cal: added -w|--week for showing week numbers

Added week numbers both in ISO-6801 and North America numbering.
The mode is determined by first day of the week, Monday
for ISO and Sunday for North America mode.

ISO week numbers are defined as the first Thursday being part of week 1.
The North America numbering is defined, at least by gcal, as first Sunday
being in the first week.

Signed-off-by: Tommi Kyntola <kynde@iki.fi>

1 files changed, 112 insertions, 29 deletions

diff --git a/misc-utils/cal.c b/misc-utils/cal.c
index f91bc8ebe..92bd395e3 100644
--- a/misc-utils/cal.c
+++ b/misc-utils/cal.c
@@ -171,6 +171,7 @@ enum {
 #define REFORMATION_MONTH	9		/* September */
 #define	FIRST_MISSING_DAY	639799		/* 3 Sep 1752 */
 #define	NUMBER_MISSING_DAYS	11		/* 11 day correction */
+#define YDAY_AFTER_MISSING	258             /* 14th in Sep 1752 */
 
 #define DAYS_IN_YEAR		365		/* the common case, leap years are calculated */
 #define MONTHS_IN_YEAR		12
@@ -223,6 +224,11 @@ static const int d_sep1752[MAXDAYS / 2] = {
 	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE,	SPACE
 };
 
+enum {
+	WEEK_NUM_DISABLED = 0,
+	WEEK_NUM_ISO,
+	WEEK_NUM_US
+};
 
 /* utf-8 can have up to 6 bytes per char; and an extra byte for ending \0 */
 static char day_headings[J_WEEK_LEN * 6 + 1];
@@ -241,11 +247,12 @@ static void center(const char *, size_t, int);
 static void day_array(int, int, long, int *);
 static int day_in_week(int, int, long);
 static int day_in_year(int, int, long);
-static void yearly(int, long, int);
-static int do_monthly(int, int, long, struct fmt_st*, int);
-static void monthly(int, int, long);
+static int week_number(int, int, long, int);
+static void yearly(int, long, int, int);
+static int do_monthly(int, int, long, int, struct fmt_st*, int);
+static void monthly(int, int, long, int);
 static int two_header_lines(int month, long year);
-static void monthly3(int, int, long);
+static void monthly3(int, int, long, int);
 static void __attribute__ ((__noreturn__)) usage(FILE * out);
 static void headers_init(int);
 
@@ -253,7 +260,7 @@ int main(int argc, char **argv)
 {
 	struct tm *local_time;
 	time_t now;
-	int ch, day = 0, month = 0, yflag = 0;
+	int ch, day = 0, month = 0, yflag = 0, wflag = WEEK_NUM_DISABLED;
 	long year;
 	int num_months = NUM_MONTHS;
 	int colormode = UL_COLORMODE_AUTO;
@@ -269,6 +276,7 @@ int main(int argc, char **argv)
 		{"monday", no_argument, NULL, 'm'},
 		{"julian", no_argument, NULL, 'j'},
 		{"year", no_argument, NULL, 'y'},
+		{"week", no_argument, NULL, 'w'},
 		{"color", optional_argument, NULL, OPT_COLOR},
 		{"version", no_argument, NULL, 'V'},
 		{"help", no_argument, NULL, 'h'},
@@ -327,7 +335,7 @@ int main(int argc, char **argv)
 	}
 #endif
 
-	while ((ch = getopt_long(argc, argv, "13mjsyVh", longopts, NULL)) != -1)
+	while ((ch = getopt_long(argc, argv, "13mjsywVh", longopts, NULL)) != -1)
 		switch(ch) {
 		case '1':
 			num_months = 1;		/* default */
@@ -347,6 +355,9 @@ int main(int argc, char **argv)
 		case 'y':
 			yflag = 1;
 			break;
+		case 'w':
+			wflag = WEEK_NUM_US;	/* default per weekstart */
+			break;
 		case OPT_COLOR:
 			if (optarg)
 				colormode = colormode_or_err(optarg,
@@ -364,6 +375,9 @@ int main(int argc, char **argv)
 	argc -= optind;
 	argv += optind;
 
+	if (wflag)
+		wflag = (weekstart == MONDAY ? WEEK_NUM_ISO : WEEK_NUM_US);
+
 	time(&now);
 	local_time = localtime(&now);
 
@@ -407,11 +421,11 @@ int main(int argc, char **argv)
 		day = 0;
 
 	if (yflag)
-		yearly(day, year, julian);
+		yearly(day, year, julian, wflag);
 	else if (num_months == 1)
-		monthly(day, month, year);
+		monthly(day, month, year, wflag);
 	else if (num_months == 3)
-		monthly3(day, month, year);
+		monthly3(day, month, year, wflag);
 
 	return EXIT_SUCCESS;
 }
@@ -448,12 +462,12 @@ static void headers_init(int julian)
 		full_month[i] = nl_langinfo(MON_1 + i);
 }
 
