Swift CPF Validator

cpfValidator.swift

static func isValidCPF(_ CPF: String) -> Bool {

    //
    //  CPF must have 14 full characters, and 11 numeric values
    //
    if CPF.count != 14 { return false }

    let cpfDigits = CPF.numericValues()

    if cpfDigits.count != 11 { return false }

    let CPFArray = cpfDigits.map({ Int(String($0)) ?? -1 })

    //
    //  Algorithm
    //
    var hasSameValues = true
    var digito = 0

    for i in 0..<(CPFArray.count - 1) {
        digito = CPFArray[i]

        if digito > 9 || digito < 0 { return false }

        if digito != CPFArray[i + 1] {
            hasSameValues = false
            break
        }
    }

    if hasSameValues { return false }

    for i in 9 ..< 11 {

        var soma = 0
        var k: Int = 0

        for _ in 0 ..< i {
            soma += CPFArray[k] * ((i + 1) - k)
            k += 1
        }

        soma = ((10 * soma) % 11) % 10
        if CPFArray[k] != soma { return false }
    }

    return true
}

extension String {
    
    func numericValues() -> String {
        if self.isEmpty { return self }
        return String.matchesForRegex("[0-9]", inText: self)
    }

    static func matchesForRegex(_ regex: String, inText text: String) -> String {

        do {
            let regex = try NSRegularExpression(pattern: regex, options: [])
            let nsString = text as NSString
            let results = regex.matches(in: text,
                                        options: [],
                                        range: NSMakeRange(0, nsString.length))
            let mappedResults = results.map { nsString.substring(with: $0.range) }
            return mappedResults.joined(separator: "")
        } catch let error as NSError {
            print("\(#function) - invalid regex: \(error.localizedDescription)")
            return text
        }
    }
}