ds323x-rs/src/ds323x/mod.rs

mod configuration;
mod status;
mod alarms;
pub use self::alarms::{ DateAlarm1, Alarm1Matching };
mod datetime;
pub use self::datetime::{ Hours, DateTime };
use super::{ BitFlags, Error };

// Transforms a decimal number to packed BCD format
fn decimal_to_packed_bcd(dec: u8) -> u8 {
    ((dec / 10) << 4) | (dec % 10)
}

// Transforms a number in packed BCD format to decimal
fn packed_bcd_to_decimal(bcd: u8) -> u8 {
    (bcd >> 4) * 10 + (bcd & 0xF)
}

fn hours_to_register<E>(hours: &Hours) -> Result<u8, Error<E>> {
    match *hours {
        Hours::H24(h) if h > 23 => Err(Error::InvalidInputData),
        Hours::H24(h) => Ok(decimal_to_packed_bcd(h)),
        Hours::AM(h) if h < 1 || h > 12 => Err(Error::InvalidInputData),
        Hours::AM(h) =>  Ok(BitFlags::H24_H12 | decimal_to_packed_bcd(h)),
        Hours::PM(h) if h < 1 || h > 12 => Err(Error::InvalidInputData),
        Hours::PM(h) =>  Ok(BitFlags::H24_H12 | BitFlags::AM_PM | decimal_to_packed_bcd(h)),
    }
}


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

    #[test]
    fn can_convert_packed_bcd_to_decimal() {
        assert_eq!(0,  packed_bcd_to_decimal(0b0000_0000));
        assert_eq!(1,  packed_bcd_to_decimal(0b0000_0001));
        assert_eq!(9,  packed_bcd_to_decimal(0b0000_1001));
        assert_eq!(10, packed_bcd_to_decimal(0b0001_0000));
        assert_eq!(11, packed_bcd_to_decimal(0b0001_0001));
        assert_eq!(19, packed_bcd_to_decimal(0b0001_1001));
        assert_eq!(20, packed_bcd_to_decimal(0b0010_0000));
        assert_eq!(21, packed_bcd_to_decimal(0b0010_0001));
        assert_eq!(59, packed_bcd_to_decimal(0b0101_1001));
    }

    #[test]
    fn can_convert_decimal_to_packed_bcd() {
        assert_eq!(0b0000_0000, decimal_to_packed_bcd( 0));
        assert_eq!(0b0000_0001, decimal_to_packed_bcd( 1));
        assert_eq!(0b0000_1001, decimal_to_packed_bcd( 9));
        assert_eq!(0b0001_0000, decimal_to_packed_bcd(10));
        assert_eq!(0b0001_0001, decimal_to_packed_bcd(11));
        assert_eq!(0b0001_1001, decimal_to_packed_bcd(19));
        assert_eq!(0b0010_0000, decimal_to_packed_bcd(20));
        assert_eq!(0b0010_0001, decimal_to_packed_bcd(21));
        assert_eq!(0b0101_1001, decimal_to_packed_bcd(59));
    }
}