public final static byte[] decodeFast(String s, boolean urlSafe) {
        // 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
        if (!urlSafe) {
            while (sIx < eIx && IA[s.charAt(sIx) & 0xff] < 0) {
                sIx++;
            }
        } else {
            while (sIx < eIx && IA_URL_SAFE[s.charAt(sIx) & 0xff] < 0) {
                sIx++;
            }
        }

        // Trim illegal chars from end
        if (!urlSafe) {
            while (eIx > 0 && IA[s.charAt(eIx) & 0xff] < 0) {
                eIx--;
            }
        } else {
            while (eIx > 0 && IA_URL_SAFE[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;
            if (!urlSafe) {
                i = IA[s.charAt(sIx++)] << 18 | IA[s.charAt(sIx++)] << 12 | IA[s.charAt(sIx++)] << 6 | IA[s.charAt(sIx++)];
            } else {
                i = IA_URL_SAFE[s.charAt(sIx++)] << 18 | IA_URL_SAFE[s.charAt(sIx++)] << 12 | IA_URL_SAFE[s.charAt(sIx++)] << 6 | IA_URL_SAFE[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++) {
                if (!urlSafe) {
                    i |= IA[s.charAt(sIx++)] << (18 - j * 6);
                } else {
                    i |= IA_URL_SAFE[s.charAt(sIx++)] << (18 - j * 6);
                }
            }

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

        return dArr;
    }
public final static byte [ ] decodeFast ( String s , boolean urlSafe ) { int sLen = s . length ( ) ; if ( sLen == 0 ) { return new byte [ 0 ] ; } int sIx = 0 , eIx = sLen - 1 ; if ( ! urlSafe ) { while ( sIx < eIx && IA [ s . charAt ( sIx ) & 0xff ] < 0 ) { sIx ++ ; } } else { while ( sIx < eIx && IA_URL_SAFE [ s . charAt ( sIx ) & 0xff ] < 0 ) { sIx ++ ; } } if ( ! urlSafe ) { while ( eIx > 0 && IA [ s . charAt ( eIx ) & 0xff ] < 0 ) { eIx -- ; } } else { while ( eIx > 0 && IA_URL_SAFE [ s . charAt ( eIx ) & 0xff ] < 0 ) { eIx -- ; } } int pad = s . charAt ( eIx ) == '=' ? ( s . charAt ( eIx - 1 ) == '=' ? 2 : 1 ) : 0 ; int cCnt = eIx - sIx + 1 ; int sepCnt = sLen > 76 ? ( s . charAt ( 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 ; if ( ! urlSafe ) { i = IA [ s . charAt ( sIx ++ ) ] << 18 | IA [ s . charAt ( sIx ++ ) ] << 12 | IA [ s . charAt ( sIx ++ ) ] << 6 | IA [ s . charAt ( sIx ++ ) ] ; } else { i = IA_URL_SAFE [ s . charAt ( sIx ++ ) ] << 18 | IA_URL_SAFE [ s . charAt ( sIx ++ ) ] << 12 | IA_URL_SAFE [ s . charAt ( sIx ++ ) ] << 6 | IA_URL_SAFE [ s . charAt ( 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 ++ ) { if ( ! urlSafe ) { i |= IA [ s . charAt ( sIx ++ ) ] << ( 18 - j * 6 ) ; } else { i |= IA_URL_SAFE [ 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.