diff --git a/Userland/Utilities/CMakeLists.txt b/Userland/Utilities/CMakeLists.txt index d9582b6eac..afad68607d 100644 --- a/Userland/Utilities/CMakeLists.txt +++ b/Userland/Utilities/CMakeLists.txt @@ -71,6 +71,7 @@ target_link_libraries(chown LibMain) target_link_libraries(chres LibGUI LibMain) target_link_libraries(cksum LibCrypto LibMain) target_link_libraries(clear LibMain) +target_link_libraries(cmp LibMain) target_link_libraries(comm LibMain) target_link_libraries(config LibConfig LibMain) target_link_libraries(copy LibGUI LibMain) diff --git a/Userland/Utilities/cmp.cpp b/Userland/Utilities/cmp.cpp new file mode 100644 index 0000000000..01374164de --- /dev/null +++ b/Userland/Utilities/cmp.cpp @@ -0,0 +1,101 @@ +/* + * Copyright (c) 2022, Sam Atkins + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +#include +#include +#include +#include +#include + +static ErrorOr> open_file_or_stdin(String const& filename) +{ + OwnPtr file; + if (filename == "-") { + file = TRY(Core::Stream::File::adopt_fd(STDIN_FILENO, Core::Stream::OpenMode::Read)); + } else { + file = TRY(Core::Stream::File::open(filename, Core::Stream::OpenMode::Read)); + } + return TRY(Core::Stream::BufferedFile::create(file.release_nonnull())); +} + +ErrorOr serenity_main(Main::Arguments arguments) +{ + Main::set_return_code_for_errors(2); + TRY(Core::System::pledge("stdio rpath")); + + Core::ArgsParser parser; + String filename1; + String filename2; + bool verbose = false; + bool silent = false; + + parser.set_general_help("Compare two files, and report the first byte that does not match. Returns 0 if files are identical, or 1 if they differ."); + parser.add_positional_argument(filename1, "First file to compare", "file1", Core::ArgsParser::Required::Yes); + parser.add_positional_argument(filename2, "Second file to compare", "file2", Core::ArgsParser::Required::Yes); + parser.add_option(verbose, "Output every byte mismatch, not just the first", "verbose", 'l'); + parser.add_option(silent, "Disable all output", "silent", 's'); + parser.parse(arguments); + + // When opening STDIN as both files, the results are undefined. + // Let's just report that it matches. + if (filename1 == "-" && filename2 == "-") + return 0; + + auto file1 = TRY(open_file_or_stdin(filename1)); + auto file2 = TRY(open_file_or_stdin(filename2)); + TRY(Core::System::unveil(nullptr, nullptr)); + + int line_number = 1; + int byte_number = 1; + Array buffer1; + Array buffer2; + bool files_match = true; + + auto report_mismatch = [&]() { + files_match = false; + if (silent) + return; + if (verbose) + outln("{} {:o} {:o}", byte_number, buffer1[0], buffer2[0]); + else + outln("{} {} differ: char {}, line {}", filename1, filename2, byte_number, line_number); + }; + + auto report_eof = [&](auto& shorter_file_name) { + files_match = false; + if (silent) + return; + auto additional_info = verbose + ? String::formatted(" after byte {}", byte_number) + : String::formatted(" after byte {}, line {}", byte_number, line_number); + warnln("cmp: EOF on {}{}", shorter_file_name, additional_info); + }; + + while (true) { + TRY(file1->read(buffer1)); + TRY(file2->read(buffer2)); + + if (file1->is_eof() && file2->is_eof()) + break; + + if (file1->is_eof() || file2->is_eof()) { + report_eof(file1->is_eof() ? filename1 : filename2); + break; + } + + if (buffer1[0] != buffer2[0]) { + report_mismatch(); + if (!verbose) + break; + } + + if (buffer1[0] == '\n') + ++line_number; + ++byte_number; + } + + return files_match ? 0 : 1; +}