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use {ByteCount, Decode, Encode, Eos, ErrorKind, Result};
#[derive(Debug, Default)]
pub struct PaddingDecoder {
expected_byte: Option<u8>,
eos: bool,
}
impl PaddingDecoder {
pub fn new(expected_byte: Option<u8>) -> Self {
PaddingDecoder {
expected_byte,
eos: false,
}
}
pub fn expected_byte(&self) -> Option<u8> {
self.expected_byte
}
pub fn set_expected_byte(&mut self, b: Option<u8>) {
self.expected_byte = b;
}
}
impl Decode for PaddingDecoder {
type Item = ();
fn decode(&mut self, buf: &[u8], eos: Eos) -> Result<usize> {
if self.eos {
Ok(0)
} else if let Some(expected) = self.expected_byte {
for &padding_byte in buf {
track_assert_eq!(padding_byte, expected, ErrorKind::InvalidInput);
}
self.eos = eos.is_reached();
Ok(buf.len())
} else {
self.eos = eos.is_reached();
Ok(buf.len())
}
}
fn finish_decoding(&mut self) -> Result<Self::Item> {
track_assert!(self.eos, ErrorKind::IncompleteDecoding);
self.eos = false;
Ok(())
}
fn is_idle(&self) -> bool {
self.eos
}
fn requiring_bytes(&self) -> ByteCount {
if self.eos {
ByteCount::Finite(0)
} else {
ByteCount::Infinite
}
}
}
#[derive(Debug, Default)]
pub struct PaddingEncoder {
padding_byte: Option<u8>,
}
impl PaddingEncoder {
pub fn new() -> Self {
Self::default()
}
}
impl Encode for PaddingEncoder {
type Item = u8;
fn encode(&mut self, buf: &mut [u8], eos: Eos) -> Result<usize> {
if let Some(padding_byte) = self.padding_byte {
for b in &mut buf[..] {
*b = padding_byte
}
if eos.is_reached() {
self.padding_byte = None;
}
Ok(buf.len())
} else {
Ok(0)
}
}
fn start_encoding(&mut self, item: Self::Item) -> Result<()> {
track_assert!(self.is_idle(), ErrorKind::EncoderFull);
self.padding_byte = Some(item);
Ok(())
}
fn requiring_bytes(&self) -> ByteCount {
if self.is_idle() {
ByteCount::Finite(0)
} else {
ByteCount::Infinite
}
}
fn is_idle(&self) -> bool {
self.padding_byte.is_none()
}
}
#[cfg(test)]
mod test {
use super::*;
use io::IoDecodeExt;
use {Encode, EncodeExt, Eos};
#[test]
fn padding_encoder_works() {
let mut encoder = track_try_unwrap!(PaddingEncoder::with_item(3));
let mut buf = [0; 8];
track_try_unwrap!(encoder.encode(&mut buf[..], Eos::new(true)));
assert_eq!(buf, [3; 8]);
assert!(encoder.is_idle());
}
#[test]
fn padding_decoder_works() {
let mut decoder = PaddingDecoder::new(None);
assert!(decoder.decode_exact(&[0; 8][..]).is_ok());
let mut decoder = PaddingDecoder::new(Some(1));
assert!(decoder.decode_exact(&[1; 8][..]).is_ok());
assert!(decoder.decode_exact(&[0; 8][..]).is_err());
}
}