.
    082         *
    083         * Thanks to "commons" project in ws.apache.org for this code.
    084         * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    085         */
    086        private static final byte[] STANDARD_ENCODE_TABLE = {
    087                'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
    088                'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    089                'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
    090                'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    091                '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
    092        };
    093
    094        /**
    095         * This is a copy of the STANDARD_ENCODE_TABLE above, but with + and /
    096         * changed to - and _ to make the encoded Base64 results more URL-SAFE.
    097         * This table is only used when the Base64's mode is set to URL-SAFE.
    098         */
    099        private static final byte[] URL_SAFE_ENCODE_TABLE = {
    100                'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
    101                'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    102                'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
    103                'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    104                '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'
    105        };
    106
    107        /**
    108         * Byte used to pad output.
    109         */
    110        private static final byte PAD = '=';
    111
    112        /**
    113         * This array is a lookup table that translates Unicode characters drawn from the "Base64 Alphabet" (as specified in
    114         * Table 1 of RFC 2045) into their 6-bit positive integer equivalents. Characters that are not in the Base64
    115         * alphabet but fall within the bounds of the array are translated to -1.
    116         *
    117         * Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both
    118         * URL_SAFE and STANDARD base64. (The encoder, on the other hand, needs to know ahead of time what to emit).
    119         *
    120         * Thanks to "commons" project in ws.apache.org for this code.
    121         * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    122         */
    123        private static final byte[] DECODE_TABLE = {
    124                -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    125                -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    126                -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, 52, 53, 54,
    127                55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4,
    128                5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
    129                24, 25, -1, -1, -1, -1, 63, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34,
    130                35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
    131        };
    132
    133        /** Mask used to extract 6 bits, used when encoding */
    134        private static final int MASK_6BITS = 0x3f;
    135
    136        /** Mask used to extract 8 bits, used in decoding base64 bytes */
    137        private static final int MASK_8BITS = 0xff;
    138
    139        // The static final fields above are used for the original static byte[] methods on Base64.
    140        // The private member fields below are used with the new streaming approach, which requires
    141        // some state be preserved between calls of encode() and decode().
    142
    143        /**
    144         * Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able
    145         * to decode both STANDARD and URL_SAFE streams, but the encodeTable must be a member variable so we can switch
    146         * between the two modes.
    147         */
    148        private final byte[] encodeTable;
    149
    150        /**
    151         * Line length for encoding. Not used when decoding. A value of zero or less implies no chunking of the base64
    152         * encoded data.
    153         */
    154        private final int lineLength;
    155
    156        /**
    157         * Line separator for encoding. Not used when decoding. Only used if lineLength > 0.
    158         */
    159        private final byte[] lineSeparator;
    160
    161        /**
    162         * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
    163         * <code>decodeSize = 3 + lineSeparator.length;</code>
    164         */
    165        private final int decodeSize;
    166
    167        /**
    168         * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
    169         * <code>encodeSize = 4 + lineSeparator.length;</code>
    170         */
    171        private final int encodeSize;
    172
    173        /**
    174         * Buffer for streaming.
    175         */
    176        private byte[] buffer;
    177
    178        /**
    179         * Position where next character should be written in the buffer.
    180         */
    181        private int pos;
    182
    183        /**
    184         * Position where next character should be read from the buffer.
    185         */
    186        private int readPos;
    187
    188        /**
    189         * Variable tracks how many characters have been written to the current line. Only used when encoding. We use it to
    190         * make sure each encoded line never goes beyond lineLength (if lineLength > 0).
    191         */
    192        private int currentLinePos;
    193
    194        /**
    195         * Writes to the buffer only occur after every 3 reads when encoding, an every 4 reads when decoding. This variable
    196         * helps track that.
    197         */
    198        private int modulus;
    199
    200        /**
    201         * Boolean flag to indicate the EOF has been reached. Once EOF has been reached, this Base64 object becomes useless,
    202         * and must be thrown away.
    203         */
    204        private boolean eof;
    205
    206        /**
    207         * Place holder for the 3 bytes we're dealing with for our base64 logic. Bitwise operations store and extract the
    208         * base64 encoding or decoding from this variable.
