    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
    018package org.apache.commons.net.util;
    019
    020import java.io.UnsupportedEncodingException;
    021import 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 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode
    042 * character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
    043 * </p>
    044 *
    045 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
    046 * @since 2.2
    047 */
    048public class Base64 {
    049    private static final int DEFAULT_BUFFER_RESIZE_FACTOR = 2;
    050
    051    private static final int DEFAULT_BUFFER_SIZE = 8192;
    052
    053    /**
    054     * Chunk size per RFC 2045 section 6.8.
    055     *
    056     * <p>
    057     * The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
    058     * equal signs.
    059     * </p>
    060     *
    061     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
    062     */
    063    static final int CHUNK_SIZE = 76;
    064
    065    /**
    066     * Chunk separator per RFC 2045 section 2.1.
    067     *
    068     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
    069     */
    070    private static final byte[] CHUNK_SEPARATOR = {'\r', '\n'};
    071
    072    private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
    073
    074    /**
    075     * This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet"
    076     * equivalents as specified in Table 1 of RFC 2045.
    077     *
    078     * Thanks to "commons" project in ws.apache.org for this code.
    079     * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    080     */
    081    private static final byte[] STANDARD_ENCODE_TABLE = {
    082            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
    083            'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    084            'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
    085            'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    086            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
    087    };
    088
    089    /**
    090     * This is a copy of the STANDARD_ENCODE_TABLE above, but with + and /
    091     * changed to - and _ to make the encoded Base64 results more URL-SAFE.
    092     * This table is only used when the Base64's mode is set to URL-SAFE.
    093     */
    094    private static final byte[] URL_SAFE_ENCODE_TABLE = {
    095            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
    096            'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    097            'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
    098            'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    099            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'
    100    };
    101
    102    /**
    103     * Byte used to pad output.
    104     */
    105    private static final byte PAD = '=';
    106
    107    /**
    108     * This array is a lookup table that translates Unicode characters drawn from the "Base64 Alphabet" (as specified in
    109     * Table 1 of RFC 2045) into their 6-bit positive integer equivalents. Characters that are not in the Base64
    110     * alphabet but fall within the bounds of the array are translated to -1.
    111     *
    112     * Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both
    113     * URL_SAFE and STANDARD base64. (The encoder, on the other hand, needs to know ahead of time what to emit).
    114     *
    115     * Thanks to "commons" project in ws.apache.org for this code.
    116     * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    117     */
    118    private static final byte[] DECODE_TABLE = {
    119            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    120            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    121            -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, 52, 53, 54,
    122            55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4,
    123            5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
    124            24, 25, -1, -1, -1, -1, 63, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34,
    125            35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
    126    };
    127
    128    /** Mask used to extract 6 bits, used when encoding */
    129    private static final int MASK_6BITS = 0x3f;
    130
    131    /** Mask used to extract 8 bits, used in decoding base64 bytes */
    132    private static final int MASK_8BITS = 0xff;
    133
    134    // The static final fields above are used for the original static byte[] methods on Base64.
    135    // The private member fields below are used with the new streaming approach, which requires
    136    // some state be preserved between calls of encode() and decode().
    137
    138    /**
    139     * Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able
    140     * to decode both STANDARD and URL_SAFE streams, but the encodeTable must be a member variable so we can switch
    141     * between the two modes.
    142     */
    143    private final byte[] encodeTable;
    144
    145    /**
    146     * Line length for encoding. Not used when decoding. A value of zero or less implies no chunking of the base64
    147     * encoded data.
    148     */
    149    private final int lineLength;
    150
    151    /**
    152     * Line separator for encoding. Not used when decoding. Only used if lineLength > 0.
    153     */
    154    private final byte[] lineSeparator;
    155
    156    /**
    157     * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
    158     * <code>decodeSize = 3 + lineSeparator.length;</code>
    159     */
    160    private final int decodeSize;
    161
    162    /**
    163     * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
    164     * <code>encodeSize = 4 + lineSeparator.length;</code>
    165     */
    166    private final int encodeSize;
    167
    168    /**
    169     * Buffer for streaming.
    170     */
    171    private byte[] buffer;
    172
    173    /**
    174     * Position where next character should be written in the buffer.
