gno/usr.bin/calendar/calendar.c

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/*
* Calendar file v1.0. Copyright 1994-1998 by Christopher Neufeld
*
* The executable for this file contains linked runtime libraries
* copyrighted by The Byte Works. Used with permission.
*
* Change Log:
*
* 1.0 -- [Christopher Neufeld, 1994] Initial version.
*
* 1.1 -- [Marlin Allred, 1 Jul 1998]
* + the date can now appear anywhere on the line
* + on the weekend, Monday events are also listed
* + man page was converted from preformatted ASCII to nroff source
* + binary linked with the v2.0.6 libraries
*
* 1.2 -- [Devin Reade, 6 Jul 1998]
* + fixed a bug introduced in 1.1 where getting an error while
* reading the calandar file could cause an infinite loop
* + added the describe entry and resource fork
* + added these "ChangeLog" comments for all versions
* + added this program to the GNO base distribution
* + eliminated "pragma stacksize" from the source file; it was too
* small (was 512 bytes, currently using 862 bytes) and overriding
* the value given on the command line during the GNO base build
* process
*
* $Id: calendar.c,v 1.3 1998/07/07 02:14:30 gdr-ftp Exp $
*/
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <time.h>
#include <ctype.h>
#include <string.h>
#include <err.h>
#ifdef __GNO__
#include <gno/gno.h>
#endif
#define NMONTHS 12
#define NDAYS 31
#define MAXLINELEN 255
#define CALFILE "calendar"
#define SECSPERDAY (24 * 60 * (long)60)
const char months[NMONTHS][4] = {"jan", "feb", "mar", "apr", "may", "jun",
"jul", "aug", "sep", "oct", "nov", "dec"};
#ifdef NODIFFTIME
#define difftime(x1,x2) (double)((x1) - (x2))
#endif /* Note that this is not necessarily portable, but works with */
/* some systems which don't have 'difftime' */
int main(void)
{
FILE *ifile;
time_t t1, t2;
static struct tm st1, st2;
int monthnum, daynum, dayschk, i, j;
char *ptr1, *ptr2, holdmnth[4];
static char thislin[MAXLINELEN+1];
long deltat;
long ldayschk;
#ifdef __GNO__
__REPORT_STACK();
#endif
if ((ifile = fopen(CALFILE, "r")) == NULL) exit(0); /* Open calendar file
in CWD. If there is none, exit successfully */
t1 = time(NULL); /* Get the current time */
st1 = *localtime(&t1); /* Convert to formatted date/time */
st1.tm_sec = st1.tm_min = st1.tm_hour = 0; /* Pretend it's midnight, it
makes the checking later much easier */
t1 = mktime(&st1); /* Make an internal representation for that midnight
(the one which heralded today's date) */
dayschk = (st1.tm_wday >= 5) ? 8 - st1.tm_wday : 2; /* Check today and
tomorrow, unless tomorrow is on the weekend, in
which case we check up to and including Monday */
thislin[MAXLINELEN] = 0;
/* Get each line from the calendar file */
while (fgets(thislin, MAXLINELEN, ifile) != NULL) {
ptr1 = thislin;
while (isspace(*ptr1) && *ptr1 != 0) ptr1++; /* Flush initial whitespace */
if (*ptr1 == 0) continue; /* Blank line */
monthnum = -1;
while (*ptr1) {
if (isdigit(*ptr1)) { /* month/day format */
monthnum = strtoul(ptr1, &ptr2, 10) - 1;
daynum = strtoul(ptr2+1, NULL, 10);
/* We've now parsed a month/day format line */
if (monthnum && monthnum < NMONTHS && daynum && daynum <= NDAYS)
break; /* Valid date, print line of the file */
} else {
for (i=0; i<3; i++) holdmnth[i] = tolower(ptr1[i]); /* make the search
case-insensitive */
holdmnth[3] = 0;
for (i = 0; i < NMONTHS; i++)
if (!(strcmp(holdmnth, months[i]))) {
monthnum = i; /* look for "jan", "feb", etc. */
break;
}
if (monthnum != -1) { /* found a valid month, get day */
while (!isspace(*ptr1) && *ptr1 != 0) ptr1++; /* flush text */
if (*ptr1 == 0) break;
while (isspace(*ptr1) && *ptr1 != 0) ptr1++; /* flush whitespace */
if (*ptr1 == 0) break; /* No day number, go to next line in file */
daynum = atoi(ptr1); /* get day number */
if (daynum >= 1 && daynum <= NDAYS) break; /* Valid, go print line */
}
}
ptr1++;
}
st2.tm_sec = st2.tm_min = st2.tm_hour = st2.tm_isdst = 0;
st2.tm_mday = daynum;
st2.tm_mon = monthnum;
st2.tm_year = st1.tm_year;
/* We've now set up the time for midnight at the
beginning of the day represented by the line we
found in the calendar file */
t2 = mktime(&st2); /* Change to internal format */
if ((deltat = difftime(t2, t1)) < 0) { /* The day was in the past, check
the same date next year */
st2.tm_year++;
t2 = mktime(&st2);
deltat = difftime(t2, t1);
}
if (deltat <= dayschk * SECSPERDAY) printf(thislin);
/* print the entire line if it is inside our acceptance window */
}
if (ferror(ifile)) {
err(1, "error while reading %s", CALFILE);
}
fclose(ifile);
exit(0);
}