    209         */
    210        private int x;
    211
    212        /**
    213         * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    214         * <p>
    215         * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
    216         * </p>
    217         *
    218         * <p>
    219         * When decoding all variants are supported.
    220         * </p>
    221         */
    222        public Base64() {
    223            this(false);
    224        }
    225
    226        /**
    227         * Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.
    228         * <p>
    229         * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
    230         * </p>
    231         *
    232         * <p>
    233         * When decoding all variants are supported.
    234         * </p>
    235         *
    236         * @param urlSafe
    237         *            if <code>true</code>, URL-safe encoding is used. In most cases this should be set to
    238         *            <code>false</code>.
    239         * @since 1.4
    240         */
    241        public Base64(boolean urlSafe) {
    242            this(CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe);
    243        }
    244
    245        /**
    246         * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    247         * <p>
    248         * When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is
    249         * STANDARD_ENCODE_TABLE.
    250         * </p>
    251         * <p>
    252         * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    253         * </p>
    254         * <p>
    255         * When decoding all variants are supported.
    256         * </p>
    257         *
    258         * @param lineLength
    259         *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4).
    260         *            If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
    261         * @since 1.4
    262         */
    263        public Base64(int lineLength) {
    264            this(lineLength, CHUNK_SEPARATOR);
    265        }
    266
    267        /**
    268         * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    269         * <p>
    270         * When encoding the line length and line separator are given in the constructor, and the encoding table is
    271         * STANDARD_ENCODE_TABLE.
    272         * </p>
    273         * <p>
    274         * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    275         * </p>
    276         * <p>
    277         * When decoding all variants are supported.
    278         * </p>
    279         *
    280         * @param lineLength
    281         *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4).
    282         *            If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
    283         * @param lineSeparator
    284         *            Each line of encoded data will end with this sequence of bytes.
    285         * @throws IllegalArgumentException
    286         *             Thrown when the provided lineSeparator included some base64 characters.
    287         * @since 1.4
    288         */
    289        public Base64(int lineLength, byte[] lineSeparator) {
    290            this(lineLength, lineSeparator, false);
    291        }
    292
    293        /**
    294         * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    295         * <p>
    296         * When encoding the line length and line separator are given in the constructor, and the encoding table is
    297         * STANDARD_ENCODE_TABLE.
    298         * </p>
    299         * <p>
    300         * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    301         * </p>
    302         * <p>
    303         * When decoding all variants are supported.
    304         * </p>
    305         *
    306         * @param lineLength
    307         *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4).
    308         *            If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
    309         * @param lineSeparator
    310         *            Each line of encoded data will end with this sequence of bytes.
    311         * @param urlSafe
    312         *            Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode
    313         *            operations. Decoding seamlessly handles both modes.
    314         * @throws IllegalArgumentException
    315         *             The provided lineSeparator included some base64 characters. That's not going to work!
    316         * @since 1.4
    317         */
    318        public Base64(int lineLength, byte[] lineSeparator, boolean urlSafe) {
    319            if (lineSeparator == null) {
    320                lineLength = 0;  // disable chunk-separating
    321                lineSeparator = CHUNK_SEPARATOR;  // this just gets ignored
    322            }
    323            this.lineLength = lineLength > 0 ? (lineLength / 4) * 4 : 0;
    324            this.lineSeparator = new byte[lineSeparator.length];
    325            System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);
    326            if (lineLength > 0) {
    327                this.encodeSize = 4 + lineSeparator.length;
    328            } else {
    329                this.encodeSize = 4;
    330            }
    331            this.decodeSize = this.encodeSize - 1;
    332            if (containsBase64Byte(lineSeparator)) {
    333                String sep = newStringUtf8(lineSeparator);
    334                throw new IllegalArgumentException("lineSeperator must not contain base64 characters: [" + sep + "]");
    335            }
    336            this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE;
    337        }
    338
    339        /**
    340         * Returns our current encode mode. True if we're URL-SAFE, false otherwise.
    341         *
    342         * @return true if we're in URL-SAFE mode, false otherwise.
