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+// Portions copyright 2002, Google, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package org.fox.ttrss.util;
+
+// This code was converted from code at http://iharder.sourceforge.net/base64/
+// Lots of extraneous features were removed.
+/* The original code said:
+ * <p>
+ * I am placing this code in the Public Domain. Do with it as you will.
+ * This software comes with no guarantees or warranties but with
+ * plenty of well-wishing instead!
+ * Please visit
+ * <a href="http://iharder.net/xmlizable">http://iharder.net/xmlizable</a>
+ * periodically to check for updates or to contribute improvements.
+ * </p>
+ *
+ * @author Robert Harder
+ * @author rharder@usa.net
+ * @version 1.3
+ */
+
+/**
+ * Base64 converter class. This code is not a complete MIME encoder; it simply
+ * converts binary data to base64 data and back.
+ *
+ * <p>
+ * Note {@link CharBase64} is a GWT-compatible implementation of this class.
+ */
+public class Base64 {
+ /** Specify encoding (value is {@code true}). */
+ public final static boolean ENCODE = true;
+
+ /** Specify decoding (value is {@code false}). */
+ public final static boolean DECODE = false;
+
+ /** The equals sign (=) as a byte. */
+ private final static byte EQUALS_SIGN = (byte) '=';
+
+ /** The new line character (\n) as a byte. */
+ private final static byte NEW_LINE = (byte) '\n';
+
+ /**
+ * The 64 valid Base64 values.
+ */
+ private final static byte[] ALPHABET = { (byte) 'A', (byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G',
+ (byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N', (byte) 'O', (byte) 'P', (byte) 'Q',
+ (byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U', (byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z', (byte) 'a',
+ (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f', (byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k',
+ (byte) 'l', (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r', (byte) 's', (byte) 't', (byte) 'u',
+ (byte) 'v', (byte) 'w', (byte) 'x', (byte) 'y', (byte) 'z', (byte) '0', (byte) '1', (byte) '2', (byte) '3', (byte) '4',
+ (byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9', (byte) '+', (byte) '/' };
+
+ /**
+ * The 64 valid web safe Base64 values.
+ */
+ private final static byte[] WEBSAFE_ALPHABET = { (byte) 'A', (byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G',
+ (byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N', (byte) 'O', (byte) 'P', (byte) 'Q',
+ (byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U', (byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z', (byte) 'a',
+ (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f', (byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k',
+ (byte) 'l', (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r', (byte) 's', (byte) 't', (byte) 'u',
+ (byte) 'v', (byte) 'w', (byte) 'x', (byte) 'y', (byte) 'z', (byte) '0', (byte) '1', (byte) '2', (byte) '3', (byte) '4',
+ (byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9', (byte) '-', (byte) '_' };
+
+ /**
+ * Translates a Base64 value to either its 6-bit reconstruction value or a
+ * negative number indicating some other meaning.
+ **/
+ private final static byte[] DECODABET = { -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal
+ // 0
+ // -
+ // 8
+ -5, -5, // Whitespace: Tab and Linefeed
+ -9, -9, // Decimal 11 - 12
+ -5, // Whitespace: Carriage Return
+ -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 -
+ // 26
+ -9, -9, -9, -9, -9, // Decimal 27 - 31
+ -5, // Whitespace: Space
+ -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
+ 62, // Plus sign at decimal 43
+ -9, -9, -9, // Decimal 44 - 46
+ 63, // Slash at decimal 47
+ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
+ -9, -9, -9, // Decimal 58 - 60
+ -1, // Equals sign at decimal 61
+ -9, -9, -9, // Decimal 62 - 64
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through
+ // 'N'
+ 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O'
+ // through 'Z'
+ -9, -9, -9, -9, -9, -9, // Decimal 91 - 96
+ 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a'
+ // through 'm'
+ 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n'
+ // through 'z'
+ -9, -9, -9, -9, -9 // Decimal 123 - 127
+ /*
+ * ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 128 - 139
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 140 - 152
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 153 - 165
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 166 - 178
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 179 - 191
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 192 - 204
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 205 - 217
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 218 - 230
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 231 - 243
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9 // Decimal 244 - 255
+ */
+ };
+
+ /** The web safe decodabet */
+ private final static byte[] WEBSAFE_DECODABET = { -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal
