| // This source file is part of the Swift.org open source project |
| // |
| // Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors |
| // Licensed under Apache License v2.0 with Runtime Library Exception |
| // |
| // See http://swift.org/LICENSE.txt for license information |
| // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors |
| // |
| |
| extension LengthFormatter { |
| public enum Unit: Int { |
| case millimeter = 8 |
| case centimeter = 9 |
| case meter = 11 |
| case kilometer = 14 |
| case inch = 1281 |
| case foot = 1282 |
| case yard = 1283 |
| case mile = 1284 |
| } |
| } |
| |
| open class LengthFormatter : Formatter { |
| |
| public override init() { |
| numberFormatter = NumberFormatter() |
| numberFormatter.numberStyle = .decimal |
| unitStyle = .medium |
| isForPersonHeightUse = false |
| super.init() |
| } |
| |
| public required init?(coder: NSCoder) { |
| numberFormatter = NumberFormatter() |
| numberFormatter.numberStyle = .decimal |
| unitStyle = .medium |
| isForPersonHeightUse = false |
| super.init(coder:coder) |
| } |
| |
| /*@NSCopying*/ open var numberFormatter: NumberFormatter! // default is NumberFormatter with NumberFormatter.Style.decimal |
| open var unitStyle: UnitStyle // default is NSFormattingUnitStyleMedium |
| |
| open var isForPersonHeightUse: Bool // default is NO; if it is set to YES, the number argument for -stringFromMeters: and -unitStringFromMeters: is considered as a person's height |
| |
| // Format a combination of a number and an unit to a localized string. |
| open func string(fromValue value: Double, unit: LengthFormatter.Unit) -> String { |
| guard let formattedValue = numberFormatter.string(from:NSNumber(value: value)) else { |
| fatalError("Cannot format \(value) as string") |
| } |
| let separator = unitStyle == LengthFormatter.UnitStyle.short ? "" : " " |
| return "\(formattedValue)\(separator)\(unitString(fromValue: value, unit: unit))" |
| } |
| |
| // Format a number in meters to a localized string with the locale-appropriate unit and an appropriate scale (e.g. 4.3m = 14.1ft in the US locale). |
| open func string(fromMeters numberInMeters: Double) -> String { |
| //Convert to the locale-appropriate unit |
| let unitFromMeters = unit(fromMeters: numberInMeters) |
| |
| //Map the unit to UnitLength type for conversion later |
| let unitLengthFromMeters = LengthFormatter.unitLength[unitFromMeters]! |
| |
| //Create a measurement object based on the value in meters |
| let meterMeasurement = Measurement<UnitLength>(value:numberInMeters, unit: .meters) |
| |
| //Convert the object to the locale-appropriate unit determined above |
| let unitMeasurement = meterMeasurement.converted(to: unitLengthFromMeters) |
| |
| //Extract the number from the measurement |
| let numberInUnit = unitMeasurement.value |
| |
| if isForPersonHeightUse && !numberFormatter.locale.usesMetricSystem { |
| let feet = numberInUnit.rounded(.towardZero) |
| let feetString = string(fromValue: feet, unit: .foot) |
| |
| let inches = abs(numberInUnit.truncatingRemainder(dividingBy: 1.0)) * 12 |
| let inchesString = string(fromValue: inches, unit: .inch) |
| |
| return ("\(feetString), \(inchesString)") |
| } |
| return string(fromValue: numberInUnit, unit: unitFromMeters) |
| } |
| |
| // Return a localized string of the given unit, and if the unit is singular or plural is based on the given number. |
| open func unitString(fromValue value: Double, unit: Unit) -> String { |
| if unitStyle == .short { |
| return LengthFormatter.shortSymbol[unit]! |
| } else if unitStyle == .medium { |
| return LengthFormatter.mediumSymbol[unit]! |
| } else if value == 1.0 { |
| return LengthFormatter.largeSingularSymbol[unit]! |
| } else { |
| return LengthFormatter.largePluralSymbol[unit]! |
| } |
| } |
| |
| // Return the locale-appropriate unit, the same unit used by -stringFromMeters:. |
| open func unitString(fromMeters numberInMeters: Double, usedUnit unitp: UnsafeMutablePointer<Unit>?) -> String { |
| |
| //Convert to the locale-appropriate unit |
| let unitFromMeters = unit(fromMeters: numberInMeters) |
| unitp?.pointee = unitFromMeters |
