int do_compare(const charT* low1, const charT* high1,
const charT* low2, const charT* high2) const;
string_type do_transform(const charT* low, const charT* high) const;
long do_hash(const charT* low, const charT* high) const;
Returns: An integer value equal to the result of calling hash() on any other string for which do_compare() returns 0 (equal) when passed the two strings. [ Note: The probability that the result equals that for another string which does not compare equal should be very small, approaching (1.0/numeric_limits<unsigned long>::max()). — end note ]
This function is useful when one string is being compared to many other strings.