freebsd-dev/usr.bin/tar/getdate.y
Tim Kientzle ecf6d502eb Overhaul getdate.y. In particular, remove minutes-based logic
(combine with existing seconds-based), treat '-' as punctuation rather
than a negative number indicator (eliminates several special cases),
use a single list of special words instead of several separate lists,
use table-driven abbreviation logic (eliminate duplicate word entries
and special-case abbreviation and plural handling).  The result is
shorter, simpler (judging from comments, earlier maintainers didn't
understand the special handling for "negative years"), handles more
cases (e.g., "tu" is now a recognized abbreviation for "tuesday",
"3rd" is now equivalent to "third") and it has 2 fewer shift/reduce
conflicts.
2005-04-23 18:38:32 +00:00

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%{
/*
* March 2005: Further modified and simplified by Tim Kientzle:
* Eliminate minutes-based calculations (just do everything in
* seconds), have lexer only recognize unsigned integers (handle '+'
* and '-' characters in grammar), combine tables into one table with
* explicit abbreviation notes, do am/pm adjustments in the grammar
* (eliminate some state variables and post-processing). Among other
* things, these changes eliminated two shift/reduce conflicts. (Went
* from 10 to 8.)
*/
/*
** Originally written by Steven M. Bellovin <smb@research.att.com> while
** at the University of North Carolina at Chapel Hill. Later tweaked by
** a couple of people on Usenet. Completely overhauled by Rich $alz
** <rsalz@bbn.com> and Jim Berets <jberets@bbn.com> in August, 1990;
**
** This grammar has 10 shift/reduce conflicts.
**
** This code is in the public domain and has no copyright.
*/
/* SUPPRESS 287 on yaccpar_sccsid *//* Unused static variable */
/* SUPPRESS 288 on yyerrlab *//* Label unused */
#include "bsdtar_platform.h"
__FBSDID("$FreeBSD$");
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#define yyparse getdate_yyparse
#define yylex getdate_yylex
#define yyerror getdate_yyerror
static int yyparse(void);
static int yylex(void);
static int yyerror(const char *);
time_t get_date(char *);
#define EPOCH 1970
#define HOUR(x) ((time_t)(x) * 60)
#define SECSPERDAY (24L * 60L * 60L)
/*
** Daylight-savings mode: on, off, or not yet known.
*/
typedef enum _DSTMODE {
DSTon, DSToff, DSTmaybe
} DSTMODE;
/*
** Meridian: am or pm.
*/
enum { tAM, tPM };
/*
** Global variables. We could get rid of most of these by using a good
** union as the yacc stack. (This routine was originally written before
** yacc had the %union construct.) Maybe someday; right now we only use
** the %union very rarely.
*/
static char *yyInput;
