CPF Checker

cpf_checker.rs

#[derive(Debug, PartialEq)]
enum CPFError {
    InvalidDigitAtIndex(u32),
    InvalidLength(u32),
    Invalid,
}

fn get_dv(cpf: &Vec<u32>, digit_position: u32) -> u32 {
    let mut count = digit_position;
    let mut sum = 0;

    for n in cpf {
        if count >= 2 {
            sum += n * count as u32;
            count -= 1;
        }
    }

    let res = (sum * 10) % 11;

    if res == 10 {
        return 0;
    }

    res
}

fn parse_cpf(raw_cpf: &str) -> Result<Vec<u32>, CPFError> {
    let mut cpf: Vec<u32> = vec![];

    let cpf_chars = raw_cpf
        .chars()
        .filter(|s| !"./-".contains(s.to_owned()))
        .collect::<Vec<_>>();

    for (i, char) in cpf_chars.into_iter().enumerate() {
        if !char.is_digit(10) {
            return Err(CPFError::InvalidDigitAtIndex(i as u32));
        }

        cpf.push(char.to_digit(10).ok_or_else(|| CPFError::Invalid)?);
    }

    if cpf.len() != 11 {
        return Err(CPFError::InvalidLength(cpf.len() as u32));
    }

    Ok(cpf)
}

fn check_digits(cpf: &Vec<u32>) -> Result<(), CPFError> {
    let dv1 = get_dv(cpf, 10);
    let dv2 = get_dv(cpf, 11);

    if dv1 == cpf[9] && dv2 == cpf[10] {
        return Ok(());
    }

    Err(CPFError::Invalid)
}

fn main() -> Result<(), CPFError> {
    // Generated at https://www.4devs.com.br/gerador_de_cpf
    let cpf = "093.519.620-08";

    let cpf_vec = parse_cpf(cpf)?;
    check_digits(&cpf_vec)?;

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_parse_cpf() {
        let cpf = "093.519.620-08";
        let cpf_vec = parse_cpf(cpf).unwrap();

        assert_eq!(cpf_vec, vec![0, 9, 3, 5, 1, 9, 6, 2, 0, 0, 8]);
    }

    #[test]
    fn test_check_digits() {
        let cpf = "093.519.620-08";
        let cpf_vec = parse_cpf(cpf).unwrap();

        assert!(check_digits(&cpf_vec).is_ok());
    }

    #[test]
    fn test_wrong_size() {
        let cpf = "093.519.620-0";
        let cpf_vec = parse_cpf(cpf);

        assert_eq!(cpf_vec.err().unwrap(), CPFError::InvalidLength(10));

        let cpf = "093.519.620-081";
        let cpf_vec = parse_cpf(cpf);

        assert_eq!(cpf_vec.err().unwrap(), CPFError::InvalidLength(12));
    }

    #[test]
    fn test_invalid_digit() {
        let cpf = "093.519.620-0a";
        let cpf_vec = parse_cpf(cpf);

        assert_eq!(cpf_vec.err().unwrap(), CPFError::InvalidDigitAtIndex(10));
    }

    #[test]
    fn test_invalid_cpf() {
        let cpf = "093.519.620-09";
        let cpf_vec = parse_cpf(cpf).unwrap();

        assert_eq!(check_digits(&cpf_vec).err().unwrap(), CPFError::Invalid);
    }

    #[test]
    fn test_some_cpfs() {
        // Generated at https://www.4devs.com.br/gerador_de_cpf
        let cpfs = vec![
            "709.348.790-44",
            "332.919.370-07",
            "243.047.880-35",
            "569.237.650-48",
            "453.022.170-90",
            "127.844.030-50",
            "420.007.790-69",
            "236.283.980-02",
        ];

        for cpf in cpfs {
            let cpf_vec = parse_cpf(cpf).unwrap();
            assert!(check_digits(&cpf_vec).is_ok());
        }
    }
}