-static int do_monthly(int day, int month, long year,
+static int do_monthly(int day, int month, long year, int wflag,
 		      struct fmt_st *out, int header_hint)
 {
 	int col, row, days[MAXDAYS];
 	char *p, lineout[FMT_ST_CHARS];
-	size_t width = (julian ? J_WEEK_LEN : WEEK_LEN) - 1;
+	size_t width = (julian ? J_WEEK_LEN : WEEK_LEN) - 1 + (wflag?3:0);
 	int pos = 0;
 
 	day_array(day, month, year, days);
@@ -478,10 +492,21 @@ static int do_monthly(int day, int month, long year,
 		pos++;
 	}
 
-	snprintf(out->s[pos++], FMT_ST_CHARS, "%s", day_headings);
+	snprintf(out->s[pos++], FMT_ST_CHARS, "%s%s",(wflag?"   ":""), day_headings);
 	for (row = 0; row < DAYS_IN_WEEK - 1; row++) {
 		int has_hl = 0;
-		for (col = 0, p = lineout; col < DAYS_IN_WEEK; col++) {
+		p = lineout;
+		if (wflag)
+			for (col = 0; col < DAYS_IN_WEEK; col++) {
+				int xd = days[row * DAYS_IN_WEEK + col];
+				if (xd != SPACE) {
+					p += sprintf(p,"%2d ",
+						week_number(xd & ~TODAY_FLAG,month,year,wflag));
+					break;
+				} else if (col+1 == DAYS_IN_WEEK)
+					p += sprintf(p,"   ");
+			}
+		for (col = 0; col < DAYS_IN_WEEK; col++) {
 			int xd = days[row * DAYS_IN_WEEK + col];
 			if (xd != SPACE && (xd & TODAY_FLAG))
 				has_hl = 1;
@@ -496,12 +521,12 @@ static int do_monthly(int day, int month, long year,
 	return pos;
 }
 
-static void monthly(int day, int month, long year)
+static void monthly(int day, int month, long year, int wflag)
 {
 	int i, rows;
 	struct fmt_st out;
 
-	rows = do_monthly(day, month, year, &out, -1);
+	rows = do_monthly(day, month, year, wflag, &out, -1);
 	for (i = 0; i < rows; i++) {
 		my_putstring(out.s[i]);
 		my_putstring("\n");
@@ -521,7 +546,7 @@ static int two_header_lines(int month, long year)
 	return 0;
 }
 
-static void monthly3(int day, int month, long year)
+static void monthly3(int day, int month, long year, int wflag)
 {
 	char lineout[FMT_ST_CHARS];
 	int i;
@@ -556,9 +581,9 @@ static void monthly3(int day, int month, long year)
 		rows = FMT_ST_LINES;
 	else
 		rows = FMT_ST_LINES - 1;
-	do_monthly(day, prev_month, prev_year, &out_prev, two_lines);
-	do_monthly(day, month,      year,      &out_curm, two_lines);
-	do_monthly(day, next_month, next_year, &out_next, two_lines);
+	do_monthly(day, prev_month, prev_year, wflag, &out_prev, two_lines);
+	do_monthly(day, month,      year,      wflag, &out_curm, two_lines);
+	do_monthly(day, next_month, next_year, wflag, &out_next, two_lines);
 
 	width = (julian ? J_WEEK_LEN : WEEK_LEN) -1;
 	for (i = 0; i < (two_lines ? 3 : 2); i++) {
@@ -585,25 +610,25 @@ static void monthly3(int day, int month, long year)
 	}
 }
 