static DSTMODE yyDSTmode;
static time_t yyDayOrdinal;
static time_t yyDayNumber;
static int yyHaveDate;
static int yyHaveDay;
static int yyHaveRel;
static int yyHaveTime;
static int yyHaveZone;
static time_t yyTimezone;
static time_t yyDay;
static time_t yyHour;
static time_t yyMinutes;
static time_t yyMonth;
static time_t yySeconds;
static time_t yyYear;
static time_t yyRelMonth;
static time_t yyRelSeconds;
%}
%union {
time_t Number;
}
%token tAGO tDAY tDAYZONE tAMPM tMONTH tMONTH_UNIT tSEC_UNIT tUNUMBER
%token tZONE tDST
%type <Number> tDAY tDAYZONE tMONTH tMONTH_UNIT
%type <Number> tSEC_UNIT tUNUMBER tZONE tAMPM
%%
spec : /* NULL */
| spec item
;
item : time { yyHaveTime++; }
| zone { yyHaveZone++; }
| date { yyHaveDate++; }
| day { yyHaveDay++; }
| rel { yyHaveRel++; }
| number
;
time : tUNUMBER tAMPM {
/* "7am" */
yyHour = $1;
if (yyHour == 12)
yyHour = 0;
yyMinutes = 0;
yySeconds = 0;
if ($2 == tPM)
yyHour += 12;
}
| bare_time {
/* "7:12:18" "19:17" */
}
| bare_time tAMPM {
/* "7:12pm", "12:20:13am" */
if (yyHour == 12)
yyHour = 0;
if ($2 == tPM)
yyHour += 12;
}
| bare_time '+' tUNUMBER {
/* "7:14+0700" */
yyDSTmode = DSToff;
yyTimezone = - ($3 % 100 + ($3 / 100) * 60);
}
| bare_time '-' tUNUMBER {
/* "19:14:12-0530" */
yyDSTmode = DSToff;
yyTimezone = + ($3 % 100 + ($3 / 100) * 60);
}
;
bare_time : tUNUMBER ':' tUNUMBER {
yyHour = $1;
yyMinutes = $3;
yySeconds = 0;
}
| tUNUMBER ':' tUNUMBER ':' tUNUMBER {
yyHour = $1;
yyMinutes = $3;
yySeconds = $5;
}
;
zone : tZONE {
yyTimezone = $1;
yyDSTmode = DSToff;
}
| tDAYZONE {
yyTimezone = $1;
yyDSTmode = DSTon;
}
| tZONE tDST {
yyTimezone = $1;
yyDSTmode = DSTon;
}
;
day : tDAY {
yyDayOrdinal = 1;
yyDayNumber = $1;
}
| tDAY ',' {
/* "tue," "wednesday," */
yyDayOrdinal = 1;
yyDayNumber = $1;
}
| tUNUMBER tDAY {
/* "second tues" "3 wed" */
yyDayOrdinal = $1;
yyDayNumber = $2;
}
;
date : tUNUMBER '/' tUNUMBER {
/* "1/15" */
yyMonth = $1;
yyDay = $3;
}
| tUNUMBER '/' tUNUMBER '/' tUNUMBER {
if ($1 >= 13) {
/* First number is big: 2004/01/29, 99/02/17 */
yyYear = $1;
yyMonth = $3;
yyDay = $5;
} else if (($5 >= 13) || ($3 >= 13)) {
/* Last number is big: 01/07/98 */
/* Middle number is big: 01/29/04 */
yyMonth = $1;
yyDay = $3;
yyYear = $5;
} else {
/* No significant clues: 02/03/04 */
yyMonth = $1;
yyDay = $3;
yyYear = $5;
}
}
| tUNUMBER '-' tUNUMBER '-' tUNUMBER {
/* ISO 8601 format. yyyy-mm-dd. */
yyYear = $1;
yyMonth = $3;
yyDay = $5;
}
| tUNUMBER '-' tMONTH '-' tUNUMBER {
if ($1 > 31) {
/* e.g. 1992-Jun-17 */
yyYear = $1;
yyMonth = $3;
yyDay = $5;
} else {
/* e.g. 17-JUN-1992. */
yyDay = $1;
yyMonth = $3;
yyYear = $5;
}
}
| tMONTH tUNUMBER {
/* "May 3" */
yyMonth = $1;
yyDay = $2;
}
