93a2fe45a6
This is useful if you have been given some time for some event in some format and you want your computer to do something to prepare for it. Without having to do time arithmetic in a shellscript. The syntax matches what the at(1) usually used on Linux supports.
671 lines
15 KiB
C
671 lines
15 KiB
C
/*
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* parsetime.c - parse time for at(1)
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* Copyright (C) 1993, 1994 Thomas Koenig
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*
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* modifications for English-language times
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* Copyright (C) 1993 David Parsons
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. The name of the author(s) may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* at [NOW] PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS
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* /NUMBER [DOT NUMBER] [AM|PM]\ /[MONTH NUMBER [NUMBER]] \
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* |NOON | |[TOMORROW] |
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* |MIDNIGHT | |[DAY OF WEEK] |
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* \TEATIME / |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
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* \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/* System Headers */
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#include <sys/types.h>
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#include <ctype.h>
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#include <err.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#ifndef __FreeBSD__
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#include <getopt.h>
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#endif
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/* Local headers */
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#include "at.h"
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#include "panic.h"
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#include "parsetime.h"
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/* Structures and unions */
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enum { /* symbols */
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MIDNIGHT, NOON, TEATIME,
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PM, AM, TOMORROW, TODAY, NOW,
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MINUTES, HOURS, DAYS, WEEKS, MONTHS, YEARS,
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NUMBER, PLUS, MINUS, DOT, SLASH, ID, JUNK,
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JAN, FEB, MAR, APR, MAY, JUN,
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JUL, AUG, SEP, OCT, NOV, DEC,
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SUN, MON, TUE, WED, THU, FRI, SAT
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};
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/* parse translation table - table driven parsers can be your FRIEND!
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*/
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static const struct {
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const char *name; /* token name */
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int value; /* token id */
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int plural; /* is this plural? */
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} Specials[] = {
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{ "midnight", MIDNIGHT,0 }, /* 00:00:00 of today or tomorrow */
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{ "noon", NOON,0 }, /* 12:00:00 of today or tomorrow */
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{ "teatime", TEATIME,0 }, /* 16:00:00 of today or tomorrow */
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{ "am", AM,0 }, /* morning times for 0-12 clock */
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{ "pm", PM,0 }, /* evening times for 0-12 clock */
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{ "tomorrow", TOMORROW,0 }, /* execute 24 hours from time */
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{ "today", TODAY, 0 }, /* execute today - don't advance time */
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{ "now", NOW,0 }, /* opt prefix for PLUS */
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{ "minute", MINUTES,0 }, /* minutes multiplier */
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{ "minutes", MINUTES,1 }, /* (pluralized) */
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{ "hour", HOURS,0 }, /* hours ... */
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{ "hours", HOURS,1 }, /* (pluralized) */
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{ "day", DAYS,0 }, /* days ... */
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{ "days", DAYS,1 }, /* (pluralized) */
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{ "week", WEEKS,0 }, /* week ... */
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{ "weeks", WEEKS,1 }, /* (pluralized) */
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{ "month", MONTHS,0 }, /* month ... */
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{ "months", MONTHS,1 }, /* (pluralized) */
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{ "year", YEARS,0 }, /* year ... */
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{ "years", YEARS,1 }, /* (pluralized) */
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{ "jan", JAN,0 },
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{ "feb", FEB,0 },
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{ "mar", MAR,0 },
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{ "apr", APR,0 },
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{ "may", MAY,0 },
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{ "jun", JUN,0 },
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{ "jul", JUL,0 },
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{ "aug", AUG,0 },
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{ "sep", SEP,0 },
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{ "oct", OCT,0 },
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{ "nov", NOV,0 },
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{ "dec", DEC,0 },
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{ "january", JAN,0 },
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{ "february", FEB,0 },
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{ "march", MAR,0 },
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{ "april", APR,0 },
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{ "may", MAY,0 },
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{ "june", JUN,0 },
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{ "july", JUL,0 },
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{ "august", AUG,0 },
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{ "september", SEP,0 },
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{ "october", OCT,0 },
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{ "november", NOV,0 },
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{ "december", DEC,0 },
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{ "sunday", SUN, 0 },
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{ "sun", SUN, 0 },
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{ "monday", MON, 0 },
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{ "mon", MON, 0 },
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{ "tuesday", TUE, 0 },
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{ "tue", TUE, 0 },
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{ "wednesday", WED, 0 },
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{ "wed", WED, 0 },
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{ "thursday", THU, 0 },
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{ "thu", THU, 0 },
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{ "friday", FRI, 0 },
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{ "fri", FRI, 0 },
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{ "saturday", SAT, 0 },
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{ "sat", SAT, 0 },
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} ;
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/* File scope variables */
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static char **scp; /* scanner - pointer at arglist */
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static char scc; /* scanner - count of remaining arguments */
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static char *sct; /* scanner - next char pointer in current argument */
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static int need; /* scanner - need to advance to next argument */
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static char *sc_token; /* scanner - token buffer */
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static size_t sc_len; /* scanner - length of token buffer */
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static int sc_tokid; /* scanner - token id */
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static int sc_tokplur; /* scanner - is token plural? */
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/* Local functions */
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/*
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* parse a token, checking if it's something special to us
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*/
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static int
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parse_token(char *arg)
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{
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size_t i;
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for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
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if (strcasecmp(Specials[i].name, arg) == 0) {
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sc_tokplur = Specials[i].plural;
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return sc_tokid = Specials[i].value;
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}
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/* not special - must be some random id */
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return ID;
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} /* parse_token */
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/*
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* init_scanner() sets up the scanner to eat arguments
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*/
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static void
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init_scanner(int argc, char **argv)
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{
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scp = argv;
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scc = argc;
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need = 1;
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sc_len = 1;
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while (argc-- > 0)
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sc_len += strlen(*argv++);
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if ((sc_token = malloc(sc_len)) == NULL)
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errx(EXIT_FAILURE, "virtual memory exhausted");
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} /* init_scanner */
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/*
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* token() fetches a token from the input stream
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*/
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static int
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token(void)
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{
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int idx;
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while (1) {
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memset(sc_token, 0, sc_len);
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sc_tokid = EOF;
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sc_tokplur = 0;
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idx = 0;
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/* if we need to read another argument, walk along the argument list;
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* when we fall off the arglist, we'll just return EOF forever
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*/
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if (need) {
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if (scc < 1)
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return sc_tokid;
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sct = *scp;
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scp++;
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scc--;
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need = 0;
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}
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/* eat whitespace now - if we walk off the end of the argument,
