serenity/Userland/Utilities/xzcat.cpp
Tim Schumacher 3ec513ecf2 xzcat: Use BufferedFile for reading inputs
This improves the decompression time of `clang-15.0.7.src.tar.xz` from
41 seconds down to about 5 seconds.

The reason for this very significant improvement is that LZMA, the
underlying compression of XZ, fills its range decompressor one byte at a
time, causing a lot of overhead at the syscall barrier.
2023-04-05 07:30:38 -04:00

37 lines
1 KiB
C++

/*
* Copyright (c) 2023, Tim Schumacher <timschumi@gmx.de>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibCompress/Xz.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/File.h>
#include <LibCore/System.h>
#include <LibMain/Main.h>
ErrorOr<int> serenity_main(Main::Arguments arguments)
{
TRY(Core::System::pledge("rpath stdio"));
StringView filename;
Core::ArgsParser args_parser;
args_parser.set_general_help("Decompress and print an XZ archive");
args_parser.add_positional_argument(filename, "File to decompress", "file");
args_parser.parse(arguments);
auto file = TRY(Core::File::open_file_or_standard_stream(filename, Core::File::OpenMode::Read));
auto buffered_file = TRY(Core::BufferedFile::create(move(file)));
auto stream = TRY(Compress::XzDecompressor::create(move(buffered_file)));
// Arbitrarily chosen buffer size.
Array<u8, 4096> buffer;
while (!stream->is_eof()) {
auto slice = TRY(stream->read_some(buffer));
out("{:s}", slice);
}
return 0;
}