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freebsd/usr.bin/at/parsetime.c

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/*
* parsetime.c - parse time for at(1)
* Copyright (C) 1993 Thomas Koenig
*
* modifications for english-language times
* Copyright (C) 1993 David Parsons
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. The name of the author(s) may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* at [NOW] PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS
* /NUMBER [DOT NUMBER] [AM|PM]\ /[MONTH NUMBER [NUMBER]] \
* |NOON | |[TOMORROW] |
* |MIDNIGHT | |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
* \TEATIME / \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
*/
/* System Headers */
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <ctype.h>
/* Local headers */
#include "at.h"
#include "panic.h"
/* Structures and unions */
enum { /* symbols */
MIDNIGHT, NOON, TEATIME,
PM, AM, TOMORROW, TODAY, NOW,
MINUTES, HOURS, DAYS, WEEKS,
NUMBER, PLUS, DOT, SLASH, ID, JUNK,
JAN, FEB, MAR, APR, MAY, JUN,
JUL, AUG, SEP, OCT, NOV, DEC
};
/*
* parse translation table - table driven parsers can be your FRIEND!
*/
struct {
char *name; /* token name */
int value; /* token id */
} Specials[] = {
{ "midnight", MIDNIGHT }, /* 00:00:00 of today or tomorrow */
{ "noon", NOON }, /* 12:00:00 of today or tomorrow */
{ "teatime", TEATIME }, /* 16:00:00 of today or tomorrow */
{ "am", AM }, /* morning times for 0-12 clock */
{ "pm", PM }, /* evening times for 0-12 clock */
{ "tomorrow", TOMORROW }, /* execute 24 hours from time */
{ "today", TODAY }, /* execute today - don't advance time */
{ "now", NOW }, /* opt prefix for PLUS */
{ "minute", MINUTES }, /* minutes multiplier */
{ "min", MINUTES },
{ "m", MINUTES },
{ "minutes", MINUTES }, /* (pluralized) */
{ "hour", HOURS }, /* hours ... */
{ "hr", HOURS }, /* abbreviated */
{ "h", HOURS },
{ "hours", HOURS }, /* (pluralized) */
{ "day", DAYS }, /* days ... */
{ "d", DAYS },
{ "days", DAYS }, /* (pluralized) */
{ "week", WEEKS }, /* week ... */
{ "w", WEEKS },
{ "weeks", WEEKS }, /* (pluralized) */
{ "jan", JAN },
{ "feb", FEB },
{ "mar", MAR },
{ "apr", APR },
{ "may", MAY },
{ "jun", JUN },
{ "jul", JUL },
{ "aug", AUG },
{ "sep", SEP },
{ "oct", OCT },
{ "nov", NOV },
{ "dec", DEC }
} ;
/* File scope variables */
static char **scp; /* scanner - pointer at arglist */
static char scc; /* scanner - count of remaining arguments */
static char *sct; /* scanner - next char pointer in current argument */
static int need; /* scanner - need to advance to next argument */
static char *sc_token; /* scanner - token buffer */
static size_t sc_len; /* scanner - lenght of token buffer */
static int sc_tokid; /* scanner - token id */
static char rcsid[] = "$Id: parsetime.c,v 1.1 1993/12/05 11:37:05 cgd Exp $";
/* Local functions */
/*
* parse a token, checking if it's something special to us
*/
static int
parse_token(arg)
char *arg;
{
int i;
for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
if (strcasecmp(Specials[i].name, arg) == 0) {
return sc_tokid = Specials[i].value;
}
/* not special - must be some random id */
return ID;
} /* parse_token */
/*
* init_scanner() sets up the scanner to eat arguments
*/
static void
init_scanner(argc, argv)
int argc;
char **argv;
{
scp = argv;
scc = argc;
need = 1;
sc_len = 1;
while (--argc > 0)
sc_len += strlen(*++argv);
sc_token = (char *) malloc(sc_len);
if (sc_token == NULL)
panic("Insufficient virtual memory");
} /* init_scanner */
/*
* token() fetches a token from the input stream
*/
static int
token()
{
int idx;
while (1) {
memset(sc_token, 0, sc_len);
sc_tokid = EOF;
idx = 0;
/*
* if we need to read another argument, walk along the argument list;
* when we fall off the arglist, we'll just return EOF forever
*/
if (need) {
if (scc < 1)
return sc_tokid;
sct = *scp;
scp++;
scc--;
need = 0;
}
/*
* eat whitespace now - if we walk off the end of the argument,
* we'll continue, which puts us up at the top of the while loop
* to fetch the next argument in
*/
while (isspace(*sct))
++sct;
if (!*sct) {
need = 1;
continue;
}
/*
* preserve the first character of the new token
*/
sc_token[0] = *sct++;
/*
* then see what it is
*/
if (isdigit(sc_token[0])) {
while (isdigit(*sct))
sc_token[++idx] = *sct++;
sc_token[++idx] = 0;
return sc_tokid = NUMBER;
} else if (isalpha(sc_token[0])) {
while (isalpha(*sct))
sc_token[++idx] = *sct++;
sc_token[++idx] = 0;
return parse_token(sc_token);
}
else if (sc_token[0] == ':' || sc_token[0] == '.')
