    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.math.BigInteger;
    021import java.nio.charset.StandardCharsets;
    022import java.util.Objects;
    023
    024/**
    025 * Provides Base64 encoding and decoding as defined by RFC 2045.
    026 *
    027 * <p>
    028 * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose Internet Mail Extensions (MIME) Part One:
    029 * Format of Internet Message Bodies</cite> by Freed and Borenstein.
    030 * </p>
    031 * <p>
    032 * The class can be parameterized in the following manner with various constructors:
    033 * <ul>
    034 * <li>URL-safe mode: Default off.</li>
    035 * <li>Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    036 * <li>Line separator: Default is CRLF ("\r\n")</li>
    037 * </ul>
    038 * <p>
    039 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode character encodings which are
    040 * compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
    041 * </p>
    042 *
    043 * @deprecated Use {@link java.util.Base64}.
    044 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
    045 * @since 2.2
    046 */
    047@Deprecated
    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 equal signs.
    058     * </p>
    059     *
    060     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
    061     */
    062    static final int CHUNK_SIZE = 76;
    063
    064    /**
    065     * Chunk separator per RFC 2045 section 2.1.
    066     *
    067     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
    068     */
    069    private static final byte[] CHUNK_SEPARATOR = { '\r', '\n' };
    070
    071    /**
    072     * This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet" equivalents as specified in Table 1 of RFC
    073     * 2045.
    074     *
    075     * Thanks to "commons" project in ws.apache.org for <a href="http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/">this code</a>.
    076     */
    077    private static final byte[] STANDARD_ENCODE_TABLE = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
    078            'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
    079            'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };
    080
    081    /**
    082     * This is a copy of the STANDARD_ENCODE_TABLE above, but with + and / changed to - and _ to make the encoded Base64 results more URL-SAFE. This table is
    083     * only used when the Base64's mode is set to URL-SAFE.
    084     */
    085    private static final byte[] URL_SAFE_ENCODE_TABLE = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
    086            'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
    087            'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_' };
    088
    089    /**
    090     * Byte used to pad output.
    091     */
    092    private static final byte PAD = '=';
    093
    094    /**
    095     * This array is a lookup table that translates Unicode characters drawn from the "Base64 Alphabet" (as specified in Table 1 of RFC 2045) into their 6-bit
    096     * positive integer equivalents. Characters that are not in the Base64 alphabet but fall within the bounds of the array are translated to -1.
    097     *
    098     * Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both URL_SAFE and STANDARD base64. (The
    099     * encoder, on the other hand, needs to know ahead of time what to emit).
    100     *
    101     * Thanks to "commons" project in ws.apache.org for <a href="http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/">this code</a>
    102     */
    103    private static final byte[] DECODE_TABLE = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    104            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1,
    105            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63, -1, 26, 27, 28, 29, 30, 31, 32,
    106            33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 };
    107
    108    /** Mask used to extract 6 bits, used when encoding */
    109    private static final int MASK_6BITS = 0x3f;
    110
    111    /** Mask used to extract 8 bits, used in decoding base64 bytes */
    112    private static final int MASK_8BITS = 0xff;
    113
    114    // The static final fields above are used for the original static byte[] methods on Base64.
    115    // The private member fields below are used with the new streaming approach, which requires
    116    // some state be preserved between calls of encode() and decode().
    117
    118    /**
    119     * Tests a given byte array to see if it contains any valid character within the Base64 alphabet.
    120     *
    121     * @param arrayOctet byte array to test
    122     * @return {@code true} if any byte is a valid character in the Base64 alphabet; {@code false} otherwise
    123     */
    124    private static boolean containsBase64Byte(final byte[] arrayOctet) {
    125        for (final byte element : arrayOctet) {
    126            if (isBase64(element)) {
    127                return true;
    128            }
    129        }
    130        return false;
    131    }
    132
    133    /**
    134     * Decodes Base64 data into octets.
    135     *
    136     * @param base64Data Byte array containing Base64 data
    137     * @return Array containing decoded data.
    138     */
    139    public static byte[] decodeBase64(final byte[] base64Data) {
    140        return new Base64().decode(base64Data);
    141    }
    142
    143    /**
    144     * Decodes a Base64 String into octets.