+ // 0
+ // -
+ // 8
+ -5, -5, // Whitespace: Tab and Linefeed
+ -9, -9, // Decimal 11 - 12
+ -5, // Whitespace: Carriage Return
+ -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 -
+ // 26
+ -9, -9, -9, -9, -9, // Decimal 27 - 31
+ -5, // Whitespace: Space
+ -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 44
+ 62, // Dash '-' sign at decimal 45
+ -9, -9, // Decimal 46-47
+ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
+ -9, -9, -9, // Decimal 58 - 60
+ -1, // Equals sign at decimal 61
+ -9, -9, -9, // Decimal 62 - 64
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through
+ // 'N'
+ 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O'
+ // through 'Z'
+ -9, -9, -9, -9, // Decimal 91-94
+ 63, // Underscore '_' at decimal 95
+ -9, // Decimal 96
+ 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a'
+ // through 'm'
+ 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n'
+ // through 'z'
+ -9, -9, -9, -9, -9 // Decimal 123 - 127
+ /*
+ * ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 128 - 139
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 140 - 152
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 153 - 165
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 166 - 178
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 179 - 191
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 192 - 204
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 205 - 217
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 218 - 230
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 231 - 243
+ * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9 // Decimal 244 - 255
+ */
+ };
+
+ // Indicates white space in encoding
+ private final static byte WHITE_SPACE_ENC = -5;
+ // Indicates equals sign in encoding
+ private final static byte EQUALS_SIGN_ENC = -1;
+
+ /** Defeats instantiation. */
+ private Base64() {
+ }
+
+ /* ******** E N C O D I N G M E T H O D S ******** */
+
+ /**
+ * Encodes up to three bytes of the array <var>source</var> and writes the
+ * resulting four Base64 bytes to <var>destination</var>. The source and
+ * destination arrays can be manipulated anywhere along their length by
+ * specifying <var>srcOffset</var> and <var>destOffset</var>. This method
+ * does not check to make sure your arrays are large enough to accommodate
+ * <var>srcOffset</var> + 3 for the <var>source</var> array or
+ * <var>destOffset</var> + 4 for the <var>destination</var> array. The
+ * actual number of significant bytes in your array is given by
+ * <var>numSigBytes</var>.
+ *
+ * @param source
+ * the array to convert
+ * @param srcOffset
+ * the index where conversion begins
+ * @param numSigBytes
+ * the number of significant bytes in your array
+ * @param destination
+ * the array to hold the conversion
+ * @param destOffset
+ * the index where output will be put
+ * @param alphabet
+ * is the encoding alphabet
+ * @return the <var>destination</var> array
+ * @since 1.3
+ */
+ private static byte[] encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset, byte[] alphabet) {
+ // 1 2 3
+ // 01234567890123456789012345678901 Bit position
+ // --------000000001111111122222222 Array position from threeBytes
+ // --------| || || || | Six bit groups to index alphabet
+ // >>18 >>12 >> 6 >> 0 Right shift necessary
+ // 0x3f 0x3f 0x3f Additional AND
+
+ // Create buffer with zero-padding if there are only one or two
+ // significant bytes passed in the array.
+ // We have to shift left 24 in order to flush out the 1's that appear
+ // when Java treats a value as negative that is cast from a byte to an
+ // int.
+ int inBuff = (numSigBytes > 0 ? ((source[srcOffset] << 24) >>> 8) : 0)
+ | (numSigBytes > 1 ? ((source[srcOffset + 1] << 24) >>> 16) : 0)
+ | (numSigBytes > 2 ? ((source[srcOffset + 2] << 24) >>> 24) : 0);
+
+ switch (numSigBytes) {
+ case 3:
+ destination[destOffset] = alphabet[(inBuff >>> 18)];
+ destination[destOffset + 1] = alphabet[(inBuff >>> 12) & 0x3f];
+ destination[destOffset + 2] = alphabet[(inBuff >>> 6) & 0x3f];
+ destination[destOffset + 3] = alphabet[(inBuff) & 0x3f];
+ return destination;
+ case 2:
+ destination[destOffset] = alphabet[(inBuff >>> 18)];
+ destination[destOffset + 1] = alphabet[(inBuff >>> 12) & 0x3f];
+ destination[destOffset + 2] = alphabet[(inBuff >>> 6) & 0x3f];
+ destination[destOffset + 3] = EQUALS_SIGN;
+ return destination;
+ case 1:
+ destination[destOffset] = alphabet[(inBuff >>> 18)];
+ destination[destOffset + 1] = alphabet[(inBuff >>> 12) & 0x3f];
+ destination[destOffset + 2] = EQUALS_SIGN;
+ destination[destOffset + 3] = EQUALS_SIGN;
+ return destination;
+ default:
+ return destination;
+ } // end switch
+ } // end encode3to4
+
+ /**
+ * Encodes a byte array into Base64 notation. Equivalent to calling {@code
+ * encodeBytes(source, 0, source.length)}
+ *
+ * @param source
+ * The data to convert
+ * @since 1.4
+ */
+ public static String encode(byte[] source) {
+ return encode(source, 0, source.length, ALPHABET, true);
+ }
+
+ /**
+ * Encodes a byte array into web safe Base64 notation.
