public final static byte[] decodeFast(String s) {
        // Check special case
        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)
        int pad = s.charAt(eIx) == '=' ? (s.charAt(eIx - 1) == '=' ? 2 : 1) : 0; // Count '=' at end.
        int cCnt = eIx - sIx + 1; // Content count including possible separators
        int sepCnt = sLen > 76 ? (s.charAt(76) == '\r' ? cCnt / 78 : 0) << 1 : 0;

        int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
        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.
            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;
    }
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.
lts-core/src/main/java/com/github/ltsopensource/core/commons/utils/Base64.java