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* we'll continue, which puts us up at the top of the while loop
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* to fetch the next argument in
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*/
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while (isspace(*sct))
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++sct;
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if (!*sct) {
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need = 1;
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continue;
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}
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/* preserve the first character of the new token
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*/
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sc_token[0] = *sct++;
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/* then see what it is
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*/
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if (isdigit(sc_token[0])) {
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while (isdigit(*sct))
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sc_token[++idx] = *sct++;
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sc_token[++idx] = 0;
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return sc_tokid = NUMBER;
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}
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else if (isalpha(sc_token[0])) {
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while (isalpha(*sct))
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sc_token[++idx] = *sct++;
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sc_token[++idx] = 0;
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return parse_token(sc_token);
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}
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else if (sc_token[0] == ':' || sc_token[0] == '.')
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return sc_tokid = DOT;
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else if (sc_token[0] == '+')
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return sc_tokid = PLUS;
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else if (sc_token[0] == '-')
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return sc_tokid = MINUS;
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else if (sc_token[0] == '/')
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return sc_tokid = SLASH;
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else
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return sc_tokid = JUNK;
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} /* while (1) */
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} /* token */
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/*
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* plonk() gives an appropriate error message if a token is incorrect
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*/
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static void
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plonk(int tok)
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{
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panic((tok == EOF) ? "incomplete time"
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: "garbled time");
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} /* plonk */
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/*
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* expect() gets a token and dies most horribly if it's not the token we want
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*/
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static void
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expect(int desired)
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{
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if (token() != desired)
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plonk(sc_tokid); /* and we die here... */
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} /* expect */
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/*
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* plus_or_minus() holds functionality common to plus() and minus()
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*/
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static void
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plus_or_minus(struct tm *tm, int delay)
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{
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int expectplur;
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expectplur = (delay != 1 && delay != -1) ? 1 : 0;
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switch (token()) {
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case YEARS:
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tm->tm_year += delay;
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break;
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case MONTHS:
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tm->tm_mon += delay;
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break;
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case WEEKS:
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delay *= 7;
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case DAYS:
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tm->tm_mday += delay;
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break;
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case HOURS:
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tm->tm_hour += delay;
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break;
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case MINUTES:
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tm->tm_min += delay;
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break;
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default:
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plonk(sc_tokid);
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break;
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}
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if (expectplur != sc_tokplur)
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warnx("pluralization is wrong");
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tm->tm_isdst = -1;
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if (mktime(tm) < 0)
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plonk(sc_tokid);
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} /* plus_or_minus */
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/*
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* plus() parses a now + time
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*
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* at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
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*
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*/
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static void
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plus(struct tm *tm)
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{
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int delay;
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expect(NUMBER);
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delay = atoi(sc_token);
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plus_or_minus(tm, delay);
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} /* plus */
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/*
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* minus() is like plus but can not be used with NOW
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*/
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static void
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minus(struct tm *tm)
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{
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int delay;
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expect(NUMBER);
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delay = -atoi(sc_token);
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plus_or_minus(tm, delay);
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} /* minus */
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/*
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* tod() computes the time of day
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* [NUMBER [DOT NUMBER] [AM|PM]]
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*/
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static void
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tod(struct tm *tm)
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{
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int hour, minute = 0;
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int tlen;
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hour = atoi(sc_token);
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tlen = strlen(sc_token);
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/* first pick out the time of day - if it's 4 digits, we assume
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* a HHMM time, otherwise it's HH DOT MM time
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*/
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if (token() == DOT) {
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expect(NUMBER);
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minute = atoi(sc_token);
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if (minute > 59)
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panic("garbled time");
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token();
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}
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else if (tlen == 4) {
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minute = hour%100;
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if (minute > 59)
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panic("garbled time");
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hour = hour/100;
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}
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/* check if an AM or PM specifier was given
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*/
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if (sc_tokid == AM || sc_tokid == PM) {
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if (hour > 12)
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panic("garbled time");
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if (sc_tokid == PM) {
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if (hour != 12) /* 12:xx PM is 12:xx, not 24:xx */
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hour += 12;
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} else {
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if (hour == 12) /* 12:xx AM is 00:xx, not 12:xx */
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hour = 0;
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}
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token();
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}
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else if (hour > 23)
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panic("garbled time");
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/* if we specify an absolute time, we don't want to bump the day even
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* if we've gone past that time - but if we're specifying a time plus
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* a relative offset, it's okay to bump things
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*/
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if ((sc_tokid == EOF || sc_tokid == PLUS || sc_tokid == MINUS) &&
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tm->tm_hour > hour) {
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tm->tm_mday++;
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tm->tm_wday++;
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}
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tm->tm_hour = hour;
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tm->tm_min = minute;
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if (tm->tm_hour == 24) {
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tm->tm_hour = 0;
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tm->tm_mday++;
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}
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} /* tod */
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/*
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* assign_date() assigns a date, wrapping to next year if needed
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*/
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static void
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assign_date(struct tm *tm, long mday, long mon, long year)
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{
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/*
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* Convert year into tm_year format (year - 1900).