    175     */
    176    private int pos;
    177
    178    /**
    179     * Position where next character should be read from the buffer.
    180     */
    181    private int readPos;
    182
    183    /**
    184     * Variable tracks how many characters have been written to the current line. Only used when encoding. We use it to
    185     * make sure each encoded line never goes beyond lineLength (if lineLength > 0).
    186     */
    187    private int currentLinePos;
    188
    189    /**
    190     * Writes to the buffer only occur after every 3 reads when encoding, an every 4 reads when decoding. This variable
    191     * helps track that.
    192     */
    193    private int modulus;
    194
    195    /**
    196     * Boolean flag to indicate the EOF has been reached. Once EOF has been reached, this Base64 object becomes useless,
    197     * and must be thrown away.
    198     */
    199    private boolean eof;
    200
    201    /**
    202     * Place holder for the 3 bytes we're dealing with for our base64 logic. Bitwise operations store and extract the
    203     * base64 encoding or decoding from this variable.
    204     */
    205    private int x;
    206
    207    /**
    208     * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    209     * <p>
    210     * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
    211     * </p>
    212     *
    213     * <p>
    214     * When decoding all variants are supported.
    215     * </p>
    216     */
    217    public Base64() {
    218        this(false);
    219    }
    220
    221    /**
    222     * Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.
    223     * <p>
    224     * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
    225     * </p>
    226     *
    227     * <p>
    228     * When decoding all variants are supported.
    229     * </p>
    230     *
    231     * @param urlSafe
    232     *            if <code>true</code>, URL-safe encoding is used. In most cases this should be set to
    233     *            <code>false</code>.
    234     * @since 1.4
    235     */
    236    public Base64(final boolean urlSafe) {
    237        this(CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe);
    238    }
    239
    240    /**
    241     * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    242     * <p>
    243     * When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is
    244     * STANDARD_ENCODE_TABLE.
    245     * </p>
    246     * <p>
    247     * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    248     * </p>
    249     * <p>
    250     * When decoding all variants are supported.
    251     * </p>
    252     *
    253     * @param lineLength
    254     *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4).
    255     *            If {@code lineLength <= 0}, then the output will not be divided into lines (chunks). Ignored when decoding.
    256     * @since 1.4
    257     */
    258    public Base64(final int lineLength) {
    259        this(lineLength, CHUNK_SEPARATOR);
    260    }
    261
    262    /**
    263     * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    264     * <p>
    265     * When encoding the line length and line separator are given in the constructor, and the encoding table is
    266     * STANDARD_ENCODE_TABLE.
    267     * </p>
    268     * <p>
    269     * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    270     * </p>
    271     * <p>
    272     * When decoding all variants are supported.
    273     * </p>
    274     *
    275     * @param lineLength
    276     *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4).
    277     *            If {@code lineLength <= 0}, then the output will not be divided into lines (chunks). Ignored when decoding.
    278     * @param lineSeparator
    279     *            Each line of encoded data will end with this sequence of bytes.
    280     * @throws IllegalArgumentException
    281     *             Thrown when the provided lineSeparator included some base64 characters.
    282     * @since 1.4
    283     */
    284    public Base64(final int lineLength, final byte[] lineSeparator) {
    285        this(lineLength, lineSeparator, false);
    286    }
    287
    288    /**
    289     * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    290     * <p>
    291     * When encoding the line length and line separator are given in the constructor, and the encoding table is
    292     * STANDARD_ENCODE_TABLE.
    293     * </p>
    294     * <p>
    295     * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    296     * </p>
    297     * <p>
    298     * When decoding all variants are supported.
    299     * </p>
    300     *
    301     * @param lineLength
    302     *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4).
    303     *            If {@code lineLength <= 0}, then the output will not be divided into lines (chunks). Ignored when decoding.
    304     * @param lineSeparator
    305     *            Each line of encoded data will end with this sequence of bytes.
    306     * @param urlSafe
    307     *            Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode
    308     *            operations. Decoding seamlessly handles both modes.
    309     * @throws IllegalArgumentException
    310     *             The provided lineSeparator included some base64 characters. That's not going to work!
