if (value == null) {
            return null;
        }

        char c;
        final int len = value.length();
        final StringBuilder buf = new StringBuilder(len * 2);

        for (int i = 0; i < len; i++) {
            c = value.charAt(i);
            String escaped = switch (c) {
            case '\\', '"' -> "\\" + c;
            case '/' -> "\\/";
            case '\b' -> "\\b";

        out[i % olen] = (byte) (b & 0xff);
        return b >>>= 8;
    }

    private static int lcm(int u, int v) {
        int a = u, b = v, c;
        while (b != 0) {
            c = b;
            b = a % b;
            a = c;
        }
        return u * v / a;
    }

    /**
     * Calculates a MAC (Message Authentication Code) for PAC data validation.

        final int blen = 2 * clen;
        final byte[] b = new byte[blen];
        final char[] c = new char[clen];
        s.getChars(0, clen, c, 0);
        for (int i = 0, j = 0; i < clen; i++) {
            b[j] = (byte) (c[i] >>> 8);
            j++;
            b[j++] = (byte) (c[i] >>> 0);
        }
        write(b, 0, blen);
    }

    @Override

            final char c = configPath.charAt(i);
            if (c == '\\') {
                buf.append('/');
            } else if (c == ' ') {
                buf.append("%20");
            } else if (CharUtil.isUrlChar(c)) {
                buf.append(c);
            } else {
                try {
                    buf.append(URLEncoder.encode(String.valueOf(c), Constants.UTF_8));

        int byteIndex = 0;

        for (char c : chars) {
            if (c < 0x80) {
                bytes[byteIndex++] = (byte) c;
            } else if (c < 0x800) {
                bytes[byteIndex++] = (byte) (0xC0 | (c >> 6));
                bytes[byteIndex++] = (byte) (0x80 | (c & 0x3F));
            } else {
                bytes[byteIndex++] = (byte) (0xE0 | (c >> 12));

    }

    @Override
    public boolean addAll(final Collection<? extends Map<String, Object>> c) {
        return parent.addAll(c);
    }

    @Override
    public boolean addAll(final int index, final Collection<? extends Map<String, Object>> c) {
        return parent.addAll(index, c);
    }

    @Override
    public void clear() {
        parent.clear();
    }

    @Override

        buf.append("\"gc\":{");
        buf.append(Arrays.stream(gc.getCollectors()).map(c -> {
            final StringBuilder b = new StringBuilder();
            b.append('"').append(StringEscapeUtils.escapeJson(c.getName())).append("\":{");
            append(b, "count", () -> c.getCollectionCount()).append(',');
            append(b, "time", () -> c.getCollectionTime().getMillis()).append('}');
            return b.toString();

        if (peekc == QUOTE) {
            ttype = QUOTE;
            int i = 0;
            int d = read();
            int c = d;
            while (d >= 0) {
                if (d == QUOTE) {
                    final int d2 = read();
                    if (d2 == QUOTE) {
                        c = QUOTE;
                    } else {
                        d = d2;
                        break;
                    }

     * .
     */
    @Test
    public void testIsEmptyCollectionOfQ() {
        Collection<String> c = null;
        assertThat(CollectionsUtil.isEmpty(c), is(true));
        c = new ArrayList<String>();
        assertThat(CollectionsUtil.isEmpty(c), is(true));
    }

    /**
     * Test method for
     * {@link org.codelibs.core.collection.CollectionsUtil#isNotEmpty(java.util.Collection)}

        final char[] c = new char[2 * size];
        for (int i = 0, j = 0; i < size; i++) {
            c[j] = HEX_DIGITS[src[srcIndex + i] >> 4 & 0x0F];
            j++;
            c[j++] = HEX_DIGITS[src[srcIndex + i] & 0x0F];
        }
        return new String(c);
    }

    /**
     * Converts a byte array to a hexadecimal string representation.
     *