    145     *
    146     * @param base64String String containing Base64 data
    147     * @return Array containing decoded data.
    148     * @since 1.4
    149     */
    150    public static byte[] decodeBase64(final String base64String) {
    151        return new Base64().decode(base64String);
    152    }
    153
    154    // Implementation of integer encoding used for crypto
    155    /**
    156     * Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
    157     *
    158     * @param pArray a byte array containing base64 character data
    159     * @return A BigInteger
    160     * @since 1.4
    161     */
    162    public static BigInteger decodeInteger(final byte[] pArray) {
    163        return new BigInteger(1, decodeBase64(pArray));
    164    }
    165
    166    /**
    167     * Encodes binary data using the base64 algorithm but does not chunk the output.
    168     *
    169     * @param binaryData binary data to encode
    170     * @return byte[] containing Base64 characters in their UTF-8 representation.
    171     */
    172    public static byte[] encodeBase64(final byte[] binaryData) {
    173        return encodeBase64(binaryData, false);
    174    }
    175
    176    /**
    177     * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
    178     *
    179     * @param binaryData Array containing binary data to encode.
    180     * @param isChunked  if {@code true} this encoder will chunk the base64 output into 76 character blocks
    181     * @return Base64-encoded data.
    182     * @throws IllegalArgumentException Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
    183     */
    184    public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked) {
    185        return encodeBase64(binaryData, isChunked, false);
    186    }
    187
    188    /**
    189     * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
    190     *
    191     * @param binaryData Array containing binary data to encode.
    192     * @param isChunked  if {@code true} this encoder will chunk the base64 output into 76 character blocks
    193     * @param urlSafe    if {@code true} this encoder will emit - and _ instead of the usual + and / characters.
    194     * @return Base64-encoded data.
    195     * @throws IllegalArgumentException Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
    196     * @since 1.4
    197     */
    198    public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe) {
    199        return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE);
    200    }
    201
    202    /**
    203     * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
    204     *
    205     * @param binaryData    Array containing binary data to encode.
    206     * @param isChunked     if {@code true} this encoder will chunk the base64 output into 76 character blocks
    207     * @param urlSafe       if {@code true} this encoder will emit - and _ instead of the usual + and / characters.
    208     * @param maxResultSize The maximum result size to accept.
    209     * @return Base64-encoded data.
    210     * @throws IllegalArgumentException Thrown when the input array needs an output array bigger than maxResultSize
    211     * @since 1.4
    212     */
    213    public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe, final int maxResultSize) {
    214        if (binaryData == null || binaryData.length == 0) {
    215            return binaryData;
    216        }
    217
    218        final long len = getEncodeLength(binaryData, isChunked ? CHUNK_SIZE : 0, isChunked ? CHUNK_SEPARATOR : NetConstants.EMPTY_BTYE_ARRAY);
    219        if (len > maxResultSize) {
    220            throw new IllegalArgumentException(
    221                    "Input array too big, the output array would be bigger (" + len + ") than the specified maxium size of " + maxResultSize);
    222        }
    223
    224        final Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe);
    225        return b64.encode(binaryData);
    226    }
    227
    228    /**
    229     * Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
    230     *
    231     * @param binaryData binary data to encode
    232     * @return Base64 characters chunked in 76 character blocks
    233     */
    234    public static byte[] encodeBase64Chunked(final byte[] binaryData) {
    235        return encodeBase64(binaryData, true);
    236    }
    237
    238    /**
    239     * Encodes binary data using the base64 algorithm into 76 character blocks separated by CRLF.
    240     * <p>
    241     * For a non-chunking version, see {@link #encodeBase64StringUnChunked(byte[])}.
    242     *
    243     * @param binaryData binary data to encode
    244     * @return String containing Base64 characters.
    245     * @since 1.4
    246     */
    247    public static String encodeBase64String(final byte[] binaryData) {
    248        return newStringUtf8(encodeBase64(binaryData, true));
    249    }
    250
    251    /**
    252     * Encodes binary data using the base64 algorithm.
    253     *
    254     * @param binaryData  binary data to encode
    255     * @param useChunking whether to split the output into chunks
    256     * @return String containing Base64 characters.