    343         * @since 1.4
    344         */
    345        public boolean isUrlSafe() {
    346            return this.encodeTable == URL_SAFE_ENCODE_TABLE;
    347        }
    348
    349        /**
    350         * Returns true if this Base64 object has buffered data for reading.
    351         *
    352         * @return true if there is Base64 object still available for reading.
    353         */
    354        boolean hasData() {
    355            return this.buffer != null;
    356        }
    357
    358        /**
    359         * Returns the amount of buffered data available for reading.
    360         *
    361         * @return The amount of buffered data available for reading.
    362         */
    363        int avail() {
    364            return buffer != null ? pos - readPos : 0;
    365        }
    366
    367        /** Doubles our buffer. */
    368        private void resizeBuffer() {
    369            if (buffer == null) {
    370                buffer = new byte[DEFAULT_BUFFER_SIZE];
    371                pos = 0;
    372                readPos = 0;
    373            } else {
    374                byte[] b = new byte[buffer.length * DEFAULT_BUFFER_RESIZE_FACTOR];
    375                System.arraycopy(buffer, 0, b, 0, buffer.length);
    376                buffer = b;
    377            }
    378        }
    379
    380        /**
    381         * Extracts buffered data into the provided byte[] array, starting at position bPos, up to a maximum of bAvail
    382         * bytes. Returns how many bytes were actually extracted.
    383         *
    384         * @param b
    385         *            byte[] array to extract the buffered data into.
    386         * @param bPos
    387         *            position in byte[] array to start extraction at.
    388         * @param bAvail
    389         *            amount of bytes we're allowed to extract. We may extract fewer (if fewer are available).
    390         * @return The number of bytes successfully extracted into the provided byte[] array.
    391         */
    392        int readResults(byte[] b, int bPos, int bAvail) {
    393            if (buffer != null) {
    394                int len = Math.min(avail(), bAvail);
    395                if (buffer != b) {
    396                    System.arraycopy(buffer, readPos, b, bPos, len);
    397                    readPos += len;
    398                    if (readPos >= pos) {
    399                        buffer = null;
    400                    }
    401                } else {
    402                    // Re-using the original consumer's output array is only
    403                    // allowed for one round.
    404                    buffer = null;
    405                }
    406                return len;
    407            }
    408            return eof ? -1 : 0;
    409        }
    410
    411        /**
    412         * Sets the streaming buffer. This is a small optimization where we try to buffer directly to the consumer's output
    413         * array for one round (if the consumer calls this method first) instead of starting our own buffer.
    414         *
    415         * @param out
    416         *            byte[] array to buffer directly to.
    417         * @param outPos
    418         *            Position to start buffering into.
    419         * @param outAvail
    420         *            Amount of bytes available for direct buffering.
    421         */
    422        void setInitialBuffer(byte[] out, int outPos, int outAvail) {
    423            // We can re-use consumer's original output array under
    424            // special circumstances, saving on some System.arraycopy().
    425            if (out != null && out.length == outAvail) {
    426                buffer = out;
    427                pos = outPos;
    428                readPos = outPos;
    429            }
    430        }
    431
    432        /**
    433         * <p>
    434         * Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with
    435         * the data to encode, and once with inAvail set to "-1" to alert encoder that EOF has been reached, so flush last
    436         * remaining bytes (if not multiple of 3).
    437         * </p>
    438         * <p>
    439         * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
    440         * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    441         * </p>
    442         *
    443         * @param in
    444         *            byte[] array of binary data to base64 encode.
    445         * @param inPos
    446         *            Position to start reading data from.
    447         * @param inAvail
    448         *            Amount of bytes available from input for encoding.
    449         */
    450        void encode(byte[] in, int inPos, int inAvail) {
    451            if (eof) {
    452                return;
    453            }
    454            // inAvail < 0 is how we're informed of EOF in the underlying data we're
    455            // encoding.
    456            if (inAvail < 0) {
    457                eof = true;
    458                if (buffer == null || buffer.length - pos < encodeSize) {
    459                    resizeBuffer();
    460                }
    461                switch (modulus) {
    462                    case 1 :
    463                        buffer[pos++] = encodeTable[(x >> 2) & MASK_6BITS];
    464                        buffer[pos++] = encodeTable[(x << 4) & MASK_6BITS];
    465                        // URL-SAFE skips the padding to further reduce size.
