DevComp/zip-rs-wasm
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Use Seek.stream_position instead of seek(0).

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BufReader can cache the result of stream_position() so it's fast, whereas seek(0) discards the read buffer and passes through straight to the OS. This drastically worsens the efficiency of loading performance when using BufReader (or anything else to avoid all these tiny reads going straight to the kernel).
This commit is contained in:
Pieter-Jan Briers 2022-04-11 14:30:27 +02:00
parent d82ccd0513
commit 6b5628bef4
2 changed files with 6 additions and 6 deletions
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2
src/read.rs
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@ -639,7 +639,7 @@ pub(crate) fn central_header_to_zip_file<R: Read + io::Seek>(
reader: &mut R,
archive_offset: u64,
) -> ZipResult<ZipFileData> {
let central_header_start = reader.seek(io::SeekFrom::Current(0))?;
let central_header_start = reader.stream_position()?;
// Parse central header
let signature = reader.read_u32::<LittleEndian>()?;
if signature != spec::CENTRAL_DIRECTORY_HEADER_SIGNATURE {

10
src/write.rs
View file

@ -348,7 +348,7 @@ impl<W: Write + io::Seek> ZipWriter<W> {
{
let writer = self.inner.get_plain();
let header_start = writer.seek(io::SeekFrom::Current(0))?;
let header_start = writer.stream_position()?;
let permissions = options.permissions.unwrap_or(0o100644);
let mut file = ZipFileData {
@ -375,7 +375,7 @@ impl<W: Write + io::Seek> ZipWriter<W> {
};
write_local_file_header(writer, &file)?;
let header_end = writer.seek(io::SeekFrom::Current(0))?;
let header_end = writer.stream_position()?;
self.stats.start = header_end;
*file.data_start.get_mut() = header_end;
@ -404,7 +404,7 @@ impl<W: Write + io::Seek> ZipWriter<W> {
file.crc32 = self.stats.hasher.clone().finalize();
file.uncompressed_size = self.stats.bytes_written;
let file_end = writer.seek(io::SeekFrom::Current(0))?;
let file_end = writer.stream_position()?;
file.compressed_size = file_end - self.stats.start;
update_local_file_header(writer, file)?;
@ -753,11 +753,11 @@ impl<W: Write + io::Seek> ZipWriter<W> {
{
let writer = self.inner.get_plain();
let central_start = writer.seek(io::SeekFrom::Current(0))?;
let central_start = writer.stream_position()?;
for file in self.files.iter() {
write_central_directory_header(writer, file)?;
}
let central_size = writer.seek(io::SeekFrom::Current(0))? - central_start;
let central_size = writer.stream_position()? - central_start;
if self.files.len() > spec::ZIP64_ENTRY_THR
|| central_size.max(central_start) > spec::ZIP64_BYTES_THR