view toys/cal.c @ 582:b88bc7dcdb48

Update chgrp so -R works, tweaking DIRTREE_COMEAGAIN design along the way.
author Rob Landley <rob@landley.net>
date Sun, 27 May 2012 00:56:17 -0500
parents 92ef50262ec7
children
line wrap: on
line source

/* vi: set sw=4 ts=4:
 *
 * cal.c - show calendar.
 *
 * Copyright 2011 Rob Landley <rob@landley.net>
 *
 * See http://opengroup.org/onlinepubs/9699919799/utilities/cal.html

USE_CAL(NEWTOY(cal, ">2", TOYFLAG_USR|TOYFLAG_BIN))

config CAL
	bool "cal"
	default y
	help
	  usage: cal [[month] year]
	  Print a calendar.

	  With one argument, prints all months of the specified year.
	  With two arguments, prints calendar for month and year.
*/

#include "toys.h"

// Write calendar into buffer: each line is 20 chars wide, end indicated
// by empty string.

static char *calstrings(char *buf, struct tm *tm)
{
	char temp[21];
	int wday, mday, start, len, line;

	// header
	len = strftime(temp, 21, "%B %Y", tm);
	len += (20-len)/2;
	buf += sprintf(buf, "%*s%*s ", len, temp, 20-len, "");
	buf++;
	buf += sprintf(buf, "Su Mo Tu We Th Fr Sa ");
	buf++;

	// What day of the week does this month start on?
	if (tm->tm_mday>1)
		start = (36+tm->tm_wday-tm->tm_mday)%7;
	else start = tm->tm_wday;

	// What day does this month end on?  Alas, libc doesn't tell us...
	len = 31;
	if (tm->tm_mon == 1) {
		int year = tm->tm_year;
		len = 28;
		if (!(year & 3) && !((year&100) && !(year&400))) len++;
	} else if ((tm->tm_mon+(tm->tm_mon>6 ? 1 : 0)) & 1) len = 30;

	for (mday=line=0;line<6;line++) {
		for (wday=0; wday<7; wday++) {
			char *pat = "   ";
			if (!mday ? wday==start : mday<len) {
				pat = "%2d ";
				mday++;
			}
			buf += sprintf(buf, pat, mday);
		}
		buf++;
	}

	return buf;
}

void xcheckrange(long val, long low, long high)
{
	char *err = "%ld %s than %ld";

	if (val < low) error_exit(err, val, "less", low);
	if (val > high) error_exit(err, val, "greater", high);
}

// Worst case scenario toybuf usage: sizeof(struct tm) plus 21 bytes/line
// plus 8 lines/month plus 12 months, comes to a bit over 2k of our 4k buffer.

void cal_main(void)
{
	struct tm *tm;
	char *buf = toybuf;

	if (toys.optc) {
		// Conveniently starts zeroed
		tm = (struct tm *)toybuf;
		buf += sizeof(struct tm);

		// Last argument is year, one before that (if any) is month.
		xcheckrange(tm->tm_year = atol(toys.optargs[--toys.optc]),1,9999);
		tm->tm_year -= 1900;
		tm->tm_mday = 1;
		tm->tm_hour = 12;  // noon to avoid timezone weirdness
		if (toys.optc) {
			xcheckrange(tm->tm_mon = atol(toys.optargs[--toys.optc]),1,12);
			tm->tm_mon--;

		// Print 12 months of the year

		} else {
			char *bufs[12];
			int i, j, k;

			for (i=0; i<12; i++) {
				tm->tm_mon=i;
				mktime(tm);
				buf = calstrings(bufs[i]=buf, tm);
			}

			// 4 rows, 6 lines each, 3 columns
			for (i=0; i<4; i++) {
				for (j=0; j<8; j++) {
					for(k=0; k<3; k++) {
						char **b = bufs+(k+i*3);
						*b += printf("%s ", *b);
					}
					puts("");
				}
			}
			return;
		}

		// What day of the week does that start on?
		mktime(tm);

	} else {
		time_t now;
		time(&now);
		tm = localtime(&now);
	}

	calstrings(buf, tm);
	while (*buf) buf += printf("%s\n", buf);
}