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use super::Status;
use miniz_oxide::{deflate, deflate::core::CompressorOxide, MZError, MZFlush, MZStatus};
use quick_error::quick_error;
use std::io;
quick_error! {
#[derive(Debug)]
pub enum Error {
Compression {
display("The compression failed due to an unknown error")
}
ZLibNeedDict {
display("Need dictionary")
}
Error(err: MZError) {
display("A compression error occurred: {:?}", err)
}
}
}
pub struct Deflate {
inner: CompressorOxide,
total_in: u64,
total_out: u64,
}
impl Default for Deflate {
fn default() -> Self {
Deflate {
inner: CompressorOxide::default(),
total_in: 0,
total_out: 0,
}
}
}
impl Deflate {
fn compress(&mut self, input: &[u8], output: &mut [u8], flush: MZFlush) -> Result<Status, Error> {
let res = deflate::stream::deflate(&mut self.inner, input, output, flush);
self.total_in += res.bytes_consumed as u64;
self.total_out += res.bytes_written as u64;
match res.status {
Ok(status) => match status {
MZStatus::Ok => Ok(Status::Ok),
MZStatus::StreamEnd => Ok(Status::StreamEnd),
MZStatus::NeedDict => Err(Error::ZLibNeedDict),
},
Err(status) => match status {
MZError::Buf => Ok(Status::BufError),
_ => Err(Error::Error(status)),
},
}
}
}
const BUF_SIZE: usize = 4096 * 8;
pub struct DeflateWriter<W> {
compressor: Deflate,
inner: W,
buf: [u8; BUF_SIZE],
}
impl<W> DeflateWriter<W>
where
W: io::Write,
{
pub fn new(inner: W) -> DeflateWriter<W> {
DeflateWriter {
compressor: Default::default(),
inner,
buf: [0; BUF_SIZE],
}
}
pub fn reset(&mut self) {
self.compressor.inner.reset();
}
pub fn into_inner(self) -> W {
self.inner
}
fn write_inner(&mut self, mut buf: &[u8], flush: MZFlush) -> io::Result<usize> {
let total_in_when_start = self.compressor.total_in;
loop {
let last_total_in = self.compressor.total_in;
let last_total_out = self.compressor.total_out;
let status = self
.compressor
.compress(buf, &mut self.buf, flush)
.map_err(|err| io::Error::new(io::ErrorKind::Other, err))?;
let written = self.compressor.total_out - last_total_out;
if written > 0 {
self.inner.write_all(&self.buf[..written as usize])?;
}
match status {
Status::StreamEnd => return Ok((self.compressor.total_in - total_in_when_start) as usize),
Status::Ok | Status::BufError => {
let consumed = self.compressor.total_in - last_total_in;
buf = &buf[consumed as usize..];
if self.compressor.total_out > last_total_out {
continue;
}
if self.compressor.total_in > last_total_in {
continue;
}
return Ok((self.compressor.total_in - total_in_when_start) as usize);
}
}
}
}
}
impl<W: io::Write> io::Write for DeflateWriter<W> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.write_inner(buf, MZFlush::None)
}
fn flush(&mut self) -> io::Result<()> {
self.write_inner(&[], MZFlush::Finish).map(|_| ())
}
}
#[cfg(test)]
mod tests;