data-stream 0.3.1

use crate::{FromStream, ToStream, collections::SizeSettings};

use std::io::{Error, ErrorKind, Read, Result, Write};

impl<S> ToStream<S> for char {
    fn to_stream<W: Write>(&self, stream: &mut W) -> Result<()> {
        let mut buf = [0u8; 4];
        let encoded = self.encode_utf8(&mut buf);
        let len = encoded.len() as u8;
        stream.write_all(&[len])?;
        stream.write_all(&buf[..len as usize])
    }
}

impl<S> FromStream<S> for char {
    fn from_stream<R: Read>(stream: &mut R) -> Result<Self> {
        let mut len_buf = [0u8; 1];
        stream.read_exact(&mut len_buf)?;
        let len = len_buf[0] as usize;

        if len == 0 || len > 4 {
            return Err(Error::new(
                ErrorKind::InvalidData,
                "Invalid UTF-8 char length",
            ));
        }

        let mut buf = [0u8; 4];
        stream.read_exact(&mut buf[..len])?;

        std::str::from_utf8(&buf[..len])
            .ok()
            .and_then(|s| s.chars().next())
            .ok_or_else(|| Error::new(ErrorKind::InvalidData, "Invalid UTF-8 char"))
    }
}

impl<S: SizeSettings> ToStream<S> for String {
    fn to_stream<W: Write>(&self, stream: &mut W) -> Result<()> {
        let bytes = self.as_bytes();
        S::size_to_stream(bytes.len(), stream)?;
        stream.write_all(bytes)
    }
}

impl<S: SizeSettings> FromStream<S> for String {
    fn from_stream<R: Read>(stream: &mut R) -> Result<Self> {
        let len = S::size_from_stream(stream)?;
        let mut buf = vec![0u8; len];
        stream.read_exact(&mut buf)?;
        Self::from_utf8(buf).map_err(|e| Error::new(ErrorKind::InvalidData, e))
    }
}

impl<S: SizeSettings> ToStream<S> for str {
    fn to_stream<W: Write>(&self, stream: &mut W) -> Result<()> {
        let bytes = self.as_bytes();
        S::size_to_stream(bytes.len(), stream)?;
        stream.write_all(bytes)
    }
}