+ *
+ * @param source
+ * The data to convert
+ * @param doPadding
+ * is {@code true} to pad result with '=' chars if it does not
+ * fall on 3 byte boundaries
+ */
+ public static String encodeWebSafe(byte[] source, boolean doPadding) {
+ return encode(source, 0, source.length, WEBSAFE_ALPHABET, doPadding);
+ }
+
+ /**
+ * Encodes a byte array into Base64 notation.
+ *
+ * @param source
+ * the data to convert
+ * @param off
+ * offset in array where conversion should begin
+ * @param len
+ * length of data to convert
+ * @param alphabet
+ * the encoding alphabet
+ * @param doPadding
+ * is {@code true} to pad result with '=' chars if it does not
+ * fall on 3 byte boundaries
+ * @since 1.4
+ */
+ public static String encode(byte[] source, int off, int len, byte[] alphabet, boolean doPadding) {
+ byte[] outBuff = encode(source, off, len, alphabet, Integer.MAX_VALUE);
+ int outLen = outBuff.length;
+
+ // If doPadding is false, set length to truncate '='
+ // padding characters
+ while (doPadding == false && outLen > 0) {
+ if (outBuff[outLen - 1] != '=') {
+ break;
+ }
+ outLen -= 1;
+ }
+
+ return new String(outBuff, 0, outLen);
+ }
+
+ /**
+ * Encodes a byte array into Base64 notation.
+ *
+ * @param source
+ * the data to convert
+ * @param off
+ * offset in array where conversion should begin
+ * @param len
+ * length of data to convert
+ * @param alphabet
+ * is the encoding alphabet
+ * @param maxLineLength
+ * maximum length of one line.
+ * @return the BASE64-encoded byte array
+ */
+ public static byte[] encode(byte[] source, int off, int len, byte[] alphabet, int maxLineLength) {
+ int lenDiv3 = (len + 2) / 3; // ceil(len / 3)
+ int len43 = lenDiv3 * 4;
+ byte[] outBuff = new byte[len43 // Main 4:3
+ + (len43 / maxLineLength)]; // New lines
+
+ int d = 0;
+ int e = 0;
+ int len2 = len - 2;
+ int lineLength = 0;
+ for (; d < len2; d += 3, e += 4) {
+
+ // The following block of code is the same as
+ // encode3to4( source, d + off, 3, outBuff, e, alphabet );
+ // but inlined for faster encoding (~20% improvement)
+ int inBuff = ((source[d + off] << 24) >>> 8) | ((source[d + 1 + off] << 24) >>> 16) | ((source[d + 2 + off] << 24) >>> 24);
+ outBuff[e] = alphabet[(inBuff >>> 18)];
+ outBuff[e + 1] = alphabet[(inBuff >>> 12) & 0x3f];
+ outBuff[e + 2] = alphabet[(inBuff >>> 6) & 0x3f];
+ outBuff[e + 3] = alphabet[(inBuff) & 0x3f];
+
+ lineLength += 4;
+ if (lineLength == maxLineLength) {
+ outBuff[e + 4] = NEW_LINE;
+ e++;
+ lineLength = 0;
+ } // end if: end of line
+ } // end for: each piece of array
+
+ if (d < len) {
+ encode3to4(source, d + off, len - d, outBuff, e, alphabet);
+
+ lineLength += 4;
+ if (lineLength == maxLineLength) {
+ // Add a last newline
+ outBuff[e + 4] = NEW_LINE;
+ e++;
+ }
+ e += 4;
+ }
+
+ assert (e == outBuff.length);
+ return outBuff;
+ }
+
+ /* ******** D E C O D I N G M E T H O D S ******** */
+
+ /**
+ * Decodes four bytes from array <var>source</var> and writes the resulting
+ * bytes (up to three of them) to <var>destination</var>. The source and
+ * destination arrays can be manipulated anywhere along their length by
+ * specifying <var>srcOffset</var> and <var>destOffset</var>. This method
+ * does not check to make sure your arrays are large enough to accommodate
+ * <var>srcOffset</var> + 4 for the <var>source</var> array or
+ * <var>destOffset</var> + 3 for the <var>destination</var> array. This
+ * method returns the actual number of bytes that were converted from the
+ * Base64 encoding.