    466                        if (encodeTable == STANDARD_ENCODE_TABLE) {
    467                            buffer[pos++] = PAD;
    468                            buffer[pos++] = PAD;
    469                        }
    470                        break;
    471
    472                    case 2 :
    473                        buffer[pos++] = encodeTable[(x >> 10) & MASK_6BITS];
    474                        buffer[pos++] = encodeTable[(x >> 4) & MASK_6BITS];
    475                        buffer[pos++] = encodeTable[(x << 2) & MASK_6BITS];
    476                        // URL-SAFE skips the padding to further reduce size.
    477                        if (encodeTable == STANDARD_ENCODE_TABLE) {
    478                            buffer[pos++] = PAD;
    479                        }
    480                        break;
    481                }
    482                if (lineLength > 0 && pos > 0) {
    483                    System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
    484                    pos += lineSeparator.length;
    485                }
    486            } else {
    487                for (int i = 0; i < inAvail; i++) {
    488                    if (buffer == null || buffer.length - pos < encodeSize) {
    489                        resizeBuffer();
    490                    }
    491                    modulus = (++modulus) % 3;
    492                    int b = in[inPos++];
    493                    if (b < 0) {
    494                        b += 256;
    495                    }
    496                    x = (x << 8) + b;
    497                    if (0 == modulus) {
    498                        buffer[pos++] = encodeTable[(x >> 18) & MASK_6BITS];
    499                        buffer[pos++] = encodeTable[(x >> 12) & MASK_6BITS];
    500                        buffer[pos++] = encodeTable[(x >> 6) & MASK_6BITS];
    501                        buffer[pos++] = encodeTable[x & MASK_6BITS];
    502                        currentLinePos += 4;
    503                        if (lineLength > 0 && lineLength <= currentLinePos) {
    504                            System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
    505                            pos += lineSeparator.length;
    506                            currentLinePos = 0;
    507                        }
    508                    }
    509                }
    510            }
    511        }
    512
    513        /**
    514         * <p>
    515         * Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once
    516         * with the data to decode, and once with inAvail set to "-1" to alert decoder that EOF has been reached. The "-1"
    517         * call is not necessary when decoding, but it doesn't hurt, either.
    518         * </p>
    519         * <p>
    520         * Ignores all non-base64 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are
    521         * silently ignored, but has implications for other bytes, too. This method subscribes to the garbage-in,
    522         * garbage-out philosophy: it will not check the provided data for validity.
    523         * </p>
    524         * <p>
    525         * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
    526         * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    527         * </p>
    528         *
    529         * @param in
    530         *            byte[] array of ascii data to base64 decode.
    531         * @param inPos
    532         *            Position to start reading data from.
    533         * @param inAvail
    534         *            Amount of bytes available from input for encoding.
    535         */
    536        void decode(byte[] in, int inPos, int inAvail) {
    537            if (eof) {
    538                return;
    539            }
    540            if (inAvail < 0) {
    541                eof = true;
    542            }
    543            for (int i = 0; i < inAvail; i++) {
    544                if (buffer == null || buffer.length - pos < decodeSize) {
    545                    resizeBuffer();
    546                }
    547                byte b = in[inPos++];
    548                if (b == PAD) {
    549                    // We're done.
    550                    eof = true;
    551                    break;
    552                } else {
    553                    if (b >= 0 && b < DECODE_TABLE.length) {
    554                        int result = DECODE_TABLE[b];
    555                        if (result >= 0) {
    556                            modulus = (++modulus) % 4;
    557                            x = (x << 6) + result;
    558                            if (modulus == 0) {
    559                                buffer[pos++] = (byte) ((x >> 16) & MASK_8BITS);
    560                                buffer[pos++] = (byte) ((x >> 8) & MASK_8BITS);
    561                                buffer[pos++] = (byte) (x & MASK_8BITS);
    562                            }
    563                        }
    564                    }
    565                }
    566            }
    567
    568            // Two forms of EOF as far as base64 decoder is concerned: actual
    569            // EOF (-1) and first time '=' character is encountered in stream.
