lastIndexOf.java

    private static final long DOLLAR_PATTERN = '$' * 0x0001_0001_0001_0001L;

    private static int firstAnyPattern(long fourChars, long charPattern) {
        long input = fourChars ^ charPattern;
        long tmp = (input & 0x7FFF_7FFF_7FFF_7FFFL) + 0x7FFF_7FFF_7FFF_7FFFL;
        tmp = ~(tmp | input | 0x7FFF_7FFF_7FFF_7FFFL);
        final int binaryPosition = Long.numberOfLeadingZeros(tmp);
        return binaryPosition >>> 4;
    }

    private static int searchLastIndexOfOrDollar(String name, char delim) {
        int pos = name.length() - 1;
        int longTrips = pos / 4;
        int off = pos - 1;
        final long delimPattern = delim * 0x0001_0001_0001_0001L;
        for (int i = 0; i < longTrips; i++) {
            final long batch = ((long) name.charAt(off)) << 48 |
               ((long) name.charAt(off - 1)) << 32 |
               name.charAt(off - 2) << 16 |
               name.charAt(off - 3);
            int delimPos = firstAnyPattern(batch, delimPattern);
            if (delimPos < 4) {
                return off - delimPos;
            }
            int dollarPos = firstAnyPattern(batch, DOLLAR_PATTERN);
            if (dollarPos < 4) {
                return off - dollarPos;
            }
            off -= 4;
        }
        while (off >= 0) {
            char c = name.charAt(off);
            if (c == delim) {
                return off;
            }
            if (c == '$') {
                return -off;
            }
            off--;
        }
        return -1;
    }

    private static int lastIndexOf(String name, char delim) {
        // Begin at second last position to avoid empty local name
        int pos = searchLastIndexOfOrDollar(name, delim);
        // avoid splitting on '$' if previous char is a delimiter or the '$'
        // is in position 0, because subsequent split would produce an empty
        // local name
        if (pos >= 0 && name.charAt(pos) == '$' && (pos == 0 || name.charAt(pos - 1) == delim)) {
            pos--;
        }

        return pos;
    }