NSDecimal+Swift.swift

import Foundation

extension NSCalculationError: ErrorType {
}

extension NSDecimal: Comparable {
}

public func ==(lhs: NSDecimal, rhs: NSDecimal) -> Bool {
    var mutableLhs = lhs
    var mutableRhs = rhs
    return (NSDecimalCompare(&mutableLhs, &mutableRhs) == .OrderedSame)
}

public func <(lhs: NSDecimal, rhs: NSDecimal) -> Bool {
    var mutableLhs = lhs
    var mutableRhs = rhs
    return (NSDecimalCompare(&mutableLhs, &mutableRhs) == .OrderedAscending)
}


extension NSDecimal {
    
    public var isNotANumber: Bool {
        var mutableSelf = self
        return NSDecimalIsNotANumber(&mutableSelf)
    }
    
    public mutating func compact() {
        NSDecimalCompact(&self)
    }
    
    public mutating func round(scale: Int = Int(NSDecimalNoScale), roundingMode: NSRoundingMode = .RoundPlain) {
        NSDecimalRound(&self, &self, scale, roundingMode)
    }
    
    public static func normalize(inout decimal1: NSDecimal, inout decimal2: NSDecimal, roundingMode: NSRoundingMode = .RoundPlain) throws {
        let error = NSDecimalNormalize(&decimal1, &decimal2, roundingMode)
        guard error == .NoError else {
            throw error
        }
    }
    
    public mutating func add(otherDecimal: NSDecimal, roundingMode: NSRoundingMode = .RoundPlain) throws {
        var mutableOtherDecimal = otherDecimal
        let error = NSDecimalAdd(&self, &self, &mutableOtherDecimal, roundingMode)
        guard error == .NoError else {
            throw error
        }
    }
    
    public mutating func subtract(otherDecimal: NSDecimal, roundingMode: NSRoundingMode = .RoundPlain) throws {
        var mutableOtherDecimal = otherDecimal
        let error = NSDecimalSubtract(&self, &self, &mutableOtherDecimal, roundingMode)
        guard error == .NoError else {
            throw error
        }
    }
    
    public mutating func multiplyBy(otherDecimal: NSDecimal, roundingMode: NSRoundingMode = .RoundPlain) throws {
        var mutableOtherDecimal = otherDecimal
        let error = NSDecimalMultiply(&self, &self, &mutableOtherDecimal, roundingMode)
        guard error == .NoError else {
            throw error
        }
    }
    
    public mutating func divideBy(otherDecimal: NSDecimal, roundingMode: NSRoundingMode = .RoundPlain) throws {
        var mutableOtherDecimal = otherDecimal
        let error = NSDecimalDivide(&self, &self, &mutableOtherDecimal, roundingMode)
        guard error == .NoError else {
            throw error
        }
    }
    
    public mutating func power(power: Int, roundingMode: NSRoundingMode = .RoundPlain) throws {
        let error = NSDecimalPower(&self, &self, power, roundingMode)
        guard error == .NoError else {
            throw error
        }
    }
    
    public mutating func multiplyByPowerOf10(power: Int16, roundingMode: NSRoundingMode = .RoundPlain) throws {
        let error = NSDecimalMultiplyByPowerOf10(&self, &self, power, roundingMode)
        guard error == .NoError else {
            throw error
        }
    }
    
    public func stringValue(locale: AnyObject? = nil) -> String {
        var mutableSelf = self
        return NSDecimalString(&mutableSelf, locale)
    }
}

public func +(lhs: NSDecimal, rhs: NSDecimal) throws -> NSDecimal {
    var result = lhs
    try result.add(rhs)
    return result
}

public func +=(inout lhs: NSDecimal, rhs: NSDecimal) throws {
    try lhs.add(rhs)
}

public func -(lhs: NSDecimal, rhs: NSDecimal) throws -> NSDecimal {
    var result = lhs
    try result.subtract(rhs)
    return result
}

public func -=(inout lhs: NSDecimal, rhs: NSDecimal) throws {
    try lhs.subtract(rhs)
}

public func *(lhs: NSDecimal, rhs: NSDecimal) throws -> NSDecimal {
    var result = lhs
    try result.multiplyBy(rhs)
    return result
}

public func *=(inout lhs: NSDecimal, rhs: NSDecimal) throws {
    try lhs.multiplyBy(rhs)
}

public func /(lhs: NSDecimal, rhs: NSDecimal) throws -> NSDecimal {
    var result = lhs
    try result.divideBy(rhs)
    return result
}

public func /=(inout lhs: NSDecimal, rhs: NSDecimal) throws {
    try lhs.divideBy(rhs)
}