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shuf: Add -r option to allow output lines to be repeated

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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.
This commit is contained in:
Tim Ledbetter 2023-05-16 20:59:15 +01:00 • committed by Andrew Kaster
parent 0f0d16bbec
commit 12d6845c4e
1 changed files with 17 additions and 8 deletions
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25
Userland/Utilities/shuf.cpp
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@ -20,9 +20,11 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
StringView path; StringView path;
Optional<size_t> head_count; Optional<size_t> head_count;
bool is_zero_terminated = false; bool is_zero_terminated = false;
bool allow_repeats = false;
args_parser.add_positional_argument(path, "File", "file", Core::ArgsParser::Required::No); args_parser.add_positional_argument(path, "File", "file", Core::ArgsParser::Required::No);
args_parser.add_option(head_count, "Output at most \"count\" lines", "head-count", 'n', "count"); args_parser.add_option(head_count, "Output at most \"count\" lines", "head-count", 'n', "count");
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');
args_parser.add_option(is_zero_terminated, "Split input on \\0, not newline", "zero-terminated", 'z'); args_parser.add_option(is_zero_terminated, "Split input on \\0, not newline", "zero-terminated", 'z');
args_parser.parse(arguments); args_parser.parse(arguments);
@ -30,14 +32,14 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
auto file = TRY(Core::File::open_file_or_standard_stream(path, Core::File::OpenMode::Read)); auto file = TRY(Core::File::open_file_or_standard_stream(path, Core::File::OpenMode::Read));
ByteBuffer buffer = TRY(file->read_until_eof()); ByteBuffer buffer = TRY(file->read_until_eof());
u8 input_delimiter = is_zero_terminated ? '\0' : '\n'; u8 delimiter = is_zero_terminated ? '\0' : '\n';
Vector<Bytes> lines; Vector<Bytes> lines;
auto bytes = buffer.span(); auto bytes = buffer.span();
size_t line_start = 0; size_t line_start = 0;
size_t line_length = 0; size_t line_length = 0;
for (size_t i = 0; i < bytes.size(); ++i) { for (size_t i = 0; i < bytes.size(); ++i) {
if (bytes[i] == input_delimiter) { if (bytes[i] == delimiter) {
lines.append(bytes.slice(line_start, line_length)); lines.append(bytes.slice(line_start, line_length));
line_start = i + 1; line_start = i + 1;
line_length = 0; line_length = 0;
@ -52,12 +54,19 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
if (lines.is_empty()) if (lines.is_empty())
return 0; return 0;
AK::shuffle(lines); Array<u8, 1> delimiter_bytes { delimiter };
if (allow_repeats) {
Array<u8, 1> output_delimiter = { '\n' }; for (size_t line_count = 0; !head_count.has_value() || line_count < head_count.value(); ++line_count) {
for (size_t i = 0; i < min(head_count.value_or(lines.size()), lines.size()); ++i) { size_t i = get_random_uniform(lines.size());
TRY(Core::System::write(STDOUT_FILENO, lines.at(i))); out(lines.at(i));
TRY(Core::System::write(STDOUT_FILENO, output_delimiter)); out(delimiter_bytes);
}
} else {
shuffle(lines);
for (size_t i = 0; i < min(head_count.value_or(lines.size()), lines.size()); ++i) {
out(lines.at(i));
out(delimiter_bytes);
}
} }
return 0; return 0;