Simplify Date.DateTime

[danieleggert]

Can we change the format of Date.DateTime to be something like

struct DateTime {
    init?(day: Int, month: Int, year: Int, hour: Int, minute: Int, seconds: Int, zone: Int)
    var day: Int { get }
    var month: Int { get }
    var year: Int { get }
    var hour: Int { get }
    var minute: Int { get }
    var seconds: Int { get }
    var zone: Int { get }
}

i.e. flatten it and simplify using the components?

Maybe move it out of Date such that it’s simply DateTime? IIRC this is only used for INTERNALDATE and if so, maybe rename it to InternalDate?

The storage can be way more compact that 7 Int, it can in fact fit into a single 64 bit value.

We used to use this code:

    init?(day: Int, month: Int, year: Int, hour: Int, minute: Int, seconds: Int, zone: Int) {
        guard
            (1...31).contains(day),
            (1...12).contains(month),
            (0...24).contains(hour),
            (0...60).contains(minute),
            (0...60).contains(seconds),
            ((-24 * 60)...(24 * 60)).contains(zone),
            (1...Int(UInt16.max)).contains(year)
            else { return nil }
        let zoneValue = UInt16(abs(zone))
        let zoneIsNegative = (zone < 0) ? 1 as UInt8 : 0

        var rawValue = 0 as UInt64

        func store<A: UnsignedInteger>(_ value: A, _ a: A) {
            rawValue *= UInt64(a + 1)
            rawValue += UInt64(value)
        }

        store(UInt16(year), 1)
        store(UInt8(zoneIsNegative), 2)
        store(UInt16(zoneValue), 24 * 60)
        store(UInt8(seconds), 60)
        store(UInt8(minute), 60)
        store(UInt8(hour), 60)
        store(UInt8(month), 12)
        store(UInt8(day), 31)

        self.rawValue = rawValue
    }

and

        var remainder = rawValue

        func take<A: UnsignedInteger>(_ a: A) -> A {
            let r = remainder % UInt64(a + 1)
            remainder /= UInt64(a + 1)
            return A(r)
        }

        let day: UInt8 = take(31)
        let month: UInt8 = take(12)
        let hour: UInt8 = take(60)
        let minute: UInt8 = take(60)
        let seconds: UInt8 = take(60)
        let zoneValue: UInt16 = take(24 * 60)
        let zoneIsNegative: UInt8 = take(2)
        let year: UInt16 = take(UInt16.max - 1)
        let zoneMinutes = Int(zoneValue) * ((zoneIsNegative == 0) ? 1 : -1)

to convert between the day, month, year, hour, minute, seconds, zone set and a single UInt64 for compact storage. But we could probably use something better / more performant.

[Davidde94]

Also used in the MULTIAPPEND extension, so not sure we can rename to InternalDate

[Davidde94]

@danieleggert just to confirm, when parsing we'd have to parse, e.g., "JUNE" and convert to "6"?

[danieleggert]

I’d go for InternalDate since that’s also what you’d use with MULTIAPPEND.

These are not dates meant for UI — hence the name.