    570            // This approach makes the '=' padding characters completely optional.
    571            if (eof && modulus != 0) {
    572                x = x << 6;
    573                switch (modulus) {
    574                    case 2 :
    575                        x = x << 6;
    576                        buffer[pos++] = (byte) ((x >> 16) & MASK_8BITS);
    577                        break;
    578                    case 3 :
    579                        buffer[pos++] = (byte) ((x >> 16) & MASK_8BITS);
    580                        buffer[pos++] = (byte) ((x >> 8) & MASK_8BITS);
    581                        break;
    582                }
    583            }
    584        }
    585
    586        /**
    587         * Returns whether or not the <code>octet</code> is in the base 64 alphabet.
    588         *
    589         * @param octet
    590         *            The value to test
    591         * @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise.
    592         * @since 1.4
    593         */
    594        public static boolean isBase64(byte octet) {
    595            return octet == PAD || (octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1);
    596        }
    597
    598        /**
    599         * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the
    600         * method treats whitespace as valid.
    601         *
    602         * @param arrayOctet
    603         *            byte array to test
    604         * @return <code>true</code> if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
    605         *         false, otherwise
    606         */
    607        public static boolean isArrayByteBase64(byte[] arrayOctet) {
    608            for (int i = 0; i < arrayOctet.length; i++) {
    609                if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[i])) {
    610                    return false;
    611                }
    612            }
    613            return true;
    614        }
    615
    616        /**
    617         * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
    618         *
    619         * @param arrayOctet
    620         *            byte array to test
    621         * @return <code>true</code> if any byte is a valid character in the Base64 alphabet; false herwise
    622         */
    623        private static boolean containsBase64Byte(byte[] arrayOctet) {
    624            for (int i = 0; i < arrayOctet.length; i++) {
    625                if (isBase64(arrayOctet[i])) {
    626                    return true;
    627                }
    628            }
    629            return false;
    630        }
    631
    632        /**
    633         * Encodes binary data using the base64 algorithm but does not chunk the output.
    634         *
    635         * @param binaryData
    636         *            binary data to encode
    637         * @return byte[] containing Base64 characters in their UTF-8 representation.
    638         */
    639        public static byte[] encodeBase64(byte[] binaryData) {
    640            return encodeBase64(binaryData, false);
    641        }
    642
    643        /**
    644         * Encodes binary data using the base64 algorithm into 76 character blocks separated by CRLF.
    645         *
    646         * @param binaryData
    647         *            binary data to encode
    648         * @return String containing Base64 characters.
    649         * @since 1.4
    650         */
    651        public static String encodeBase64String(byte[] binaryData) {
    652            return newStringUtf8(encodeBase64(binaryData, true));
    653        }
    654
    655        /**
    656         * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
    657         * url-safe variation emits - and _ instead of + and / characters.
    658         *
    659         * @param binaryData
    660         *            binary data to encode
    661         * @return byte[] containing Base64 characters in their UTF-8 representation.
    662         * @since 1.4
    663         */
    664        public static byte[] encodeBase64URLSafe(byte[] binaryData) {
    665            return encodeBase64(binaryData, false, true);
    666        }
    667
    668        /**
    669         * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
    670         * url-safe variation emits - and _ instead of + and / characters.
    671         *
    672         * @param binaryData
    673         *            binary data to encode
    674         * @return String containing Base64 characters
    675         * @since 1.4
    676         */
    677        public static String encodeBase64URLSafeString(byte[] binaryData) {
    678            return newStringUtf8(encodeBase64(binaryData, false, true));
    679        }
    680
    681        /**
    682         * Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
    683         *
    684         * @param binaryData
    685         *            binary data to encode
    686         * @return Base64 characters chunked in 76 character blocks
    687         */
    688        public static byte[] encodeBase64Chunked(byte[] binaryData) {
    689            return encodeBase64(binaryData, true);
    690        }
    691
    692        /**
    693         * Decodes an Object using the base64 algorithm. This method is provided in order to satisfy the requirements of the
    694         * Decoder interface, and will throw a DecoderException if the supplied object is not of type byte[] or String.
