private static void addSpecialLetterValue(final char c, final int lettervalue) {
        //add both uppercase and lowercase
        SPECIAL_LETTER_VALUE_MAP.put(Character.toUpperCase(c), lettervalue);
        SPECIAL_LETTER_VALUE_MAP.put(Character.toLowerCase(c), lettervalue);
    }
Holds implementations for functions in Formula
main/src/main/java/cgeo/geocaching/utils/formulas/FormulaUtils.java