-static void yearly(int day, long year, int julian)
+static void yearly(int day, long year, int julian, int wflag)
 {
 	int col, *dp, i, month, row, which_cal;
 	int maxrow, sep_len, week_len;
 	int days[MONTHS_IN_YEAR][MAXDAYS];
 	char *p;
 	/* three weeks + separators + \0 */
-	char lineout[ sizeof(day_headings) + 2 +
-		      sizeof(day_headings) + 2 +
-		      sizeof(day_headings) + 1 ];
-
+	int wnumlen = (wflag?3:0);
+	char lineout[ wnumlen + sizeof(day_headings) + 2 +
+		      wnumlen + sizeof(day_headings) + 2 +
+		      wnumlen + sizeof(day_headings) + 1 ];
 	if (julian) {
 		maxrow = J_MONTH_COLS;
 		sep_len = J_HEAD_SEP;
-		week_len = J_WEEK_LEN;
+		week_len = J_WEEK_LEN + wnumlen;
 	} else {
 		maxrow = MONTH_COLS;
 		sep_len = HEAD_SEP;
-		week_len = WEEK_LEN;
+		week_len = WEEK_LEN + wnumlen;
 	}
 	snprintf(lineout, sizeof(lineout), "%ld", year);
 	/* 2013-04-28: The -1 near sep_len makes year header to be
@@ -625,17 +650,32 @@ static void yearly(int day, long year, int julian)
 		}
 		if (julian)
 			snprintf(lineout, sizeof(lineout),
-				 "\n%s%*s %s\n", day_headings, sep_len, "", day_headings);
+				 "\n%*s%s%*s %*s%s\n",
+				 wnumlen,"", day_headings, sep_len, "",
+				 wnumlen,"", day_headings);
 		else
 			snprintf(lineout, sizeof(lineout),
-				 "\n%s%*s %s%*s %s\n", day_headings, sep_len,
-				 "", day_headings, sep_len, "", day_headings);
+				 "\n%*s%s%*s %*s%s%*s %*s%s\n",
+				 wnumlen,"", day_headings, sep_len, "",
+				 wnumlen,"", day_headings, sep_len, "",
+				 wnumlen,"", day_headings);
 
 		my_putstring(lineout);
 		for (row = 0; row < DAYS_IN_WEEK - 1; row++) {
 			p = lineout;
 			for (which_cal = 0; which_cal < maxrow; which_cal++) {
 				dp = &days[month + which_cal][row * DAYS_IN_WEEK];
+				if (wflag) {
+					for (col = 0; col < DAYS_IN_WEEK; col++) {
+						int xd = days[month + which_cal][row * DAYS_IN_WEEK + col];
+						if (xd != SPACE) {
+							p += sprintf(p,"%2d ",
+								week_number(xd & ~TODAY_FLAG,month + which_cal + 1,year,wflag));
+							break;
+						} else if (col+1 == DAYS_IN_WEEK)
+							p += sprintf(p,"   ");
+					}
+				}
 				for (col = 0; col < DAYS_IN_WEEK; col++)
 					p = ascii_day(p, *dp++);
 				p += sprintf(p, "  ");
@@ -729,6 +769,48 @@ static int day_in_week(int d, int m, long y)
 	return NONEDAY;
 }
 
+/*
+ * week_number
+ *      return the week number of a given date, 1..53.
+ *      Supports ISO-8601 and North American modes.
+ *      Day may be given as Julian day of the year mode, in which
+ *      case the month is disregarded entirely.
+ */
+static int week_number(int day, int month, long year, int wflag) {
+	int fday = 0,wday,yday;
+	wday = day_in_week(1,1,year);
+	if (wflag == WEEK_NUM_ISO)
+		fday = wday + (wday>=FRIDAY?-2:5);
+	else	/* WEEK_NUM_US */
+		/* according to gcal, the first Sun is in the first week */
+		fday = wday + (wday==SUNDAY?6:-1);
+		/* according to wikipedia, i.e. the first Sat is in the first week */
+		/* fday = wday + 6; */
+	/* For julian dates the month can be set to 1, the global julian variable
+	 * cannot be relied upon here, because we may recurse internally for
+	 * 31.12. which would not work. */
+	if (day > 31) month = 1;
+	yday = day_in_year(day,month,year);
+	if (year == REFORMATION_YEAR)
+		if (yday >= YDAY_AFTER_MISSING)
+			fday -= NUMBER_MISSING_DAYS;
+	/* Last year is last year */
+	if (yday+fday < 7)
+		return week_number(31,12,year-1,wflag);
+	/* Or it could be part of the next year.
+	 * The reformation year had less days than 365 making this check
+	 * invalid, but reformation year ended on Sunday and in week 51,
+	 * so it's ok here. */
+	if (wflag == WEEK_NUM_ISO && yday >= 363 &&
+		day_in_week(day,month,year) >= MONDAY &&
+		day_in_week(day,month,year) <= WEDNESDAY &&
+		day_in_week(31,12,year) >= MONDAY &&
+		day_in_week(31,12,year) <= WEDNESDAY) {
+		return  week_number(1,1,year+1,wflag);
+	}
+	return (yday+fday) / 7;
+}
+
 static char *ascii_day(char *p, int day)
 {
 	int display, val;
@@ -818,6 +900,7 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out)
 	fputs(_(" -m, --monday          Monday as first day of week\n"), out);
 	fputs(_(" -j, --julian          output Julian dates\n"), out);
 	fputs(_(" -y, --year            show the whole year\n"), out);
+	fputs(_(" -w, --week            show US or ISO-8601 week numbers\n"), out);
 	fputs(_("     --color[=<when>]  colorize messages (auto, always or never)\n"), out);
 
 	fputs(USAGE_SEPARATOR, out);