    257     * @since 3.2
    258     */
    259    public static String encodeBase64String(final byte[] binaryData, final boolean useChunking) {
    260        return newStringUtf8(encodeBase64(binaryData, useChunking));
    261    }
    262
    263    /**
    264     * Encodes binary data using the base64 algorithm, without using chunking.
    265     * <p>
    266     * For a chunking version, see {@link #encodeBase64String(byte[])}.
    267     *
    268     * @param binaryData binary data to encode
    269     * @return String containing Base64 characters.
    270     * @since 3.2
    271     */
    272    public static String encodeBase64StringUnChunked(final byte[] binaryData) {
    273        return newStringUtf8(encodeBase64(binaryData, false));
    274    }
    275
    276    /**
    277     * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The url-safe variation emits - and _ instead of +
    278     * and / characters.
    279     *
    280     * @param binaryData binary data to encode
    281     * @return byte[] containing Base64 characters in their UTF-8 representation.
    282     * @since 1.4
    283     */
    284    public static byte[] encodeBase64URLSafe(final byte[] binaryData) {
    285        return encodeBase64(binaryData, false, true);
    286    }
    287
    288    /**
    289     * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The url-safe variation emits - and _ instead of +
    290     * and / characters.
    291     *
    292     * @param binaryData binary data to encode
    293     * @return String containing Base64 characters
    294     * @since 1.4
    295     */
    296    public static String encodeBase64URLSafeString(final byte[] binaryData) {
    297        return newStringUtf8(encodeBase64(binaryData, false, true));
    298    }
    299
    300    /**
    301     * Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
    302     *
    303     * @param bigInt a BigInteger
    304     * @return A byte array containing base64 character data
    305     * @throws NullPointerException if null is passed in
    306     * @since 1.4
    307     */
    308    public static byte[] encodeInteger(final BigInteger bigInt) {
    309        return encodeBase64(toIntegerBytes(bigInt), false);
    310    }
    311
    312    /**
    313     * Pre-calculates the amount of space needed to base64-encode the supplied array.
    314     *
    315     * @param pArray         byte[] array which will later be encoded
    316     * @param chunkSize      line-length of the output (<= 0 means no chunking) between each chunkSeparator (e.g. CRLF).
    317     * @param chunkSeparator the sequence of bytes used to separate chunks of output (e.g. CRLF).
    318     *
    319     * @return amount of space needed to encode the supplied array. Returns a long since a max-len array will require Integer.MAX_VALUE + 33%.
    320     */
    321    private static long getEncodeLength(final byte[] pArray, int chunkSize, final byte[] chunkSeparator) {
    322        // base64 always encodes to multiples of 4.
    323        chunkSize = chunkSize / 4 * 4;
    324
    325        long len = pArray.length * 4 / 3;
    326        final long mod = len % 4;
    327        if (mod != 0) {
    328            len += 4 - mod;
    329        }
    330        if (chunkSize > 0) {
    331            final boolean lenChunksPerfectly = len % chunkSize == 0;
    332            len += len / chunkSize * chunkSeparator.length;
    333            if (!lenChunksPerfectly) {
    334                len += chunkSeparator.length;
    335            }
    336        }
    337        return len;
    338    }
    339
    340    /**
    341     * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently, the method treats whitespace as valid.
    342     *
    343     * @param arrayOctet byte array to test
    344     * @return {@code true} if all bytes are valid characters in the Base64 alphabet or if the byte array is empty; false, otherwise
    345     */
    346    public static boolean isArrayByteBase64(final byte[] arrayOctet) {
    347        for (final byte element : arrayOctet) {
    348            if (!isBase64(element) && !isWhiteSpace(element)) {
    349                return false;
    350            }
    351        }
    352        return true;
    353    }
    354
    355    /**
    356     * Returns whether or not the <code>octet</code> is in the base 64 alphabet.
    357     *
    358     * @param octet The value to test
    359     * @return {@code true} if the value is defined in the base 64 alphabet, {@code false} otherwise.
    360     * @since 1.4
    361     */
    362    public static boolean isBase64(final byte octet) {
    363        return octet == PAD || octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1;
    364    }
    365
    366    /**
    367     * Checks if a byte value is whitespace or not.
