final byte[] decodeFast(char[] sArr) throws DecodingException {

        // Check special case
        int sLen = sArr != null ? sArr.length : 0;
        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 && IALPHABET[sArr[sIx]] < 0) {
            sIx++;
        }

        // Trim illegal chars from end
        while (eIx > 0 && IALPHABET[sArr[eIx]] < 0) {
            eIx--;
        }

        // get the padding count (=) (0, 1 or 2)
        int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0;  // Count '=' at end.
        int cCnt = eIx - sIx + 1;   // Content count including possible separators
        int sepCnt = sLen > 76 ? (sArr[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 = ctoi(sArr[sIx++]) << 18 | ctoi(sArr[sIx++]) << 12 | ctoi(sArr[sIx++]) << 6 | ctoi(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 |= ctoi(sArr[sIx++]) << (18 - j * 6);
            }

            for (int r = 16; d < len; r -= 8) {
                dArr[d++] = (byte) (i >> r);
            }
        }

        return dArr;
    }
final byte [ ] decodeFast ( char [ ] sArr ) throws DecodingException { int sLen = sArr != null ? sArr . length : 0 ; if ( sLen == 0 ) { return new byte [ 0 ] ; } int sIx = 0 , eIx = sLen - 1 ; while ( sIx < eIx && IALPHABET [ sArr [ sIx ] ] < 0 ) { sIx ++ ; } while ( eIx > 0 && IALPHABET [ sArr [ eIx ] ] < 0 ) { eIx -- ; } int pad = sArr [ eIx ] == '=' ? ( sArr [ eIx - 1 ] == '=' ? 2 : 1 ) : 0 ; int cCnt = eIx - sIx + 1 ; int sepCnt = sLen > 76 ? ( sArr [ 76 ] == '\r' ? cCnt / 78 : 0 ) << 1 : 0 ; int len = ( ( cCnt - sepCnt ) * 6 > > 3 ) - pad ; byte [ ] dArr = new byte [ len ] ; int d = 0 ; for ( int cc = 0 , eLen = ( len / 3 ) * 3 ; d < eLen ; ) { int i = ctoi ( sArr [ sIx ++ ] ) << 18 | ctoi ( sArr [ sIx ++ ] ) << 12 | ctoi ( sArr [ sIx ++ ] ) << 6 | ctoi ( sArr [ sIx ++ ] ) ; dArr [ d ++ ] = ( byte ) ( i > > 16 ) ; dArr [ d ++ ] = ( byte ) ( i > > 8 ) ; dArr [ d ++ ] = ( byte ) i ; if ( sepCnt > 0 && ++ cc == 19 ) { sIx += 2 ; cc = 0 ; } } if ( d < len ) { int i = 0 ; for ( int j = 0 ; sIx <= eIx - pad ; j ++ ) { i |= ctoi ( sArr [ sIx ++ ] ) << ( 18 - j * 6 ) ; } for ( int r = 16 ; d < len ; r -= 8 ) { dArr [ d ++ ] = ( byte ) ( i > > r ) ; } } return dArr ; }
Decodes a BASE64 encoded char array that is known to be reasonably well formatted. 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.
@throws DecodingException on illegal input