    311     * @since 1.4
    312     */
    313    public Base64(int lineLength, byte[] lineSeparator, final boolean urlSafe) {
    314        if (lineSeparator == null) {
    315            lineLength = 0;  // disable chunk-separating
    316            lineSeparator = EMPTY_BYTE_ARRAY;  // this just gets ignored
    317        }
    318        this.lineLength = lineLength > 0 ? (lineLength / 4) * 4 : 0;
    319        this.lineSeparator = new byte[lineSeparator.length];
    320        System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);
    321        if (lineLength > 0) {
    322            this.encodeSize = 4 + lineSeparator.length;
    323        } else {
    324            this.encodeSize = 4;
    325        }
    326        this.decodeSize = this.encodeSize - 1;
    327        if (containsBase64Byte(lineSeparator)) {
    328            final String sep = newStringUtf8(lineSeparator);
    329            throw new IllegalArgumentException("lineSeperator must not contain base64 characters: [" + sep + "]");
    330        }
    331        this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE;
    332    }
    333
    334    /**
    335     * Returns our current encode mode. True if we're URL-SAFE, false otherwise.
    336     *
    337     * @return true if we're in URL-SAFE mode, false otherwise.
    338     * @since 1.4
    339     */
    340    public boolean isUrlSafe() {
    341        return this.encodeTable == URL_SAFE_ENCODE_TABLE;
    342    }
    343
    344    /**
    345     * Returns true if this Base64 object has buffered data for reading.
    346     *
    347     * @return true if there is Base64 object still available for reading.
    348     */
    349    boolean hasData() {
    350        return this.buffer != null;
    351    }
    352
    353    /**
    354     * Returns the amount of buffered data available for reading.
    355     *
    356     * @return The amount of buffered data available for reading.
    357     */
    358    int avail() {
    359        return buffer != null ? pos - readPos : 0;
    360    }
    361
    362    /** Doubles our buffer. */
    363    private void resizeBuffer() {
    364        if (buffer == null) {
    365            buffer = new byte[DEFAULT_BUFFER_SIZE];
    366            pos = 0;
    367            readPos = 0;
    368        } else {
    369            final byte[] b = new byte[buffer.length * DEFAULT_BUFFER_RESIZE_FACTOR];
    370            System.arraycopy(buffer, 0, b, 0, buffer.length);
    371            buffer = b;
    372        }
    373    }
    374
    375    /**
    376     * Extracts buffered data into the provided byte[] array, starting at position bPos, up to a maximum of bAvail
    377     * bytes. Returns how many bytes were actually extracted.
    378     *
    379     * @param b
    380     *            byte[] array to extract the buffered data into.
    381     * @param bPos
    382     *            position in byte[] array to start extraction at.
    383     * @param bAvail
    384     *            amount of bytes we're allowed to extract. We may extract fewer (if fewer are available).
    385     * @return The number of bytes successfully extracted into the provided byte[] array.
    386     */
    387    int readResults(final byte[] b, final int bPos, final int bAvail) {
    388        if (buffer != null) {
    389            final int len = Math.min(avail(), bAvail);
    390            if (buffer != b) {
    391                System.arraycopy(buffer, readPos, b, bPos, len);
    392                readPos += len;
    393                if (readPos >= pos) {
    394                    buffer = null;
    395                }
    396            } else {
    397                // Re-using the original consumer's output array is only
    398                // allowed for one round.
    399                buffer = null;
    400            }
    401            return len;
    402        }
    403        return eof ? -1 : 0;
    404    }
    405
    406    /**
    407     * Sets the streaming buffer. This is a small optimization where we try to buffer directly to the consumer's output
    408     * array for one round (if the consumer calls this method first) instead of starting our own buffer.
    409     *
    410     * @param out
    411     *            byte[] array to buffer directly to.
    412     * @param outPos
    413     *            Position to start buffering into.
    414     * @param outAvail
    415     *            Amount of bytes available for direct buffering.
    416     */
    417    void setInitialBuffer(final byte[] out, final int outPos, final int outAvail) {
    418        // We can re-use consumer's original output array under
    419        // special circumstances, saving on some System.arraycopy().
    420        if (out != null && out.length == outAvail) {
    421            buffer = out;
    422            pos = outPos;
    423            readPos = outPos;
    424        }
    425    }
    426
    427    /**
    428     * <p>
    429     * Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with
    430     * the data to encode, and once with inAvail set to "-1" to alert encoder that EOF has been reached, so flush last
    431     * remaining bytes (if not multiple of 3).