    368     *
    369     * @param byteToCheck the byte to check
    370     * @return true if byte is whitespace, false otherwise
    371     */
    372    private static boolean isWhiteSpace(final byte byteToCheck) {
    373        switch (byteToCheck) {
    374        case ' ':
    375        case '\n':
    376        case '\r':
    377        case '\t':
    378            return true;
    379        default:
    380            return false;
    381        }
    382    }
    383
    384    private static String newStringUtf8(final byte[] encode) {
    385        return new String(encode, StandardCharsets.UTF_8);
    386    }
    387
    388    /**
    389     * Returns a byte-array representation of a <code>BigInteger</code> without sign bit.
    390     *
    391     * @param bigInt <code>BigInteger</code> to be converted
    392     * @return a byte array representation of the BigInteger parameter
    393     */
    394    static byte[] toIntegerBytes(final BigInteger bigInt) {
    395        Objects.requireNonNull(bigInt, "bigInt");
    396        int bitlen = bigInt.bitLength();
    397        // round bitlen
    398        bitlen = bitlen + 7 >> 3 << 3;
    399        final byte[] bigBytes = bigInt.toByteArray();
    400
    401        if (bigInt.bitLength() % 8 != 0 && bigInt.bitLength() / 8 + 1 == bitlen / 8) {
    402            return bigBytes;
    403        }
    404        // set up params for copying everything but sign bit
    405        int startSrc = 0;
    406        int len = bigBytes.length;
    407
    408        // if bigInt is exactly byte-aligned, just skip signbit in copy
    409        if (bigInt.bitLength() % 8 == 0) {
    410            startSrc = 1;
    411            len--;
    412        }
    413        final int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec
    414        final byte[] resizedBytes = new byte[bitlen / 8];
    415        System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);
    416        return resizedBytes;
    417    }
    418
    419    /**
    420     * Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able to decode both STANDARD and URL_SAFE
    421     * streams, but the encodeTable must be a member variable, so we can switch between the two modes.
    422     */
    423    private final byte[] encodeTable;
    424
    425    /**
    426     * Line length for encoding. Not used when decoding. A value of zero or less implies no chunking of the base64 encoded data.
    427     */
    428    private final int lineLength;
    429
    430    /**
    431     * Line separator for encoding. Not used when decoding. Only used if lineLength > 0.
    432     */
    433    private final byte[] lineSeparator;
    434
    435    /**
    436     * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
    437     * <code>decodeSize = 3 + lineSeparator.length;</code>
    438     */
    439    private final int decodeSize;
    440
    441    /**
    442     * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
    443     * <code>encodeSize = 4 + lineSeparator.length;</code>
    444     */
    445    private final int encodeSize;
    446
    447    /**
    448     * Buffer for streaming.
    449     */
    450    private byte[] buffer;
    451
    452    /**
    453     * Position where next character should be written in the buffer.
    454     */
    455    private int pos;
    456
    457    /**
    458     * Position where next character should be read from the buffer.
    459     */
    460    private int readPos;
    461
    462    /**
    463     * Variable tracks how many characters have been written to the current line. Only used when encoding. We use it to make sure each encoded line never goes
    464     * beyond lineLength (if lineLength > 0).
    465     */
    466    private int currentLinePos;
    467
    468    /**
    469     * Writes to the buffer only occur after every 3 reads when encoding, an every 4 reads when decoding. This variable helps track that.
    470     */
    471    private int modulus;
    472
    473    /**
    474     * Boolean flag to indicate the EOF has been reached. Once EOF has been reached, this Base64 object becomes useless, and must be thrown away.
    475     */
    476    private boolean eof;
    477
    478    /**
    479     * Placeholder for the 3 bytes we're dealing with for our base64 logic. Bitwise operations store and extract the base64 encoding or decoding from this
    480     * variable.
    481     */
    482    private int x;
    483
    484    /**
    485     * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    486     * <p>
    487     * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
    488     * </p>
    489     *
    490     * <p>
    491     * When decoding all variants are supported.
    492     * </p>
    493     */
    494    public Base64() {
    495        this(false);
    496    }
    497
    498    /**
    499     * Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.
