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author | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
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committer | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
commit | 1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch) | |
tree | 7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/weezl/src/encode_into_async.rs | |
parent | 5ecd8cf2cba827454317368b68571df0d13d7842 (diff) | |
download | fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip |
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
Diffstat (limited to 'vendor/weezl/src/encode_into_async.rs')
-rw-r--r-- | vendor/weezl/src/encode_into_async.rs | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/vendor/weezl/src/encode_into_async.rs b/vendor/weezl/src/encode_into_async.rs new file mode 100644 index 0000000..6973540 --- /dev/null +++ b/vendor/weezl/src/encode_into_async.rs @@ -0,0 +1,142 @@ +use crate::encode::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> { + /// Encode data from a reader. + /// + /// This will drain the supplied reader. It will not encode an end marker after all data has + /// been processed. + pub async fn encode(&mut self, read: impl futures::io::AsyncBufRead) -> StreamResult { + self.encode_part(read, false).await + } + + /// Encode data from a reader and an end marker. + pub async fn encode_all(mut self, read: impl futures::io::AsyncBufRead) -> StreamResult { + self.encode_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 encode_part( + &mut self, + read: impl futures::io::AsyncBufRead, + finish: bool, + ) -> StreamResult { + use futures::io::AsyncBufReadExt; + use futures::io::AsyncWriteExt; + + let IntoAsync { + encoder, + 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), + }; + + if data.is_empty() { + if finish { + encoder.finish(); + } else { + break Ok(()); + } + } + + // Decode as much of the buffer as fits. + let result = encoder.encode_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 done = match result.status { + Ok(ok) => ok, + Err(err) => { + break Err(io::Error::new( + io::ErrorKind::InvalidData, + &*format!("{:?}", err), + )); + } + }; + + if let LzwStatus::Done = done { + break writer.write_all(&outbuf[..result.consumed_out]).await; + } + + if let LzwStatus::NoProgress = done { + break Err(io::Error::new( + io::ErrorKind::UnexpectedEof, + "No more data but no end marker detected", + )); + } + + // 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), + } + }; + + StreamResult { + bytes_read, + bytes_written, + status, + } + } +} |