    432     * </p>
    433     * <p>
    434     * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
    435     * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    436     * </p>
    437     *
    438     * @param in
    439     *            byte[] array of binary data to base64 encode.
    440     * @param inPos
    441     *            Position to start reading data from.
    442     * @param inAvail
    443     *            Amount of bytes available from input for encoding.
    444     */
    445    void encode(final byte[] in, int inPos, final int inAvail) {
    446        if (eof) {
    447            return;
    448        }
    449        // inAvail < 0 is how we're informed of EOF in the underlying data we're
    450        // encoding.
    451        if (inAvail < 0) {
    452            eof = true;
    453            if (buffer == null || buffer.length - pos < encodeSize) {
    454                resizeBuffer();
    455            }
    456            switch (modulus) {
    457                case 1 :
    458                    buffer[pos++] = encodeTable[(x >> 2) & MASK_6BITS];
    459                    buffer[pos++] = encodeTable[(x << 4) & MASK_6BITS];
    460                    // URL-SAFE skips the padding to further reduce size.
    461                    if (encodeTable == STANDARD_ENCODE_TABLE) {
    462                        buffer[pos++] = PAD;
    463                        buffer[pos++] = PAD;
    464                    }
    465                    break;
    466
    467                case 2 :
    468                    buffer[pos++] = encodeTable[(x >> 10) & MASK_6BITS];
    469                    buffer[pos++] = encodeTable[(x >> 4) & MASK_6BITS];
    470                    buffer[pos++] = encodeTable[(x << 2) & MASK_6BITS];
    471                    // URL-SAFE skips the padding to further reduce size.
    472                    if (encodeTable == STANDARD_ENCODE_TABLE) {
    473                        buffer[pos++] = PAD;
    474                    }
    475                    break;
    476                default:
    477                    break;  // other values ignored
    478            }
    479            if (lineLength > 0 && pos > 0) {
    480                System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
    481                pos += lineSeparator.length;
    482            }
    483        } else {
    484            for (int i = 0; i < inAvail; i++) {
    485                if (buffer == null || buffer.length - pos < encodeSize) {
    486                    resizeBuffer();
    487                }
    488                modulus = (++modulus) % 3;
    489                int b = in[inPos++];
    490                if (b < 0) {
    491                    b += 256;
    492                }
    493                x = (x << 8) + b;
    494                if (0 == modulus) {
    495                    buffer[pos++] = encodeTable[(x >> 18) & MASK_6BITS];
    496                    buffer[pos++] = encodeTable[(x >> 12) & MASK_6BITS];
    497                    buffer[pos++] = encodeTable[(x >> 6) & MASK_6BITS];
    498                    buffer[pos++] = encodeTable[x & MASK_6BITS];
    499                    currentLinePos += 4;
    500                    if (lineLength > 0 && lineLength <= currentLinePos) {
    501                        System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
    502                        pos += lineSeparator.length;
    503                        currentLinePos = 0;
    504                    }
    505                }
    506            }
    507        }
    508    }
    509
    510    /**
    511     * <p>
    512     * Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once
    513     * with the data to decode, and once with inAvail set to "-1" to alert decoder that EOF has been reached. The "-1"
    514     * call is not necessary when decoding, but it doesn't hurt, either.
    515     * </p>
    516     * <p>
    517     * Ignores all non-base64 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are
    518     * silently ignored, but has implications for other bytes, too. This method subscribes to the garbage-in,
    519     * garbage-out philosophy: it will not check the provided data for validity.
    520     * </p>
    521     * <p>
    522     * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
    523     * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    524     * </p>
    525     *
    526     * @param in
    527     *            byte[] array of ascii data to base64 decode.
    528     * @param inPos
    529     *            Position to start reading data from.
    530     * @param inAvail
    531     *            Amount of bytes available from input for encoding.
    532     */
    533    void decode(final byte[] in, int inPos, final int inAvail) {
    534        if (eof) {
    535            return;
    536        }
    537        if (inAvail < 0) {
    538            eof = true;
    539        }
    540        for (int i = 0; i < inAvail; i++) {
    541            if (buffer == null || buffer.length - pos < decodeSize) {
    542                resizeBuffer();
    543            }
    544            final byte b = in[inPos++];
    545            if (b == PAD) {
    546                // We're done.