    500     * <p>
    501     * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
    502     * </p>
    503     *
    504     * <p>
    505     * When decoding all variants are supported.
    506     * </p>
    507     *
    508     * @param urlSafe if {@code true}, URL-safe encoding is used. In most cases this should be set to {@code false}.
    509     * @since 1.4
    510     */
    511    public Base64(final boolean urlSafe) {
    512        this(CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe);
    513    }
    514
    515    /**
    516     * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    517     * <p>
    518     * When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
    519     * </p>
    520     * <p>
    521     * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    522     * </p>
    523     * <p>
    524     * When decoding all variants are supported.
    525     * </p>
    526     *
    527     * @param lineLength Each line of encoded data will be at most of the given length (rounded down to the nearest multiple of 4).
    528     *                   If {@code lineLength <= 0}, then the output will not be divided into lines (chunks). Ignored when decoding.
    529     * @since 1.4
    530     */
    531    public Base64(final int lineLength) {
    532        this(lineLength, CHUNK_SEPARATOR);
    533    }
    534
    535    /**
    536     * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    537     * <p>
    538     * When encoding the line length and line separator are given in the constructor, and the encoding table is STANDARD_ENCODE_TABLE.
    539     * </p>
    540     * <p>
    541     * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    542     * </p>
    543     * <p>
    544     * When decoding all variants are supported.
    545     * </p>
    546     *
    547     * @param lineLength    Each line of encoded data will be at most of the given length (rounded down to the nearest multiple of 4).
    548     *                      If {@code lineLength <= 0}, then the output will not be divided into lines (chunks). Ignored when decoding.
    549     * @param lineSeparator Each line of encoded data will end with this sequence of bytes.
    550     * @throws IllegalArgumentException Thrown when the provided lineSeparator included some base64 characters.
    551     * @since 1.4
    552     */
    553    public Base64(final int lineLength, final byte[] lineSeparator) {
    554        this(lineLength, lineSeparator, false);
    555    }
    556
    557    /**
    558     * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    559     * <p>
    560     * When encoding the line length and line separator are given in the constructor, and the encoding table is STANDARD_ENCODE_TABLE.
    561     * </p>
    562     * <p>
    563     * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    564     * </p>
    565     * <p>
    566     * When decoding all variants are supported.
    567     * </p>
    568     *
    569     * @param lineLength    Each line of encoded data will be at most of the given length (rounded down to the nearest multiple of 4).
    570     *                      If {@code lineLength <= 0}, then the output will not be divided into lines (chunks). Ignored when decoding.
    571     * @param lineSeparator Each line of encoded data will end with this sequence of bytes.
    572     * @param urlSafe       Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode operations. Decoding seamlessly
    573     *                      handles both modes.
    574     * @throws IllegalArgumentException The provided lineSeparator included some base64 characters. That's not going to work!
    575     * @since 1.4
    576     */
    577    public Base64(int lineLength, byte[] lineSeparator, final boolean urlSafe) {
    578        if (lineSeparator == null) {
    579            lineLength = 0; // disable chunk-separating
    580            lineSeparator = NetConstants.EMPTY_BTYE_ARRAY; // this just gets ignored
    581        }
    582        this.lineLength = lineLength > 0 ? lineLength / 4 * 4 : 0;
    583        this.lineSeparator = new byte[lineSeparator.length];
    584        System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);
    585        if (lineLength > 0) {
    586            this.encodeSize = 4 + lineSeparator.length;
    587        } else {
    588            this.encodeSize = 4;
    589        }
    590        this.decodeSize = this.encodeSize - 1;
    591        if (containsBase64Byte(lineSeparator)) {
    592            final String sep = newStringUtf8(lineSeparator);
    593            throw new IllegalArgumentException("lineSeperator must not contain base64 characters: [" + sep + "]");
    594        }
    595        this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE;
    596    }
    597
    598    /**
    599     * Returns the amount of buffered data available for reading.
    600     *
    601     * @return The amount of buffered data available for reading.
    602     */
    603    int avail() {
    604        return buffer != null ? pos - readPos : 0;
    605    }
    606
    607    /**
    608     * Decodes a byte array containing characters in the Base64 alphabet.
