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- package net.miginfocom;
-
- import java.util.Arrays;
-
- /**
- * A very fast and memory efficient class to encode and decode to and from
- * BASE64 in full accordance
- * with RFC 2045.<br>
- * <br>
- * On Windows XP sp1 with 1.4.2_04 and later ;), this encoder and decoder is
- * about 10 times faster
- * on small arrays (10 - 1000 bytes) and 2-3 times as fast on larger arrays
- * (10000 - 1000000 bytes)
- * compared to <code>sun.misc.Encoder()/Decoder()</code>.<br>
- * <br>
- *
- * On byte arrays the encoder is about 20% faster than Jakarta Commons Base64
- * Codec for encode and
- * about 50% faster for decoding large arrays. This implementation is about
- * twice as fast on very small
- * arrays (< 30 bytes). If source/destination is a <code>String</code> this
- * version is about three times as fast due to the fact that the Commons Codec
- * result has to be recoded
- * to a <code>String</code> from <code>byte[]</code>, which is very expensive.<br>
- * <br>
- *
- * This encode/decode algorithm doesn't create any temporary arrays as many
- * other codecs do, it only
- * allocates the resulting array. This produces less garbage and it is possible
- * to handle arrays twice
- * as large as algorithms that create a temporary array. (E.g. Jakarta Commons
- * Codec). It is unknown
- * whether Sun's <code>sun.misc.Encoder()/Decoder()</code> produce temporary
- * arrays but since performance
- * is quite low it probably does.<br>
- * <br>
- *
- * The encoder produces the same output as the Sun one except that the Sun's
- * encoder appends
- * a trailing line separator if the last character isn't a pad. Unclear why but
- * it only adds to the
- * length and is probably a side effect. Both are in conformance with RFC 2045
- * though.<br>
- * Commons codec seem to always att a trailing line separator.<br>
- * <br>
- *
- * <b>Note!</b>
- * The encode/decode method pairs (types) come in three versions with the
- * <b>exact</b> same algorithm and
- * thus a lot of code redundancy. This is to not create any temporary arrays for
- * transcoding to/from different
- * format types. The methods not used can simply be commented out.<br>
- * <br>
- *
- * There is also a "fast" version of all decode methods that works the same way
- * as the normal ones, but
- * har a few demands on the decoded input. Normally though, these fast verions
- * should be used if the source if
- * the input is known and it hasn't bee tampered with.<br>
- * <br>
- *
- * If you find the code useful or you find a bug, please send me a note at
- * base64 @ miginfocom . com.
- *
- * Licence (BSD):
- * ==============
- *
- * Copyright (c) 2004, Mikael Grev, MiG InfoCom AB. (base64 @ miginfocom . com)
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification,
- * are permitted provided that the following conditions are met:
- * Redistributions of source code must retain the above copyright notice, this
- * list
- * of conditions and the following disclaimer.
- * Redistributions in binary form must reproduce the above copyright notice,
- * this
- * list of conditions and the following disclaimer in the documentation and/or
- * other
- * materials provided with the distribution.
- * Neither the name of the MiG InfoCom AB nor the names of its contributors may
- * be
- * used to endorse or promote products derived from this software without
- * specific
- * prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
- * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED.
- * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY
- * DIRECT,
- * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- * (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA,
- * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- * LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY
- * OF SUCH DAMAGE.
- *
- * @version 2.2
- * @author Mikael Grev
- * Date: 2004-aug-02
- * Time: 11:31:11
- */
-
- public class Base64 {
- private static final char[] CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
- .toCharArray();
- private static final int[] IA = new int[256];
- static {
- Arrays.fill(IA, -1);
- for (int i = 0, iS = CA.length; i < iS; i++) {
- IA[CA[i]] = i;
- }
- IA['='] = 0;
- }
-
- // ****************************************************************************************
- // * char[] version
- // ****************************************************************************************
-
- /**
- * Encodes a raw byte array into a BASE64 <code>char[]</code> representation
- * i accordance with RFC 2045.
