Adding upstream version 0.70.1+ds1.upstream/0.70.1+ds1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 2146 insertions, 0 deletions

diff --git a/vendor/flate2/src/gz/bufread.rs b/vendor/flate2/src/gz/bufread.rs
new file mode 100644
index 0000000..679b4a7
--- /dev/null
+++ b/vendor/flate2/src/gz/bufread.rs
@@ -0,0 +1,483 @@
+use std::cmp;
+use std::io;
+use std::io::prelude::*;
+use std::mem;
+
+use super::{corrupt, read_into, GzBuilder, GzHeader, GzHeaderParser};
+use crate::crc::CrcReader;
+use crate::deflate;
+use crate::Compression;
+
+fn copy(into: &mut [u8], from: &[u8], pos: &mut usize) -> usize {
+    let min = cmp::min(into.len(), from.len() - *pos);
+    for (slot, val) in into.iter_mut().zip(from[*pos..*pos + min].iter()) {
+        *slot = *val;
+    }
+    *pos += min;
+    min
+}
+
+/// A gzip streaming encoder
+///
+/// This structure implements a [`Read`] interface. When read from, it reads
+/// uncompressed data from the underlying [`BufRead`] and provides the compressed data.
+///
+/// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
+/// [`BufRead`]: https://doc.rust-lang.org/std/io/trait.BufRead.html
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io;
+/// use flate2::Compression;
+/// use flate2::bufread::GzEncoder;
+/// use std::fs::File;
+/// use std::io::BufReader;
+///
+/// // Opens sample file, compresses the contents and returns a Vector or error
+/// // File wrapped in a BufReader implements BufRead
+///
+/// fn open_hello_world() -> io::Result<Vec<u8>> {
+///     let f = File::open("examples/hello_world.txt")?;
+///     let b = BufReader::new(f);
+///     let mut gz = GzEncoder::new(b, Compression::fast());
+///     let mut buffer = Vec::new();
+///     gz.read_to_end(&mut buffer)?;
+///     Ok(buffer)
+/// }
+/// ```
+#[derive(Debug)]
+pub struct GzEncoder<R> {
+    inner: deflate::bufread::DeflateEncoder<CrcReader<R>>,
+    header: Vec<u8>,
+    pos: usize,
+    eof: bool,
+}
+
+pub fn gz_encoder<R: BufRead>(header: Vec<u8>, r: R, lvl: Compression) -> GzEncoder<R> {
+    let crc = CrcReader::new(r);
+    GzEncoder {
+        inner: deflate::bufread::DeflateEncoder::new(crc, lvl),
+        header,
+        pos: 0,
+        eof: false,
+    }
+}
+
+impl<R: BufRead> GzEncoder<R> {
+    /// Creates a new encoder which will use the given compression level.
+    ///
+    /// The encoder is not configured specially for the emitted header. For
+    /// header configuration, see the `GzBuilder` type.
+    ///
+    /// The data read from the stream `r` will be compressed and available
+    /// through the returned reader.
+    pub fn new(r: R, level: Compression) -> GzEncoder<R> {
+        GzBuilder::new().buf_read(r, level)
+    }
+
+    fn read_footer(&mut self, into: &mut [u8]) -> io::Result<usize> {
+        if self.pos == 8 {
+            return Ok(0);
+        }
+        let crc = self.inner.get_ref().crc();
+        let ref arr = [
+            (crc.sum() >> 0) as u8,
+            (crc.sum() >> 8) as u8,
+            (crc.sum() >> 16) as u8,
+            (crc.sum() >> 24) as u8,
+            (crc.amount() >> 0) as u8,
+            (crc.amount() >> 8) as u8,
+            (crc.amount() >> 16) as u8,
+            (crc.amount() >> 24) as u8,
+        ];
+        Ok(copy(into, arr, &mut self.pos))
+    }
+}
+
+impl<R> GzEncoder<R> {
+    /// Acquires a reference to the underlying reader.
+    pub fn get_ref(&self) -> &R {
+        self.inner.get_ref().get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying reader.
+    ///
+    /// Note that mutation of the reader may result in surprising results if
+    /// this encoder is continued to be used.
+    pub fn get_mut(&mut self) -> &mut R {
+        self.inner.get_mut().get_mut()
+    }
+
+    /// Returns the underlying stream, consuming this encoder
+    pub fn into_inner(self) -> R {
+        self.inner.into_inner().into_inner()
+    }
+}
+
+#[inline]
+fn finish(buf: &[u8; 8]) -> (u32, u32) {
+    let crc = ((buf[0] as u32) << 0)
+        | ((buf[1] as u32) << 8)
+        | ((buf[2] as u32) << 16)
+        | ((buf[3] as u32) << 24);
+    let amt = ((buf[4] as u32) << 0)
+        | ((buf[5] as u32) << 8)
+        | ((buf[6] as u32) << 16)
+        | ((buf[7] as u32) << 24);
+    (crc, amt)
+}
+
+impl<R: BufRead> Read for GzEncoder<R> {
+    fn read(&mut self, mut into: &mut [u8]) -> io::Result<usize> {
+        let mut amt = 0;
+        if self.eof {
+            return self.read_footer(into);
+        } else if self.pos < self.header.len() {
+            amt += copy(into, &self.header, &mut self.pos);
+            if amt == into.len() {
+                return Ok(amt);
+            }
+            let tmp = into;
+            into = &mut tmp[amt..];
+        }
+        match self.inner.read(into)? {
+            0 => {
+                self.eof = true;
+                self.pos = 0;
+                self.read_footer(into)
+            }
+            n => Ok(amt + n),
+        }
+    }
+}
+
+impl<R: BufRead + Write> Write for GzEncoder<R> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.get_mut().write(buf)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.get_mut().flush()
+    }
+}
+
+/// A decoder for a single member of a [gzip file].
+///
+/// This structure implements a [`Read`] interface. When read from, it reads
+/// compressed data from the underlying [`BufRead`] and provides the uncompressed data.
+///
+/// After reading a single member of the gzip data this reader will return
+/// Ok(0) even if there are more bytes available in the underlying reader.
+/// If you need the following bytes, call `into_inner()` after Ok(0) to
+/// recover the underlying reader.
+///
+/// To handle gzip files that may have multiple members, see [`MultiGzDecoder`]
+/// or read more
+/// [in the introduction](../index.html#about-multi-member-gzip-files).
+///
+/// [gzip file]: https://www.rfc-editor.org/rfc/rfc1952#page-5
+/// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
+/// [`BufRead`]: https://doc.rust-lang.org/std/io/trait.BufRead.html
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io;
+/// # use flate2::Compression;
+/// # use flate2::write::GzEncoder;
+/// use flate2::bufread::GzDecoder;
+///
+/// # fn main() {
+/// #   let mut e = GzEncoder::new(Vec::new(), Compression::default());
+/// #   e.write_all(b"Hello World").unwrap();
+/// #   let bytes = e.finish().unwrap();
+/// #   println!("{}", decode_reader(bytes).unwrap());
+/// # }
+/// #
+/// // Uncompresses a Gz Encoded vector of bytes and returns a string or error
+/// // Here &[u8] implements BufRead
+///
+/// fn decode_reader(bytes: Vec<u8>) -> io::Result<String> {
+///    let mut gz = GzDecoder::new(&bytes[..]);
+///    let mut s = String::new();
+///    gz.read_to_string(&mut s)?;
+///    Ok(s)
+/// }
+/// ```
+#[derive(Debug)]
+pub struct GzDecoder<R> {
+    state: GzState,
+    reader: CrcReader<deflate::bufread::DeflateDecoder<R>>,
+    multi: bool,
+}
+
+#[derive(Debug)]
+enum GzState {
+    Header(GzHeaderParser),
+    Body(GzHeader),
+    Finished(GzHeader, usize, [u8; 8]),
+    Err(io::Error),
+    End(Option<GzHeader>),
+}
+
+impl<R: BufRead> GzDecoder<R> {
+    /// Creates a new decoder from the given reader, immediately parsing the
+    /// gzip header.
+    pub fn new(mut r: R) -> GzDecoder<R> {
+        let mut header_parser = GzHeaderParser::new();
+
+        let state = match header_parser.parse(&mut r) {
+            Ok(_) => GzState::Body(GzHeader::from(header_parser)),
+            Err(ref err) if io::ErrorKind::WouldBlock == err.kind() => {
+                GzState::Header(header_parser)
+            }
+            Err(err) => GzState::Err(err),
+        };
+
+        GzDecoder {
+            state,
+            reader: CrcReader::new(deflate::bufread::DeflateDecoder::new(r)),
+            multi: false,
+        }
+    }
+
+    fn multi(mut self, flag: bool) -> GzDecoder<R> {
+        self.multi = flag;
+        self
+    }
+}
+
+impl<R> GzDecoder<R> {
+    /// Returns the header associated with this stream, if it was valid
+    pub fn header(&self) -> Option<&GzHeader> {
+        match &self.state {
+            GzState::Body(header) | GzState::Finished(header, _, _) => Some(header),
+            GzState::End(header) => header.as_ref(),
+            _ => None,
+        }
+    }
+
+    /// Acquires a reference to the underlying reader.