| tMONTH tUNUMBER ',' tUNUMBER {
/* "June 17, 2001" */
yyMonth = $1;
yyDay = $2;
yyYear = $4;
}
| tUNUMBER tMONTH {
/* "12 Sept" */
yyDay = $1;
yyMonth = $2;
}
| tUNUMBER tMONTH tUNUMBER {
/* "12 Sept 1997" */
yyDay = $1;
yyMonth = $2;
yyYear = $3;
}
;
rel : relunit tAGO {
yyRelSeconds = -yyRelSeconds;
yyRelMonth = -yyRelMonth;
}
| relunit
;
relunit : '-' tUNUMBER tSEC_UNIT {
/* "-3 hours" */
yyRelSeconds -= $2 * $3;
}
| '+' tUNUMBER tSEC_UNIT {
/* "+1 minute" */
yyRelSeconds += $2 * $3;
}
| tUNUMBER tSEC_UNIT {
/* "1 day" */
yyRelSeconds += $1;
}
| tSEC_UNIT {
/* "hour" */
yyRelSeconds++;
}
| '-' tUNUMBER tMONTH_UNIT {
/* "-3 months" */
yyRelMonth -= $2 * $3;
}
| '+' tUNUMBER tMONTH_UNIT {
/* "+5 years" */
yyRelMonth += $2 * $3;
}
| tUNUMBER tMONTH_UNIT {
/* "2 years" */
yyRelMonth += $1 * $2;
}
| tMONTH_UNIT {
/* "6 months" */
yyRelMonth += $1;
}
;
number : tUNUMBER {
if (yyHaveTime && yyHaveDate && !yyHaveRel)
yyYear = $1;
else {
if($1>10000) {
/* "20040301" */
yyHaveDate++;
yyDay= ($1)%100;
yyMonth= ($1/100)%100;
yyYear = $1/10000;
}
else {
/* "513" is same as "5:13" */
yyHaveTime++;
if ($1 < 100) {
yyHour = $1;
yyMinutes = 0;
}
else {
yyHour = $1 / 100;
yyMinutes = $1 % 100;
}
yySeconds = 0;
}
}
}
;
%%
static struct TABLE {
size_t abbrev;
const char *name;
int type;
time_t value;
} const TimeWords[] = {
/* am/pm */
{ 0, "am", tAMPM, tAM },
{ 0, "pm", tAMPM, tPM },
/* Month names. */
{ 3, "january", tMONTH, 1 },
{ 3, "february", tMONTH, 2 },
{ 3, "march", tMONTH, 3 },
{ 3, "april", tMONTH, 4 },
{ 3, "may", tMONTH, 5 },
{ 3, "june", tMONTH, 6 },
{ 3, "july", tMONTH, 7 },
{ 3, "august", tMONTH, 8 },
{ 3, "september", tMONTH, 9 },
{ 3, "october", tMONTH, 10 },
{ 3, "november", tMONTH, 11 },
{ 3, "december", tMONTH, 12 },
/* Days of the week. */
{ 2, "sunday", tDAY, 0 },
{ 3, "monday", tDAY, 1 },
{ 2, "tuesday", tDAY, 2 },
{ 3, "wednesday", tDAY, 3 },
{ 2, "thursday", tDAY, 4 },
{ 2, "friday", tDAY, 5 },
{ 2, "saturday", tDAY, 6 },
/* Timezones: Offsets are in minutes. */
{ 0, "gmt", tZONE, HOUR( 0) }, /* Greenwich Mean */
{ 0, "ut", tZONE, HOUR( 0) }, /* Universal (Coordinated) */
{ 0, "utc", tZONE, HOUR( 0) },
{ 0, "wet", tZONE, HOUR( 0) }, /* Western European */
{ 0, "bst", tDAYZONE, HOUR( 0) }, /* British Summer */
{ 0, "wat", tZONE, HOUR( 1) }, /* West Africa */
{ 0, "at", tZONE, HOUR( 2) }, /* Azores */
/* { 0, "bst", tZONE, HOUR( 3) }, */ /* Brazil Standard: Conflict */
/* { 0, "gst", tZONE, HOUR( 3) }, */ /* Greenland Standard: Conflict*/
{ 0, "nft", tZONE, HOUR(3)+30 }, /* Newfoundland */
{ 0, "nst", tZONE, HOUR(3)+30 }, /* Newfoundland Standard */
{ 0, "ndt", tDAYZONE, HOUR(3)+30 }, /* Newfoundland Daylight */