- *
- * @param sArr
- * The bytes to convert. If <code>null</code> or length 0 an
- * empty array will be returned.
- * @param lineSep
- * Optional "\r\n" after 76 characters, unless end of file.<br>
- * No line separator will be in breach of RFC 2045 which
- * specifies max 76 per line but will be a
- * little faster.
- * @return A BASE64 encoded array. Never <code>null</code>.
- */
- public static final char[] encodeToChar(final byte[] sArr,
- final boolean lineSep) {
- // Check special case
- final int sLen = sArr != null ? sArr.length : 0;
- if (sLen == 0) {
- return new char[0];
- }
-
- final int eLen = sLen / 3 * 3; // Length of even 24-bits.
- final int cCnt = (sLen - 1) / 3 + 1 << 2; // Returned character count
- final int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length
- // of
- // returned
- // array
- final char[] dArr = new char[dLen];
-
- // Encode even 24-bits
- for (int s = 0, d = 0, cc = 0; s < eLen;) {
- // Copy next three bytes into lower 24 bits of int, paying attension
- // to sign.
- final int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8
- | sArr[s++] & 0xff;
-
- // Encode the int into four chars
- dArr[d++] = CA[i >>> 18 & 0x3f];
- dArr[d++] = CA[i >>> 12 & 0x3f];
- dArr[d++] = CA[i >>> 6 & 0x3f];
- dArr[d++] = CA[i & 0x3f];
-
- // Add optional line separator
- if (lineSep && ++cc == 19 && d < dLen - 2) {
- dArr[d++] = '\r';
- dArr[d++] = '\n';
- cc = 0;
- }
- }
-
- // Pad and encode last bits if source isn't even 24 bits.
- final int left = sLen - eLen; // 0 - 2.
- if (left > 0) {
- // Prepare the int
- final int i = (sArr[eLen] & 0xff) << 10
- | (left == 2 ? (sArr[sLen - 1] & 0xff) << 2 : 0);
-
- // Set last four chars
- dArr[dLen - 4] = CA[i >> 12];
- dArr[dLen - 3] = CA[i >>> 6 & 0x3f];
- dArr[dLen - 2] = left == 2 ? CA[i & 0x3f] : '=';
- dArr[dLen - 1] = '=';
- }
- return dArr;
- }
-
- /**
- * Decodes a BASE64 encoded char array. All illegal characters will be
- * ignored and can handle both arrays with
- * and without line separators.
- *
- * @param sArr
- * The source array. <code>null</code> or length 0 will return an
- * empty array.
- * @return The decoded array of bytes. May be of length 0. Will be
- * <code>null</code> if the legal characters
- * (including '=') isn't divideable by 4. (I.e. definitely
- * corrupted).
- */
- public static final byte[] decode(final char[] sArr) {
- // Check special case
- final int sLen = sArr != null ? sArr.length : 0;
- if (sLen == 0) {
- return new byte[0];
- }
-
- // Count illegal characters (including '\r', '\n') to know what size the
- // returned array will be,
- // so we don't have to reallocate & copy it later.
- int sepCnt = 0; // Number of separator characters. (Actually illegal
- // characters, but that's a bonus...)
- for (int i = 0; i < sLen; i++) {
- if (IA[sArr[i]] < 0) {
- sepCnt++;
- }
- }
-
- // Check so that legal chars (including '=') are evenly divideable by 4
- // as specified in RFC 2045.
- if ((sLen - sepCnt) % 4 != 0) {
- return null;
- }
-
- int pad = 0;
- for (int i = sLen; i > 1 && IA[sArr[--i]] <= 0;) {
- if (sArr[i] == '=') {
- pad++;
- }
- }
-
- final int len = ((sLen - sepCnt) * 6 >> 3) - pad;
-
- final byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
-
- for (int s = 0, d = 0; d < len;) {
- // Assemble three bytes into an int from four "valid" characters.
- int i = 0;
- for (int j = 0; j < 4; j++) { // j only increased if a valid char
- // was found.