+    pub fn get_ref(&self) -> &R {
+        self.reader.get_ref().get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying stream.
+    ///
+    /// Note that mutation of the stream may result in surprising results if
+    /// this decoder is continued to be used.
+    pub fn get_mut(&mut self) -> &mut R {
+        self.reader.get_mut().get_mut()
+    }
+
+    /// Consumes this decoder, returning the underlying reader.
+    pub fn into_inner(self) -> R {
+        self.reader.into_inner().into_inner()
+    }
+}
+
+impl<R: BufRead> Read for GzDecoder<R> {
+    fn read(&mut self, into: &mut [u8]) -> io::Result<usize> {
+        loop {
+            match &mut self.state {
+                GzState::Header(parser) => {
+                    parser.parse(self.reader.get_mut().get_mut())?;
+                    self.state = GzState::Body(GzHeader::from(mem::take(parser)));
+                }
+                GzState::Body(header) => {
+                    if into.is_empty() {
+                        return Ok(0);
+                    }
+                    match self.reader.read(into)? {
+                        0 => {
+                            self.state = GzState::Finished(mem::take(header), 0, [0; 8]);
+                        }
+                        n => {
+                            return Ok(n);
+                        }
+                    }
+                }
+                GzState::Finished(header, pos, buf) => {
+                    if *pos < buf.len() {
+                        *pos += read_into(self.reader.get_mut().get_mut(), &mut buf[*pos..])?;
+                    } else {
+                        let (crc, amt) = finish(&buf);
+
+                        if crc != self.reader.crc().sum() || amt != self.reader.crc().amount() {
+                            self.state = GzState::End(Some(mem::take(header)));
+                            return Err(corrupt());
+                        } else if self.multi {
+                            let is_eof = self
+                                .reader
+                                .get_mut()
+                                .get_mut()
+                                .fill_buf()
+                                .map(|buf| buf.is_empty())?;
+
+                            if is_eof {
+                                self.state = GzState::End(Some(mem::take(header)));
+                            } else {
+                                self.reader.reset();
+                                self.reader.get_mut().reset_data();
+                                self.state = GzState::Header(GzHeaderParser::new())
+                            }
+                        } else {
+                            self.state = GzState::End(Some(mem::take(header)));
+                        }
+                    }
+                }
+                GzState::Err(err) => {
+                    let result = Err(mem::replace(err, io::ErrorKind::Other.into()));
+                    self.state = GzState::End(None);
+                    return result;
+                }
+                GzState::End(_) => return Ok(0),
+            }
+        }
+    }
+}
+
+impl<R: BufRead + Write> Write for GzDecoder<R> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.get_mut().write(buf)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.get_mut().flush()
+    }
+}
+
+/// A gzip streaming decoder that decodes a [gzip file] that may have multiple members.
+///
+/// This structure implements a [`Read`] interface. When read from, it reads
+/// compressed data from the underlying [`BufRead`] and provides the uncompressed data.
+///
+/// A gzip file consists of a series of *members* concatenated one after another.
+/// MultiGzDecoder decodes all members from the data and only returns Ok(0) when the
+/// underlying reader does. For a file, this reads to the end of the file.
+///
+/// To handle members seperately, see [GzDecoder] or read more
+/// [in the introduction](../index.html#about-multi-member-gzip-files).
+///
+/// [gzip file]: https://www.rfc-editor.org/rfc/rfc1952#page-5
+/// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
+/// [`BufRead`]: https://doc.rust-lang.org/std/io/trait.BufRead.html
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io;
+/// # use flate2::Compression;
+/// # use flate2::write::GzEncoder;
+/// use flate2::bufread::MultiGzDecoder;
+///
+/// # fn main() {
+/// #   let mut e = GzEncoder::new(Vec::new(), Compression::default());
+/// #   e.write_all(b"Hello World").unwrap();
+/// #   let bytes = e.finish().unwrap();
+/// #   println!("{}", decode_reader(bytes).unwrap());
+/// # }
+/// #
+/// // Uncompresses a Gz Encoded vector of bytes and returns a string or error
+/// // Here &[u8] implements BufRead
+///
+/// fn decode_reader(bytes: Vec<u8>) -> io::Result<String> {
+///    let mut gz = MultiGzDecoder::new(&bytes[..]);
+///    let mut s = String::new();
+///    gz.read_to_string(&mut s)?;
+///    Ok(s)
+/// }
+/// ```
+#[derive(Debug)]
+pub struct MultiGzDecoder<R>(GzDecoder<R>);
+
+impl<R: BufRead> MultiGzDecoder<R> {
+    /// Creates a new decoder from the given reader, immediately parsing the
+    /// (first) gzip header. If the gzip stream contains multiple members all will
+    /// be decoded.
+    pub fn new(r: R) -> MultiGzDecoder<R> {
+        MultiGzDecoder(GzDecoder::new(r).multi(true))
+    }
+}
+
+impl<R> MultiGzDecoder<R> {
+    /// Returns the current header associated with this stream, if it's valid
+    pub fn header(&self) -> Option<&GzHeader> {
+        self.0.header()
+    }
+
+    /// Acquires a reference to the underlying reader.
+    pub fn get_ref(&self) -> &R {
+        self.0.get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying stream.
+    ///
+    /// Note that mutation of the stream may result in surprising results if
+    /// this decoder is continued to be used.
+    pub fn get_mut(&mut self) -> &mut R {
+        self.0.get_mut()
+    }
+
+    /// Consumes this decoder, returning the underlying reader.
+    pub fn into_inner(self) -> R {
+        self.0.into_inner()
+    }
+}
+
+impl<R: BufRead> Read for MultiGzDecoder<R> {
+    fn read(&mut self, into: &mut [u8]) -> io::Result<usize> {
+        self.0.read(into)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::bufread::GzDecoder;
+    use crate::gz::write;
+    use crate::Compression;
+    use std::io::{Read, Write};
+
+    // GzDecoder consumes one gzip member and then returns 0 for subsequent reads, allowing any
+    // additional data to be consumed by the caller.
+    #[test]
+    fn decode_extra_data() {
+        let expected = "Hello World";
+
+        let compressed = {
+            let mut e = write::GzEncoder::new(Vec::new(), Compression::default());
+            e.write(expected.as_ref()).unwrap();
+            let mut b = e.finish().unwrap();
+            b.push(b'x');
+            b
+        };
+
+        let mut output = Vec::new();
+        let mut decoder = GzDecoder::new(compressed.as_slice());
+        let decoded_bytes = decoder.read_to_end(&mut output).unwrap();
+        assert_eq!(decoded_bytes, output.len());
+        let actual = std::str::from_utf8(&output).expect("String parsing error");
+        assert_eq!(
+            actual, expected,
+            "after decompression we obtain the original input"
+        );
+
+        output.clear();
+        assert_eq!(
+            decoder.read(&mut output).unwrap(),
+            0,
+            "subsequent read of decoder returns 0, but inner reader can return additional data"
+        );
+        let mut reader = decoder.into_inner();
+        assert_eq!(
+            reader.read_to_end(&mut output).unwrap(),
+            1,
+            "extra data is accessible in underlying buf-read"
+        );
+        assert_eq!(output, b"x");
+    }
+}
diff --git a/vendor/flate2/src/gz/mod.rs b/vendor/flate2/src/gz/mod.rs
new file mode 100644
index 0000000..31a6961
--- /dev/null
+++ b/vendor/flate2/src/gz/mod.rs
@@ -0,0 +1,644 @@
+use std::ffi::CString;
+use std::io::{BufRead, Error, ErrorKind, Read, Result, Write};
+use std::time;
+
+use crate::bufreader::BufReader;
+use crate::{Compression, Crc};
+
+pub static FHCRC: u8 = 1 << 1;
+pub static FEXTRA: u8 = 1 << 2;
+pub static FNAME: u8 = 1 << 3;
+pub static FCOMMENT: u8 = 1 << 4;
+pub static FRESERVED: u8 = 1 << 5 | 1 << 6 | 1 << 7;
+
+pub mod bufread;
+pub mod read;
+pub mod write;
+
+// The maximum length of the header filename and comment fields. More than
+// enough for these fields in reasonable use, but prevents possible attacks.
+const MAX_HEADER_BUF: usize = 65535;
+
+/// A structure representing the header of a gzip stream.
+///
+/// The header can contain metadata about the file that was compressed, if
+/// present.
+#[derive(PartialEq, Clone, Debug, Default)]
+pub struct GzHeader {
+    extra: Option<Vec<u8>>,
+    filename: Option<Vec<u8>>,
+    comment: Option<Vec<u8>>,
+    operating_system: u8,
+    mtime: u32,
+}
+
+impl GzHeader {
+    /// Returns the `filename` field of this gzip stream's header, if present.
+    pub fn filename(&self) -> Option<&[u8]> {
+        self.filename.as_ref().map(|s| &s[..])
+    }
+
+    /// Returns the `extra` field of this gzip stream's header, if present.
+    pub fn extra(&self) -> Option<&[u8]> {
+        self.extra.as_ref().map(|s| &s[..])
+    }
+
+    /// Returns the `comment` field of this gzip stream's header, if present.
