final int unusedChars = readInt();
        final int usedChars = readInt();

        if (unusedChars > totalChars || usedChars > totalChars - unusedChars) {
            throw new PACDecodingException("Malformed string in PAC");
        }

        this.dis.skip(unusedChars * 2);
        final char[] chars = new char[usedChars];
        for (int l = 0; l < usedChars; l++) {
            chars[l] = (char) readShort();
        }

        int totalChars = testString.length();
        writeLittleEndianInt(dos, totalChars); // totalChars
        writeLittleEndianInt(dos, 0); // unusedChars
        writeLittleEndianInt(dos, totalChars); // usedChars

        // Write the actual characters (as shorts in little-endian)
        for (char c : testString.toCharArray()) {
            writeLittleEndianShort(dos, (short) c);
        }