{ 0, "ast", tZONE, HOUR( 4) }, /* Atlantic Standard */
{ 0, "adt", tDAYZONE, HOUR( 4) }, /* Atlantic Daylight */
{ 0, "est", tZONE, HOUR( 5) }, /* Eastern Standard */
{ 0, "edt", tDAYZONE, HOUR( 5) }, /* Eastern Daylight */
{ 0, "cst", tZONE, HOUR( 6) }, /* Central Standard */
{ 0, "cdt", tDAYZONE, HOUR( 6) }, /* Central Daylight */
{ 0, "mst", tZONE, HOUR( 7) }, /* Mountain Standard */
{ 0, "mdt", tDAYZONE, HOUR( 7) }, /* Mountain Daylight */
{ 0, "pst", tZONE, HOUR( 8) }, /* Pacific Standard */
{ 0, "pdt", tDAYZONE, HOUR( 8) }, /* Pacific Daylight */
{ 0, "yst", tZONE, HOUR( 9) }, /* Yukon Standard */
{ 0, "ydt", tDAYZONE, HOUR( 9) }, /* Yukon Daylight */
{ 0, "hst", tZONE, HOUR(10) }, /* Hawaii Standard */
{ 0, "hdt", tDAYZONE, HOUR(10) }, /* Hawaii Daylight */
{ 0, "cat", tZONE, HOUR(10) }, /* Central Alaska */
{ 0, "ahst", tZONE, HOUR(10) }, /* Alaska-Hawaii Standard */
{ 0, "nt", tZONE, HOUR(11) }, /* Nome */
{ 0, "idlw", tZONE, HOUR(12) }, /* Intl Date Line West */
{ 0, "cet", tZONE, -HOUR(1) }, /* Central European */
{ 0, "met", tZONE, -HOUR(1) }, /* Middle European */
{ 0, "mewt", tZONE, -HOUR(1) }, /* Middle European Winter */
{ 0, "mest", tDAYZONE, -HOUR(1) }, /* Middle European Summer */
{ 0, "swt", tZONE, -HOUR(1) }, /* Swedish Winter */
{ 0, "sst", tDAYZONE, -HOUR(1) }, /* Swedish Summer */
{ 0, "fwt", tZONE, -HOUR(1) }, /* French Winter */
{ 0, "fst", tDAYZONE, -HOUR(1) }, /* French Summer */
{ 0, "eet", tZONE, -HOUR(2) }, /* Eastern Eur, USSR Zone 1 */
{ 0, "bt", tZONE, -HOUR(3) }, /* Baghdad, USSR Zone 2 */
{ 0, "it", tZONE, -HOUR(3)-30 },/* Iran */
{ 0, "zp4", tZONE, -HOUR(4) }, /* USSR Zone 3 */
{ 0, "zp5", tZONE, -HOUR(5) }, /* USSR Zone 4 */
{ 0, "ist", tZONE, -HOUR(5)-30 },/* Indian Standard */
{ 0, "zp6", tZONE, -HOUR(6) }, /* USSR Zone 5 */
/* { 0, "nst", tZONE, -HOUR(6.5) }, */ /* North Sumatra: Conflict */
/* { 0, "sst", tZONE, -HOUR(7) }, */ /* So Sumatra, USSR 6: Conflict */
{ 0, "wast", tZONE, -HOUR(7) }, /* West Australian Standard */
{ 0, "wadt", tDAYZONE, -HOUR(7) }, /* West Australian Daylight */
{ 0, "jt", tZONE, -HOUR(7)-30 },/* Java (3pm in Cronusland!)*/
{ 0, "cct", tZONE, -HOUR(8) }, /* China Coast, USSR Zone 7 */
{ 0, "jst", tZONE, -HOUR(9) }, /* Japan Std, USSR Zone 8 */
{ 0, "cast", tZONE, -HOUR(9)-30 },/* Central Australian Std */
{ 0, "cadt", tDAYZONE, -HOUR(9)-30 },/* Central Australian Daylt */
{ 0, "east", tZONE, -HOUR(10) }, /* Eastern Australian Std */
{ 0, "eadt", tDAYZONE, -HOUR(10) }, /* Eastern Australian Daylt */
{ 0, "gst", tZONE, -HOUR(10) }, /* Guam Std, USSR Zone 9 */
{ 0, "nzt", tZONE, -HOUR(12) }, /* New Zealand */
{ 0, "nzst", tZONE, -HOUR(12) }, /* New Zealand Standard */