+    pub fn comment(&self) -> Option<&[u8]> {
+        self.comment.as_ref().map(|s| &s[..])
+    }
+
+    /// Returns the `operating_system` field of this gzip stream's header.
+    ///
+    /// There are predefined values for various operating systems.
+    /// 255 means that the value is unknown.
+    pub fn operating_system(&self) -> u8 {
+        self.operating_system
+    }
+
+    /// This gives the most recent modification time of the original file being compressed.
+    ///
+    /// The time is in Unix format, i.e., seconds since 00:00:00 GMT, Jan. 1, 1970.
+    /// (Note that this may cause problems for MS-DOS and other systems that use local
+    /// rather than Universal time.) If the compressed data did not come from a file,
+    /// `mtime` is set to the time at which compression started.
+    /// `mtime` = 0 means no time stamp is available.
+    ///
+    /// The usage of `mtime` is discouraged because of Year 2038 problem.
+    pub fn mtime(&self) -> u32 {
+        self.mtime
+    }
+
+    /// Returns the most recent modification time represented by a date-time type.
+    /// Returns `None` if the value of the underlying counter is 0,
+    /// indicating no time stamp is available.
+    ///
+    ///
+    /// The time is measured as seconds since 00:00:00 GMT, Jan. 1 1970.
+    /// See [`mtime`](#method.mtime) for more detail.
+    pub fn mtime_as_datetime(&self) -> Option<time::SystemTime> {
+        if self.mtime == 0 {
+            None
+        } else {
+            let duration = time::Duration::new(u64::from(self.mtime), 0);
+            let datetime = time::UNIX_EPOCH + duration;
+            Some(datetime)
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum GzHeaderState {
+    Start(u8, [u8; 10]),
+    Xlen(Option<Box<Crc>>, u8, [u8; 2]),
+    Extra(Option<Box<Crc>>, u16),
+    Filename(Option<Box<Crc>>),
+    Comment(Option<Box<Crc>>),
+    Crc(Option<Box<Crc>>, u8, [u8; 2]),
+    Complete,
+}
+
+impl Default for GzHeaderState {
+    fn default() -> Self {
+        Self::Complete
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct GzHeaderParser {
+    state: GzHeaderState,
+    flags: u8,
+    header: GzHeader,
+}
+
+impl GzHeaderParser {
+    fn new() -> Self {
+        GzHeaderParser {
+            state: GzHeaderState::Start(0, [0; 10]),
+            flags: 0,
+            header: GzHeader::default(),
+        }
+    }
+
+    fn parse<'a, R: Read>(&mut self, r: &'a mut R) -> Result<()> {
+        loop {
+            match &mut self.state {
+                GzHeaderState::Start(count, buffer) => {
+                    while (*count as usize) < buffer.len() {
+                        *count += read_into(r, &mut buffer[*count as usize..])? as u8;
+                    }
+                    // Gzip identification bytes
+                    if buffer[0] != 0x1f || buffer[1] != 0x8b {
+                        return Err(bad_header());
+                    }
+                    // Gzip compression method (8 = deflate)
+                    if buffer[2] != 8 {
+                        return Err(bad_header());
+                    }
+                    self.flags = buffer[3];
+                    // RFC1952: "must give an error indication if any reserved bit is non-zero"
+                    if self.flags & FRESERVED != 0 {
+                        return Err(bad_header());
+                    }
+                    self.header.mtime = ((buffer[4] as u32) << 0)
+                        | ((buffer[5] as u32) << 8)
+                        | ((buffer[6] as u32) << 16)
+                        | ((buffer[7] as u32) << 24);
+                    let _xfl = buffer[8];
+                    self.header.operating_system = buffer[9];
+                    let crc = if self.flags & FHCRC != 0 {
+                        let mut crc = Box::new(Crc::new());
+                        crc.update(buffer);
+                        Some(crc)
+                    } else {
+                        None
+                    };
+                    self.state = GzHeaderState::Xlen(crc, 0, [0; 2]);
+                }
+                GzHeaderState::Xlen(crc, count, buffer) => {
+                    if self.flags & FEXTRA != 0 {
+                        while (*count as usize) < buffer.len() {
+                            *count += read_into(r, &mut buffer[*count as usize..])? as u8;
+                        }
+                        if let Some(crc) = crc {
+                            crc.update(buffer);
+                        }
+                        let xlen = parse_le_u16(&buffer);
+                        self.header.extra = Some(vec![0; xlen as usize]);
+                        self.state = GzHeaderState::Extra(crc.take(), 0);
+                    } else {
+                        self.state = GzHeaderState::Filename(crc.take());
+                    }
+                }
+                GzHeaderState::Extra(crc, count) => {
+                    debug_assert!(self.header.extra.is_some());
+                    let extra = self.header.extra.as_mut().unwrap();
+                    while (*count as usize) < extra.len() {
+                        *count += read_into(r, &mut extra[*count as usize..])? as u16;
+                    }
+                    if let Some(crc) = crc {
+                        crc.update(extra);
+                    }
+                    self.state = GzHeaderState::Filename(crc.take());
+                }
+                GzHeaderState::Filename(crc) => {
+                    if self.flags & FNAME != 0 {
+                        let filename = self.header.filename.get_or_insert_with(Vec::new);
+                        read_to_nul(r, filename)?;
+                        if let Some(crc) = crc {
+                            crc.update(filename);
+                            crc.update(b"\0");
+                        }
+                    }
+                    self.state = GzHeaderState::Comment(crc.take());
+                }
+                GzHeaderState::Comment(crc) => {
+                    if self.flags & FCOMMENT != 0 {
+                        let comment = self.header.comment.get_or_insert_with(Vec::new);
+                        read_to_nul(r, comment)?;
+                        if let Some(crc) = crc {
+                            crc.update(comment);
+                            crc.update(b"\0");
+                        }
+                    }
+                    self.state = GzHeaderState::Crc(crc.take(), 0, [0; 2]);
+                }
+                GzHeaderState::Crc(crc, count, buffer) => {
+                    if let Some(crc) = crc {
+                        debug_assert!(self.flags & FHCRC != 0);
+                        while (*count as usize) < buffer.len() {
+                            *count += read_into(r, &mut buffer[*count as usize..])? as u8;
+                        }
+                        let stored_crc = parse_le_u16(&buffer);
+                        let calced_crc = crc.sum() as u16;
+                        if stored_crc != calced_crc {
+                            return Err(corrupt());
+                        }
+                    }
+                    self.state = GzHeaderState::Complete;
+                }
+                GzHeaderState::Complete => {
+                    return Ok(());
+                }
+            }
+        }
+    }
+
+    fn header(&self) -> Option<&GzHeader> {
+        match self.state {
+            GzHeaderState::Complete => Some(&self.header),
+            _ => None,
+        }
+    }
+}
+
+impl From<GzHeaderParser> for GzHeader {
+    fn from(parser: GzHeaderParser) -> Self {
+        debug_assert!(matches!(parser.state, GzHeaderState::Complete));
+        parser.header
+    }
+}
+
+// Attempt to fill the `buffer` from `r`. Return the number of bytes read.
+// Return an error if EOF is read before the buffer is full.  This differs
+// from `read` in that Ok(0) means that more data may be available.
+fn read_into<R: Read>(r: &mut R, buffer: &mut [u8]) -> Result<usize> {
+    debug_assert!(!buffer.is_empty());
+    match r.read(buffer) {
+        Ok(0) => Err(ErrorKind::UnexpectedEof.into()),
+        Ok(n) => Ok(n),
+        Err(ref e) if e.kind() == ErrorKind::Interrupted => Ok(0),
+        Err(e) => Err(e),
+    }
+}
+
+// Read `r` up to the first nul byte, pushing non-nul bytes to `buffer`.
+fn read_to_nul<R: Read>(r: &mut R, buffer: &mut Vec<u8>) -> Result<()> {
+    let mut bytes = r.bytes();
+    loop {
+        match bytes.next().transpose()? {
+            Some(byte) if byte == 0 => {
+                return Ok(());
+            }
+            Some(_) if buffer.len() == MAX_HEADER_BUF => {
+                return Err(Error::new(
+                    ErrorKind::InvalidInput,
+                    "gzip header field too long",
+                ));
+            }
+            Some(byte) => {
+                buffer.push(byte);
+            }
+            None => {
+                return Err(ErrorKind::UnexpectedEof.into());
+            }
+        }
+    }
+}
+
+fn parse_le_u16(buffer: &[u8; 2]) -> u16 {
+    (buffer[0] as u16) | ((buffer[1] as u16) << 8)
+}
+
+fn bad_header() -> Error {
+    Error::new(ErrorKind::InvalidInput, "invalid gzip header")
+}
+
+fn corrupt() -> Error {
+    Error::new(
+        ErrorKind::InvalidInput,
+        "corrupt gzip stream does not have a matching checksum",
+    )
+}
+
+/// A builder structure to create a new gzip Encoder.