    609     *
    610     * @param pArray A byte array containing Base64 character data
    611     * @return a byte array containing binary data; will return {@code null} if provided byte array is {@code null}.
    612     */
    613    public byte[] decode(final byte[] pArray) {
    614        reset();
    615        if (pArray == null || pArray.length == 0) {
    616            return pArray;
    617        }
    618        final long len = pArray.length * 3 / 4;
    619        final byte[] buf = new byte[(int) len];
    620        setInitialBuffer(buf, 0, buf.length);
    621        decode(pArray, 0, pArray.length);
    622        decode(pArray, 0, -1); // Notify decoder of EOF.
    623
    624        // Would be nice to just return buf (like we sometimes do in the encode
    625        // logic), but we have no idea what the line-length was (could even be
    626        // variable). So we cannot determine ahead of time exactly how big an
    627        // array is necessary. Hence, the need to construct a 2nd byte array to
    628        // hold the final result:
    629
    630        final byte[] result = new byte[pos];
    631        readResults(result, 0, result.length);
    632        return result;
    633    }
    634
    635    /**
    636     * <p>
    637     * Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once with the data to decode, and once with
    638     * inAvail set to "-1" to alert decoder that EOF has been reached. The "-1" call is not necessary when decoding, but it doesn't hurt, either.
    639     * </p>
    640     * <p>
    641     * Ignores all non-base64 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are silently ignored, but has implications
    642     * for other bytes, too. This method subscribes to the garbage-in, garbage-out philosophy: it will not check the provided data for validity.
    643     * </p>
    644     * <p>
    645     * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
    646     * <p>
    647     * See: <a href="http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/">
    648     * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    649     * </a>
    650     *
    651     * </p>
    652     *
    653     * @param in      byte[] array of ascii data to base64 decode.
    654     * @param inPos   Position to start reading data from.
    655     * @param inAvail Amount of bytes available from input for encoding.
    656     */
    657    void decode(final byte[] in, int inPos, final int inAvail) {
    658        if (eof) {
    659            return;
    660        }
    661        if (inAvail < 0) {
    662            eof = true;
    663        }
    664        for (int i = 0; i < inAvail; i++) {
    665            if (buffer == null || buffer.length - pos < decodeSize) {
    666                resizeBuffer();
    667            }
    668            final byte b = in[inPos++];
    669            if (b == PAD) {
    670                // We're done.
    671                eof = true;
    672                break;
    673            }
    674            if (b >= 0 && b < DECODE_TABLE.length) {
    675                final int result = DECODE_TABLE[b];
    676                if (result >= 0) {
    677                    modulus = ++modulus % 4;
    678                    x = (x << 6) + result;
    679                    if (modulus == 0) {
    680                        buffer[pos++] = (byte) (x >> 16 & MASK_8BITS);
    681                        buffer[pos++] = (byte) (x >> 8 & MASK_8BITS);
    682                        buffer[pos++] = (byte) (x & MASK_8BITS);
    683                    }
    684                }
    685            }
    686        }
    687
    688        // Two forms of EOF as far as base64 decoder is concerned: actual
    689        // EOF (-1) and first time '=' character is encountered in stream.
    690        // This approach makes the '=' padding characters completely optional.
    691        if (eof && modulus != 0) {
    692            x = x << 6;
    693            switch (modulus) {
    694            case 2:
    695                x = x << 6;
    696                buffer[pos++] = (byte) (x >> 16 & MASK_8BITS);
    697                break;
    698            case 3:
    699                buffer[pos++] = (byte) (x >> 16 & MASK_8BITS);
    700                buffer[pos++] = (byte) (x >> 8 & MASK_8BITS);
    701                break;
    702            default:
    703                break; // other values ignored
    704            }
    705        }
    706    }
    707
    708    /**
    709     * Decodes a String containing characters in the Base64 alphabet.
    710     *
    711     * @param pArray A String containing Base64 character data, must not be {@code null}
    712     * @return a byte array containing binary data
    713     * @since 1.4
    714     */
    715    public byte[] decode(final String pArray) {
    716        return decode(getBytesUtf8(pArray));
    717    }
    718
    719    /**
    720     * Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.
