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use std::io;
use std::io::prelude::*;
use std::mem;
use crate::{Compress, Decompress, DecompressError, FlushCompress, FlushDecompress, Status};
#[derive(Debug)]
pub struct Writer<W: Write, D: Ops> {
obj: Option<W>,
pub data: D,
buf: Vec<u8>,
}
pub trait Ops {
type Flush: Flush;
fn total_in(&self) -> u64;
fn total_out(&self) -> u64;
fn run(
&mut self,
input: &[u8],
output: &mut [u8],
flush: Self::Flush,
) -> Result<Status, DecompressError>;
fn run_vec(
&mut self,
input: &[u8],
output: &mut Vec<u8>,
flush: Self::Flush,
) -> Result<Status, DecompressError>;
}
impl Ops for Compress {
type Flush = FlushCompress;
fn total_in(&self) -> u64 {
self.total_in()
}
fn total_out(&self) -> u64 {
self.total_out()
}
fn run(
&mut self,
input: &[u8],
output: &mut [u8],
flush: FlushCompress,
) -> Result<Status, DecompressError> {
Ok(self.compress(input, output, flush).unwrap())
}
fn run_vec(
&mut self,
input: &[u8],
output: &mut Vec<u8>,
flush: FlushCompress,
) -> Result<Status, DecompressError> {
Ok(self.compress_vec(input, output, flush).unwrap())
}
}
impl Ops for Decompress {
type Flush = FlushDecompress;
fn total_in(&self) -> u64 {
self.total_in()
}
fn total_out(&self) -> u64 {
self.total_out()
}
fn run(
&mut self,
input: &[u8],
output: &mut [u8],
flush: FlushDecompress,
) -> Result<Status, DecompressError> {
self.decompress(input, output, flush)
}
fn run_vec(
&mut self,
input: &[u8],
output: &mut Vec<u8>,
flush: FlushDecompress,
) -> Result<Status, DecompressError> {
self.decompress_vec(input, output, flush)
}
}
pub trait Flush {
fn none() -> Self;
fn sync() -> Self;
fn finish() -> Self;
}
impl Flush for FlushCompress {
fn none() -> Self {
FlushCompress::None
}
fn sync() -> Self {
FlushCompress::Sync
}
fn finish() -> Self {
FlushCompress::Finish
}
}
impl Flush for FlushDecompress {
fn none() -> Self {
FlushDecompress::None
}
fn sync() -> Self {
FlushDecompress::Sync
}
fn finish() -> Self {
FlushDecompress::Finish
}
}
pub fn read<R, D>(obj: &mut R, data: &mut D, dst: &mut [u8]) -> io::Result<usize>
where
R: BufRead,
D: Ops,
{
loop {
let (read, consumed, ret, eof);
{
let input = obj.fill_buf()?;
eof = input.is_empty();
let before_out = data.total_out();
let before_in = data.total_in();
let flush = if eof {
D::Flush::finish()
} else {
D::Flush::none()
};
ret = data.run(input, dst, flush);
read = (data.total_out() - before_out) as usize;
consumed = (data.total_in() - before_in) as usize;
}
obj.consume(consumed);
match ret {
// If we haven't ready any data and we haven't hit EOF yet,
// then we need to keep asking for more data because if we
// return that 0 bytes of data have been read then it will
// be interpreted as EOF.
Ok(Status::Ok | Status::BufError) if read == 0 && !eof && !dst.is_empty() => continue,
Ok(Status::Ok | Status::BufError | Status::StreamEnd) => return Ok(read),
Err(..) => {
return Err(io::Error::new(
io::ErrorKind::InvalidInput,
"corrupt deflate stream",
))
}
}
}
}
impl<W: Write, D: Ops> Writer<W, D> {
pub fn new(w: W, d: D) -> Writer<W, D> {
Writer {
obj: Some(w),
data: d,
buf: Vec::with_capacity(32 * 1024),
}
}
pub fn finish(&mut self) -> io::Result<()> {
loop {
self.dump()?;
let before = self.data.total_out();
self.data.run_vec(&[], &mut self.buf, D::Flush::finish())?;
if before == self.data.total_out() {
return Ok(());
}
}
}
pub fn replace(&mut self, w: W) -> W {
self.buf.truncate(0);
mem::replace(self.get_mut(), w)
}
pub fn get_ref(&self) -> &W {
self.obj.as_ref().unwrap()
}
pub fn get_mut(&mut self) -> &mut W {
self.obj.as_mut().unwrap()
}
// Note that this should only be called if the outer object is just about
// to be consumed!
//
// (e.g. an implementation of `into_inner`)
pub fn take_inner(&mut self) -> W {
self.obj.take().unwrap()
}
pub fn is_present(&self) -> bool {
self.obj.is_some()
}
// Returns total written bytes and status of underlying codec
pub(crate) fn write_with_status(&mut self, buf: &[u8]) -> io::Result<(usize, Status)> {
// miniz isn't guaranteed to actually write any of the buffer provided,
// it may be in a flushing mode where it's just giving us data before
// we're actually giving it any data. We don't want to spuriously return
// `Ok(0)` when possible as it will cause calls to write_all() to fail.
// As a result we execute this in a loop to ensure that we try our
// darndest to write the data.
loop {
self.dump()?;
let before_in = self.data.total_in();
let ret = self.data.run_vec(buf, &mut self.buf, D::Flush::none());
let written = (self.data.total_in() - before_in) as usize;
let is_stream_end = matches!(ret, Ok(Status::StreamEnd));
if !buf.is_empty() && written == 0 && ret.is_ok() && !is_stream_end {
continue;
}
return match ret {
Ok(st) => match st {
Status::Ok | Status::BufError | Status::StreamEnd => Ok((written, st)),
},
Err(..) => Err(io::Error::new(
io::ErrorKind::InvalidInput,
"corrupt deflate stream",
)),
};
}
}
fn dump(&mut self) -> io::Result<()> {
// TODO: should manage this buffer not with `drain` but probably more of
// a deque-like strategy.
while !self.buf.is_empty() {
let n = self.obj.as_mut().unwrap().write(&self.buf)?;
if n == 0 {
return Err(io::ErrorKind::WriteZero.into());
}
self.buf.drain(..n);
}
Ok(())
}
}
impl<W: Write, D: Ops> Write for Writer<W, D> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.write_with_status(buf).map(|res| res.0)
}
fn flush(&mut self) -> io::Result<()> {
self.data
.run_vec(&[], &mut self.buf, D::Flush::sync())
.unwrap();
// Unfortunately miniz doesn't actually tell us when we're done with
// pulling out all the data from the internal stream. To remedy this we
// have to continually ask the stream for more memory until it doesn't
// give us a chunk of memory the same size as our own internal buffer,
// at which point we assume it's reached the end.
loop {
self.dump()?;
let before = self.data.total_out();
self.data
.run_vec(&[], &mut self.buf, D::Flush::none())
.unwrap();
if before == self.data.total_out() {
break;
}
}
self.obj.as_mut().unwrap().flush()
}
}
impl<W: Write, D: Ops> Drop for Writer<W, D> {
fn drop(&mut self) {
if self.obj.is_some() {
let _ = self.finish();
}
}
}