+///
+/// This structure controls header configuration options such as the filename.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// # use std::io;
+/// use std::fs::File;
+/// use flate2::GzBuilder;
+/// use flate2::Compression;
+///
+/// // GzBuilder opens a file and writes a sample string using GzBuilder pattern
+///
+/// # fn sample_builder() -> Result<(), io::Error> {
+/// let f = File::create("examples/hello_world.gz")?;
+/// let mut gz = GzBuilder::new()
+///                 .filename("hello_world.txt")
+///                 .comment("test file, please delete")
+///                 .write(f, Compression::default());
+/// gz.write_all(b"hello world")?;
+/// gz.finish()?;
+/// # Ok(())
+/// # }
+/// ```
+#[derive(Debug)]
+pub struct GzBuilder {
+    extra: Option<Vec<u8>>,
+    filename: Option<CString>,
+    comment: Option<CString>,
+    operating_system: Option<u8>,
+    mtime: u32,
+}
+
+impl Default for GzBuilder {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl GzBuilder {
+    /// Create a new blank builder with no header by default.
+    pub fn new() -> GzBuilder {
+        GzBuilder {
+            extra: None,
+            filename: None,
+            comment: None,
+            operating_system: None,
+            mtime: 0,
+        }
+    }
+
+    /// Configure the `mtime` field in the gzip header.
+    pub fn mtime(mut self, mtime: u32) -> GzBuilder {
+        self.mtime = mtime;
+        self
+    }
+
+    /// Configure the `operating_system` field in the gzip header.
+    pub fn operating_system(mut self, os: u8) -> GzBuilder {
+        self.operating_system = Some(os);
+        self
+    }
+
+    /// Configure the `extra` field in the gzip header.
+    pub fn extra<T: Into<Vec<u8>>>(mut self, extra: T) -> GzBuilder {
+        self.extra = Some(extra.into());
+        self
+    }
+
+    /// Configure the `filename` field in the gzip header.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the `filename` slice contains a zero.
+    pub fn filename<T: Into<Vec<u8>>>(mut self, filename: T) -> GzBuilder {
+        self.filename = Some(CString::new(filename.into()).unwrap());
+        self
+    }
+
+    /// Configure the `comment` field in the gzip header.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the `comment` slice contains a zero.
+    pub fn comment<T: Into<Vec<u8>>>(mut self, comment: T) -> GzBuilder {
+        self.comment = Some(CString::new(comment.into()).unwrap());
+        self
+    }
+
+    /// Consume this builder, creating a writer encoder in the process.
+    ///
+    /// The data written to the returned encoder will be compressed and then
+    /// written out to the supplied parameter `w`.
+    pub fn write<W: Write>(self, w: W, lvl: Compression) -> write::GzEncoder<W> {
+        write::gz_encoder(self.into_header(lvl), w, lvl)
+    }
+
+    /// Consume this builder, creating a reader encoder in the process.
+    ///
+    /// Data read from the returned encoder will be the compressed version of
+    /// the data read from the given reader.
+    pub fn read<R: Read>(self, r: R, lvl: Compression) -> read::GzEncoder<R> {
+        read::gz_encoder(self.buf_read(BufReader::new(r), lvl))
+    }
+
+    /// Consume this builder, creating a reader encoder in the process.
+    ///
+    /// Data read from the returned encoder will be the compressed version of
+    /// the data read from the given reader.
+    pub fn buf_read<R>(self, r: R, lvl: Compression) -> bufread::GzEncoder<R>
+    where
+        R: BufRead,
+    {
+        bufread::gz_encoder(self.into_header(lvl), r, lvl)
+    }
+
+    fn into_header(self, lvl: Compression) -> Vec<u8> {
+        let GzBuilder {
+            extra,
+            filename,
+            comment,
+            operating_system,
+            mtime,
+        } = self;
+        let mut flg = 0;
+        let mut header = vec![0u8; 10];
+        if let Some(v) = extra {
+            flg |= FEXTRA;
+            header.push((v.len() >> 0) as u8);
+            header.push((v.len() >> 8) as u8);
+            header.extend(v);
+        }
+        if let Some(filename) = filename {
+            flg |= FNAME;
+            header.extend(filename.as_bytes_with_nul().iter().copied());
+        }
+        if let Some(comment) = comment {
+            flg |= FCOMMENT;
+            header.extend(comment.as_bytes_with_nul().iter().copied());
+        }
+        header[0] = 0x1f;
+        header[1] = 0x8b;
+        header[2] = 8;
+        header[3] = flg;
+        header[4] = (mtime >> 0) as u8;
+        header[5] = (mtime >> 8) as u8;
+        header[6] = (mtime >> 16) as u8;
+        header[7] = (mtime >> 24) as u8;
+        header[8] = if lvl.0 >= Compression::best().0 {
+            2
+        } else if lvl.0 <= Compression::fast().0 {
+            4
+        } else {
+            0
+        };
+
+        // Typically this byte indicates what OS the gz stream was created on,
+        // but in an effort to have cross-platform reproducible streams just
+        // default this value to 255. I'm not sure that if we "correctly" set
+        // this it'd do anything anyway...
+        header[9] = operating_system.unwrap_or(255);
+        header
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::io::prelude::*;
+
+    use super::{read, write, GzBuilder, GzHeaderParser};
+    use crate::{Compression, GzHeader};
+    use rand::{thread_rng, Rng};
+
+    #[test]
+    fn roundtrip() {
+        let mut e = write::GzEncoder::new(Vec::new(), Compression::default());
+        e.write_all(b"foo bar baz").unwrap();
+        let inner = e.finish().unwrap();
+        let mut d = read::GzDecoder::new(&inner[..]);
+        let mut s = String::new();
+        d.read_to_string(&mut s).unwrap();
+        assert_eq!(s, "foo bar baz");
+    }
+
+    #[test]
+    fn roundtrip_zero() {
+        let e = write::GzEncoder::new(Vec::new(), Compression::default());
+        let inner = e.finish().unwrap();
+        let mut d = read::GzDecoder::new(&inner[..]);
+        let mut s = String::new();
+        d.read_to_string(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn roundtrip_big() {
+        let mut real = Vec::new();
+        let mut w = write::GzEncoder::new(Vec::new(), Compression::default());
+        let v = crate::random_bytes().take(1024).collect::<Vec<_>>();
+        for _ in 0..200 {
+            let to_write = &v[..thread_rng().gen_range(0..v.len())];
+            real.extend(to_write.iter().copied());
+            w.write_all(to_write).unwrap();
+        }
+        let result = w.finish().unwrap();
+        let mut r = read::GzDecoder::new(&result[..]);
+        let mut v = Vec::new();
+        r.read_to_end(&mut v).unwrap();
+        assert_eq!(v, real);
+    }
+
+    #[test]
+    fn roundtrip_big2() {
+        let v = crate::random_bytes().take(1024 * 1024).collect::<Vec<_>>();
+        let mut r = read::GzDecoder::new(read::GzEncoder::new(&v[..], Compression::default()));
+        let mut res = Vec::new();
+        r.read_to_end(&mut res).unwrap();
+        assert_eq!(res, v);
+    }
+
+    // A Rust implementation of CRC that closely matches the C code in RFC1952.
+    // Only use this to create CRCs for tests.
+    struct Rfc1952Crc {
+        /* Table of CRCs of all 8-bit messages. */
+        crc_table: [u32; 256],
+    }
+
+    impl Rfc1952Crc {
+        fn new() -> Self {
+            let mut crc = Rfc1952Crc {
+                crc_table: [0; 256],
+            };
+            /* Make the table for a fast CRC. */
+            for n in 0usize..256 {
+                let mut c = n as u32;
+                for _k in 0..8 {
+                    if c & 1 != 0 {
+                        c = 0xedb88320 ^ (c >> 1);
+                    } else {
+                        c = c >> 1;
+                    }
+                }
+                crc.crc_table[n] = c;
+            }
+            crc
+        }
+
+        /*
+         Update a running crc with the bytes buf and return
+         the updated crc. The crc should be initialized to zero. Pre- and
+         post-conditioning (one's complement) is performed within this
+         function so it shouldn't be done by the caller.
