Userland: Add support for printing multiple columns to the cal command

Now cal is able to print the entire year when only that is passed
as an argument. For example: `cal 1992`.

However this meant breaking the highlighted day escape sequence
as it messed up the layout and the character count for each of the
rows :(

Now the current day is specified like 17* (for example for day 17).

Userland/cal.cpp

@@ -1,6 +1,21 @@
+#include <LibCore/CArgsParser.h>
 #include <stdio.h>
 #include <time.h>
 
+const int line_width = 70;
+const int line_count = 8;
+const int column_width = 22;
+
+char print_buffer[line_width * line_count];
+char temp_buffer[line_width * 8];
+
+int target_year;
+int target_month;
+int target_day;
+
+int current_year;
+int current_month;
+
 int day_of_week(int day, int month, int year)
 {
  static const int seek_table[] = { 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4 };
@@ -21,29 +36,139 @@ int get_number_of_days(int month, int year)
  return is_long_month ? 31 : 30;
 }
 
+void append_to_print(char* buffer, int row, int column, char* text)
+{
+ int starting_point = (line_width * row) + (column * column_width);
+ for (int i = 0; text[i] != '\0'; i++) {
+ buffer[starting_point + i] = text[i];
+ }
+}
+
+void insert_month_to_print(int column, int month, int year)
+{
+ int printing_column = column;
+ int printing_row = 0;
+
+ // FIXME: Both the month name and month header text should be provided by a locale
+ sprintf(temp_buffer, " %02u - %04u ", month, year);
+ append_to_print(print_buffer, printing_row, printing_column, temp_buffer);
+ printing_row++;
+
+ sprintf(temp_buffer, "Su Mo Tu We Th Fr Sa");
+ append_to_print(print_buffer, printing_row, printing_column, temp_buffer);
+ printing_row++;
+
+ int day_to_print = 1;
+ int first_day_of_week_for_month = day_of_week(1, month, year);
+ int days_in_the_month = get_number_of_days(month, year);
+ int last_written_chars = 0;
+ for (int i = 1; day_to_print <= days_in_the_month; ++i) {
+ if (i - 1 < first_day_of_week_for_month) {
+ last_written_chars += sprintf(temp_buffer + last_written_chars, " ");
+ } else {
+ if (year == current_year && month == current_month && target_day == day_to_print) {
+ // FIXME: To replicate Unix cal it would be better to use "\x1b[30;47m%2d\x1b[0m " in here instead of *.
+ // However, doing that messes up the layout.
+ last_written_chars += sprintf(temp_buffer + last_written_chars, "%2d*", day_to_print);
+ } else {
+ last_written_chars += sprintf(temp_buffer + last_written_chars, "%2d ", day_to_print);
+ }
+ day_to_print++;
+ }
+
+ append_to_print(print_buffer, printing_row, printing_column, temp_buffer);
+
+ if (i % 7 == 0) {
+ printing_row++;
+ memset(temp_buffer, ' ', line_width * 8);
+ temp_buffer[line_width * 8 - 1] = '\0';
+ last_written_chars = 0;
+ }
+ }
+}
+
+void clean_buffers()
+{
+ for (int i = 1; i < line_width * line_count; ++i) {
+ print_buffer[i - 1] = i % line_width == 0 ? '\n' : ' ';
+ }
+ print_buffer[line_width * line_count - 1] = '\0';
+
+ for (int i = 0; i < line_width; ++i) {
+ temp_buffer[i] = ' ';
+ }
+ temp_buffer[line_width - 1] = '\0';
+}
+
 int main(int argc, char** argv)
 {
- (void)argc;
- (void)argv;
+ CArgsParser args_parser("cal");
+ // FIXME: This i a bit of a cheat, as no nested optional args are available on CArgsParser
+ args_parser.add_single_value("[[day] month] year");
+
+ CArgsParserResult args = args_parser.parse(argc, argv);
+ Vector<String> values = args.get_single_values();
+
+ if (values.size() > 3) {
+ printf("Invalid number of values\n");
+ args_parser.print_usage();
+ return 0;
+ }
 
  time_t now = time(nullptr);
  auto* tm = localtime(&now);
- int target_day = tm->tm_mday;
- int target_month = tm->tm_mon + 1;
- int target_year = tm->tm_year + 1900;
- int target_day_of_week = day_of_week(1, target_month, target_year);
 
- printf(" %02u - %04u \n", target_month, target_year);
- printf("Su Mo Tu We Th Fr Sa\n");
+ target_year = tm->tm_year + 1900;
+ target_month = tm->tm_mon + 1;
+ target_day = tm->tm_mday;
 
- for (int i = 1; i <= get_number_of_days(target_month, target_year); ++i) {
- if (i < target_day_of_week) {
- printf(" ");
- } else {
- printf(i != target_day ? "%2d" : "\x1b[30;47m%2d\x1b[0m", i);
- }
+ current_year = target_year;
+ current_month = target_month;
+
+ bool year_mode = false;
+ switch (values.size()) {
+ case 3:
+ target_day = atoi(values[0].characters());
+ target_month = atoi(values[1].characters());
+ target_year = atoi(values[2].characters());
 
- printf(i % 7 == 0 ? "\n" : " ");
+ // When passing the 3 parameters (day, month and year) we assume we're there.
+ current_year = target_year;
+ current_month = target_month;
+ break;
+ case 2:
+ target_month = atoi(values[0].characters());
+ target_year = atoi(values[1].characters());
+ break;
+ case 1:
+ target_year = atoi(values[0].characters());
+ year_mode = true;
+ break;
+ default:
+ break;
  }
- printf("\n\n");
+
+ clean_buffers();
+
+ if (year_mode) {
+ printf(" ");
+ printf("Year %4d", target_year);
+ printf(" \n\n");
+
+ for (int i = 1; i < 12; ++i) {
+ insert_month_to_print(0, i++, target_year);
+ insert_month_to_print(1, i++, target_year);
+ insert_month_to_print(2, i, target_year);
+ printf(print_buffer);
+ printf("\n");
+ clean_buffers();
+ }
+ } else {
+ insert_month_to_print(0, target_month, target_year);
+ printf(print_buffer);
+ printf("\n\n");
+ clean_buffers();
+ }
+
+ return 0;
 }