{ 0, "nzdt", tDAYZONE, -HOUR(12) }, /* New Zealand Daylight */
{ 0, "idle", tZONE, -HOUR(12) }, /* Intl Date Line East */
{ 0, "dst", tDST, 0 },
/* Time units. */
{ 4, "years", tMONTH_UNIT, 12 },
{ 5, "months", tMONTH_UNIT, 1 },
{ 9, "fortnights", tSEC_UNIT, 14 * 24 * 60 * 60 },
{ 4, "weeks", tSEC_UNIT, 7 * 24 * 60 * 60 },
{ 3, "days", tSEC_UNIT, 1 * 24 * 60 * 60 },
{ 4, "hours", tSEC_UNIT, 60 * 60 },
{ 3, "minutes", tSEC_UNIT, 60 },
{ 3, "seconds", tSEC_UNIT, 1 },
/* Relative-time words. */
{ 0, "tomorrow", tSEC_UNIT, 1 * 24 * 60 * 60 },
{ 0, "yesterday", tSEC_UNIT, -1 * 24 * 60 * 60 },
{ 0, "today", tSEC_UNIT, 0 },
{ 0, "now", tSEC_UNIT, 0 },
{ 0, "last", tUNUMBER, -1 },
{ 0, "this", tSEC_UNIT, 0 },
{ 0, "next", tUNUMBER, 2 },
{ 0, "first", tUNUMBER, 1 },
{ 0, "1st", tUNUMBER, 1 },
/* { 0, "second", tUNUMBER, 2 }, */
{ 0, "2nd", tUNUMBER, 2 },
{ 0, "third", tUNUMBER, 3 },
{ 0, "3rd", tUNUMBER, 3 },
{ 0, "fourth", tUNUMBER, 4 },
{ 0, "4th", tUNUMBER, 4 },
{ 0, "fifth", tUNUMBER, 5 },
{ 0, "5th", tUNUMBER, 5 },
{ 0, "sixth", tUNUMBER, 6 },
{ 0, "seventh", tUNUMBER, 7 },
{ 0, "eighth", tUNUMBER, 8 },
{ 0, "ninth", tUNUMBER, 9 },
{ 0, "tenth", tUNUMBER, 10 },
{ 0, "eleventh", tUNUMBER, 11 },
{ 0, "twelfth", tUNUMBER, 12 },
{ 0, "ago", tAGO, 1 },
/* Military timezones. */
{ 0, "a", tZONE, HOUR( 1) },
{ 0, "b", tZONE, HOUR( 2) },
{ 0, "c", tZONE, HOUR( 3) },
{ 0, "d", tZONE, HOUR( 4) },
{ 0, "e", tZONE, HOUR( 5) },
{ 0, "f", tZONE, HOUR( 6) },
{ 0, "g", tZONE, HOUR( 7) },
{ 0, "h", tZONE, HOUR( 8) },
{ 0, "i", tZONE, HOUR( 9) },
{ 0, "k", tZONE, HOUR( 10) },
{ 0, "l", tZONE, HOUR( 11) },
{ 0, "m", tZONE, HOUR( 12) },
{ 0, "n", tZONE, HOUR(- 1) },
{ 0, "o", tZONE, HOUR(- 2) },
{ 0, "p", tZONE, HOUR(- 3) },
{ 0, "q", tZONE, HOUR(- 4) },
{ 0, "r", tZONE, HOUR(- 5) },
{ 0, "s", tZONE, HOUR(- 6) },
{ 0, "t", tZONE, HOUR(- 7) },
{ 0, "u", tZONE, HOUR(- 8) },
{ 0, "v", tZONE, HOUR(- 9) },
{ 0, "w", tZONE, HOUR(-10) },
{ 0, "x", tZONE, HOUR(-11) },
{ 0, "y", tZONE, HOUR(-12) },
{ 0, "z", tZONE, HOUR( 0) },
/* End of table. */
{ 0, NULL, 0, 0 }
};
/* ARGSUSED */
static int
yyerror(const char *s)
{
(void)s;
return 0;
}
static time_t
ToSeconds(time_t Hours, time_t Minutes, time_t Seconds)
{
if (Minutes < 0 || Minutes > 59 || Seconds < 0 || Seconds > 59)
return -1;
if (Hours < 0 || Hours > 23)
return -1;
return (Hours * 60L + Minutes) * 60L + Seconds;
}
/* Year is either
* A number from 0 to 99, which means a year from 1970 to 2069, or
* The actual year (>=100). */
static time_t
Convert(time_t Month, time_t Day, time_t Year,
time_t Hours, time_t Minutes, time_t Seconds, DSTMODE DSTmode)
{
static int DaysInMonth[12] = {
31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