+        */
+        fn update_crc(&self, crc: u32, buf: &[u8]) -> u32 {
+            let mut c = crc ^ 0xffffffff;
+
+            for b in buf {
+                c = self.crc_table[(c as u8 ^ *b) as usize] ^ (c >> 8);
+            }
+            c ^ 0xffffffff
+        }
+
+        /* Return the CRC of the bytes buf. */
+        fn crc(&self, buf: &[u8]) -> u32 {
+            self.update_crc(0, buf)
+        }
+    }
+
+    #[test]
+    fn roundtrip_header() {
+        let mut header = GzBuilder::new()
+            .mtime(1234)
+            .operating_system(57)
+            .filename("filename")
+            .comment("comment")
+            .into_header(Compression::fast());
+
+        // Add a CRC to the header
+        header[3] = header[3] ^ super::FHCRC;
+        let rfc1952_crc = Rfc1952Crc::new();
+        let crc32 = rfc1952_crc.crc(&header);
+        let crc16 = crc32 as u16;
+        header.extend(&crc16.to_le_bytes());
+
+        let mut parser = GzHeaderParser::new();
+        parser.parse(&mut header.as_slice()).unwrap();
+        let actual = parser.header().unwrap();
+        assert_eq!(
+            actual,
+            &GzHeader {
+                extra: None,
+                filename: Some("filename".as_bytes().to_vec()),
+                comment: Some("comment".as_bytes().to_vec()),
+                operating_system: 57,
+                mtime: 1234
+            }
+        )
+    }
+
+    #[test]
+    fn fields() {
+        let r = vec![0, 2, 4, 6];
+        let e = GzBuilder::new()
+            .filename("foo.rs")
+            .comment("bar")
+            .extra(vec![0, 1, 2, 3])
+            .read(&r[..], Compression::default());
+        let mut d = read::GzDecoder::new(e);
+        assert_eq!(d.header().unwrap().filename(), Some(&b"foo.rs"[..]));
+        assert_eq!(d.header().unwrap().comment(), Some(&b"bar"[..]));
+        assert_eq!(d.header().unwrap().extra(), Some(&b"\x00\x01\x02\x03"[..]));
+        let mut res = Vec::new();
+        d.read_to_end(&mut res).unwrap();
+        assert_eq!(res, vec![0, 2, 4, 6]);
+    }
+
+    #[test]
+    fn keep_reading_after_end() {
+        let mut e = write::GzEncoder::new(Vec::new(), Compression::default());
+        e.write_all(b"foo bar baz").unwrap();
+        let inner = e.finish().unwrap();
+        let mut d = read::GzDecoder::new(&inner[..]);
+        let mut s = String::new();
+        d.read_to_string(&mut s).unwrap();
+        assert_eq!(s, "foo bar baz");
+        d.read_to_string(&mut s).unwrap();
+        assert_eq!(s, "foo bar baz");
+    }
+
+    #[test]
+    fn qc_reader() {
+        ::quickcheck::quickcheck(test as fn(_) -> _);
+
+        fn test(v: Vec<u8>) -> bool {
+            let r = read::GzEncoder::new(&v[..], Compression::default());
+            let mut r = read::GzDecoder::new(r);
+            let mut v2 = Vec::new();
+            r.read_to_end(&mut v2).unwrap();
+            v == v2
+        }
+    }
+
+    #[test]
+    fn flush_after_write() {
+        let mut f = write::GzEncoder::new(Vec::new(), Compression::default());
+        write!(f, "Hello world").unwrap();
+        f.flush().unwrap();
+    }
+}
diff --git a/vendor/flate2/src/gz/read.rs b/vendor/flate2/src/gz/read.rs
new file mode 100644
index 0000000..9dbadbd
--- /dev/null
+++ b/vendor/flate2/src/gz/read.rs
@@ -0,0 +1,378 @@
+use std::io;
+use std::io::prelude::*;
+
+use super::bufread;
+use super::{GzBuilder, GzHeader};
+use crate::bufreader::BufReader;
+use crate::Compression;
+
+/// A gzip streaming encoder
+///
+/// This structure implements a [`Read`] interface. When read from, it reads
+/// uncompressed data from the underlying [`Read`] and provides the compressed data.
+///
+/// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io;
+/// use flate2::Compression;
+/// use flate2::read::GzEncoder;
+///
+/// // Return a vector containing the GZ compressed version of hello world
+///
+/// fn gzencode_hello_world() -> io::Result<Vec<u8>> {
+///     let mut ret_vec = Vec::new();
+///     let bytestring = b"hello world";
+///     let mut gz = GzEncoder::new(&bytestring[..], Compression::fast());
+///     gz.read_to_end(&mut ret_vec)?;
+///     Ok(ret_vec)
+/// }
+/// ```
+#[derive(Debug)]
+pub struct GzEncoder<R> {
+    inner: bufread::GzEncoder<BufReader<R>>,
+}
+
+pub fn gz_encoder<R: Read>(inner: bufread::GzEncoder<BufReader<R>>) -> GzEncoder<R> {
+    GzEncoder { inner }
+}
+
+impl<R: Read> GzEncoder<R> {
+    /// Creates a new encoder which will use the given compression level.
+    ///
+    /// The encoder is not configured specially for the emitted header. For
+    /// header configuration, see the `GzBuilder` type.
+    ///
+    /// The data read from the stream `r` will be compressed and available
+    /// through the returned reader.
+    pub fn new(r: R, level: Compression) -> GzEncoder<R> {
+        GzBuilder::new().read(r, level)
+    }
+}
+
+impl<R> GzEncoder<R> {
+    /// Acquires a reference to the underlying reader.
+    pub fn get_ref(&self) -> &R {
+        self.inner.get_ref().get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying reader.
+    ///
+    /// Note that mutation of the reader may result in surprising results if
+    /// this encoder is continued to be used.
+    pub fn get_mut(&mut self) -> &mut R {
+        self.inner.get_mut().get_mut()
+    }
+
+    /// Returns the underlying stream, consuming this encoder
+    pub fn into_inner(self) -> R {
+        self.inner.into_inner().into_inner()
+    }
+}
+
+impl<R: Read> Read for GzEncoder<R> {
+    fn read(&mut self, into: &mut [u8]) -> io::Result<usize> {
+        self.inner.read(into)
+    }
+}
+
+impl<R: Read + Write> Write for GzEncoder<R> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.get_mut().write(buf)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.get_mut().flush()
+    }
+}
+
+/// A decoder for a single member of a [gzip file].
+///
+/// This structure implements a [`Read`] interface. When read from, it reads
+/// compressed data from the underlying [`Read`] and provides the uncompressed data.
+///
+/// After reading a single member of the gzip data this reader will return
+/// Ok(0) even if there are more bytes available in the underlying reader.
+/// `GzDecoder` may have read additional bytes past the end of the gzip data.
+/// If you need the following bytes, wrap the `Reader` in a `std::io::BufReader`
+/// and use `bufread::GzDecoder` instead.
+///
+/// To handle gzip files that may have multiple members, see [`MultiGzDecoder`]
+/// or read more
+/// [in the introduction](../index.html#about-multi-member-gzip-files).
+///
+/// [gzip file]: https://www.rfc-editor.org/rfc/rfc1952#page-5
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io;
+/// # use flate2::Compression;
+/// # use flate2::write::GzEncoder;
+/// use flate2::read::GzDecoder;
+///
+/// # fn main() {
+/// #    let mut e = GzEncoder::new(Vec::new(), Compression::default());
+/// #    e.write_all(b"Hello World").unwrap();
+/// #    let bytes = e.finish().unwrap();
+/// #    println!("{}", decode_reader(bytes).unwrap());
+/// # }
+/// #
+/// // Uncompresses a Gz Encoded vector of bytes and returns a string or error
+/// // Here &[u8] implements Read
+///
+/// fn decode_reader(bytes: Vec<u8>) -> io::Result<String> {
+///    let mut gz = GzDecoder::new(&bytes[..]);
+///    let mut s = String::new();
+///    gz.read_to_string(&mut s)?;
+///    Ok(s)
+/// }
+/// ```
+#[derive(Debug)]
+pub struct GzDecoder<R> {
+    inner: bufread::GzDecoder<BufReader<R>>,
+}
+
+impl<R: Read> GzDecoder<R> {
+    /// Creates a new decoder from the given reader, immediately parsing the
+    /// gzip header.
+    pub fn new(r: R) -> GzDecoder<R> {
+        GzDecoder {
+            inner: bufread::GzDecoder::new(BufReader::new(r)),
+        }
+    }
+}
+
+impl<R> GzDecoder<R> {
+    /// Returns the header associated with this stream, if it was valid.
+    pub fn header(&self) -> Option<&GzHeader> {
+        self.inner.header()
+    }
+
+    /// Acquires a reference to the underlying reader.
+    ///
+    /// Note that the decoder may have read past the end of the gzip data.
+    /// To prevent this use [`bufread::GzDecoder`] instead.
+    pub fn get_ref(&self) -> &R {
+        self.inner.get_ref().get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying stream.
+    ///
+    /// Note that mutation of the stream may result in surprising results if
+    /// this decoder continues to be used.
+    ///
+    /// Note that the decoder may have read past the end of the gzip data.
+    /// To prevent this use [`bufread::GzDecoder`] instead.
+    pub fn get_mut(&mut self) -> &mut R {
+        self.inner.get_mut().get_mut()
+    }
+
+    /// Consumes this decoder, returning the underlying reader.
+    ///
+    /// Note that the decoder may have read past the end of the gzip data.
+    /// Subsequent reads will skip those bytes. To prevent this use
+    /// [`bufread::GzDecoder`] instead.
+    pub fn into_inner(self) -> R {
+        self.inner.into_inner().into_inner()
+    }
+}
+
+impl<R: Read> Read for GzDecoder<R> {
+    fn read(&mut self, into: &mut [u8]) -> io::Result<usize> {
+        self.inner.read(into)
+    }
+}
+
+impl<R: Read + Write> Write for GzDecoder<R> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.get_mut().write(buf)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.get_mut().flush()
+    }
+}
+
+/// A gzip streaming decoder that decodes a [gzip file] that may have multiple members.
+///
+/// This structure implements a [`Read`] interface. When read from, it reads
+/// compressed data from the underlying [`Read`] and provides the uncompressed
+/// data.
+///
+/// A gzip file consists of a series of *members* concatenated one after another.
+/// MultiGzDecoder decodes all members of a file and returns Ok(0) once the
+/// underlying reader does.