return sc_tokid = DOT;
else if (sc_token[0] == '+')
return sc_tokid = PLUS;
else if (*sct == '/')
return sc_tokid = SLASH;
else
return sc_tokid = JUNK;
} /* while (1) */
} /* token */
/*
* plonk() gives an appropriate error message if a token is incorrect
*/
static void
plonk(tok)
int tok;
{
panic((tok == EOF) ? "incomplete time"
: "garbled time");
} /* plonk */
/*
* expect() gets a token and dies most horribly if it's not the token we want
*/
static void
expect(desired)
int desired;
{
if (token() != desired)
plonk(sc_tokid); /* and we die here... */
} /* expect */
/*
* dateadd() adds a number of minutes to a date. It is extraordinarily
* stupid regarding day-of-month overflow, and will most likely not
* work properly
*/
static void
dateadd(minutes, tm)
int minutes;
struct tm *tm;
{
/* increment days */
while (minutes > 24*60) {
minutes -= 24*60;
tm->tm_mday++;
}
/* increment hours */
while (minutes > 60) {
minutes -= 60;
tm->tm_hour++;
if (tm->tm_hour > 23) {
tm->tm_mday++;
tm->tm_hour = 0;
}
}
/* increment minutes */
tm->tm_min += minutes;
if (tm->tm_min > 59) {
tm->tm_hour++;
tm->tm_min -= 60;
if (tm->tm_hour > 23) {
tm->tm_mday++;
tm->tm_hour = 0;
}
}
} /* dateadd */
/*
* plus() parses a now + time
*
* at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS]
*
*/
static void
plus(tm)
struct tm *tm;
{
int delay;
expect(NUMBER);
delay = atoi(sc_token);
switch (token()) {
case WEEKS:
delay *= 7;
case DAYS:
delay *= 24;
case HOURS:
delay *= 60;
case MINUTES:
dateadd(delay, tm);
return;
}
plonk(sc_tokid);
} /* plus */
/*
* tod() computes the time of day
* [NUMBER [DOT NUMBER] [AM|PM]]
*/
static void
tod(tm)
struct tm *tm;
{
int hour, minute = 0;
int tlen;
hour = atoi(sc_token);
tlen = strlen(sc_token);
/*
* first pick out the time of day - if it's 4 digits, we assume
* a HHMM time, otherwise it's HH DOT MM time
*/
if (token() == DOT) {
expect(NUMBER);
minute = atoi(sc_token);
if (minute > 59)
panic("garbled time");
token();
} else if (tlen == 4) {
minute = hour%100;
if (minute > 59)
panic("garbeld time");
hour = hour/100;
}
/*
* check if an AM or PM specifier was given
*/
if (sc_tokid == AM || sc_tokid == PM) {
if (hour > 12)
panic("garbled time");
if (sc_tokid == PM)
hour += 12;
token();
} else if (hour > 23)
panic("garbled time");
/*
* if we specify an absolute time, we don't want to bump the day even
* if we've gone past that time - but if we're specifying a time plus
* a relative offset, it's okay to bump things
*/
if ((sc_tokid == EOF || sc_tokid == PLUS) && tm->tm_hour > hour)
tm->tm_mday++;
tm->tm_hour = hour;
tm->tm_min = minute;
if (tm->tm_hour == 24) {
tm->tm_hour = 0;
tm->tm_mday++;
}
} /* tod */
/*
* assign_date() assigns a date, wrapping to next year if needed
*/
static void
assign_date(tm, mday, mon, year)
struct tm *tm;
long mday, mon, year;
{
if (year > 99) {
if (year > 1899)
year -= 1900;
else
panic("garbled time");
}
if (year < 0 &&
(tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
year = tm->tm_year + 1;
tm->tm_mday = mday;
tm->tm_mon = mon;
if (year >= 0)
tm->tm_year = year;
} /* assign_date */
/*
