1 files changed, 143 insertions, 0 deletions
diff --git a/vendor/weezl/src/decode_into_async.rs b/vendor/weezl/src/decode_into_async.rs
new file mode 100644
index 0000000..e39a26f
--- /dev/null
+++ b/vendor/weezl/src/decode_into_async.rs
@@ -0,0 +1,143 @@
+use crate::decode::IntoAsync;
+use crate::error::LzwStatus;
+use crate::error::StreamResult;
+use crate::StreamBuf;
+use std::io;
+
+impl<'d, W: futures::io::AsyncWrite + core::marker::Unpin> IntoAsync<'d, W> {
+    /// Decode data from a reader.
+    ///
+    /// This will read data until the stream is empty or an end marker is reached.
+    pub async fn decode(&mut self, read: impl futures::io::AsyncBufRead) -> StreamResult {
+        self.decode_part(read, false).await
+    }
+
+    /// Decode data from a reader, requiring an end marker.
+    pub async fn decode_all(mut self, read: impl futures::io::AsyncBufRead) -> StreamResult {
+        self.decode_part(read, true).await
+    }
+
+    /// Set the size of the intermediate decode buffer.
+    ///
+    /// A buffer of this size is allocated to hold one part of the decoded stream when no buffer is
+    /// available and any decoding method is called. No buffer is allocated if `set_buffer` has
+    /// been called. The buffer is reused.
+    ///
+    /// # Panics
+    /// This method panics if `size` is `0`.
+    pub fn set_buffer_size(&mut self, size: usize) {
+        assert_ne!(size, 0, "Attempted to set empty buffer");
+        self.default_size = size;
+    }
+
+    /// Use a particular buffer as an intermediate decode buffer.
+    ///
+    /// Calling this sets or replaces the buffer. When a buffer has been set then it is used
+    /// instead of dynamically allocating a buffer. Note that the size of the buffer is critical
+    /// for efficient decoding. Some optimization techniques require the buffer to hold one or more
+    /// previous decoded words. There is also additional overhead from `write` calls each time the
+    /// buffer has been filled.
+    ///
+    /// # Panics
+    /// This method panics if the `buffer` is empty.
+    pub fn set_buffer(&mut self, buffer: &'d mut [u8]) {
+        assert_ne!(buffer.len(), 0, "Attempted to set empty buffer");
+        self.buffer = Some(StreamBuf::Borrowed(buffer));
+    }
+
+    async fn decode_part(
+        &mut self,
+        read: impl futures::io::AsyncBufRead,
+        must_finish: bool,
+    ) -> StreamResult {
+        use futures::io::AsyncBufReadExt;
+        use futures::io::AsyncWriteExt;
+
+        let IntoAsync {
+            decoder,
+            writer,
+            buffer,
+            default_size,
+        } = self;
+
+        futures::pin_mut!(read);
+        let mut read: core::pin::Pin<_> = read;
+
+        let mut bytes_read = 0;
+        let mut bytes_written = 0;
+
+        // Converting to mutable refs to move into the `once` closure.
+        let read_bytes = &mut bytes_read;
+        let write_bytes = &mut bytes_written;
+
+        let outbuf: &mut [u8] =
+            match { buffer.get_or_insert_with(|| StreamBuf::Owned(vec![0u8; *default_size])) } {
+                StreamBuf::Borrowed(slice) => &mut *slice,
+                StreamBuf::Owned(vec) => &mut *vec,
+            };
+        assert!(!outbuf.is_empty());
+
+        let status = loop {
+            // Try to grab one buffer of input data.
+            let mut filler = read.as_mut();
+            let data = match filler.fill_buf().await {
+                Ok(buf) => buf,
+                Err(err) => break Err(err),
+            };
+
+            // Decode as much of the buffer as fits.
+            let result = decoder.decode_bytes(data, &mut outbuf[..]);
+            // Do the bookkeeping and consume the buffer.
+            *read_bytes += result.consumed_in;
+            *write_bytes += result.consumed_out;
+            read.as_mut().consume(result.consumed_in);
+
+            // Handle an error status in the result.
+            let status = match result.status {
+                Ok(ok) => ok,
+                Err(err) => {
+                    break Err(io::Error::new(
+                        io::ErrorKind::InvalidData,
+                        &*format!("{:?}", err),
+                    ));
+                }
+            };
+
+            // Check if we had any new data at all.
+            if let LzwStatus::NoProgress = status {
+                debug_assert_eq!(
+                    result.consumed_out, 0,
+                    "No progress means we have not decoded any data"
+                );
+                // In particular we did not finish decoding.
+                if must_finish {
+                    break Err(io::Error::new(
+                        io::ErrorKind::UnexpectedEof,
+                        "No more data but no end marker detected",
+                    ));
+                } else {
+                    break Ok(());
+                }
+            }
+
+            // And finish by writing our result.
+            // TODO: we may lose data on error (also on status error above) which we might want to
+            // deterministically handle so that we don't need to restart everything from scratch as
+            // the only recovery strategy. Any changes welcome.
+            match writer.write_all(&outbuf[..result.consumed_out]).await {
+                Ok(_) => {}
+                Err(err) => break Err(err),
+            }
+
+            if let LzwStatus::Done = status {
+                break Ok(());
+            }
+        };
+
+        StreamResult {
+            bytes_read,
+            bytes_written,
+            status,
+        }
+    }
+}