+ *
+ *
+ * @param source
+ * the array to convert
+ * @param srcOffset
+ * the index where conversion begins
+ * @param destination
+ * the array to hold the conversion
+ * @param destOffset
+ * the index where output will be put
+ * @param decodabet
+ * the decodabet for decoding Base64 content
+ * @return the number of decoded bytes converted
+ * @since 1.3
+ */
+ private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset, byte[] decodabet) {
+ // Example: Dk==
+ if (source[srcOffset + 2] == EQUALS_SIGN) {
+ int outBuff = ((decodabet[source[srcOffset]] << 24) >>> 6) | ((decodabet[source[srcOffset + 1]] << 24) >>> 12);
+
+ destination[destOffset] = (byte) (outBuff >>> 16);
+ return 1;
+ } else if (source[srcOffset + 3] == EQUALS_SIGN) {
+ // Example: DkL=
+ int outBuff = ((decodabet[source[srcOffset]] << 24) >>> 6) | ((decodabet[source[srcOffset + 1]] << 24) >>> 12)
+ | ((decodabet[source[srcOffset + 2]] << 24) >>> 18);
+
+ destination[destOffset] = (byte) (outBuff >>> 16);
+ destination[destOffset + 1] = (byte) (outBuff >>> 8);
+ return 2;
+ } else {
+ // Example: DkLE
+ int outBuff = ((decodabet[source[srcOffset]] << 24) >>> 6) | ((decodabet[source[srcOffset + 1]] << 24) >>> 12)
+ | ((decodabet[source[srcOffset + 2]] << 24) >>> 18) | ((decodabet[source[srcOffset + 3]] << 24) >>> 24);
+
+ destination[destOffset] = (byte) (outBuff >> 16);
+ destination[destOffset + 1] = (byte) (outBuff >> 8);
+ destination[destOffset + 2] = (byte) (outBuff);
+ return 3;
+ }
+ } // end decodeToBytes
+
+ /**
+ * Decodes data from Base64 notation.
+ *
+ * @param s
+ * the string to decode (decoded in default encoding)
+ * @return the decoded data
+ * @since 1.4
+ */
+ public static byte[] decode(String s) throws Base64DecoderException {
+ byte[] bytes = s.getBytes();
+ return decode(bytes, 0, bytes.length);
+ }
+
+ /**
+ * Decodes data from web safe Base64 notation. Web safe encoding uses '-'
+ * instead of '+', '_' instead of '/'
+ *
+ * @param s
+ * the string to decode (decoded in default encoding)
+ * @return the decoded data
+ */
+ public static byte[] decodeWebSafe(String s) throws Base64DecoderException {
+ byte[] bytes = s.getBytes();
+ return decodeWebSafe(bytes, 0, bytes.length);
+ }
+
+ /**
+ * Decodes Base64 content in byte array format and returns the decoded byte
+ * array.
+ *
+ * @param source
+ * The Base64 encoded data
+ * @return decoded data
+ * @since 1.3
+ * @throws Base64DecoderException
+ */
+ public static byte[] decode(byte[] source) throws Base64DecoderException {
+ return decode(source, 0, source.length);
+ }
+
+ /**
+ * Decodes web safe Base64 content in byte array format and returns the
+ * decoded data. Web safe encoding uses '-' instead of '+', '_' instead of
+ * '/'
+ *
+ * @param source
+ * the string to decode (decoded in default encoding)
+ * @return the decoded data
+ */
+ public static byte[] decodeWebSafe(byte[] source) throws Base64DecoderException {
+ return decodeWebSafe(source, 0, source.length);
+ }
+
+ /**
+ * Decodes Base64 content in byte array format and returns the decoded byte
+ * array.