    547                eof = true;
    548                break;
    549            }
    550            if (b >= 0 && b < DECODE_TABLE.length) {
    551                final int result = DECODE_TABLE[b];
    552                if (result >= 0) {
    553                    modulus = (++modulus) % 4;
    554                    x = (x << 6) + result;
    555                    if (modulus == 0) {
    556                        buffer[pos++] = (byte) ((x >> 16) & MASK_8BITS);
    557                        buffer[pos++] = (byte) ((x >> 8) & MASK_8BITS);
    558                        buffer[pos++] = (byte) (x & MASK_8BITS);
    559                    }
    560                }
    561            }
    562        }
    563
    564        // Two forms of EOF as far as base64 decoder is concerned: actual
    565        // EOF (-1) and first time '=' character is encountered in stream.
    566        // This approach makes the '=' padding characters completely optional.
    567        if (eof && modulus != 0) {
    568            x = x << 6;
    569            switch (modulus) {
    570                case 2 :
    571                    x = x << 6;
    572                    buffer[pos++] = (byte) ((x >> 16) & MASK_8BITS);
    573                    break;
    574                case 3 :
    575                    buffer[pos++] = (byte) ((x >> 16) & MASK_8BITS);
    576                    buffer[pos++] = (byte) ((x >> 8) & MASK_8BITS);
    577                    break;
    578                default:
    579                    break;  // other values ignored
    580            }
    581        }
    582    }
    583
    584    /**
    585     * Returns whether or not the <code>octet</code> is in the base 64 alphabet.
    586     *
    587     * @param octet
    588     *            The value to test
    589     * @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise.
    590     * @since 1.4
    591     */
    592    public static boolean isBase64(final byte octet) {
    593        return octet == PAD || (octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1);
    594    }
    595
    596    /**
    597     * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the
    598     * method treats whitespace as valid.
    599     *
    600     * @param arrayOctet
    601     *            byte array to test
    602     * @return <code>true</code> if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
    603     *         false, otherwise
    604     */
    605    public static boolean isArrayByteBase64(final byte[] arrayOctet) {
    606        for (final byte element : arrayOctet) {
    607            if (!isBase64(element) && !isWhiteSpace(element)) {
    608                return false;
    609            }
    610        }
    611        return true;
    612    }
    613
    614    /**
    615     * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
    616     *
    617     * @param arrayOctet
    618     *            byte array to test
    619     * @return <code>true</code> if any byte is a valid character in the Base64 alphabet; false herwise
    620     */
    621    private static boolean containsBase64Byte(final byte[] arrayOctet) {
    622        for (final byte element : arrayOctet)
    623        {
    624            if (isBase64(element)) {
    625                return true;
    626            }
    627        }
    628        return false;
    629    }
    630
    631    /**
    632     * Encodes binary data using the base64 algorithm but does not chunk the output.
    633     *
    634     * @param binaryData
    635     *            binary data to encode
    636     * @return byte[] containing Base64 characters in their UTF-8 representation.
    637     */
    638    public static byte[] encodeBase64(final byte[] binaryData) {
    639        return encodeBase64(binaryData, false);
    640    }
    641
    642    /**
    643     * Encodes binary data using the base64 algorithm into 76 character blocks separated by CRLF.
    644     * <p>
    645     * For a non-chunking version, see {@link #encodeBase64StringUnChunked(byte[])}.
    646     *
    647     * @param binaryData
    648     *            binary data to encode
    649     * @return String containing Base64 characters.
    650     * @since 1.4
    651     */
    652    public static String encodeBase64String(final byte[] binaryData) {
    653        return newStringUtf8(encodeBase64(binaryData, true));
    654    }
    655
    656    /**
    657     * Encodes binary data using the base64 algorithm, without using chunking.
    658     * <p>
    659     * For a chunking version, see {@link #encodeBase64String(byte[])}.
    660     *
    661     * @param binaryData
    662     *            binary data to encode
    663     * @return String containing Base64 characters.
