use {
    crate::Error,
    std::io::{Read, Write},
};

/// Represents the major and minor numbers of a Unix special Device node
#[derive(Debug)]
pub struct Special {
    pub major: u32,
    pub minor: u32,
}

impl Special {
    pub fn read<T: Read>(reader: &mut T) -> Result<Self, Error> {
        let mut buf = [0; 8];
        reader.read_exact(&mut buf)?;
        let major: [u8; 4] = buf[..4].try_into()?;
        let major = u32::from_le_bytes(major);
        let minor: [u8; 4] = buf[4..].try_into()?;
        let minor = u32::from_le_bytes(minor);
        Ok(Self { major, minor })
    }

    pub fn write<T: Write>(&self, writer: &mut T) -> Result<(), Error> {
        writer.write_all(&self.major.to_le_bytes())?;
        writer.write_all(&self.minor.to_le_bytes())?;
        Ok(())
    }

    pub(super) fn from_rdev(rdev: u32) -> Self {
        Self {
            major: rdev >> 8,
            minor: rdev & 0xff,
        }
    }
}