From ba29aec0d346e08258ee2c2ac5ab6f3250ed3b52 Mon Sep 17 00:00:00 2001
From: Garrett Wollman <wollman@FreeBSD.org>
Date: Mon, 22 Dec 2008 21:22:42 +0000
Subject: [PATCH] Implement a new feature for the "-m" option: if the month
 number is followed by 'f' or 'p', use the following or preceding month of
 that number, respectively.  Document this.  Also includes other minor
 grammatical and punctuation fixes to the manual page (capitalize Easter,
 etc.).

MFC after:	1 month
---
 usr.bin/ncal/ncal.1 | 24 ++++++++++++++++--------
 usr.bin/ncal/ncal.c | 42 +++++++++++++++++++++++++++++-------------
 2 files changed, 45 insertions(+), 21 deletions(-)

diff --git a/usr.bin/ncal/ncal.1 b/usr.bin/ncal/ncal.1
index 6bcddd2e2157..ccb711b12b91 100644
--- a/usr.bin/ncal/ncal.1
+++ b/usr.bin/ncal/ncal.1
@@ -30,7 +30,7 @@
 .Sh NAME
 .Nm cal ,
 .Nm ncal
-.Nd displays a calendar and the date of easter
+.Nd displays a calendar and the date of Easter
 .Sh SYNOPSIS
 .Nm
 .Op Fl jy
@@ -57,7 +57,7 @@ The
 .Nm
 utility displays a simple calendar in traditional format and
 .Nm ncal
-offers an alternative layout, more options and the date of easter.
+offers an alternative layout, more options and the date of Easter.
 The new format is a little cramped but it makes a year fit
 on a 25x80 terminal.
 If arguments are not specified,
@@ -68,16 +68,24 @@ The options are as follows:
 .It Fl J
 Display Julian Calendar, if combined with the
 .Fl e
-option, display date of easter according to the Julian Calendar.
+option, display date of Easter according to the Julian Calendar.
 .It Fl e
-Display date of easter (for western churches).
+Display date of Easter (for western churches).
 .It Fl j
 Display Julian days (days one-based, numbered from January 1).
 .It Fl m Ar month
 Display the specified
 .Ar month .
+If
+.Ar month
+is specified as a decimal number, it may be followed by the letter
+.Ql f
+or
+.Ql p
+to indicate the following or preceding month of that number,
+respectively.
 .It Fl o
-Display date of orthodox easter (Greek and Russian
+Display date of Orthodox Easter (Greek and Russian
 Orthodox Churches).
 .It Fl p
 Print the country codes and switching days from Julian to Gregorian
@@ -101,7 +109,7 @@ Print the number of the week below each week column.
 Display a calendar for the specified year.
 .El
 .Pp
-A single parameter specifies the year (1 - 9999) to be displayed;
+A single parameter specifies the year (1\(en9999) to be displayed;
 note the year must be fully specified:
 .Dq Li cal 89
 will
@@ -113,7 +121,7 @@ Month and year default to those of the current system clock and time zone (so
 .Dq Li cal -m 8
 will display a calendar for the month of August in the current year).
 .Pp
-A year starts on Jan 1.
+A year starts on January 1.
 .Sh SEE ALSO
 .Xr calendar 3 ,
 .Xr strftime 3
@@ -132,7 +140,7 @@ The
 command and manual were written by
 .An Wolfgang Helbig Aq helbig@FreeBSD.org .
 .Sh BUGS
-The assignment of Julian\(emGregorian switching dates to
+The assignment of Julian\(enGregorian switching dates to
 country codes is historically naive for many countries.
 .Pp
 The
diff --git a/usr.bin/ncal/ncal.c b/usr.bin/ncal/ncal.c
index 7e0d5eed09cc..1b125d68e114 100644
--- a/usr.bin/ncal/ncal.c
+++ b/usr.bin/ncal/ncal.c
@@ -162,7 +162,7 @@ char   *center(char *s, char *t, int w);
 void	mkmonth(int year, int month, int jd_flag, struct monthlines * monthl);
 void    mkmonthb(int year, int month, int jd_flag, struct monthlines * monthl);
 void    mkweekdays(struct weekdays * wds);
-int     parsemonth(const char *s);
+int     parsemonth(const char *s, int *m, int *y);
 void    printcc(void);
 void    printeaster(int year, int julian, int orthodox);
 void    printmonth(int year, int month, int jd_flag);
@@ -322,11 +322,11 @@ main(int argc, char *argv[])
 	}
 
 	if (flag_month != NULL) {
-		m = parsemonth(flag_month);
-		if (m < 1 || m > 12)
+		if (parsemonth(flag_month, &m, &y)) {
 			errx(EX_USAGE,
 			    "%s is neither a month number (1..12) nor a name",
 			    flag_month);
+		}
 	}
 
 	if (flag_easter)
@@ -859,18 +859,34 @@ center(char *s, char *t, int w)
 }
 
 int
-parsemonth(const char *s)
+parsemonth(const char *s, int *m, int *y)
 {
-	int v;
+	int nm, ny;
 	char *cp;
 	struct tm tm;
 
-	v = (int)strtol(s, &cp, 10);
-	if (cp != s)
-		return (v);
-	if (strptime(s, "%B", &tm) != NULL)
-		return (tm.tm_mon + 1);
-	if (strptime(s, "%b", &tm) != NULL)
-		return (tm.tm_mon + 1);
-	return (0);
+	nm = (int)strtol(s, &cp, 10);
+	if (cp != s) {
+		ny = *y;
+		if (*cp == '\0') {
+			;	/* no special action */
+		} else if (*cp == 'f' || *cp == 'F') {
+			if (nm <= *m)
+				ny++;
+		} else if (*cp == 'p' || *cp == 'P') {
+			if (nm >= *m)
+				ny--;
+		} else
+			return (1);
+		if (nm < 1 || nm > 12)
+			return 1;
+		*m = nm;
+		*y = ny;
+		return (0);
+	}
+	if (strptime(s, "%B", &tm) != NULL || strptime(s, "%b", &tm) != NULL) {
+		*m = tm.tm_mon + 1;
+		return (0);
+	}
+	return (1);
 }