    664     * @since 3.2
    665     */
    666    public static String encodeBase64StringUnChunked(final byte[] binaryData) {
    667        return newStringUtf8(encodeBase64(binaryData, false));
    668    }
    669
    670    /**
    671     * Encodes binary data using the base64 algorithm.
    672     *
    673     * @param binaryData
    674     *            binary data to encode
    675     * @param useChunking whether to split the output into chunks
    676     * @return String containing Base64 characters.
    677     * @since 3.2
    678     */
    679    public static String encodeBase64String(final byte[] binaryData, final boolean useChunking) {
    680        return newStringUtf8(encodeBase64(binaryData, useChunking));
    681    }
    682
    683    /**
    684     * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
    685     * url-safe variation emits - and _ instead of + and / characters.
    686     *
    687     * @param binaryData
    688     *            binary data to encode
    689     * @return byte[] containing Base64 characters in their UTF-8 representation.
    690     * @since 1.4
    691     */
    692    public static byte[] encodeBase64URLSafe(final byte[] binaryData) {
    693        return encodeBase64(binaryData, false, true);
    694    }
    695
    696    /**
    697     * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
    698     * url-safe variation emits - and _ instead of + and / characters.
    699     *
    700     * @param binaryData
    701     *            binary data to encode
    702     * @return String containing Base64 characters
    703     * @since 1.4
    704     */
    705    public static String encodeBase64URLSafeString(final byte[] binaryData) {
    706        return newStringUtf8(encodeBase64(binaryData, false, true));
    707    }
    708
    709    /**
    710     * Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
    711     *
    712     * @param binaryData
    713     *            binary data to encode
    714     * @return Base64 characters chunked in 76 character blocks
    715     */
    716    public static byte[] encodeBase64Chunked(final byte[] binaryData) {
    717        return encodeBase64(binaryData, true);
    718    }
    719
    720    /**
    721     * Decodes a String containing containing characters in the Base64 alphabet.
    722     *
    723     * @param pArray
    724     *            A String containing Base64 character data
    725     * @return a byte array containing binary data
    726     * @since 1.4
    727     */
    728    public byte[] decode(final String pArray) {
    729        return decode(getBytesUtf8(pArray));
    730    }
    731
    732    private byte[] getBytesUtf8(final String pArray) {
    733        try {
    734            return pArray.getBytes("UTF8");
    735        } catch (final UnsupportedEncodingException e) {
    736            throw new RuntimeException(e);
    737        }
    738    }
    739
    740    /**
    741     * Decodes a byte[] containing containing characters in the Base64 alphabet.
    742     *
    743     * @param pArray
    744     *            A byte array containing Base64 character data
    745     * @return a byte array containing binary data
    746     */
    747    public byte[] decode(final byte[] pArray) {
    748        reset();
    749        if (pArray == null || pArray.length == 0) {
    750            return pArray;
    751        }
    752        final long len = (pArray.length * 3) / 4;
    753        final byte[] buf = new byte[(int) len];
    754        setInitialBuffer(buf, 0, buf.length);
    755        decode(pArray, 0, pArray.length);
    756        decode(pArray, 0, -1); // Notify decoder of EOF.
    757
    758        // Would be nice to just return buf (like we sometimes do in the encode
    759        // logic), but we have no idea what the line-length was (could even be
    760        // variable).  So we cannot determine ahead of time exactly how big an
    761        // array is necessary.  Hence the need to construct a 2nd byte array to
    762        // hold the final result:
    763
    764        final byte[] result = new byte[pos];
    765        readResults(result, 0, result.length);
    766        return result;
    767    }
    768
    769    /**
    770     * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
    771     *
    772     * @param binaryData
    773     *            Array containing binary data to encode.
    774     * @param isChunked
    775     *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
    776     * @return Base64-encoded data.
    777     * @throws IllegalArgumentException
    778     *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
    779     */
    780    public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked) {
    781        return encodeBase64(binaryData, isChunked, false);
    782    }
    783
    784    /**
    785     * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
    786     *
    787     * @param binaryData
    788     *            Array containing binary data to encode.
    789     * @param isChunked
    790     *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
    791     * @param urlSafe
    792     *            if <code>true</code> this encoder will emit - and _ instead of the usual + and / characters.
    793     * @return Base64-encoded data.