    695         *
    696         * @param pObject
    697         *            Object to decode
    698         * @return An object (of type byte[]) containing the binary data which corresponds to the byte[] or String supplied.
    699         * @throws RuntimeException
    700         *             if the parameter supplied is not of type byte[]
    701         */
    702        public Object decode(Object pObject) {
    703            if (pObject instanceof byte[]) {
    704                return decode((byte[]) pObject);
    705            } else if (pObject instanceof String) {
    706                return decode((String) pObject);
    707            } else {
    708                throw new RuntimeException("Parameter supplied to Base64 decode is not a byte[] or a String");
    709            }
    710        }
    711
    712        /**
    713         * Decodes a String containing containing characters in the Base64 alphabet.
    714         *
    715         * @param pArray
    716         *            A String containing Base64 character data
    717         * @return a byte array containing binary data
    718         * @since 1.4
    719         */
    720        public byte[] decode(String pArray) {
    721            return decode(getBytesUtf8(pArray));
    722        }
    723
    724        private byte[] getBytesUtf8(String pArray) {
    725            try {
    726                return pArray.getBytes("UTF8");
    727            } catch (UnsupportedEncodingException e) {
    728                throw new RuntimeException(e);
    729            }
    730        }
    731
    732        /**
    733         * Decodes a byte[] containing containing characters in the Base64 alphabet.
    734         *
    735         * @param pArray
    736         *            A byte array containing Base64 character data
    737         * @return a byte array containing binary data
    738         */
    739        public byte[] decode(byte[] pArray) {
    740            reset();
    741            if (pArray == null || pArray.length == 0) {
    742                return pArray;
    743            }
    744            long len = (pArray.length * 3) / 4;
    745            byte[] buf = new byte[(int) len];
    746            setInitialBuffer(buf, 0, buf.length);
    747            decode(pArray, 0, pArray.length);
    748            decode(pArray, 0, -1); // Notify decoder of EOF.
    749
    750            // Would be nice to just return buf (like we sometimes do in the encode
    751            // logic), but we have no idea what the line-length was (could even be
    752            // variable).  So we cannot determine ahead of time exactly how big an
    753            // array is necessary.  Hence the need to construct a 2nd byte array to
    754            // hold the final result:
    755
    756            byte[] result = new byte[pos];
    757            readResults(result, 0, result.length);
    758            return result;
    759        }
    760
    761        /**
    762         * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
    763         *
    764         * @param binaryData
    765         *            Array containing binary data to encode.
    766         * @param isChunked
    767         *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
    768         * @return Base64-encoded data.
    769         * @throws IllegalArgumentException
    770         *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
    771         */
    772        public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {
    773            return encodeBase64(binaryData, isChunked, false);
    774        }
    775
    776        /**
    777         * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
    778         *
    779         * @param binaryData
    780         *            Array containing binary data to encode.
    781         * @param isChunked
    782         *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
    783         * @param urlSafe
    784         *            if <code>true</code> this encoder will emit - and _ instead of the usual + and / characters.
    785         * @return Base64-encoded data.
    786         * @throws IllegalArgumentException
    787         *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
    788         * @since 1.4
    789         */
    790        public static byte[] encodeBase64(byte[] binaryData, boolean isChunked, boolean urlSafe) {
    791            return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE);
    792        }
    793
    794        /**
    795         * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
    796         *
    797         * @param binaryData
    798         *            Array containing binary data to encode.
    799         * @param isChunked
    800         *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
    801         * @param urlSafe
    802         *            if <code>true</code> this encoder will emit - and _ instead of the usual + and / characters.
    803         * @param maxResultSize
    804         *            The maximum result size to accept.
    805         * @return Base64-encoded data.
