Skip to content

Optimize Vec capacity in DeflateEncoder output_buffers #420

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
404Setup merged 1 commit into from
Apr 12, 2026
Merged

Optimize Vec capacity in DeflateEncoder output_buffers #420

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
20 changes: 15 additions & 5 deletions src/stream.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -50,11 +50,20 @@ impl<W: Write + Send> DeflateEncoder<W> {
let chunks: Vec<&[u8]> = self.buffer.chunks(chunk_size).collect();
let num_chunks = chunks.len();

while self.compressors.len() < num_chunks {
self.compressors.push(Compressor::new(self.level));
if self.compressors.len() < num_chunks {
self.compressors.reserve(num_chunks - self.compressors.len());
while self.compressors.len() < num_chunks {
self.compressors.push(Compressor::new(self.level));
}
}
while self.output_buffers.len() < num_chunks {
self.output_buffers.push(Vec::new());

if self.output_buffers.len() < num_chunks {
self.output_buffers
.reserve(num_chunks - self.output_buffers.len());
let bound = Compressor::deflate_compress_bound(chunk_size) + 5;
while self.output_buffers.len() < num_chunks {
self.output_buffers.push(Vec::with_capacity(bound));
}
}

if num_chunks == 1 {
Expand Down Expand Up @@ -135,7 +144,8 @@ impl<W: Write + Send> DeflateEncoder<W> {
self.compressors.push(Compressor::new(self.level));
}
if self.output_buffers.is_empty() {
self.output_buffers.push(Vec::new());
let bound = Compressor::deflate_compress_bound(self.buffer.len()) + 5;
self.output_buffers.push(Vec::with_capacity(bound));
}

let compressor = &mut self.compressors[0];
Expand Down