binary unit transform

BinaryUnitTransform.swift

public enum BinaryUnit: Int {
    case b = 0, B, KB, MB, GB, TB, PB, ZB, YB
}

public func binaryUnitTransform(value: Double, #unit: BinaryUnit) -> (value: Double, unitString: String) {
    var raw = unit.rawValue
    if value < 1.0 && value > 0 && unit != .b {
        return binaryUnitTransform(value * 1024.0, unit: BinaryUnit(rawValue: --raw)!)
    } else if value > 1024.0 && unit != .YB {
        return binaryUnitTransform(value / 1024.0, unit: BinaryUnit(rawValue: ++raw)!)
    } else {
        let units = ["\(BinaryUnit.b.rawValue)":"b",
            "\(BinaryUnit.B.rawValue)":"B",
            "\(BinaryUnit.KB.rawValue)":"KB",
            "\(BinaryUnit.MB.rawValue)":"MB",
            "\(BinaryUnit.GB.rawValue)":"GB",
            "\(BinaryUnit.TB.rawValue)":"TB",
            "\(BinaryUnit.PB.rawValue)":"PB",
            "\(BinaryUnit.ZB.rawValue)":"ZB",
            "\(BinaryUnit.YB.rawValue)":"YB"]
        return (value, units["\(raw)"]!)
    }
}