    806         * @throws IllegalArgumentException
    807         *             Thrown when the input array needs an output array bigger than maxResultSize
    808         * @since 1.4
    809         */
    810        public static byte[] encodeBase64(byte[] binaryData, boolean isChunked, boolean urlSafe, int maxResultSize) {
    811            if (binaryData == null || binaryData.length == 0) {
    812                return binaryData;
    813            }
    814
    815            long len = getEncodeLength(binaryData, CHUNK_SIZE, CHUNK_SEPARATOR);
    816            if (len > maxResultSize) {
    817                throw new IllegalArgumentException("Input array too big, the output array would be bigger (" +
    818                    len +
    819                    ") than the specified maxium size of " +
    820                    maxResultSize);
    821            }
    822
    823            Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe);
    824            return b64.encode(binaryData);
    825        }
    826
    827        /**
    828         * Decodes a Base64 String into octets
    829         *
    830         * @param base64String
    831         *            String containing Base64 data
    832         * @return Array containing decoded data.
    833         * @since 1.4
    834         */
    835        public static byte[] decodeBase64(String base64String) {
    836            return new Base64().decode(base64String);
    837        }
    838
    839        /**
    840         * Decodes Base64 data into octets
    841         *
    842         * @param base64Data
    843         *            Byte array containing Base64 data
    844         * @return Array containing decoded data.
    845         */
    846        public static byte[] decodeBase64(byte[] base64Data) {
    847            return new Base64().decode(base64Data);
    848        }
    849
    850
    851
    852        /**
    853         * Checks if a byte value is whitespace or not.
    854         *
    855         * @param byteToCheck
    856         *            the byte to check
    857         * @return true if byte is whitespace, false otherwise
    858         */
    859        private static boolean isWhiteSpace(byte byteToCheck) {
    860            switch (byteToCheck) {
    861                case ' ' :
    862                case '\n' :
    863                case '\r' :
    864                case '\t' :
    865                    return true;
    866                default :
    867                    return false;
    868            }
    869        }
    870
    871        // Implementation of the Encoder Interface
    872
    873        /**
    874         * Encodes an Object using the base64 algorithm. This method is provided in order to satisfy the requirements of the
    875         * Encoder interface, and will throw an EncoderException if the supplied object is not of type byte[].
    876         *
    877         * @param pObject
    878         *            Object to encode
    879         * @return An object (of type byte[]) containing the base64 encoded data which corresponds to the byte[] supplied.
    880         * @throws RuntimeException
    881         *             if the parameter supplied is not of type byte[]
    882         */
    883        public Object encode(Object pObject)  {
    884            if (!(pObject instanceof byte[])) {
    885                throw new RuntimeException("Parameter supplied to Base64 encode is not a byte[]");
    886            }
    887            return encode((byte[]) pObject);
    888        }
    889
    890        /**
    891         * Encodes a byte[] containing binary data, into a String containing characters in the Base64 alphabet.
    892         *
    893         * @param pArray
    894         *            a byte array containing binary data
    895         * @return A String containing only Base64 character data
    896         * @since 1.4
    897         */
    898        public String encodeToString(byte[] pArray) {
    899            return newStringUtf8(encode(pArray));
    900        }
    901
    902        private static String newStringUtf8(byte[] encode) {
    903            String str = null;
    904            try {
    905                str = new String(encode, "UTF8");
    906            } catch (UnsupportedEncodingException ue) {
    907                throw new RuntimeException(ue);
    908            }
    909            return str;
    910        }
    911
    912        /**
    913         * Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.
    914         *
    915         * @param pArray
    916         *            a byte array containing binary data
    917         * @return A byte array containing only Base64 character data
    918         */
    919        public byte[] encode(byte[] pArray) {
    920            reset();
    921            if (pArray == null || pArray.length == 0) {
    922                return pArray;
    923            }
    924            long len = getEncodeLength(pArray, lineLength, lineSeparator);
    925            byte[] buf = new byte[(int) len];
    926            setInitialBuffer(buf, 0, buf.length);
    927            encode(pArray, 0, pArray.length);
    928            encode(pArray, 0, -1); // Notify encoder of EOF.
    929            // Encoder might have resized, even though it was unnecessary.
    930            if (buffer != buf) {
    931                readResults(buf, 0, buf.length);
    932            }
    933            // In URL-SAFE mode we skip the padding characters, so sometimes our
    934            // final length is a bit smaller.