time_t tod;
time_t Julian;
int i;
if (Year < 69)
Year += 2000;
else if (Year < 100)
Year += 1900;
DaysInMonth[1] = Year % 4 == 0 && (Year % 100 != 0 || Year % 400 == 0)
? 29 : 28;
/* Checking for 2038 bogusly assumes that time_t is 32 bits. But
I'm too lazy to try to check for time_t overflow in another way. */
if (Year < EPOCH || Year > 2038
|| Month < 1 || Month > 12
/* Lint fluff: "conversion from long may lose accuracy" */
|| Day < 1 || Day > DaysInMonth[(int)--Month])
return -1;
Julian = Day - 1;
for (i = 0; i < Month; i++)
Julian += DaysInMonth[i];
for (i = EPOCH; i < Year; i++)
Julian += 365 + (i % 4 == 0);
Julian *= SECSPERDAY;
Julian += yyTimezone * 60L;
if ((tod = ToSeconds(Hours, Minutes, Seconds)) < 0)
return -1;
Julian += tod;
if (DSTmode == DSTon
|| (DSTmode == DSTmaybe && localtime(&Julian)->tm_isdst))
Julian -= 60 * 60;
return Julian;
}
static time_t
DSTcorrect(time_t Start, time_t Future)
{
time_t StartDay;
time_t FutureDay;
StartDay = (localtime(&Start)->tm_hour + 1) % 24;
FutureDay = (localtime(&Future)->tm_hour + 1) % 24;
return (Future - Start) + (StartDay - FutureDay) * 60L * 60L;
}
static time_t
RelativeDate(time_t Start, time_t DayOrdinal, time_t DayNumber)
{
struct tm *tm;
time_t now;
now = Start;
tm = localtime(&now);
now += SECSPERDAY * ((DayNumber - tm->tm_wday + 7) % 7);
now += 7 * SECSPERDAY * (DayOrdinal <= 0 ? DayOrdinal : DayOrdinal - 1);
return DSTcorrect(Start, now);
}
static time_t
RelativeMonth(time_t Start, time_t RelMonth)
{
struct tm *tm;
time_t Month;
time_t Year;
if (RelMonth == 0)
return 0;
tm = localtime(&Start);
Month = 12 * (tm->tm_year + 1900) + tm->tm_mon + RelMonth;
Year = Month / 12;
Month = Month % 12 + 1;
return DSTcorrect(Start,
Convert(Month, (time_t)tm->tm_mday, Year,
(time_t)tm->tm_hour, (time_t)tm->tm_min, (time_t)tm->tm_sec,
DSTmaybe));
}
static int
yylex(void)
{
char c;
char buff[64];
for ( ; ; ) {
while (isspace(*yyInput))
yyInput++;
/* Skip parenthesized comments. */
if (*yyInput == '(') {
int Count = 0;
do {
c = *yyInput++;
if (c == '\0')
return c;
if (c == '(')
Count++;
else if (c == ')')
Count--;
} while (Count > 0);
continue;
}
/* Try the next token in the word table first. */
/* This allows us to match "2nd", for example. */
{
char *src = yyInput;
const struct TABLE *tp;
unsigned i = 0;
/* Force to lowercase and strip '.' characters. */
while (*src != '\0'
&& (isalnum(*src) || *src == '.')
&& i < sizeof(buff)-1) {
if (*src != '.') {
if (isupper(*src))
buff[i++] = tolower(*src);
else
buff[i++] = *src;
}
src++;
}
buff[i++] = '\0';
/*
* Find the first match. If the word can be
* abbreviated, make sure we match at least
* the minimum abbreviation.
