Re: Plist max size

john daniel wrote:

I think most people take up more space than that for icons on buttons.

Right.  But this will be considerably bigger if you put it in an XML plist.

@DenisO, For a rectangular array like this I’d probably put the data into a file in binary form and then memory map that.  You can then access the values at random and the VM subsystem will take care of the rest.

Furthermore, I’d wrap this in a nice, Swift-friendly data structure.  Something like this:

class DataMap {
    let rowCount = 16
    let columnCount = 16
    init?(file: URL) {
        guard let d = try? NSData(contentsOf: file, options: [.alwaysMapped]) else {
            return nil
        }
        guard d.length == (self.rowCount * self.columnCount * MemoryLayout<Double>.size) else {
            return nil
        }
        self.data = d
        let base = d.bytes.assumingMemoryBound(to: Double.self)
        self.buffer = UnsafeBufferPointer(start: base, count: d.length)
    }
    private let data: NSData
    private let buffer: UnsafeBufferPointer<Double>
    subscript (row: Int, column: Int) -> Double {
        precondition((0..<self.rowCount).contains(row))
        precondition((0..<self.columnCount).contains(column))
        return self.buffer[row * self.rowCount + column]
    }
}

Note that I’ve hard-coded the row and column counts, which makes sense if all of these objects have the same dimensions.  If not, those values would need to be parameters to the initialiser.

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