    935            if (isUrlSafe() && pos < buf.length) {
    936                byte[] smallerBuf = new byte[pos];
    937                System.arraycopy(buf, 0, smallerBuf, 0, pos);
    938                buf = smallerBuf;
    939            }
    940            return buf;
    941        }
    942
    943        /**
    944         * Pre-calculates the amount of space needed to base64-encode the supplied array.
    945         *
    946         * @param pArray byte[] array which will later be encoded
    947         * @param chunkSize line-length of the output (<= 0 means no chunking) between each
    948         *        chunkSeparator (e.g. CRLF).
    949         * @param chunkSeparator the sequence of bytes used to separate chunks of output (e.g. CRLF).
    950         *
    951         * @return amount of space needed to encoded the supplied array.  Returns
    952         *         a long since a max-len array will require Integer.MAX_VALUE + 33%.
    953         */
    954        private static long getEncodeLength(byte[] pArray, int chunkSize, byte[] chunkSeparator) {
    955            // base64 always encodes to multiples of 4.
    956            chunkSize = (chunkSize / 4) * 4;
    957
    958            long len = (pArray.length * 4) / 3;
    959            long mod = len % 4;
    960            if (mod != 0) {
    961                len += 4 - mod;
    962            }
    963            if (chunkSize > 0) {
    964                boolean lenChunksPerfectly = len % chunkSize == 0;
    965                len += (len / chunkSize) * chunkSeparator.length;
    966                if (!lenChunksPerfectly) {
    967                    len += chunkSeparator.length;
    968                }
    969            }
    970            return len;
    971        }
    972
    973        // Implementation of integer encoding used for crypto
    974        /**
    975         * Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
    976         *
    977         * @param pArray
    978         *            a byte array containing base64 character data
    979         * @return A BigInteger
    980         * @since 1.4
    981         */
    982        public static BigInteger decodeInteger(byte[] pArray) {
    983            return new BigInteger(1, decodeBase64(pArray));
    984        }
    985
    986        /**
    987         * Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
    988         *
    989         * @param bigInt
    990         *            a BigInteger
    991         * @return A byte array containing base64 character data
    992         * @throws NullPointerException
    993         *             if null is passed in
    994         * @since 1.4
    995         */
    996        public static byte[] encodeInteger(BigInteger bigInt) {
    997            if (bigInt == null) {
    998                throw new NullPointerException("encodeInteger called with null parameter");
    999            }
    1000            return encodeBase64(toIntegerBytes(bigInt), false);
    1001        }
    1002
    1003        /**
    1004         * Returns a byte-array representation of a <code>BigInteger</code> without sign bit.
    1005         *
    1006         * @param bigInt
    1007         *            <code>BigInteger</code> to be converted
    1008         * @return a byte array representation of the BigInteger parameter
    1009         */
    1010        static byte[] toIntegerBytes(BigInteger bigInt) {
    1011            int bitlen = bigInt.bitLength();
    1012            // round bitlen
    1013            bitlen = ((bitlen + 7) >> 3) << 3;
    1014            byte[] bigBytes = bigInt.toByteArray();
    1015
    1016            if (((bigInt.bitLength() % 8) != 0) && (((bigInt.bitLength() / 8) + 1) == (bitlen / 8))) {
    1017                return bigBytes;
    1018            }
    1019            // set up params for copying everything but sign bit
    1020            int startSrc = 0;
    1021            int len = bigBytes.length;
    1022
    1023            // if bigInt is exactly byte-aligned, just skip signbit in copy
    1024            if ((bigInt.bitLength() % 8) == 0) {
    1025                startSrc = 1;
    1026                len--;
    1027            }
    1028            int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec
    1029            byte[] resizedBytes = new byte[bitlen / 8];
    1030            System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);
    1031            return resizedBytes;
    1032        }
    1033
    1034        /**
    1035         * Resets this Base64 object to its initial newly constructed state.
    1036         */
    1037        private void reset() {
    1038            buffer = null;
    1039            pos = 0;
    1040            readPos = 0;
    1041            currentLinePos = 0;
    1042            modulus = 0;
    1043            eof = false;
    1044        }
    1045
    1046    }