How can I make the map::find operation case insensitive?

Question

Does the map::find method support case insensitive search? I have a map as follows:

map > directory;
<         


        

Answer 1

In case you don't want to touch the map type (to keep it's original simplicity and efficiency), but don't mind using a slower case-insensitive find function (O(N)):

string to_lower(string s) {
    transform(s.begin(), s.end(), s.begin(), (int(*)(int)) tolower );
    return s;
}

typedef map map_type;

struct key_lcase_equal {
    string lcs;
    key_lcase_equal(const string& s) : lcs(to_lower(s)) {}
    bool operator()(const map_type::value_type& p) const {
        return to_lower(p.first) == lcs;
    }
};

map_type::iterator find_ignore_case(map_type& m, const string& s) {
    return find_if(m.begin(), m.end(), key_lcase_equal(s));
}

PS: Maybe it was Roger Pate's idea, but not sure, since some details were a bit off (std::search?, direct string comparator?)