    794     * @throws IllegalArgumentException
    795     *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
    796     * @since 1.4
    797     */
    798    public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe) {
    799        return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE);
    800    }
    801
    802    /**
    803     * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
    804     *
    805     * @param binaryData
    806     *            Array containing binary data to encode.
    807     * @param isChunked
    808     *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
    809     * @param urlSafe
    810     *            if <code>true</code> this encoder will emit - and _ instead of the usual + and / characters.
    811     * @param maxResultSize
    812     *            The maximum result size to accept.
    813     * @return Base64-encoded data.
    814     * @throws IllegalArgumentException
    815     *             Thrown when the input array needs an output array bigger than maxResultSize
    816     * @since 1.4
    817     */
    818    public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe,
    819            final int maxResultSize) {
    820        if (binaryData == null || binaryData.length == 0) {
    821            return binaryData;
    822        }
    823
    824        final long len = getEncodeLength(binaryData, isChunked ? CHUNK_SIZE : 0,
    825                isChunked ? CHUNK_SEPARATOR : EMPTY_BYTE_ARRAY);
    826        if (len > maxResultSize) {
    827            throw new IllegalArgumentException("Input array too big, the output array would be bigger (" + len
    828                    + ") than the specified maxium size of " + maxResultSize);
    829        }
    830
    831        final Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe);
    832        return b64.encode(binaryData);
    833    }
    834
    835    /**
    836     * Decodes a Base64 String into octets
    837     *
    838     * @param base64String
    839     *            String containing Base64 data
    840     * @return Array containing decoded data.
    841     * @since 1.4
    842     */
    843    public static byte[] decodeBase64(final String base64String) {
    844        return new Base64().decode(base64String);
    845    }
    846
    847    /**
    848     * Decodes Base64 data into octets
    849     *
    850     * @param base64Data
    851     *            Byte array containing Base64 data
    852     * @return Array containing decoded data.
    853     */
    854    public static byte[] decodeBase64(final byte[] base64Data) {
    855        return new Base64().decode(base64Data);
    856    }
    857
    858
    859
    860    /**
    861     * Checks if a byte value is whitespace or not.
    862     *
    863     * @param byteToCheck
    864     *            the byte to check
    865     * @return true if byte is whitespace, false otherwise
    866     */
    867    private static boolean isWhiteSpace(final byte byteToCheck) {
    868        switch (byteToCheck) {
    869            case ' ' :
    870            case '\n' :
    871            case '\r' :
    872            case '\t' :
    873                return true;
    874            default :
    875                return false;
    876        }
    877    }
    878
    879    /**
    880     * Encodes a byte[] containing binary data, into a String containing characters in the Base64 alphabet.
    881     *
    882     * @param pArray
    883     *            a byte array containing binary data
    884     * @return A String containing only Base64 character data
    885     * @since 1.4
    886     */
    887    public String encodeToString(final byte[] pArray) {
    888        return newStringUtf8(encode(pArray));
    889    }
    890
    891    private static String newStringUtf8(final byte[] encode) {
    892        String str = null;
    893        try {
    894            str = new String(encode, "UTF8");
    895        } catch (final UnsupportedEncodingException ue) {
    896            throw new RuntimeException(ue);
    897        }
    898        return str;
    899    }
    900
    901    /**
    902     * Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.
    903     *
    904     * @param pArray
    905     *            a byte array containing binary data
    906     * @return A byte array containing only Base64 character data
    907     */
    908    public byte[] encode(final byte[] pArray) {
    909        reset();
    910        if (pArray == null || pArray.length == 0) {
    911            return pArray;
    912        }
    913        final long len = getEncodeLength(pArray, lineLength, lineSeparator);
    914        byte[] buf = new byte[(int) len];
    915        setInitialBuffer(buf, 0, buf.length);
    916        encode(pArray, 0, pArray.length);
    917        encode(pArray, 0, -1); // Notify encoder of EOF.
    918        // Encoder might have resized, even though it was unnecessary.
    919        if (buffer != buf) {
    920            readResults(buf, 0, buf.length);
    921        }
    922        // In URL-SAFE mode we skip the padding characters, so sometimes our
    923        // final length is a bit smaller.