- final int c = IA[sArr[s++]];
- if (c >= 0) {
- i |= c << 18 - j * 6;
- } else {
- j--;
- }
- }
- // Add the bytes
- dArr[d++] = (byte) (i >> 16);
- if (d < len) {
- dArr[d++] = (byte) (i >> 8);
- if (d < len) {
- dArr[d++] = (byte) i;
- }
- }
- }
- return dArr;
- }
-
- /**
- * Decodes a BASE64 encoded char array that is known to be resonably well
- * formatted. The method is about twice as
- * fast as {@link #decode(char[])}. The preconditions are:<br>
- * + The array must have a line length of 76 chars OR no line separators at
- * all (one line).<br>
- * + Line separator must be "\r\n", as specified in RFC 2045
- * + The array must not contain illegal characters within the encoded string<br>
- * + The array CAN have illegal characters at the beginning and end, those
- * will be dealt with appropriately.<br>
- *
- * @param sArr
- * The source array. Length 0 will return an empty array.
- * <code>null</code> will throw an exception.
- * @return The decoded array of bytes. May be of length 0.
- */
- public static final byte[] decodeFast(final char[] sArr) {
- // Check special case
- final int sLen = sArr.length;
- if (sLen == 0) {
- return new byte[0];
- }
-
- int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
-
- // Trim illegal chars from start
- while (sIx < eIx && IA[sArr[sIx]] < 0) {
- sIx++;
- }
-
- // Trim illegal chars from end
- while (eIx > 0 && IA[sArr[eIx]] < 0) {
- eIx--;
- }
-
- // get the padding count (=) (0, 1 or 2)
- final int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count
- // '='
- // at
- // end.
- final int cCnt = eIx - sIx + 1; // Content count including possible
- // separators
- final int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1
- : 0;
-
- final int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of
- // decoded bytes
- final byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
-
- // Decode all but the last 0 - 2 bytes.
- int d = 0;
- for (int cc = 0, eLen = len / 3 * 3; d < eLen;) {
- // Assemble three bytes into an int from four "valid" characters.
- final int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12
- | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];
-
- // Add the bytes
- dArr[d++] = (byte) (i >> 16);
- dArr[d++] = (byte) (i >> 8);
- dArr[d++] = (byte) i;
-
- // If line separator, jump over it.
- if (sepCnt > 0 && ++cc == 19) {
- sIx += 2;
- cc = 0;
- }
- }
-
- if (d < len) {
- // Decode last 1-3 bytes (incl '=') into 1-3 bytes
- int i = 0;
- for (int j = 0; sIx <= eIx - pad; j++) {
- i |= IA[sArr[sIx++]] << 18 - j * 6;
- }
-
- for (int r = 16; d < len; r -= 8) {
- dArr[d++] = (byte) (i >> r);
- }
- }
-
- return dArr;
- }
-
- // ****************************************************************************************
- // * byte[] version
- // ****************************************************************************************
-
- /**
- * Encodes a raw byte array into a BASE64 <code>byte[]</code> representation
- * i accordance with RFC 2045.
- *
- * @param sArr
- * The bytes to convert. If <code>null</code> or length 0 an
- * empty array will be returned.
- * @param lineSep
- * Optional "\r\n" after 76 characters, unless end of file.<br>
- * No line separator will be in breach of RFC 2045 which
- * specifies max 76 per line but will be a
- * little faster.
- * @return A BASE64 encoded array. Never <code>null</code>.
- */
- public static final byte[] encodeToByte(final byte[] sArr,
- final boolean lineSep) {
- // Check special case
- final int sLen = sArr != null ? sArr.length : 0;
- if (sLen == 0) {
- return new byte[0];
- }
-
- final int eLen = sLen / 3 * 3; // Length of even 24-bits.
- final int cCnt = (sLen - 1) / 3 + 1 << 2; // Returned character count
- final int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length
- // of
- // returned
- // array
- final byte[] dArr = new byte[dLen];
-
- // Encode even 24-bits
- for (int s = 0, d = 0, cc = 0; s < eLen;) {
- // Copy next three bytes into lower 24 bits of int, paying attension
- // to sign.
