use std::io::Read;
use std::ffi::CString;

fn main() {

    let test = "Hello this is my world!\0";
    let string = from_reader(test.as_bytes());
    println!("{:?}", string.unwrap());

    let test2 = "Hello this \0is my world!\0";
    let string2 = from_reader(test2.as_bytes());
    println!("{:?}", string2.unwrap());

    let test3 = "Hello this is my world!";
    let result = from_reader(test3.as_bytes());
    println!("{:?}", result);
}

fn from_reader(mut reader: impl Read) -> Result<CString, std::io::Error>
{
    let mut buffer = Vec::new();
    loop {
        // Read a single byte, same way as byteorder::read_u8 does it.
        // If the specific implementation of Read::read is buffered and inlined
        // I am quite sure this can be optimized well.
        let mut character: u8 = 0;
        let slice = std::slice::from_mut(&mut character);
        reader.read_exact(slice)?;

        // Check if a null character has been found, if so return the Vec as CString.
        if character == 0 {
            return Ok(unsafe { CString::from_vec_unchecked(buffer) });
        }

        // Push a new character.
        buffer.push(character);
    }
}