ladybird/Userland/gunzip.cpp
asynts 96edcbc27c AK: Lower the requirements for InputStream::eof and rename it.
Consider the following snippet:

    void foo(InputStream& stream) {
        if(!stream.eof()) {
            u8 byte;
            stream >> byte;
        }
    }

There is a very subtle bug in this snippet, for some input streams eof()
might return false even if no more data can be read. In this case an
error flag would be set on the stream.

Until now I've always ensured that this is not the case, but this made
the implementation of eof() unnecessarily complicated.
InputFileStream::eof had to keep a ByteBuffer around just to make this
possible. That meant a ton of unnecessary copies just to get a reliable
eof().

In most cases it isn't actually necessary to have a reliable eof()
implementation.

In most other cases a reliable eof() is avaliable anyways because in
some cases like InputMemoryStream it is very easy to implement.
2020-09-14 20:58:12 +02:00

80 lines
3.3 KiB
C++

/*
* Copyright (c) 2020, the SerenityOS developers.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <LibCompress/Gzip.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/FileStream.h>
static void decompress_file(Buffered<Core::InputFileStream>& input_stream, Buffered<Core::OutputFileStream>& output_stream)
{
auto gzip_stream = Compress::GzipDecompressor { input_stream };
u8 buffer[4096];
while (!gzip_stream.unreliable_eof()) {
const auto nread = gzip_stream.read({ buffer, sizeof(buffer) });
output_stream.write_or_error({ buffer, nread });
}
}
int main(int argc, char** argv)
{
Vector<const char*> filenames;
bool keep_input_files { false };
bool write_to_stdout { false };
Core::ArgsParser args_parser;
args_parser.add_option(keep_input_files, "Keep (don't delete) input files", "keep", 'k');
args_parser.add_option(write_to_stdout, "Write to stdout, keep original files unchanged", "stdout", 'c');
args_parser.add_positional_argument(filenames, "File to decompress", "FILE");
args_parser.parse(argc, argv);
if (write_to_stdout)
keep_input_files = true;
for (String filename : filenames) {
if (!filename.ends_with(".gz"))
filename = String::format("%s.gz", filename);
const auto input_filename = filename;
const auto output_filename = filename.substring_view(0, filename.length() - 3);
auto input_stream_result = Core::InputFileStream::open_buffered(input_filename);
if (write_to_stdout) {
auto stdout = Core::OutputFileStream::stdout_buffered();
decompress_file(input_stream_result.value(), stdout);
} else {
auto output_stream_result = Core::OutputFileStream::open_buffered(output_filename);
decompress_file(input_stream_result.value(), output_stream_result.value());
}
if (!keep_input_files) {
const auto retval = unlink(String { input_filename }.characters());
ASSERT(retval == 0);
}
}
}