Utilities: Add gzip utility

This is a small utility that is similar to gunzip but is used
for compression instead of decompression.

Userland/Utilities/CMakeLists.txt

@@ -51,6 +51,7 @@ target_link_libraries(tt LibPthread)
 target_link_libraries(grep LibRegex)
 target_link_libraries(zip LibArchive LibCompress LibCrypto)
 target_link_libraries(unzip LibArchive LibCompress)
+target_link_libraries(gzip LibCompress)
 target_link_libraries(gunzip LibCompress)
 target_link_libraries(CppParserTest LibCpp LibGUI)
 target_link_libraries(PreprocessorTest LibCpp LibGUI)

Userland/Utilities/gzip.cpp

@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2021, Idan Horowitz <idan.horowitz@gmail.com>
+ * 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 <AK/MappedFile.h>
+#include <LibCompress/Gzip.h>
+#include <LibCore/ArgsParser.h>
+#include <LibCore/FileStream.h>
+#include <unistd.h>
+
+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 compress", "FILE");
+    args_parser.parse(argc, argv);
+
+    if (write_to_stdout)
+        keep_input_files = true;
+
+    for (const String& input_filename : filenames) {
+        auto output_filename = String::formatted("{}.gz", input_filename);
+
+        // We map the whole file instead of streaming to reduce size overhead (gzip header) and increase the deflate block size (better compression)
+        // TODO: automatically fallback to buffered streaming for very large files
+        auto file_or_error = MappedFile::map(input_filename);
+        if (file_or_error.is_error()) {
+            warnln("Failed opening input file for reading: {}", file_or_error.error());
+            return 1;
+        }
+        auto file = file_or_error.value();
+
+        auto compressed_file = Compress::GzipCompressor::compress_all(file->bytes());
+        if (!compressed_file.has_value()) {
+            warnln("Failed gzip compressing input file");
+            return 1;
+        }
+
+        auto success = false;
+        if (write_to_stdout) {
+            auto stdout = Core::OutputFileStream { Core::File::standard_output() };
+            success = stdout.write_or_error(compressed_file.value());
+        } else {
+            auto output_stream_result = Core::OutputFileStream::open(output_filename);
+            if (output_stream_result.is_error()) {
+                warnln("Failed opening output file for writing: {}", output_stream_result.error());
+                return 1;
+            }
+            success = output_stream_result.value().write_or_error(compressed_file.value());
+        }
+        if (!success) {
+            warnln("Failed writing compressed file to output");
+            return 1;
+        }
+
+        if (!keep_input_files) {
+            const auto retval = unlink(input_filename.characters());
+            if (retval != 0) {
+                warnln("Failed removing input file");
+                return 1;
+            }
+        }
+    }
+    return 0;
+}