How to parse an ISO-8601 duration in Objective C?

Question

I\'m looking for an easy way to parse a string that contains an ISO-8601 duration in Objective C. The result should be something usable like a NSTimeI

Answer 1

Here is swift 3 version of headkaze example: This format was most suitable in my case:

private func parseISO8601Time(iso8601: String) -> String {

    let nsISO8601 = NSString(string: iso8601)

    var days = 0, hours = 0, minutes = 0, seconds = 0
    var i = 0

    while i < nsISO8601.length  {

        var str = nsISO8601.substring(with: NSRange(location: i, length: nsISO8601.length - i))

        i += 1

        if str.hasPrefix("P") || str.hasPrefix("T") { continue }

        let scanner = Scanner(string: str)
        var value = 0

        if scanner.scanInt(&value) {

            i += scanner.scanLocation - 1

            str = nsISO8601.substring(with: NSRange(location: i, length: nsISO8601.length - i))

            i += 1

            if str.hasPrefix("D") {
                days = value
            } else if str.hasPrefix("H") {
                hours = value
            } else if str.hasPrefix("M") {
                minutes = value
            } else if str.hasPrefix("S") {
                seconds = value
            }
        }
    }

    if days > 0 {
        hours += 24 * days
    }

    if hours > 0 {
        return String(format: "%d:%02d:%02d", hours, minutes, seconds)
    }

    return String(format: "%d:%02d", minutes, seconds)

}