async_compression/codec/xz/
decoder.rs

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1use crate::{codec::Decode, util::PartialBuffer};
2
3use std::io::{Error, ErrorKind, Result};
4
5#[derive(Debug)]
6pub struct XzDecoder {
7    inner: crate::codec::Xz2Decoder,
8    skip_padding: Option<u8>,
9}
10
11impl XzDecoder {
12    pub fn new() -> Self {
13        Self {
14            inner: crate::codec::Xz2Decoder::new(u64::max_value()),
15            skip_padding: None,
16        }
17    }
18
19    pub fn with_memlimit(memlimit: u64) -> Self {
20        Self {
21            inner: crate::codec::Xz2Decoder::new(memlimit),
22            skip_padding: None,
23        }
24    }
25}
26
27impl Decode for XzDecoder {
28    fn reinit(&mut self) -> Result<()> {
29        self.skip_padding = Some(4);
30        self.inner.reinit()
31    }
32
33    fn decode(
34        &mut self,
35        input: &mut PartialBuffer<impl AsRef<[u8]>>,
36        output: &mut PartialBuffer<impl AsRef<[u8]> + AsMut<[u8]>>,
37    ) -> Result<bool> {
38        if let Some(ref mut count) = self.skip_padding {
39            while input.unwritten().first() == Some(&0) {
40                input.advance(1);
41                *count -= 1;
42                if *count == 0 {
43                    *count = 4;
44                }
45            }
46            if input.unwritten().is_empty() {
47                return Ok(true);
48            }
49            // If this is non-padding then it cannot start with null bytes, so it must be invalid
50            // padding
51            if *count != 4 {
52                return Err(Error::new(
53                    ErrorKind::InvalidData,
54                    "stream padding was not a multiple of 4 bytes",
55                ));
56            }
57            self.skip_padding = None;
58        }
59        self.inner.decode(input, output)
60    }
61
62    fn flush(
63        &mut self,
64        output: &mut PartialBuffer<impl AsRef<[u8]> + AsMut<[u8]>>,
65    ) -> Result<bool> {
66        if self.skip_padding.is_some() {
67            return Ok(true);
68        }
69        self.inner.flush(output)
70    }
71
72    fn finish(
73        &mut self,
74        output: &mut PartialBuffer<impl AsRef<[u8]> + AsMut<[u8]>>,
75    ) -> Result<bool> {
76        if self.skip_padding.is_some() {
77            return Ok(true);
78        }
79        self.inner.finish(output)
80    }
81}
async_compression/codec/xz/decoder.rs

async_compression/codec/xz/
decoder.rs