* month() picks apart a month specification
*
* /[<month> NUMBER [NUMBER]] \
* |[TOMORROW] |
* |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
* \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
*/
static void
month(tm)
struct tm *tm;
{
long year= (-1);
long mday, mon;
int tlen;
switch (sc_tokid) {
case PLUS:
plus(tm);
break;
case TOMORROW:
/* do something tomorrow */
tm->tm_mday ++;
case TODAY: /* force ourselves to stay in today - no further processing */
token();
break;
case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
/*
* do month mday [year]
*/
mon = (sc_tokid-JAN);
expect(NUMBER);
mday = atol(sc_token)-1;
if (token() == NUMBER) {
year = atol(sc_token);
token();
}
assign_date(tm, mday, mon, year);
break;
case NUMBER:
/*
* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
*/
tlen = strlen(sc_token);
mon = atol(sc_token);
token();
if (sc_tokid == SLASH || sc_tokid == DOT) {
int sep;
sep = sc_tokid;
expect(NUMBER);
mday = atol(sc_token);
if (token() == sep) {
expect(NUMBER);
year = atol(sc_token);
token();
}
/*
* flip months and days for european timing
*/
if (sep == DOT) {
int x = mday;
mday = mon;
mon = x;
}
} else if (tlen == 6 || tlen == 8) {
if (tlen == 8) {
year = (mon % 10000) - 1900;
mon /= 10000;
} else {
year = mon % 100;
mon /= 100;
}
mday = mon % 100;
mon /= 100;
} else
panic("garbled time");
mon--;
if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
panic("garbled time");
assign_date(tm, mday, mon, year);
break;
} /* case */
} /* month */
/* Global functions */
time_t
parsetime(argc, argv)
int argc;
char **argv;
{
/*
* Do the argument parsing, die if necessary, and return the time the job
* should be run.
*/
time_t nowtimer, runtimer;
struct tm nowtime, runtime;
int hr = 0;
/* this MUST be initialized to zero for midnight/noon/teatime */
nowtimer = time(NULL);
nowtime = *localtime(&nowtimer);
runtime = nowtime;
runtime.tm_sec = 0;
runtime.tm_isdst = 0;
if (argc <= optind)
usage();
init_scanner(argc-optind, argv+optind);
switch (token()) {
case NOW: /* now is optional prefix for PLUS tree */
expect(PLUS);
case PLUS:
plus(&runtime);
break;
case NUMBER:
tod(&runtime);
month(&runtime);
break;
/*
* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
* hr to zero up above, then fall into this case in such a
* way so we add +12 +4 hours to it for teatime, +12 hours
* to it for noon, and nothing at all for midnight, then
* set our runtime to that hour before leaping into the
* month scanner
*/
case TEATIME:
hr += 4;
case NOON:
hr += 12;
case MIDNIGHT:
if (runtime.tm_hour >= hr)
runtime.tm_mday++;
runtime.tm_hour = hr;
runtime.tm_min = 0;
token();
/* fall through to month setting */
default:
month(&runtime);
break;
} /* ugly case statement */
expect(EOF);
/*
* adjust for daylight savings time
*/
runtime.tm_isdst = -1;
runtimer = mktime(&runtime);
if (runtime.tm_isdst > 0) {
runtimer -= 3600;
runtimer = mktime(&runtime);
}
if (runtimer < 0)
panic("garbled time");
if (nowtimer > runtimer)
panic("Trying to travel back in time");
return runtimer;
} /* parsetime */
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