Question

I have a c++ code which build an expiration date string for cookie (something like: "Thu, 31-Dec-2037 22:00:00 GMT") I need it to be 90 from “now”. This is my code:

    ptime toDay(second_clock::universal_time());
    toDay += days(90);
    date d = toDay.date();
    string dayOfWeek = d.day_of_week().as_short_string();
    int dayOfMonth = d.day();
    string month = d.month().as_short_string();
    int year = (int)toDay.date().year();

    stringstream strs;
    strs << dayOfWeek << ", " << std::setfill('0') << std::setw(2) << dayOfMonth << "-" << month << "-" << year << " " << toDay.time_of_day() << " GMT";

    string defaultExpiration = strs.str();

The performance of this code is really bad, I would guess it’s the stringstream use.
If any of you have an alternative which should be faster, I would be happy to test it.
Thanks !

Answer 1

Found a sagnificant faster way to do it using FastFormat, and now it looks like that:

ptime today(second_clock::universal_time());
today += days(90);
date d = today.date();
int dayOfMonth = d.day();
int hoursOfDay = today.time_of_day().hours();
int minutesOfDay = today.time_of_day().minutes();

//this function if from "FastFormat"
string defaultExpiration(StringFormatter::Format("{0}, {1}{2}-{3}-{4} {5}{6}:{7}{8}:00 GMT",
    d.day_of_week().as_short_string(),
    dayOfMonth < 10 ? "0" : "",
    dayOfMonth,
    d.month().as_short_string(),
    (int)d.year(),
    hoursOfDay < 10 ? "0" : "",
    hoursOfDay,
    minutesOfDay < 10 ? "0" : "",
    minutesOfDay
    ));