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* We may be given the year in 2 digit, 4 digit, or tm_year format.
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*/
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if (year != -1) {
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if (year >= 1900)
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year -= 1900; /* convert from 4 digit year */
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else if (year < 100) {
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/* convert from 2 digit year */
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struct tm *lt;
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time_t now;
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time(&now);
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lt = localtime(&now);
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/* Convert to tm_year assuming current century */
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year += (lt->tm_year / 100) * 100;
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if (year == lt->tm_year - 1) year++;
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else if (year < lt->tm_year)
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year += 100; /* must be in next century */
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}
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}
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if (year < 0 &&
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(tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
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year = tm->tm_year + 1;
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tm->tm_mday = mday;
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tm->tm_mon = mon;
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if (year >= 0)
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tm->tm_year = year;
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} /* assign_date */
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/*
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* month() picks apart a month specification
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*
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* /[<month> NUMBER [NUMBER]] \
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* |[TOMORROW] |
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* |[DAY OF WEEK] |
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* |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
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* \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
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*/
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static void
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month(struct tm *tm)
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{
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long year= (-1);
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long mday = 0, wday, mon;
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int tlen;
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switch (sc_tokid) {
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case PLUS:
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plus(tm);
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break;
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case MINUS:
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minus(tm);
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break;
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case TOMORROW:
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/* do something tomorrow */
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tm->tm_mday ++;
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tm->tm_wday ++;
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case TODAY: /* force ourselves to stay in today - no further processing */
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token();
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break;
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case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
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case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
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/* do month mday [year]
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*/
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mon = (sc_tokid-JAN);
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expect(NUMBER);
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mday = atol(sc_token);
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if (token() == NUMBER) {
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year = atol(sc_token);
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token();
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}
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assign_date(tm, mday, mon, year);
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break;
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case SUN: case MON: case TUE:
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case WED: case THU: case FRI:
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case SAT:
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/* do a particular day of the week
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*/
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wday = (sc_tokid-SUN);
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mday = tm->tm_mday;
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/* if this day is < today, then roll to next week
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*/
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if (wday < tm->tm_wday)
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mday += 7 - (tm->tm_wday - wday);
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else
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mday += (wday - tm->tm_wday);
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tm->tm_wday = wday;
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assign_date(tm, mday, tm->tm_mon, tm->tm_year);
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break;
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case NUMBER:
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/* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
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*/
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tlen = strlen(sc_token);
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mon = atol(sc_token);
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token();
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if (sc_tokid == SLASH || sc_tokid == DOT) {
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int sep;
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sep = sc_tokid;
|
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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(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:
|
|
if (scc < 1) {
|
|
return nowtimer;
|
|
}
|
|
/* now is optional prefix for PLUS tree */
|
|
expect(PLUS);
|
|
case PLUS:
|
|
plus(&runtime);
|
|
break;
|
|
|
|
/* MINUS is different from PLUS in that NOW is not
|
|
* an optional prefix for it
|
|
*/
|
|
case MINUS:
|
|
minus(&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_wday++;
|
|
}
|
|
runtime.tm_hour = hr;
|
|
runtime.tm_min = 0;
|
|
token();
|
|
/* FALLTHROUGH to month setting */
|
|
default:
|
|
month(&runtime);
|
|
break;
|
|
} /* ugly case statement */
|
|
expect(EOF);
|
|
|
|
/* convert back to time_t
|
|
*/
|
|
runtime.tm_isdst = -1;
|
|
runtimer = mktime(&runtime);
|
|
|
|
if (runtimer < 0)
|
|
panic("garbled time");
|
|
|
|
if (nowtimer > runtimer)
|
|
panic("trying to travel back in time");
|
|
|
|
return runtimer;
|
|
} /* parsetime */
|