lzss 0.8.2

A LZSS en-/decompressor (lossless data compression, no_std capable, in pure Rust)
Documentation 
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/* This file is based on the LZSS encoder-decoder  (c) Haruhiko Okumura */

use crate::bits::BitReader;
use crate::generic::Lzss;
use crate::read_write::{Read, Write};
use crate::LzssError;

impl<
    const EI: usize,
    const EJ: usize,
    const C: u8,
    const UNSAFE_N: usize,
    const UNSAFE_N2: usize,
  > Lzss<EI, EJ, C, UNSAFE_N, UNSAFE_N2>
{
  #[inline(always)]
  pub(crate) fn decompress_internal<R: Read, W: Write>(
    reader: &mut R,
    writer: &mut W,
    buffer: &mut [u8; UNSAFE_N],
  ) -> Result<(), LzssError<R::Error, W::Error>> {
    let mut bit_reader = BitReader::new(reader);

    let mut r = Self::N - Self::F;
    loop {
      if let Some(inp) = bit_reader.read_bits(9).map_err(LzssError::ReadError)? {
        if (inp & 0x100) != 0 {
          writer.write(inp as u8).map_err(LzssError::WriteError)?;
          *unsafe { buffer.get_unchecked_mut(r) } = inp as u8;
          r = (r + 1) & (Self::N - 1);
        } else if let Some(inp2) = bit_reader
          .read_bits(EI + EJ - 8)
          .map_err(LzssError::ReadError)?
        {
          let inp = (inp << (EI + EJ - 8)) | inp2;
          let i = (inp >> EJ) as usize;
          let j = (inp & ((1 << EJ) - 1)) as usize;
          for k in 0..=j + Self::P {
            let b = *unsafe { buffer.get_unchecked((i + k) & (Self::N - 1)) };
            writer.write(b).map_err(LzssError::WriteError)?;
            *unsafe { buffer.get_unchecked_mut(r) } = b;
            r = (r + 1) & (Self::N - 1);
          }
        } else {
          return Ok(());
        }
      } else {
        return Ok(());
      }
    }
  }
}