+ *
+ * @param source
+ * the Base64 encoded data
+ * @param off
+ * the offset of where to begin decoding
+ * @param len
+ * the length of characters to decode
+ * @return decoded data
+ * @since 1.3
+ * @throws Base64DecoderException
+ */
+ public static byte[] decode(byte[] source, int off, int len) throws Base64DecoderException {
+ return decode(source, off, len, DECODABET);
+ }
+
+ /**
+ * Decodes web safe Base64 content in byte array format and returns the
+ * decoded byte array. Web safe encoding uses '-' instead of '+', '_'
+ * instead of '/'
+ *
+ * @param source
+ * the Base64 encoded data
+ * @param off
+ * the offset of where to begin decoding
+ * @param len
+ * the length of characters to decode
+ * @return decoded data
+ */
+ public static byte[] decodeWebSafe(byte[] source, int off, int len) throws Base64DecoderException {
+ return decode(source, off, len, WEBSAFE_DECODABET);
+ }
+
+ /**
+ * Decodes Base64 content using the supplied decodabet and returns the
+ * decoded byte array.
+ *
+ * @param source
+ * the Base64 encoded data
+ * @param off
+ * the offset of where to begin decoding
+ * @param len
+ * the length of characters to decode
+ * @param decodabet
+ * the decodabet for decoding Base64 content
+ * @return decoded data
+ */
+ public static byte[] decode(byte[] source, int off, int len, byte[] decodabet) throws Base64DecoderException {
+ int len34 = len * 3 / 4;
+ byte[] outBuff = new byte[2 + len34]; // Upper limit on size of output
+ int outBuffPosn = 0;
+
+ byte[] b4 = new byte[4];
+ int b4Posn = 0;
+ int i = 0;
+ byte sbiCrop = 0;
+ byte sbiDecode = 0;
+ for (i = 0; i < len; i++) {
+ sbiCrop = (byte) (source[i + off] & 0x7f); // Only the low seven
+ // bits
+ sbiDecode = decodabet[sbiCrop];
+
+ if (sbiDecode >= WHITE_SPACE_ENC) { // White space Equals sign or
+ // better
+ if (sbiDecode >= EQUALS_SIGN_ENC) {
+ // An equals sign (for padding) must not occur at position 0
+ // or 1
+ // and must be the last byte[s] in the encoded value
+ if (sbiCrop == EQUALS_SIGN) {
+ int bytesLeft = len - i;
+ byte lastByte = (byte) (source[len - 1 + off] & 0x7f);
+ if (b4Posn == 0 || b4Posn == 1) {
+ throw new Base64DecoderException("invalid padding byte '=' at byte offset " + i);
+ } else if ((b4Posn == 3 && bytesLeft > 2) || (b4Posn == 4 && bytesLeft > 1)) {
+ throw new Base64DecoderException("padding byte '=' falsely signals end of encoded value " + "at offset " + i);
+ } else if (lastByte != EQUALS_SIGN && lastByte != NEW_LINE) {
+ throw new Base64DecoderException("encoded value has invalid trailing byte");
+ }
+ break;
+ }
+
+ b4[b4Posn++] = sbiCrop;
+ if (b4Posn == 4) {
+ outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn, decodabet);
+ b4Posn = 0;
+ }
+ }
+ } else {
+ throw new Base64DecoderException("Bad Base64 input character at " + i + ": " + source[i + off] + "(decimal)");
+ }
+ }
+
+ // Because web safe encoding allows non padding base64 encodes, we
+ // need to pad the rest of the b4 buffer with equal signs when
+ // b4Posn != 0. There can be at most 2 equal signs at the end of
+ // four characters, so the b4 buffer must have two or three
+ // characters. This also catches the case where the input is
+ // padded with EQUALS_SIGN
+ if (b4Posn != 0) {
+ if (b4Posn == 1) {
+ // Ensure you have set your public key
+ throw new Base64DecoderException("single trailing character at offset " + (len - 1));
+ }
+ b4[b4Posn++] = EQUALS_SIGN;
+ outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn, decodabet);
+ }
+
+ byte[] out = new byte[outBuffPosn];
+ System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
+ return out;
+ }
+}
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2025-11-16 03:07:54 +0000