io_mem_str.rs

use  std::io::{MemReader, MemWriter,IoResult, IoError, InvalidInput};

trait StringReader {
    fn read_le_string(&mut self) -> IoResult<String>;
}

impl StringReader for  MemReader {
    fn read_le_string(&mut self) -> IoResult<String> {
        let str_b_len = self.read_le_u16();
        match str_b_len {
            Ok(l)       => {
                let vec_str_b = self.read_exact(l as uint);
                match vec_str_b {
                    Ok(v)       => {
                        let str_b = String::from_utf8(v);
                        match str_b {
                            Ok(s)   => Ok(s),
                            Err(_)  => Err(IoError { kind: InvalidInput,desc: "can't build the string buffer from vector", detail: None })
                        }
                    },
                    Err(err)    => Err(err)
                }
            },
            Err(_)      => Err(IoError { kind: InvalidInput,desc: "invalid len", detail: None })
        }
    }
}

trait StringWriter {
    fn write_le_string(&mut self, s: String) -> IoResult<()>;
}

impl StringWriter for MemWriter {
    fn write_le_string(&mut self, s: String) -> IoResult<()> {
        match self.write_le_u16(s.len() as u16) {
            Ok(_) => self.write_str(s.as_slice()),
            Err(e) => Err(e)
        }
        
    }
}