mirror of
https://github.com/SerenityOS/serenity
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12d6845c4e
This commit also modifies the behavior of the `-z` option, so that a '\0' character now delimits output lines, as well as input lines. This matches the behavior of the GNU coreutils and FreeBSD implementations of shuf.
74 lines
2.3 KiB
C++
74 lines
2.3 KiB
C++
/*
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* Copyright (c) 2021, Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
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* Copyright (c) 2022, Eli Youngs <eli.m.youngs@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Random.h>
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#include <AK/Vector.h>
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#include <LibCore/ArgsParser.h>
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#include <LibCore/File.h>
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#include <LibCore/System.h>
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#include <LibMain/Main.h>
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ErrorOr<int> serenity_main(Main::Arguments arguments)
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{
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TRY(Core::System::pledge("stdio rpath"));
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Core::ArgsParser args_parser;
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StringView path;
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Optional<size_t> head_count;
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bool is_zero_terminated = false;
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bool allow_repeats = false;
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args_parser.add_positional_argument(path, "File", "file", Core::ArgsParser::Required::No);
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args_parser.add_option(head_count, "Output at most \"count\" lines", "head-count", 'n', "count");
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args_parser.add_option(allow_repeats, "Pick lines at random rather than shuffling. The program will continue indefinitely if no `-n` option is specified", "repeat", 'r');
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args_parser.add_option(is_zero_terminated, "Split input on \\0, not newline", "zero-terminated", 'z');
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args_parser.parse(arguments);
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auto file = TRY(Core::File::open_file_or_standard_stream(path, Core::File::OpenMode::Read));
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ByteBuffer buffer = TRY(file->read_until_eof());
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u8 delimiter = is_zero_terminated ? '\0' : '\n';
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Vector<Bytes> lines;
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auto bytes = buffer.span();
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size_t line_start = 0;
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size_t line_length = 0;
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for (size_t i = 0; i < bytes.size(); ++i) {
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if (bytes[i] == delimiter) {
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lines.append(bytes.slice(line_start, line_length));
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line_start = i + 1;
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line_length = 0;
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} else {
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++line_length;
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}
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}
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if (line_length > 0) {
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lines.append(bytes.slice(line_start));
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}
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if (lines.is_empty())
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return 0;
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Array<u8, 1> delimiter_bytes { delimiter };
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if (allow_repeats) {
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for (size_t line_count = 0; !head_count.has_value() || line_count < head_count.value(); ++line_count) {
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size_t i = get_random_uniform(lines.size());
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out(lines.at(i));
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out(delimiter_bytes);
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}
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} else {
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shuffle(lines);
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for (size_t i = 0; i < min(head_count.value_or(lines.size()), lines.size()); ++i) {
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out(lines.at(i));
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out(delimiter_bytes);
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}
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}
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return 0;
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}
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