- final int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8
- | sArr[s++] & 0xff;
-
- // Encode the int into four chars
- dArr[d++] = (byte) CA[i >>> 18 & 0x3f];
- dArr[d++] = (byte) CA[i >>> 12 & 0x3f];
- dArr[d++] = (byte) CA[i >>> 6 & 0x3f];
- dArr[d++] = (byte) CA[i & 0x3f];
-
- // Add optional line separator
- if (lineSep && ++cc == 19 && d < dLen - 2) {
- dArr[d++] = '\r';
- dArr[d++] = '\n';
- cc = 0;
- }
- }
-
- // Pad and encode last bits if source isn't an even 24 bits.
- final int left = sLen - eLen; // 0 - 2.
- if (left > 0) {
- // Prepare the int
- final int i = (sArr[eLen] & 0xff) << 10
- | (left == 2 ? (sArr[sLen - 1] & 0xff) << 2 : 0);
-
- // Set last four chars
- dArr[dLen - 4] = (byte) CA[i >> 12];
- dArr[dLen - 3] = (byte) CA[i >>> 6 & 0x3f];
- dArr[dLen - 2] = left == 2 ? (byte) CA[i & 0x3f] : (byte) '=';
- dArr[dLen - 1] = '=';
- }
- return dArr;
- }
-
- /**
- * Decodes a BASE64 encoded byte array. All illegal characters will be
- * ignored and can handle both arrays with
- * and without line separators.
- *
- * @param sArr
- * The source array. Length 0 will return an empty array.
- * <code>null</code> will throw an exception.
- * @return The decoded array of bytes. May be of length 0. Will be
- * <code>null</code> if the legal characters
- * (including '=') isn't divideable by 4. (I.e. definitely
- * corrupted).
- */
- public static final byte[] decode(final byte[] sArr) {
- // Check special case
- final int sLen = sArr.length;
-
- // Count illegal characters (including '\r', '\n') to know what size the
- // returned array will be,
- // so we don't have to reallocate & copy it later.
- int sepCnt = 0; // Number of separator characters. (Actually illegal
- // characters, but that's a bonus...)
- for (int i = 0; i < sLen; i++) {
- if (IA[sArr[i] & 0xff] < 0) {
- sepCnt++;
- }
- }
-
- // Check so that legal chars (including '=') are evenly divideable by 4
- // as specified in RFC 2045.
- if ((sLen - sepCnt) % 4 != 0) {
- return null;
- }
-
- int pad = 0;
- for (int i = sLen; i > 1 && IA[sArr[--i] & 0xff] <= 0;) {
- if (sArr[i] == '=') {
- pad++;
- }
- }
-
- final int len = ((sLen - sepCnt) * 6 >> 3) - pad;
-
- final byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
-
- for (int s = 0, d = 0; d < len;) {
- // Assemble three bytes into an int from four "valid" characters.
- int i = 0;
- for (int j = 0; j < 4; j++) { // j only increased if a valid char
- // was found.
- final int c = IA[sArr[s++] & 0xff];
- if (c >= 0) {
- i |= c << 18 - j * 6;
- } else {
- j--;
- }
- }
-
- // Add the bytes
- dArr[d++] = (byte) (i >> 16);
- if (d < len) {
- dArr[d++] = (byte) (i >> 8);
- if (d < len) {
- dArr[d++] = (byte) i;
- }
- }
- }
-
- return dArr;
- }
-
- /**
- * Decodes a BASE64 encoded byte array that is known to be resonably well
- * formatted. The method is about twice as
- * fast as {@link #decode(byte[])}. The preconditions are:<br>
- * + The array must have a line length of 76 chars OR no line separators at
- * all (one line).<br>
- * + Line separator must be "\r\n", as specified in RFC 2045
- * + The array must not contain illegal characters within the encoded string<br>
- * + The array CAN have illegal characters at the beginning and end, those
- * will be dealt with appropriately.<br>
- *
- * @param sArr
- * The source array. Length 0 will return an empty array.