    924        if (isUrlSafe() && pos < buf.length) {
    925            final byte[] smallerBuf = new byte[pos];
    926            System.arraycopy(buf, 0, smallerBuf, 0, pos);
    927            buf = smallerBuf;
    928        }
    929        return buf;
    930    }
    931
    932    /**
    933     * Pre-calculates the amount of space needed to base64-encode the supplied array.
    934     *
    935     * @param pArray byte[] array which will later be encoded
    936     * @param chunkSize line-length of the output (<= 0 means no chunking) between each
    937     *        chunkSeparator (e.g. CRLF).
    938     * @param chunkSeparator the sequence of bytes used to separate chunks of output (e.g. CRLF).
    939     *
    940     * @return amount of space needed to encoded the supplied array.  Returns
    941     *         a long since a max-len array will require Integer.MAX_VALUE + 33%.
    942     */
    943    private static long getEncodeLength(final byte[] pArray, int chunkSize, final byte[] chunkSeparator) {
    944        // base64 always encodes to multiples of 4.
    945        chunkSize = (chunkSize / 4) * 4;
    946
    947        long len = (pArray.length * 4) / 3;
    948        final long mod = len % 4;
    949        if (mod != 0) {
    950            len += 4 - mod;
    951        }
    952        if (chunkSize > 0) {
    953            final boolean lenChunksPerfectly = len % chunkSize == 0;
    954            len += (len / chunkSize) * chunkSeparator.length;
    955            if (!lenChunksPerfectly) {
    956                len += chunkSeparator.length;
    957            }
    958        }
    959        return len;
    960    }
    961
    962    // Implementation of integer encoding used for crypto
    963    /**
    964     * Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
    965     *
    966     * @param pArray
    967     *            a byte array containing base64 character data
    968     * @return A BigInteger
    969     * @since 1.4
    970     */
    971    public static BigInteger decodeInteger(final byte[] pArray) {
    972        return new BigInteger(1, decodeBase64(pArray));
    973    }
    974
    975    /**
    976     * Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
    977     *
    978     * @param bigInt
    979     *            a BigInteger
    980     * @return A byte array containing base64 character data
    981     * @throws NullPointerException
    982     *             if null is passed in
    983     * @since 1.4
    984     */
    985    public static byte[] encodeInteger(final BigInteger bigInt) {
    986        if (bigInt == null) {
    987            throw new NullPointerException("encodeInteger called with null parameter");
    988        }
    989        return encodeBase64(toIntegerBytes(bigInt), false);
    990    }
    991
    992    /**
    993     * Returns a byte-array representation of a <code>BigInteger</code> without sign bit.
    994     *
    995     * @param bigInt
    996     *            <code>BigInteger</code> to be converted
    997     * @return a byte array representation of the BigInteger parameter
    998     */
    999    static byte[] toIntegerBytes(final BigInteger bigInt) {
    1000        int bitlen = bigInt.bitLength();
    1001        // round bitlen
    1002        bitlen = ((bitlen + 7) >> 3) << 3;
    1003        final byte[] bigBytes = bigInt.toByteArray();
    1004
    1005        if (((bigInt.bitLength() % 8) != 0) && (((bigInt.bitLength() / 8) + 1) == (bitlen / 8))) {
    1006            return bigBytes;
    1007        }
    1008        // set up params for copying everything but sign bit
    1009        int startSrc = 0;
    1010        int len = bigBytes.length;
    1011
    1012        // if bigInt is exactly byte-aligned, just skip signbit in copy
    1013        if ((bigInt.bitLength() % 8) == 0) {
    1014            startSrc = 1;
    1015            len--;
    1016        }
    1017        final int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec
    1018        final byte[] resizedBytes = new byte[bitlen / 8];
    1019        System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);
    1020        return resizedBytes;
    1021    }
    1022
    1023    /**
    1024     * Resets this Base64 object to its initial newly constructed state.
    1025     */
    1026    private void reset() {
    1027        buffer = null;
    1028        pos = 0;
    1029        readPos = 0;
    1030        currentLinePos = 0;
    1031        modulus = 0;
    1032        eof = false;
    1033    }
    1034
    1035    // Getters for use in testing
    1036
    1037    int getLineLength() {
    1038        return lineLength;
    1039    }
    1040
    1041    byte[] getLineSeparator() {
    1042        return lineSeparator.clone();
    1043    }
    1044}