+///
+/// To handle members seperately, see [GzDecoder] or read more
+/// [in the introduction](../index.html#about-multi-member-gzip-files).
+///
+/// [gzip file]: https://www.rfc-editor.org/rfc/rfc1952#page-5
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io;
+/// # use flate2::Compression;
+/// # use flate2::write::GzEncoder;
+/// use flate2::read::MultiGzDecoder;
+///
+/// # fn main() {
+/// #    let mut e = GzEncoder::new(Vec::new(), Compression::default());
+/// #    e.write_all(b"Hello World").unwrap();
+/// #    let bytes = e.finish().unwrap();
+/// #    println!("{}", decode_reader(bytes).unwrap());
+/// # }
+/// #
+/// // Uncompresses a Gz Encoded vector of bytes and returns a string or error
+/// // Here &[u8] implements Read
+///
+/// fn decode_reader(bytes: Vec<u8>) -> io::Result<String> {
+///    let mut gz = MultiGzDecoder::new(&bytes[..]);
+///    let mut s = String::new();
+///    gz.read_to_string(&mut s)?;
+///    Ok(s)
+/// }
+/// ```
+#[derive(Debug)]
+pub struct MultiGzDecoder<R> {
+    inner: bufread::MultiGzDecoder<BufReader<R>>,
+}
+
+impl<R: Read> MultiGzDecoder<R> {
+    /// Creates a new decoder from the given reader, immediately parsing the
+    /// (first) gzip header. If the gzip stream contains multiple members all will
+    /// be decoded.
+    pub fn new(r: R) -> MultiGzDecoder<R> {
+        MultiGzDecoder {
+            inner: bufread::MultiGzDecoder::new(BufReader::new(r)),
+        }
+    }
+}
+
+impl<R> MultiGzDecoder<R> {
+    /// Returns the current header associated with this stream, if it's valid.
+    pub fn header(&self) -> Option<&GzHeader> {
+        self.inner.header()
+    }
+
+    /// Acquires a reference to the underlying reader.
+    pub fn get_ref(&self) -> &R {
+        self.inner.get_ref().get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying stream.
+    ///
+    /// Note that mutation of the stream may result in surprising results if
+    /// this decoder is continued to be used.
+    pub fn get_mut(&mut self) -> &mut R {
+        self.inner.get_mut().get_mut()
+    }
+
+    /// Consumes this decoder, returning the underlying reader.
+    pub fn into_inner(self) -> R {
+        self.inner.into_inner().into_inner()
+    }
+}
+
+impl<R: Read> Read for MultiGzDecoder<R> {
+    fn read(&mut self, into: &mut [u8]) -> io::Result<usize> {
+        self.inner.read(into)
+    }
+}
+
+impl<R: Read + Write> Write for MultiGzDecoder<R> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.get_mut().write(buf)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.get_mut().flush()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::io::{Cursor, ErrorKind, Read, Result, Write};
+
+    use super::GzDecoder;
+
+    //a cursor turning EOF into blocking errors
+    #[derive(Debug)]
+    pub struct BlockingCursor {
+        pub cursor: Cursor<Vec<u8>>,
+    }
+
+    impl BlockingCursor {
+        pub fn new() -> BlockingCursor {
+            BlockingCursor {
+                cursor: Cursor::new(Vec::new()),
+            }
+        }
+
+        pub fn set_position(&mut self, pos: u64) {
+            return self.cursor.set_position(pos);
+        }
+    }
+
+    impl Write for BlockingCursor {
+        fn write(&mut self, buf: &[u8]) -> Result<usize> {
+            return self.cursor.write(buf);
+        }
+        fn flush(&mut self) -> Result<()> {
+            return self.cursor.flush();
+        }
+    }
+
+    impl Read for BlockingCursor {
+        fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+            //use the cursor, except it turns eof into blocking error
+            let r = self.cursor.read(buf);
+            match r {
+                Err(ref err) => {
+                    if err.kind() == ErrorKind::UnexpectedEof {
+                        return Err(ErrorKind::WouldBlock.into());
+                    }
+                }
+                Ok(0) => {
+                    //regular EOF turned into blocking error
+                    return Err(ErrorKind::WouldBlock.into());
+                }
+                Ok(_n) => {}
+            }
+            return r;
+        }
+    }
+
+    #[test]
+    fn blocked_partial_header_read() {
+        // this is a reader which receives data afterwards
+        let mut r = BlockingCursor::new();
+        let data = vec![1, 2, 3];
+
+        match r.write_all(&data) {
+            Ok(()) => {}
+            _ => {
+                panic!("Unexpected result for write_all");
+            }
+        }
+        r.set_position(0);
+
+        // this is unused except for the buffering
+        let mut decoder = GzDecoder::new(r);
+        let mut out = Vec::with_capacity(7);
+        match decoder.read(&mut out) {
+            Err(e) => {
+                assert_eq!(e.kind(), ErrorKind::WouldBlock);
+            }
+            _ => {
+                panic!("Unexpected result for decoder.read");
+            }
+        }
+    }
+}
diff --git a/vendor/flate2/src/gz/write.rs b/vendor/flate2/src/gz/write.rs
new file mode 100644
index 0000000..74d6c5a
--- /dev/null
+++ b/vendor/flate2/src/gz/write.rs
@@ -0,0 +1,641 @@
+use std::cmp;
+use std::io;
+use std::io::prelude::*;
+
+use super::{corrupt, GzBuilder, GzHeader, GzHeaderParser};
+use crate::crc::{Crc, CrcWriter};
+use crate::zio;
+use crate::{Compress, Compression, Decompress, Status};
+
+/// A gzip streaming encoder
+///
+/// This structure exposes a [`Write`] interface that will emit compressed data
+/// to the underlying writer `W`.
+///
+/// [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use flate2::Compression;
+/// use flate2::write::GzEncoder;
+///
+/// // Vec<u8> implements Write to print the compressed bytes of sample string
+/// # fn main() {
+///
+/// let mut e = GzEncoder::new(Vec::new(), Compression::default());
+/// e.write_all(b"Hello World").unwrap();
+/// println!("{:?}", e.finish().unwrap());
+/// # }
+/// ```
+#[derive(Debug)]
+pub struct GzEncoder<W: Write> {
+    inner: zio::Writer<W, Compress>,
+    crc: Crc,
+    crc_bytes_written: usize,
+    header: Vec<u8>,
+}
+
+pub fn gz_encoder<W: Write>(header: Vec<u8>, w: W, lvl: Compression) -> GzEncoder<W> {
+    GzEncoder {
+        inner: zio::Writer::new(w, Compress::new(lvl, false)),
+        crc: Crc::new(),
+        header,
+        crc_bytes_written: 0,
+    }
+}
+
+impl<W: Write> GzEncoder<W> {
+    /// Creates a new encoder which will use the given compression level.
+    ///
+    /// The encoder is not configured specially for the emitted header. For
+    /// header configuration, see the `GzBuilder` type.
+    ///
+    /// The data written to the returned encoder will be compressed and then
+    /// written to the stream `w`.
+    pub fn new(w: W, level: Compression) -> GzEncoder<W> {
+        GzBuilder::new().write(w, level)
+    }
+
+    /// Acquires a reference to the underlying writer.
+    pub fn get_ref(&self) -> &W {
+        self.inner.get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying writer.
+    ///
+    /// Note that mutation of the writer may result in surprising results if
+    /// this encoder is continued to be used.
+    pub fn get_mut(&mut self) -> &mut W {
+        self.inner.get_mut()
+    }
+
+    /// Attempt to finish this output stream, writing out final chunks of data.
+    ///
+    /// Note that this function can only be used once data has finished being
+    /// written to the output stream. After this function is called then further
+    /// calls to `write` may result in a panic.
+    ///
+    /// # Panics
+    ///
+    /// Attempts to write data to this stream may result in a panic after this
+    /// function is called.
+    ///
+    /// # Errors
+    ///
+    /// This function will perform I/O to complete this stream, and any I/O
+    /// errors which occur will be returned from this function.
+    pub fn try_finish(&mut self) -> io::Result<()> {
+        self.write_header()?;
+        self.inner.finish()?;
+
+        while self.crc_bytes_written < 8 {
+            let (sum, amt) = (self.crc.sum(), self.crc.amount());
+            let buf = [
+                (sum >> 0) as u8,
+                (sum >> 8) as u8,
+                (sum >> 16) as u8,
+                (sum >> 24) as u8,
+                (amt >> 0) as u8,
+                (amt >> 8) as u8,
+                (amt >> 16) as u8,
+                (amt >> 24) as u8,
+            ];
+            let inner = self.inner.get_mut();
+            let n = inner.write(&buf[self.crc_bytes_written..])?;
+            self.crc_bytes_written += n;
+        }
+        Ok(())
+    }
+
+    /// Finish encoding this stream, returning the underlying writer once the
+    /// encoding is done.
+    ///
+    /// Note that this function may not be suitable to call in a situation where
+    /// the underlying stream is an asynchronous I/O stream. To finish a stream
+    /// the `try_finish` (or `shutdown`) method should be used instead. To
+    /// re-acquire ownership of a stream it is safe to call this method after
+    /// `try_finish` or `shutdown` has returned `Ok`.