- * <code>null</code> will throw an exception.
- * @return The decoded array of bytes. May be of length 0.
- */
- public static final byte[] decodeFast(final byte[] sArr) {
- // Check special case
- final int sLen = sArr.length;
- if (sLen == 0) {
- return new byte[0];
- }
-
- int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
-
- // Trim illegal chars from start
- while (sIx < eIx && IA[sArr[sIx] & 0xff] < 0) {
- sIx++;
- }
-
- // Trim illegal chars from end
- while (eIx > 0 && IA[sArr[eIx] & 0xff] < 0) {
- eIx--;
- }
-
- // get the padding count (=) (0, 1 or 2)
- final int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count
- // '='
- // at
- // end.
- final int cCnt = eIx - sIx + 1; // Content count including possible
- // separators
- final int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1
- : 0;
-
- final int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of
- // decoded bytes
- final byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
-
- // Decode all but the last 0 - 2 bytes.
- int d = 0;
- for (int cc = 0, eLen = len / 3 * 3; d < eLen;) {
- // Assemble three bytes into an int from four "valid" characters.
- final int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12
- | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];
-
- // Add the bytes
- dArr[d++] = (byte) (i >> 16);
- dArr[d++] = (byte) (i >> 8);
- dArr[d++] = (byte) i;
-
- // If line separator, jump over it.
- if (sepCnt > 0 && ++cc == 19) {
- sIx += 2;
- cc = 0;
- }
- }
-
- if (d < len) {
- // Decode last 1-3 bytes (incl '=') into 1-3 bytes
- int i = 0;
- for (int j = 0; sIx <= eIx - pad; j++) {
- i |= IA[sArr[sIx++]] << 18 - j * 6;
- }
-
- for (int r = 16; d < len; r -= 8) {
- dArr[d++] = (byte) (i >> r);
- }
- }
-
- return dArr;
- }
-
- // ****************************************************************************************
- // * String version
- // ****************************************************************************************
-
- /**
- * Encodes a raw byte array into a BASE64 <code>String</code> representation
- * i accordance with RFC 2045.
- *
- * @param sArr
- * The bytes to convert. If <code>null</code> or length 0 an
- * empty array will be returned.
- * @param lineSep
- * Optional "\r\n" after 76 characters, unless end of file.<br>
- * No line separator will be in breach of RFC 2045 which
- * specifies max 76 per line but will be a
- * little faster.
- * @return A BASE64 encoded array. Never <code>null</code>.
- */
- public static final String encodeToString(final byte[] sArr,
- final boolean lineSep) {
- // Reuse char[] since we can't create a String incrementally anyway and
- // StringBuffer/Builder would be slower.
- return new String(encodeToChar(sArr, lineSep));
- }
-
- /**
- * Decodes a BASE64 encoded <code>String</code>. All illegal characters will
- * be ignored and can handle both strings with
- * and without line separators.<br>
- * <b>Note!</b> It can be up to about 2x the speed to call
- * <code>decode(str.toCharArray())</code> instead. That
- * will create a temporary array though. This version will use
- * <code>str.charAt(i)</code> to iterate the string.
- *
- * @param str
- * The source string. <code>null</code> or length 0 will return
- * an empty array.
- * @return The decoded array of bytes. May be of length 0. Will be
- * <code>null</code> if the legal characters
- * (including '=') isn't divideable by 4. (I.e. definitely
- * corrupted).
- */
- public static final byte[] decode(final String str) {
- // Check special case
- final int sLen = str != null ? str.length() : 0;
- if (sLen == 0) {
- return new byte[0];
- }
-
- // Count illegal characters (including '\r', '\n') to know what size the
- // returned array will be,
- // so we don't have to reallocate & copy it later.
- int sepCnt = 0; // Number of separator characters. (Actually illegal
- // characters, but that's a bonus...)