    721     *
    722     * @param pArray a byte array containing binary data
    723     * @return A byte array containing only Base64 character data
    724     */
    725    public byte[] encode(final byte[] pArray) {
    726        reset();
    727        if (pArray == null || pArray.length == 0) {
    728            return pArray;
    729        }
    730        final long len = getEncodeLength(pArray, lineLength, lineSeparator);
    731        byte[] buf = new byte[(int) len];
    732        setInitialBuffer(buf, 0, buf.length);
    733        encode(pArray, 0, pArray.length);
    734        encode(pArray, 0, -1); // Notify encoder of EOF.
    735        // Encoder might have resized, even though it was unnecessary.
    736        if (buffer != buf) {
    737            readResults(buf, 0, buf.length);
    738        }
    739        // In URL-SAFE mode we skip the padding characters, so sometimes our
    740        // final length is a bit smaller.
    741        if (isUrlSafe() && pos < buf.length) {
    742            final byte[] smallerBuf = new byte[pos];
    743            System.arraycopy(buf, 0, smallerBuf, 0, pos);
    744            buf = smallerBuf;
    745        }
    746        return buf;
    747    }
    748
    749    /**
    750     * <p>
    751     * Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with the data to encode, and once with
    752     * inAvail set to "-1" to alert encoder that EOF has been reached, so flush last remaining bytes (if not multiple of 3).
    753     * </p>
    754     * <p>
    755     * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
    756     * <p>
    757     * See: <a href="http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/">
    758     * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
    759     * </a>
    760     * </p>
    761     *
    762     * @param in      byte[] array of binary data to base64 encode.
    763     * @param inPos   Position to start reading data from.
    764     * @param inAvail Amount of bytes available from input for encoding.
    765     */
    766    void encode(final byte[] in, int inPos, final int inAvail) {
    767        if (eof) {
    768            return;
    769        }
    770        // inAvail < 0 is how we're informed of EOF in the underlying data we're
    771        // encoding.
    772        if (inAvail < 0) {
    773            eof = true;
    774            if (buffer == null || buffer.length - pos < encodeSize) {
    775                resizeBuffer();
    776            }
    777            switch (modulus) {
    778            case 1:
    779                buffer[pos++] = encodeTable[x >> 2 & MASK_6BITS];
    780                buffer[pos++] = encodeTable[x << 4 & MASK_6BITS];
    781                // URL-SAFE skips the padding to further reduce size.
    782                if (encodeTable == STANDARD_ENCODE_TABLE) {
    783                    buffer[pos++] = PAD;
    784                    buffer[pos++] = PAD;
    785                }
    786                break;
    787
    788            case 2:
    789                buffer[pos++] = encodeTable[x >> 10 & MASK_6BITS];
    790                buffer[pos++] = encodeTable[x >> 4 & MASK_6BITS];
    791                buffer[pos++] = encodeTable[x << 2 & MASK_6BITS];
    792                // URL-SAFE skips the padding to further reduce size.
    793                if (encodeTable == STANDARD_ENCODE_TABLE) {
    794                    buffer[pos++] = PAD;
    795                }
    796                break;
    797            default:
    798                break; // other values ignored
    799            }
    800            if (lineLength > 0 && pos > 0) {
    801                System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
    802                pos += lineSeparator.length;
    803            }
    804        } else {
    805            for (int i = 0; i < inAvail; i++) {
    806                if (buffer == null || buffer.length - pos < encodeSize) {
    807                    resizeBuffer();
    808                }
    809                modulus = ++modulus % 3;
    810                int b = in[inPos++];
    811                if (b < 0) {
    812                    b += 256;
    813                }
    814                x = (x << 8) + b;
    815                if (0 == modulus) {
    816                    buffer[pos++] = encodeTable[x >> 18 & MASK_6BITS];
    817                    buffer[pos++] = encodeTable[x >> 12 & MASK_6BITS];
    818                    buffer[pos++] = encodeTable[x >> 6 & MASK_6BITS];
    819                    buffer[pos++] = encodeTable[x & MASK_6BITS];
    820                    currentLinePos += 4;
    821                    if (lineLength > 0 && lineLength <= currentLinePos) {
    822                        System.arraycopy(lineSeparator, 0, buffer, pos, lineSeparator.length);
    823                        pos += lineSeparator.length;
    824                        currentLinePos = 0;
    825                    }
    826                }
    827            }
    828        }
    829    }
    830
    831    /**
    832     * Encodes a byte[] containing binary data, into a String containing characters in the Base64 alphabet.
