use std::io::{Read, Result};

pub trait ReadExt {
    fn read_u16_be(&mut self) -> Result<u16>;
    fn read_u32_be(&mut self) -> Result<u32>;
    fn read_u64_be(&mut self) -> Result<u64>;
    fn read_u128_be(&mut self) -> Result<u128>;
    fn read_cstr(&mut self) -> Result<String>;
}
impl<T: Read> ReadExt for T {
    fn read_u16_be(&mut self) -> Result<u16> {
        let mut buf = [0; 2];
        self.read_exact(&mut buf)?;
        Ok(u16::from_be_bytes(buf))
    }
    fn read_u32_be(&mut self) -> Result<u32> {
        let mut buf = [0; 4];
        self.read_exact(&mut buf)?;
        Ok(u32::from_be_bytes(buf))
    }
    fn read_u64_be(&mut self) -> Result<u64> {
        let mut buf = [0; 8];
        self.read_exact(&mut buf)?;
        Ok(u64::from_be_bytes(buf))
    }
    fn read_u128_be(&mut self) -> Result<u128> {
        let mut buf = [0; 16];
        self.read_exact(&mut buf)?;
        Ok(u128::from_be_bytes(buf))
    }
    fn read_cstr(&mut self) -> Result<String> {
        let mut buf = [0; 1];
        let mut s = Vec::new();
        loop {
            self.read_exact(&mut buf)?;
            if buf[0] == 0 {
                break;
            }
            s.push(buf[0]);
        }
        Ok(String::from_utf8_lossy(&s).to_string())
    }
}