- for (int i = 0; i < sLen; i++) {
- if (IA[str.charAt(i)] < 0) {
- sepCnt++;
- }
- }
-
- // Check so that legal chars (including '=') are evenly divideable by 4
- // as specified in RFC 2045.
- if ((sLen - sepCnt) % 4 != 0) {
- return null;
- }
-
- // Count '=' at end
- int pad = 0;
- for (int i = sLen; i > 1 && IA[str.charAt(--i)] <= 0;) {
- if (str.charAt(i) == '=') {
- pad++;
- }
- }
-
- final int len = ((sLen - sepCnt) * 6 >> 3) - pad;
-
- final byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
-
- for (int s = 0, d = 0; d < len;) {
- // Assemble three bytes into an int from four "valid" characters.
- int i = 0;
- for (int j = 0; j < 4; j++) { // j only increased if a valid char
- // was found.
- final int c = IA[str.charAt(s++)];
- if (c >= 0) {
- i |= c << 18 - j * 6;
- } else {
- j--;
- }
- }
- // Add the bytes
- dArr[d++] = (byte) (i >> 16);
- if (d < len) {
- dArr[d++] = (byte) (i >> 8);
- if (d < len) {
- dArr[d++] = (byte) i;
- }
- }
- }
- return dArr;
- }
-
- /**
- * Decodes a BASE64 encoded string that is known to be resonably well
- * formatted. The method is about twice as
- * fast as {@link #decode(String)}. The preconditions are:<br>
- * + The array must have a line length of 76 chars OR no line separators at
- * all (one line).<br>
- * + Line separator must be "\r\n", as specified in RFC 2045
- * + The array must not contain illegal characters within the encoded string<br>
- * + The array CAN have illegal characters at the beginning and end, those
- * will be dealt with appropriately.<br>
- *
- * @param s
- * The source string. Length 0 will return an empty array.
- * <code>null</code> will throw an exception.
- * @return The decoded array of bytes. May be of length 0.
- */
- public static final byte[] decodeFast(final String s) {
- // Check special case
- final int sLen = s.length();
- if (sLen == 0) {
- return new byte[0];
- }
-
- int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
-
- // Trim illegal chars from start
- while (sIx < eIx && IA[s.charAt(sIx) & 0xff] < 0) {
- sIx++;
- }
-
- // Trim illegal chars from end
- while (eIx > 0 && IA[s.charAt(eIx) & 0xff] < 0) {
- eIx--;
- }
-
- // get the padding count (=) (0, 1 or 2)
- final int pad = s.charAt(eIx) == '=' ? (s.charAt(eIx - 1) == '=' ? 2
- : 1) : 0; // Count '=' at end.
- final int cCnt = eIx - sIx + 1; // Content count including possible
- // separators
- final int sepCnt = sLen > 76 ? (s.charAt(76) == '\r' ? cCnt / 78 : 0) << 1
- : 0;
-
- final int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of
- // decoded bytes
- final byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
-
- // Decode all but the last 0 - 2 bytes.
- int d = 0;
- for (int cc = 0, eLen = len / 3 * 3; d < eLen;) {
- // Assemble three bytes into an int from four "valid" characters.
- final int i = IA[s.charAt(sIx++)] << 18 | IA[s.charAt(sIx++)] << 12
- | IA[s.charAt(sIx++)] << 6 | IA[s.charAt(sIx++)];
-
- // Add the bytes
- dArr[d++] = (byte) (i >> 16);
- dArr[d++] = (byte) (i >> 8);
- dArr[d++] = (byte) i;
-
- // If line separator, jump over it.
- if (sepCnt > 0 && ++cc == 19) {
- sIx += 2;
- cc = 0;
- }
- }
-
- if (d < len) {
- // Decode last 1-3 bytes (incl '=') into 1-3 bytes
- int i = 0;
- for (int j = 0; sIx <= eIx - pad; j++) {
- i |= IA[s.charAt(sIx++)] << 18 - j * 6;
- }
-
- for (int r = 16; d < len; r -= 8) {
- dArr[d++] = (byte) (i >> r);
- }
- }
-
- return dArr;
- }
- }
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