    833     *
    834     * @param pArray a byte array containing binary data
    835     * @return A String containing only Base64 character data
    836     * @since 1.4
    837     */
    838    public String encodeToString(final byte[] pArray) {
    839        return newStringUtf8(encode(pArray));
    840    }
    841
    842    private byte[] getBytesUtf8(final String pArray) {
    843        return pArray.getBytes(StandardCharsets.UTF_8);
    844    }
    845
    846    int getLineLength() {
    847        return lineLength;
    848    }
    849
    850    byte[] getLineSeparator() {
    851        return lineSeparator.clone();
    852    }
    853
    854    /**
    855     * Returns true if this Base64 object has buffered data for reading.
    856     *
    857     * @return true if there is Base64 object still available for reading.
    858     */
    859    boolean hasData() {
    860        return this.buffer != null;
    861    }
    862
    863    /**
    864     * Returns our current encode mode. True if we're URL-SAFE, false otherwise.
    865     *
    866     * @return true if we're in URL-SAFE mode, false otherwise.
    867     * @since 1.4
    868     */
    869    public boolean isUrlSafe() {
    870        return this.encodeTable == URL_SAFE_ENCODE_TABLE;
    871    }
    872
    873    /**
    874     * Extracts buffered data into the provided byte[] array, starting at position bPos, up to a maximum of bAvail bytes. Returns how many bytes were actually
    875     * extracted.
    876     *
    877     * @param b      byte[] array to extract the buffered data into.
    878     * @param bPos   position in byte[] array to start extraction at.
    879     * @param bAvail amount of bytes we're allowed to extract. We may extract fewer (if fewer are available).
    880     * @return The number of bytes successfully extracted into the provided byte[] array.
    881     */
    882    int readResults(final byte[] b, final int bPos, final int bAvail) {
    883        if (buffer != null) {
    884            final int len = Math.min(avail(), bAvail);
    885            if (buffer != b) {
    886                System.arraycopy(buffer, readPos, b, bPos, len);
    887                readPos += len;
    888                if (readPos >= pos) {
    889                    buffer = null;
    890                }
    891            } else {
    892                // Re-using the original consumer's output array is only
    893                // allowed for one round.
    894                buffer = null;
    895            }
    896            return len;
    897        }
    898        return eof ? -1 : 0;
    899    }
    900
    901    /**
    902     * Resets this Base64 object to its initial newly constructed state.
    903     */
    904    private void reset() {
    905        buffer = null;
    906        pos = 0;
    907        readPos = 0;
    908        currentLinePos = 0;
    909        modulus = 0;
    910        eof = false;
    911    }
    912
    913    // Getters for use in testing
    914
    915    /** Doubles our buffer. */
    916    private void resizeBuffer() {
    917        if (buffer == null) {
    918            buffer = new byte[DEFAULT_BUFFER_SIZE];
    919            pos = 0;
    920            readPos = 0;
    921        } else {
    922            final byte[] b = new byte[buffer.length * DEFAULT_BUFFER_RESIZE_FACTOR];
    923            System.arraycopy(buffer, 0, b, 0, buffer.length);
    924            buffer = b;
    925        }
    926    }
    927
    928    /**
    929     * Sets the streaming buffer. This is a small optimization where we try to buffer directly to the consumer's output array for one round (if the consumer
    930     * calls this method first) instead of starting our own buffer.
    931     *
    932     * @param out      byte[] array to buffer directly to.
    933     * @param outPos   Position to start buffering into.
    934     * @param outAvail Amount of bytes available for direct buffering.
    935     */
    936    void setInitialBuffer(final byte[] out, final int outPos, final int outAvail) {
    937        // We can re-use consumer's original output array under
    938        // special circumstances, saving on some System.arraycopy().
    939        if (out != null && out.length == outAvail) {
    940            buffer = out;
    941            pos = outPos;
    942            readPos = outPos;
    943        }
    944    }
    945}