*/
for (tp = TimeWords; tp->name; tp++) {
size_t abbrev = tp->abbrev;
if (abbrev == 0)
abbrev = strlen(tp->name);
if (strlen(buff) >= abbrev
&& strncmp(tp->name, buff, strlen(buff))
== 0) {
/* Skip over token. */
yyInput = src;
/* Return the match. */
yylval.Number = tp->value;
return tp->type;
}
}
}
/*
* Not in the word table, maybe it's a number. Note:
* Because '-' and '+' have other special meanings, I
* don't deal with signed numbers here.
*/
if (isdigit(c = *yyInput)) {
for (yylval.Number = 0; isdigit(c = *yyInput++); )
yylval.Number = 10 * yylval.Number + c - '0';
yyInput--;
return (tUNUMBER);
}
return (*yyInput++);
}
}
#define TM_YEAR_ORIGIN 1900
/* Yield A - B, measured in seconds. */
static long
difftm (struct tm *a, struct tm *b)
{
int ay = a->tm_year + (TM_YEAR_ORIGIN - 1);
int by = b->tm_year + (TM_YEAR_ORIGIN - 1);
int days = (
/* difference in day of year */
a->tm_yday - b->tm_yday
/* + intervening leap days */
+ ((ay >> 2) - (by >> 2))
- (ay/100 - by/100)
+ ((ay/100 >> 2) - (by/100 >> 2))
/* + difference in years * 365 */
+ (long)(ay-by) * 365
);
return (60*(60*(24*days + (a->tm_hour - b->tm_hour))
+ (a->tm_min - b->tm_min))
+ (a->tm_sec - b->tm_sec));
}
time_t
get_date(char *p)
{
struct tm *tm;
struct tm gmt, *gmt_ptr;
time_t Start;
time_t tod;
time_t nowtime;
long tzone;
yyInput = p;
(void)time (&nowtime);
gmt_ptr = gmtime (&nowtime);
if (gmt_ptr != NULL) {
/* Copy, in case localtime and gmtime use the same buffer. */
gmt = *gmt_ptr;
}
if (! (tm = localtime (&nowtime)))
return -1;
if (gmt_ptr != NULL)
tzone = difftm (&gmt, tm) / 60;
else
/* This system doesn't understand timezones; fake it. */
tzone = 0;
if(tm->tm_isdst)
tzone += 60;
yyYear = tm->tm_year + 1900;
yyMonth = tm->tm_mon + 1;
yyDay = tm->tm_mday;
yyTimezone = tzone;
yyDSTmode = DSTmaybe;
yyHour = 0;
yyMinutes = 0;
yySeconds = 0;
yyRelSeconds = 0;
yyRelMonth = 0;
yyHaveDate = 0;
yyHaveDay = 0;
yyHaveRel = 0;
yyHaveTime = 0;
yyHaveZone = 0;
if (yyparse()
|| yyHaveTime > 1 || yyHaveZone > 1
|| yyHaveDate > 1 || yyHaveDay > 1)
return -1;
if (yyHaveDate || yyHaveTime || yyHaveDay) {
Start = Convert(yyMonth, yyDay, yyYear,
yyHour, yyMinutes, yySeconds, yyDSTmode);
if (Start < 0)
return -1;
} else {
Start = nowtime;
if (!yyHaveRel)
Start -= ((tm->tm_hour * 60L + tm->tm_min) * 60L) + tm->tm_sec;
}
Start += yyRelSeconds;
Start += RelativeMonth(Start, yyRelMonth);
if (yyHaveDay && !yyHaveDate) {
tod = RelativeDate(Start, yyDayOrdinal, yyDayNumber);
Start += tod;
}
/* Have to do *something* with a legitimate -1 so it's
* distinguishable from the error return value. (Alternately
* could set errno on error.) */
return Start == -1 ? 0 : Start;
}
#if defined(TEST)
/* ARGSUSED */
int
main(int argc, char **argv)
{
time_t d;
while (*++argv != NULL) {
(void)printf("Input: %s\n", *argv);
d = get_date(*argv);
if (d == -1)
(void)printf("Bad format - couldn't convert.\n");
else
(void)printf("Output: %s\n", ctime(&d));
}
exit(0);
/* NOTREACHED */
}
#endif /* defined(TEST) */