+    ///
+    /// # Errors
+    ///
+    /// This function will perform I/O to complete this stream, and any I/O
+    /// errors which occur will be returned from this function.
+    pub fn finish(mut self) -> io::Result<W> {
+        self.try_finish()?;
+        Ok(self.inner.take_inner())
+    }
+
+    fn write_header(&mut self) -> io::Result<()> {
+        while !self.header.is_empty() {
+            let n = self.inner.get_mut().write(&self.header)?;
+            self.header.drain(..n);
+        }
+        Ok(())
+    }
+}
+
+impl<W: Write> Write for GzEncoder<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        assert_eq!(self.crc_bytes_written, 0);
+        self.write_header()?;
+        let n = self.inner.write(buf)?;
+        self.crc.update(&buf[..n]);
+        Ok(n)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        assert_eq!(self.crc_bytes_written, 0);
+        self.write_header()?;
+        self.inner.flush()
+    }
+}
+
+impl<R: Read + Write> Read for GzEncoder<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        self.get_mut().read(buf)
+    }
+}
+
+impl<W: Write> Drop for GzEncoder<W> {
+    fn drop(&mut self) {
+        if self.inner.is_present() {
+            let _ = self.try_finish();
+        }
+    }
+}
+
+/// A decoder for a single member of a [gzip file].
+///
+/// This structure exposes a [`Write`] interface, receiving compressed data and
+/// writing uncompressed data to the underlying writer.
+///
+/// After decoding a single member of the gzip data this writer will return the number of bytes up to
+/// to the end of the gzip member and subsequent writes will return Ok(0) allowing the caller to
+/// handle any data following the gzip member.
+///
+/// To handle gzip files that may have multiple members, see [`MultiGzDecoder`]
+/// or read more
+/// [in the introduction](../index.html#about-multi-member-gzip-files).
+///
+/// [gzip file]: https://www.rfc-editor.org/rfc/rfc1952#page-5
+/// [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io;
+/// use flate2::Compression;
+/// use flate2::write::{GzEncoder, GzDecoder};
+///
+/// # fn main() {
+/// #    let mut e = GzEncoder::new(Vec::new(), Compression::default());
+/// #    e.write(b"Hello World").unwrap();
+/// #    let bytes = e.finish().unwrap();
+/// #    assert_eq!("Hello World", decode_writer(bytes).unwrap());
+/// # }
+/// // Uncompresses a gzip encoded vector of bytes and returns a string or error
+/// // Here Vec<u8> implements Write
+/// fn decode_writer(bytes: Vec<u8>) -> io::Result<String> {
+///    let mut writer = Vec::new();
+///    let mut decoder = GzDecoder::new(writer);
+///    decoder.write_all(&bytes[..])?;
+///    writer = decoder.finish()?;
+///    let return_string = String::from_utf8(writer).expect("String parsing error");
+///    Ok(return_string)
+/// }
+/// ```
+#[derive(Debug)]
+pub struct GzDecoder<W: Write> {
+    inner: zio::Writer<CrcWriter<W>, Decompress>,
+    crc_bytes: Vec<u8>,
+    header_parser: GzHeaderParser,
+}
+
+const CRC_BYTES_LEN: usize = 8;
+
+impl<W: Write> GzDecoder<W> {
+    /// Creates a new decoder which will write uncompressed data to the stream.
+    ///
+    /// When this encoder is dropped or unwrapped the final pieces of data will
+    /// be flushed.
+    pub fn new(w: W) -> GzDecoder<W> {
+        GzDecoder {
+            inner: zio::Writer::new(CrcWriter::new(w), Decompress::new(false)),
+            crc_bytes: Vec::with_capacity(CRC_BYTES_LEN),
+            header_parser: GzHeaderParser::new(),
+        }
+    }
+
+    /// Returns the header associated with this stream.
+    pub fn header(&self) -> Option<&GzHeader> {
+        self.header_parser.header()
+    }
+
+    /// Acquires a reference to the underlying writer.
+    pub fn get_ref(&self) -> &W {
+        self.inner.get_ref().get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying writer.
+    ///
+    /// Note that mutating the output/input state of the stream may corrupt this
+    /// object, so care must be taken when using this method.
+    pub fn get_mut(&mut self) -> &mut W {
+        self.inner.get_mut().get_mut()
+    }
+
+    /// Attempt to finish this output stream, writing out final chunks of data.
+    ///
+    /// Note that this function can only be used once data has finished being
+    /// written to the output stream. After this function is called then further
+    /// calls to `write` may result in a panic.
+    ///
+    /// # Panics
+    ///
+    /// Attempts to write data to this stream may result in a panic after this
+    /// function is called.
+    ///
+    /// # Errors
+    ///
+    /// This function will perform I/O to finish the stream, returning any
+    /// errors which happen.
+    pub fn try_finish(&mut self) -> io::Result<()> {
+        self.finish_and_check_crc()?;
+        Ok(())
+    }
+
+    /// Consumes this decoder, flushing the output stream.
+    ///
+    /// This will flush the underlying data stream and then return the contained
+    /// writer if the flush succeeded.
+    ///
+    /// Note that this function may not be suitable to call in a situation where
+    /// the underlying stream is an asynchronous I/O stream. To finish a stream
+    /// the `try_finish` (or `shutdown`) method should be used instead. To
+    /// re-acquire ownership of a stream it is safe to call this method after
+    /// `try_finish` or `shutdown` has returned `Ok`.
+    ///
+    /// # Errors
+    ///
+    /// This function will perform I/O to complete this stream, and any I/O
+    /// errors which occur will be returned from this function.
+    pub fn finish(mut self) -> io::Result<W> {
+        self.finish_and_check_crc()?;
+        Ok(self.inner.take_inner().into_inner())
+    }
+
+    fn finish_and_check_crc(&mut self) -> io::Result<()> {
+        self.inner.finish()?;
+
+        if self.crc_bytes.len() != 8 {
+            return Err(corrupt());
+        }
+
+        let crc = ((self.crc_bytes[0] as u32) << 0)
+            | ((self.crc_bytes[1] as u32) << 8)
+            | ((self.crc_bytes[2] as u32) << 16)
+            | ((self.crc_bytes[3] as u32) << 24);
+        let amt = ((self.crc_bytes[4] as u32) << 0)
+            | ((self.crc_bytes[5] as u32) << 8)
+            | ((self.crc_bytes[6] as u32) << 16)
+            | ((self.crc_bytes[7] as u32) << 24);
+        if crc != self.inner.get_ref().crc().sum() {
+            return Err(corrupt());
+        }
+        if amt != self.inner.get_ref().crc().amount() {
+            return Err(corrupt());
+        }
+        Ok(())
+    }
+}
+
+impl<W: Write> Write for GzDecoder<W> {
+    fn write(&mut self, mut buf: &[u8]) -> io::Result<usize> {
+        let buflen = buf.len();
+        if self.header().is_none() {
+            match self.header_parser.parse(&mut buf) {
+                Err(err) => {
+                    if err.kind() == io::ErrorKind::UnexpectedEof {
+                        // all data read but header still not complete
+                        Ok(buflen)
+                    } else {
+                        Err(err)
+                    }
+                }
+                Ok(_) => {
+                    debug_assert!(self.header().is_some());
+                    // buf now contains the unread part of the original buf
+                    let n = buflen - buf.len();
+                    Ok(n)
+                }
+            }
+        } else {
+            let (n, status) = self.inner.write_with_status(buf)?;
+
+            if status == Status::StreamEnd && n < buf.len() && self.crc_bytes.len() < 8 {
+                let remaining = buf.len() - n;
+                let crc_bytes = cmp::min(remaining, CRC_BYTES_LEN - self.crc_bytes.len());
+                self.crc_bytes.extend(&buf[n..n + crc_bytes]);
+                return Ok(n + crc_bytes);
+            }
+            Ok(n)
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.inner.flush()
+    }
+}
+
+impl<W: Read + Write> Read for GzDecoder<W> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        self.inner.get_mut().get_mut().read(buf)
+    }
+}
+
+/// A gzip streaming decoder that decodes a [gzip file] with multiple members.
+///
+/// This structure exposes a [`Write`] interface that will consume compressed data and
+/// write uncompressed data to the underlying writer.
+///
+/// A gzip file consists of a series of *members* concatenated one after another.
+/// `MultiGzDecoder` decodes all members of a file and writes them to the
+/// underlying writer one after another.
+///
+/// To handle members separately, see [GzDecoder] or read more
+/// [in the introduction](../index.html#about-multi-member-gzip-files).
+///
+/// [gzip file]: https://www.rfc-editor.org/rfc/rfc1952#page-5
+#[derive(Debug)]
+pub struct MultiGzDecoder<W: Write> {
+    inner: GzDecoder<W>,
+}
+
+impl<W: Write> MultiGzDecoder<W> {
+    /// Creates a new decoder which will write uncompressed data to the stream.
+    /// If the gzip stream contains multiple members all will be decoded.
+    pub fn new(w: W) -> MultiGzDecoder<W> {
+        MultiGzDecoder {
+            inner: GzDecoder::new(w),
+        }
+    }
+
+    /// Returns the header associated with the current member.