| |
| //Map the unit to UnitLength type for conversion later |
| let unitLengthFromMeters = LengthFormatter.unitLength[unitFromMeters]! |
| |
| //Create a measurement object based on the value in meters |
| let meterMeasurement = Measurement<UnitLength>(value:numberInMeters, unit: .meters) |
| |
| //Convert the object to the locale-appropriate unit determined above |
| let unitMeasurement = meterMeasurement.converted(to: unitLengthFromMeters) |
| |
| //Extract the number from the measurement |
| let numberInUnit = unitMeasurement.value |
| |
| //Return the appropriate representation of the unit based on the selected unit style |
| return unitString(fromValue: numberInUnit, unit: unitFromMeters) |
| } |
| |
| /// This method selects the appropriate unit based on the formatter’s locale, |
| /// the magnitude of the value, and isForPersonHeightUse property. |
| /// |
| /// - Parameter numberInMeters: the magnitude in terms of meters |
| /// - Returns: Returns the appropriate unit |
| private func unit(fromMeters numberInMeters: Double) -> Unit { |
| if numberFormatter.locale.usesMetricSystem { |
| //Person height is always returned in cm for metric system |
| if isForPersonHeightUse { return .centimeter } |
| |
| if numberInMeters > 1000 || numberInMeters < 0.0 { |
| return .kilometer |
| } else if numberInMeters > 1.0 { |
| return .meter |
| } else if numberInMeters > 0.01 { |
| return .centimeter |
| } else { return .millimeter } |
| } else { |
| //Person height is always returned in ft for U.S. system |
| if isForPersonHeightUse { return .foot } |
| |
| let metricMeasurement = Measurement<UnitLength>(value:numberInMeters, unit: .meters) |
| let usMeasurement = metricMeasurement.converted(to: .feet) |
| let numberInFeet = usMeasurement.value |
| |
| if numberInFeet < 0.0 || numberInFeet > 5280 { |
| return .mile |
| } else if numberInFeet > 3 || numberInFeet == 0.0 { |
| return .yard |
| } else if numberInFeet >= 1.0 { |
| return .foot |
| } else { return .inch } |
| } |
| } |
| |
| |
| /// - Experiment: This is a draft API currently under consideration for official import into Foundation as a suitable alternative |
| /// - Note: Since this API is under consideration it may be either removed or revised in the near future |
| open override func objectValue(_ string: String) throws -> Any? { return nil } |
| |
| |
| /// Maps LengthFormatter.Unit enum to UnitLength class. Used for measurement conversion. |
| private static let unitLength: [Unit:UnitLength] = [.millimeter:.millimeters, |
| .centimeter:.centimeters, |
| .meter:.meters, |
| .kilometer:.kilometers, |
| .inch:.inches, |
| .foot:.feet, |
| .yard:.yards, |
| .mile:.miles] |
| |
| /// Maps a unit to its short symbol. Reuses strings from UnitLength wherever possible. |
| private static let shortSymbol: [Unit: String] = [.millimeter:UnitLength.millimeters.symbol, |
| .centimeter:UnitLength.centimeters.symbol, |
| .meter:UnitLength.meters.symbol, |
| .kilometer:UnitLength.kilometers.symbol, |
| .inch:"\"", |
| .foot:"′", |
| .yard:UnitLength.yards.symbol, |
| .mile:UnitLength.miles.symbol] |
| |
| /// Maps a unit to its medium symbol. Reuses strings from UnitLength. |
| private static let mediumSymbol: [Unit: String] = [.millimeter:UnitLength.millimeters.symbol, |
| .centimeter:UnitLength.centimeters.symbol, |
| .meter:UnitLength.meters.symbol, |
| .kilometer:UnitLength.kilometers.symbol, |
| .inch:UnitLength.inches.symbol, |
| .foot:UnitLength.feet.symbol, |
| .yard:UnitLength.yards.symbol, |
| .mile:UnitLength.miles.symbol] |
| |
| /// Maps a unit to its large, singular symbol. |
| private static let largeSingularSymbol: [Unit: String] = [.millimeter:"millimeter", |
| .centimeter:"centimeter", |
| .meter:"meter", |
| .kilometer:"kilometer", |
| .inch:"inch", |
| .foot:"foot", |
| .yard:"yard", |
| .mile:"mile"] |
| |
| /// Maps a unit to its large, plural symbol. |
| private static let largePluralSymbol: [Unit: String] = [.millimeter:"millimeters", |
| .centimeter:"centimeters", |
| .meter:"meters", |
| .kilometer:"kilometers", |
| .inch:"inches", |
| .foot:"feet", |
| .yard:"yards", |
| .mile:"miles"] |
| } |
