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Utilities: cut: Implement field-based cutting

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This commit is contained in:
Tim Schumacher 2021-11-09 03:58:05 +01:00 • committed by Andreas Kling
parent 96ea4f71bd
commit ba29798039
1 changed files with 88 additions and 41 deletions
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129
Userland/Utilities/cut.cpp
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@ -120,45 +120,12 @@ static bool expand_list(String& list, Vector<Range>& ranges)
return true;
}
static void cut_file(const String& file, const Vector<Range>& ranges, void (*process_line)(char*, size_t, const Vector<Range>&))
{
FILE* fp = stdin;
if (!file.is_null()) {
fp = fopen(file.characters(), "r");
if (!fp) {
warnln("cut: Could not open file '{}'", file);
return;
}
}
char* line = nullptr;
ssize_t line_length = 0;
size_t line_capacity = 0;
while ((line_length = getline(&line, &line_capacity, fp)) != -1) {
if (line_length < 0) {
warnln("cut: Failed to read line from file '{}'", file);
return;
}
line[line_length - 1] = '\0';
line_length--;
process_line(line, line_length, ranges);
}
if (line)
free(line);
if (!file.is_null())
fclose(fp);
}
static void process_line_bytes(char* line, size_t length, const Vector<Range>& ranges)
{
for (auto& i : ranges) {
if (i.m_from >= length)
continue;
auto to = min(i.m_to, length);
auto sub_string = String(line).substring(i.m_from - 1, to - i.m_from + 1);
out("{}", sub_string);
@ -166,35 +133,81 @@ static void process_line_bytes(char* line, size_t length, const Vector<Range>& r
outln();
}
static void process_line_fields(char* line, size_t length, const Vector<Range>& ranges, char delimiter)
{
auto string_split = String(line, length).split(delimiter);
Vector<String> output_fields;
for (auto& range : ranges) {
for (size_t i = range.m_from - 1; i < min(range.m_to, string_split.size()); i++) {
output_fields.append(string_split[i]);
}
}
outln("{}", String::join(delimiter, output_fields));
}
int main(int argc, char** argv)
{
String byte_list = "";
String fields_list = "";
String delimiter = "\t";
Vector<String> files;
Core::ArgsParser args_parser;
args_parser.add_positional_argument(files, "file(s) to cut", "file", Core::ArgsParser::Required::No);
args_parser.add_option(byte_list, "select only these bytes", "bytes", 'b', "list");
args_parser.add_option(fields_list, "select only these fields", "fields", 'f', "list");
args_parser.add_option(delimiter, "set a custom delimiter", "delimiter", 'd', "delimiter");
args_parser.parse(argc, argv);
if (byte_list == "") {
warnln("cut: you must specify a list of bytes");
bool selected_bytes = (byte_list != "");
bool selected_fields = (fields_list != "");
int selected_options_count = (selected_bytes ? 1 : 0) + (selected_fields ? 1 : 0);
if (selected_options_count == 0) {
warnln("cut: you must specify a list of bytes, or fields");
args_parser.print_usage(stderr, argv[0]);
return 1;
}
Vector<Range> byte_vector;
auto expansion_successful = expand_list(byte_list, byte_vector);
if (selected_options_count > 1) {
warnln("cut: you must specify only one of bytes, or fields");
args_parser.print_usage(stderr, argv[0]);
return 1;
}
if (delimiter.length() != 1) {
warnln("cut: the delimiter must be a single character");
args_parser.print_usage(stderr, argv[0]);
return 1;
}
String ranges_list;
Vector<Range> ranges_vector;
if (selected_bytes) {
ranges_list = byte_list;
} else if (selected_fields) {
ranges_list = fields_list;
} else {
// This should never happen, since we already checked the options count above.
VERIFY_NOT_REACHED();
}
auto expansion_successful = expand_list(ranges_list, ranges_vector);
if (!expansion_successful) {
args_parser.print_usage(stderr, argv[0]);
return 1;
}
quick_sort(byte_vector, [](auto& a, auto& b) { return a.m_from < b.m_from; });
quick_sort(ranges_vector, [](auto& a, auto& b) { return a.m_from < b.m_from; });
Vector<Range> disjoint_ranges;
for (auto& range : byte_vector) {
for (auto& range : ranges_vector) {
if (disjoint_ranges.is_empty()) {
disjoint_ranges.append(range);
continue;
@ -214,8 +227,42 @@ int main(int argc, char** argv)
files.append(String());
/* Process each file */
for (auto& file : files)
cut_file(file, disjoint_ranges, process_line_bytes);
for (auto& file : files) {
FILE* fp = stdin;
if (!file.is_null()) {
fp = fopen(file.characters(), "r");
if (!fp) {
warnln("cut: Could not open file '{}'", file);
continue;
}
}
char* line = nullptr;
ssize_t line_length = 0;
size_t line_capacity = 0;
while ((line_length = getline(&line, &line_capacity, fp)) != -1) {
if (line_length < 0) {
warnln("cut: Failed to read line from file '{}'", file);
break;
}
line[line_length - 1] = '\0';
line_length--;
if (selected_bytes) {
process_line_bytes(line, line_length, disjoint_ranges);
} else if (selected_fields) {
process_line_fields(line, line_length, disjoint_ranges, delimiter[0]);
} else {
VERIFY_NOT_REACHED();
}
}
if (line)
free(line);
if (!file.is_null())
fclose(fp);
}
return 0;
}