+    pub fn header(&self) -> Option<&GzHeader> {
+        self.inner.header()
+    }
+
+    /// Acquires a reference to the underlying writer.
+    pub fn get_ref(&self) -> &W {
+        self.inner.get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying writer.
+    ///
+    /// Note that mutating the output/input state of the stream may corrupt this
+    /// object, so care must be taken when using this method.
+    pub fn get_mut(&mut self) -> &mut W {
+        self.inner.get_mut()
+    }
+
+    /// Attempt to finish this output stream, writing out final chunks of data.
+    ///
+    /// Note that this function can only be used once data has finished being
+    /// written to the output stream. After this function is called then further
+    /// calls to `write` may result in a panic.
+    ///
+    /// # Panics
+    ///
+    /// Attempts to write data to this stream may result in a panic after this
+    /// function is called.
+    ///
+    /// # Errors
+    ///
+    /// This function will perform I/O to finish the stream, returning any
+    /// errors which happen.
+    pub fn try_finish(&mut self) -> io::Result<()> {
+        self.inner.try_finish()
+    }
+
+    /// Consumes this decoder, flushing the output stream.
+    ///
+    /// This will flush the underlying data stream and then return the contained
+    /// writer if the flush succeeded.
+    ///
+    /// Note that this function may not be suitable to call in a situation where
+    /// the underlying stream is an asynchronous I/O stream. To finish a stream
+    /// the `try_finish` (or `shutdown`) method should be used instead. To
+    /// re-acquire ownership of a stream it is safe to call this method after
+    /// `try_finish` or `shutdown` has returned `Ok`.
+    ///
+    /// # Errors
+    ///
+    /// This function will perform I/O to complete this stream, and any I/O
+    /// errors which occur will be returned from this function.
+    pub fn finish(self) -> io::Result<W> {
+        self.inner.finish()
+    }
+}
+
+impl<W: Write> Write for MultiGzDecoder<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if buf.is_empty() {
+            Ok(0)
+        } else {
+            match self.inner.write(buf) {
+                Ok(0) => {
+                    // When the GzDecoder indicates that it has finished
+                    // create a new GzDecoder to handle additional data.
+                    self.inner.try_finish()?;
+                    let w = self.inner.inner.take_inner().into_inner();
+                    self.inner = GzDecoder::new(w);
+                    self.inner.write(buf)
+                }
+                res => res,
+            }
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.inner.flush()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const STR: &str = "Hello World Hello World Hello World Hello World Hello World \
+                               Hello World Hello World Hello World Hello World Hello World \
+                               Hello World Hello World Hello World Hello World Hello World \
+                               Hello World Hello World Hello World Hello World Hello World \
+                               Hello World Hello World Hello World Hello World Hello World";
+
+    #[test]
+    fn decode_writer_one_chunk() {
+        let mut e = GzEncoder::new(Vec::new(), Compression::default());
+        e.write(STR.as_ref()).unwrap();
+        let bytes = e.finish().unwrap();
+
+        let mut writer = Vec::new();
+        let mut decoder = GzDecoder::new(writer);
+        let n = decoder.write(&bytes[..]).unwrap();
+        decoder.write(&bytes[n..]).unwrap();
+        decoder.try_finish().unwrap();
+        writer = decoder.finish().unwrap();
+        let return_string = String::from_utf8(writer).expect("String parsing error");
+        assert_eq!(return_string, STR);
+    }
+
+    #[test]
+    fn decode_writer_partial_header() {
+        let mut e = GzEncoder::new(Vec::new(), Compression::default());
+        e.write(STR.as_ref()).unwrap();
+        let bytes = e.finish().unwrap();
+
+        let mut writer = Vec::new();
+        let mut decoder = GzDecoder::new(writer);
+        assert_eq!(decoder.write(&bytes[..5]).unwrap(), 5);
+        let n = decoder.write(&bytes[5..]).unwrap();
+        if n < bytes.len() - 5 {
+            decoder.write(&bytes[n + 5..]).unwrap();
+        }
+        writer = decoder.finish().unwrap();
+        let return_string = String::from_utf8(writer).expect("String parsing error");
+        assert_eq!(return_string, STR);
+    }
+
+    #[test]
+    fn decode_writer_partial_header_filename() {
+        let filename = "test.txt";
+        let mut e = GzBuilder::new()
+            .filename(filename)
+            .read(STR.as_bytes(), Compression::default());
+        let mut bytes = Vec::new();
+        e.read_to_end(&mut bytes).unwrap();
+
+        let mut writer = Vec::new();
+        let mut decoder = GzDecoder::new(writer);
+        assert_eq!(decoder.write(&bytes[..12]).unwrap(), 12);
+        let n = decoder.write(&bytes[12..]).unwrap();
+        if n < bytes.len() - 12 {
+            decoder.write(&bytes[n + 12..]).unwrap();
+        }
+        assert_eq!(
+            decoder.header().unwrap().filename().unwrap(),
+            filename.as_bytes()
+        );
+        writer = decoder.finish().unwrap();
+        let return_string = String::from_utf8(writer).expect("String parsing error");
+        assert_eq!(return_string, STR);
+    }
+
+    #[test]
+    fn decode_writer_partial_header_comment() {
+        let comment = "test comment";
+        let mut e = GzBuilder::new()
+            .comment(comment)
+            .read(STR.as_bytes(), Compression::default());
+        let mut bytes = Vec::new();
+        e.read_to_end(&mut bytes).unwrap();
+
+        let mut writer = Vec::new();
+        let mut decoder = GzDecoder::new(writer);
+        assert_eq!(decoder.write(&bytes[..12]).unwrap(), 12);
+        let n = decoder.write(&bytes[12..]).unwrap();
+        if n < bytes.len() - 12 {
+            decoder.write(&bytes[n + 12..]).unwrap();
+        }
+        assert_eq!(
+            decoder.header().unwrap().comment().unwrap(),
+            comment.as_bytes()
+        );
+        writer = decoder.finish().unwrap();
+        let return_string = String::from_utf8(writer).expect("String parsing error");
+        assert_eq!(return_string, STR);
+    }
+
+    #[test]
+    fn decode_writer_exact_header() {
+        let mut e = GzEncoder::new(Vec::new(), Compression::default());
+        e.write(STR.as_ref()).unwrap();
+        let bytes = e.finish().unwrap();
+
+        let mut writer = Vec::new();
+        let mut decoder = GzDecoder::new(writer);
+        assert_eq!(decoder.write(&bytes[..10]).unwrap(), 10);
+        decoder.write(&bytes[10..]).unwrap();
+        writer = decoder.finish().unwrap();
+        let return_string = String::from_utf8(writer).expect("String parsing error");
+        assert_eq!(return_string, STR);
+    }
+
+    #[test]
+    fn decode_writer_partial_crc() {
+        let mut e = GzEncoder::new(Vec::new(), Compression::default());
+        e.write(STR.as_ref()).unwrap();
+        let bytes = e.finish().unwrap();
+
+        let mut writer = Vec::new();
+        let mut decoder = GzDecoder::new(writer);
+        let l = bytes.len() - 5;
+        let n = decoder.write(&bytes[..l]).unwrap();
+        decoder.write(&bytes[n..]).unwrap();
+        writer = decoder.finish().unwrap();
+        let return_string = String::from_utf8(writer).expect("String parsing error");
+        assert_eq!(return_string, STR);
+    }
+
+    // Two or more gzip files concatenated form a multi-member gzip file. MultiGzDecoder will
+    // concatenate the decoded contents of all members.
+    #[test]
+    fn decode_multi_writer() {
+        let mut e = GzEncoder::new(Vec::new(), Compression::default());
+        e.write(STR.as_ref()).unwrap();
+        let bytes = e.finish().unwrap().repeat(2);
+
+        let mut writer = Vec::new();
+        let mut decoder = MultiGzDecoder::new(writer);
+        let mut count = 0;
+        while count < bytes.len() {
+            let n = decoder.write(&bytes[count..]).unwrap();
+            assert!(n != 0);
+            count += n;
+        }
+        writer = decoder.finish().unwrap();
+        let return_string = String::from_utf8(writer).expect("String parsing error");
+        let expected = STR.repeat(2);
+        assert_eq!(return_string, expected);
+    }
+
+    // GzDecoder consumes one gzip member and then returns 0 for subsequent writes, allowing any
+    // additional data to be consumed by the caller.
+    #[test]
+    fn decode_extra_data() {
+        let compressed = {
+            let mut e = GzEncoder::new(Vec::new(), Compression::default());
+            e.write(STR.as_ref()).unwrap();
+            let mut b = e.finish().unwrap();
+            b.push(b'x');
+            b
+        };
+
+        let mut writer = Vec::new();
+        let mut decoder = GzDecoder::new(writer);
+        let mut consumed_bytes = 0;
+        loop {
+            let n = decoder.write(&compressed[consumed_bytes..]).unwrap();
+            if n == 0 {
+                break;
+            }
+            consumed_bytes += n;
+        }
+        writer = decoder.finish().unwrap();
+        let actual = String::from_utf8(writer).expect("String parsing error");
+        assert_eq!(actual, STR);
+        assert_eq!(&compressed[consumed_bytes..], b"x");
+    }
+}