1 files changed, 184 insertions, 0 deletions
diff --git a/third_party/rust/flate2/src/crc.rs b/third_party/rust/flate2/src/crc.rs
new file mode 100644
index 0000000000..cd00cebe18
--- /dev/null
+++ b/third_party/rust/flate2/src/crc.rs
@@ -0,0 +1,184 @@
+//! Simple CRC bindings backed by miniz.c
+
+use std::io;
+use std::io::prelude::*;
+
+use crc32fast::Hasher;
+
+/// The CRC calculated by a [`CrcReader`].
+///
+/// [`CrcReader`]: struct.CrcReader.html
+#[derive(Debug)]
+pub struct Crc {
+    amt: u32,
+    hasher: Hasher,
+}
+
+/// A wrapper around a [`Read`] that calculates the CRC.
+///
+/// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
+#[derive(Debug)]
+pub struct CrcReader<R> {
+    inner: R,
+    crc: Crc,
+}
+
+impl Default for Crc {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Crc {
+    /// Create a new CRC.
+    pub fn new() -> Crc {
+        Crc {
+            amt: 0,
+            hasher: Hasher::new(),
+        }
+    }
+
+    /// Returns the current crc32 checksum.
+    pub fn sum(&self) -> u32 {
+        self.hasher.clone().finalize()
+    }
+
+    /// The number of bytes that have been used to calculate the CRC.
+    /// This value is only accurate if the amount is lower than 2<sup>32</sup>.
+    pub fn amount(&self) -> u32 {
+        self.amt
+    }
+
+    /// Update the CRC with the bytes in `data`.
+    pub fn update(&mut self, data: &[u8]) {
+        self.amt = self.amt.wrapping_add(data.len() as u32);
+        self.hasher.update(data);
+    }
+
+    /// Reset the CRC.
+    pub fn reset(&mut self) {
+        self.amt = 0;
+        self.hasher.reset();
+    }
+
+    /// Combine the CRC with the CRC for the subsequent block of bytes.
+    pub fn combine(&mut self, additional_crc: &Crc) {
+        self.amt += additional_crc.amt;
+        self.hasher.combine(&additional_crc.hasher);
+    }
+}
+
+impl<R: Read> CrcReader<R> {
+    /// Create a new CrcReader.
+    pub fn new(r: R) -> CrcReader<R> {
+        CrcReader {
+            inner: r,
+            crc: Crc::new(),
+        }
+    }
+}
+
+impl<R> CrcReader<R> {
+    /// Get the Crc for this CrcReader.
+    pub fn crc(&self) -> &Crc {
+        &self.crc
+    }
+
+    /// Get the reader that is wrapped by this CrcReader.
+    pub fn into_inner(self) -> R {
+        self.inner
+    }
+
+    /// Get the reader that is wrapped by this CrcReader by reference.
+    pub fn get_ref(&self) -> &R {
+        &self.inner
+    }
+
+    /// Get a mutable reference to the reader that is wrapped by this CrcReader.
+    pub fn get_mut(&mut self) -> &mut R {
+        &mut self.inner
+    }
+
+    /// Reset the Crc in this CrcReader.
+    pub fn reset(&mut self) {
+        self.crc.reset();
+    }
+}
+
+impl<R: Read> Read for CrcReader<R> {
+    fn read(&mut self, into: &mut [u8]) -> io::Result<usize> {
+        let amt = self.inner.read(into)?;
+        self.crc.update(&into[..amt]);
+        Ok(amt)
+    }
+}
+
+impl<R: BufRead> BufRead for CrcReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        self.inner.fill_buf()
+    }
+    fn consume(&mut self, amt: usize) {
+        if let Ok(data) = self.inner.fill_buf() {
+            self.crc.update(&data[..amt]);
+        }
+        self.inner.consume(amt);
+    }
+}
+
+/// A wrapper around a [`Write`] that calculates the CRC.
+///
+/// [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
+#[derive(Debug)]
+pub struct CrcWriter<W> {
+    inner: W,
+    crc: Crc,
+}
+
+impl<W> CrcWriter<W> {
+    /// Get the Crc for this CrcWriter.
+    pub fn crc(&self) -> &Crc {
+        &self.crc
+    }
+
+    /// Get the writer that is wrapped by this CrcWriter.
+    pub fn into_inner(self) -> W {
+        self.inner
+    }
+
+    /// Get the writer that is wrapped by this CrcWriter by reference.
+    pub fn get_ref(&self) -> &W {
+        &self.inner
+    }
+
+    /// Get a mutable reference to the writer that is wrapped by this CrcWriter.
+    pub fn get_mut(&mut self) -> &mut W {
+        &mut self.inner
+    }
+
+    /// Reset the Crc in this CrcWriter.
+    pub fn reset(&mut self) {
+        self.crc.reset();
+    }
+}
+
+impl<W: Write> CrcWriter<W> {
+    /// Create a new CrcWriter.
+    pub fn new(w: W) -> CrcWriter<W> {
+        CrcWriter {
+            inner: w,
+            crc: Crc::new(),
+        }
+    }
+}
+
+impl<W: Write> Write for CrcWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let amt = self.inner.write(buf)?;
+        self.crc.update(&buf[..amt]);
+        Ok(amt)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.inner.flush()
+    }
+}