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use lzma_rs::decompress::{Options, Stream, UnpackedSize};
use std::collections::VecDeque;
use std::io::{copy, Error, Read, Result, Write};
const COMPRESSED_BYTES_TO_BUFFER: usize = 4096;
const OPTIONS: Options = Options {
unpacked_size: UnpackedSize::ReadFromHeader,
memlimit: None,
allow_incomplete: true,
};
#[derive(Debug)]
pub struct LzmaDecoder<R> {
compressed_reader: R,
stream: Stream<VecDeque<u8>>,
}
impl<R: Read> LzmaDecoder<R> {
pub fn new(inner: R) -> Self {
LzmaDecoder {
compressed_reader: inner,
stream: Stream::new_with_options(&OPTIONS, VecDeque::new()),
}
}
pub fn finish(mut self) -> Result<VecDeque<u8>> {
copy(&mut self.compressed_reader, &mut self.stream)?;
self.stream.finish().map_err(Error::from)
}
}
impl<R: Read> Read for LzmaDecoder<R> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
let mut bytes_read = self.stream.get_output_mut().unwrap().read(buf)?;
while bytes_read < buf.len() {
let mut next_compressed = [0u8; COMPRESSED_BYTES_TO_BUFFER];
let compressed_bytes_read = self.compressed_reader.read(&mut next_compressed)?;
if compressed_bytes_read == 0 {
break;
}
self.stream
.write_all(&next_compressed[..compressed_bytes_read])?;
bytes_read += self
.stream
.get_output_mut()
.unwrap()
.read(&mut buf[bytes_read..])?;
}
Ok(bytes_read)
}
}