Deleted tokenising code

toke2.cc

strings multi_split(const string& line, char c)
{
        strings result;
        std::size_t prev = 0, pos;
        while((pos = line.find_first_of(c, prev)) != std::string::npos)
        {
                if(pos>prev)
                        result.push_back(line.substr(prev, pos-prev));
                prev = pos+1;
        }
        if (prev<line.length())
                result.push_back(line.substr(prev, std::string::npos));
        return result;

}

// TODO definitely reusable!
string char_to_string(char c)
{
        char cstr[] = {c};
        return cstr;
}


strings tokenise_2(const string& line)
{
        constexpr char FS = 0x1C;
        bool found_quote = false;

        char* line_cs = (char *)line.c_str(); // potentially tricky, I guess
        for(int i=0; i< line.size(); ++i){
                char c = line[i];
                if(c == '"') {
                        found_quote = true ;
                        line_cs[i] = FS;
                }
                if(found_quote) continue;
                if(c == ' ' || c == '\t') line_cs[i] = FS;
        }

        return multi_split(line, FS);
}
void check_tokeniser_2(const string& msg, const string& input, const strings& expected_result)
{
        strings strs = tokenise_2(input);
        if(false) { // for debugging purposes
                for(auto s:strs) cout << "[" << s << "] ";
                cout << endl;
        }

        bool ok = strs == expected_result;
        check(ok, msg);
}
void check_tokeniser_2_all()
{
        check_tokeniser_2("toke2-01", "  how   now brown cow",
                        {"how", "now", "brown", "cow"});
        check_tokeniser_2("toke2-02", "how now    \"brown  cow\"",
                        {"how", "now", "brown  cow"});

        string cow = "how now\t \"brown cow\"";
        Timer time;
        time.start();
        for(int i =0; i<1000; ++i) parse::tokenise_line(cow);
        time.stop();
        cout << "Elapsed: " << time.nanos() << endl;
        time.start();
        for(int i =0; i<1000; ++i) tokenise_2(cow);
        time.stop();
        cout << "Elapsed: " << time.nanos() << endl;

}

It turns out that this code is slower than my original code. So I should just stick to my original code. I am surprised there is such a bottleneck. find_first_of() perhaps??