79 lines
2.3 KiB
Rust
79 lines
2.3 KiB
Rust
//! Compression of events passed between a broker and clients.
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//! Currently we use the gzip compression algorithm for its fast decompression performance.
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use alloc::vec::Vec;
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use core::fmt::Debug;
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use miniz_oxide::{
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deflate::{compress_to_vec, CompressionLevel},
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inflate::decompress_to_vec,
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};
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use crate::Error;
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/// Compression for your stream compression needs.
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#[derive(Debug)]
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pub struct GzipCompressor {
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/// If less bytes than threshold are being passed to `compress`, the payload is not getting compressed.
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threshold: usize,
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}
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impl GzipCompressor {
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/// If the buffer is at least larger as large as the `threshold` value, we compress the buffer.
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/// When given a `threshold` of `0`, the `GzipCompressor` will always compress.
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#[must_use]
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pub fn new(threshold: usize) -> Self {
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Self { threshold }
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}
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}
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impl GzipCompressor {
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/// Compression.
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/// If the buffer is smaller than the threshold of this compressor, `None` will be returned.
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/// Else, the buffer is compressed.
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pub fn compress(&self, buf: &[u8]) -> Result<Option<Vec<u8>>, Error> {
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if buf.len() >= self.threshold {
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//compress if the buffer is large enough
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let compressed = compress_to_vec(buf, CompressionLevel::BestSpeed as u8);
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Ok(Some(compressed))
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} else {
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Ok(None)
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}
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}
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/// Decompression.
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/// Flag is used to indicate if it's compressed or not
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#[allow(clippy::unused_self)]
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pub fn decompress(&self, buf: &[u8]) -> Result<Vec<u8>, Error> {
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let decompressed = decompress_to_vec(buf);
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match decompressed {
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Ok(buf) => Ok(buf),
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Err(_) => Err(Error::compression()),
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use crate::bolts::compress::GzipCompressor;
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#[test]
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fn test_compression() {
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let compressor = GzipCompressor::new(1);
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assert!(
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compressor
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.decompress(&compressor.compress(&[1u8; 1024]).unwrap().unwrap())
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.unwrap()
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== vec![1u8; 1024]
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);
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}
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#[test]
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fn test_threshold() {
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let compressor = GzipCompressor::new(1024);
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assert!(compressor.compress(&[1u8; 1023]).unwrap().is_none());
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assert!(compressor.compress(&[1u8; 1024]).unwrap().is_some());
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}
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}
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