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freebsd/usr.bin/tar/getdate.c
Tim Kientzle 95332e994e Minor code rework.
2010-02-07 01:16:05 +00:00

1038 lines
27 KiB
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/*
* This code is in the public domain and has no copyright.
*
* This is a plain C recursive-descent translation of an old
* public-domain YACC grammar that has been used for parsing dates in
* very many open-source projects.
*
* Since the original authors were generous enough to donate their
* work to the public domain, I feel compelled to match their
* generosity.
*
* Tim Kientzle, February 2009.
*/
/*
* Header comment from original getdate.y:
*/
/*
** 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 $alz
** <rsalz@bbn.com> and Jim Berets <jberets@bbn.com> in August, 1990;
**
** This grammar has 10 shift/reduce conflicts.
**
** This code is in the public domain and has no copyright.
*/
#ifdef __FreeBSD__
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#endif
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
/* This file defines a single public function. */
time_t get_date(time_t now, char *);
/* Basic time units. */
#define EPOCH 1970
#define MINUTE (60L)
#define HOUR (60L * MINUTE)
#define DAY (24L * HOUR)
/* Daylight-savings mode: on, off, or not yet known. */
enum DSTMODE { DSTon, DSToff, DSTmaybe };
/* Meridian: am or pm. */
enum { tAM, tPM };
/* Token types returned by nexttoken() */
enum { tAGO = 260, tDAY, tDAYZONE, tAMPM, tMONTH, tMONTH_UNIT, tSEC_UNIT,
tUNUMBER, tZONE, tDST };
struct token { int token; time_t value; };
/*
* Parser state.
*/
struct gdstate {
struct token *tokenp; /* Pointer to next token. */
/* HaveXxxx counts how many of this kind of phrase we've seen;
* it's a fatal error to have more than one time, zone, day,
* or date phrase. */
int HaveYear;
int HaveMonth;
int HaveDay;
int HaveWeekDay; /* Day of week */
int HaveTime; /* Hour/minute/second */
int HaveZone; /* timezone and/or DST info */
int HaveRel; /* time offset; we can have more than one */
/* Absolute time values. */
time_t Timezone; /* Seconds offset from GMT */
time_t Day;
time_t Hour;
time_t Minutes;
time_t Month;
time_t Seconds;
time_t Year;
/* DST selection */
enum DSTMODE DSTmode;
/* Day of week accounting, e.g., "3rd Tuesday" */
time_t DayOrdinal; /* "3" in "3rd Tuesday" */
time_t DayNumber; /* "Tuesday" in "3rd Tuesday" */
/* Relative time values: hour/day/week offsets are measured in
* seconds, month/year are counted in months. */
time_t RelMonth;
time_t RelSeconds;
};
/*
* A series of functions that recognize certain common time phrases.
* Each function returns 1 if it managed to make sense of some of the
* tokens, zero otherwise.
*/
/*
* hour:minute or hour:minute:second with optional AM, PM, or numeric
* timezone offset
*/
static int
timephrase(struct gdstate *gds)
{
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == ':'
&& gds->tokenp[2].token == tUNUMBER
&& gds->tokenp[3].token == ':'
&& gds->tokenp[4].token == tUNUMBER) {
/* "12:14:18" or "22:08:07" */
++gds->HaveTime;
gds->Hour = gds->tokenp[0].value;
gds->Minutes = gds->tokenp[2].value;
gds->Seconds = gds->tokenp[4].value;
gds->tokenp += 5;
}
else if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == ':'
&& gds->tokenp[2].token == tUNUMBER) {
/* "12:14" or "22:08" */
++gds->HaveTime;
gds->Hour = gds->tokenp[0].value;
gds->Minutes = gds->tokenp[2].value;
gds->Seconds = 0;
gds->tokenp += 3;
}
else if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == tAMPM) {
/* "7" is a time if it's followed by "am" or "pm" */
++gds->HaveTime;
gds->Hour = gds->tokenp[0].value;
gds->Minutes = gds->Seconds = 0;
/* We'll handle the AM/PM below. */
gds->tokenp += 1;
} else {
/* We can't handle this. */
return 0;
}
if (gds->tokenp[0].token == tAMPM) {
/* "7:12pm", "12:20:13am" */
if (gds->Hour == 12)
gds->Hour = 0;
if (gds->tokenp[0].value == tPM)
gds->Hour += 12;
gds->tokenp += 1;
}
if (gds->tokenp[0].token == '+'
&& gds->tokenp[1].token == tUNUMBER) {
/* "7:14+0700" */
gds->HaveZone++;
gds->DSTmode = DSToff;
gds->Timezone = - ((gds->tokenp[1].value / 100) * HOUR
+ (gds->tokenp[1].value % 100) * MINUTE);
gds->tokenp += 2;
}
if (gds->tokenp[0].token == '-'
&& gds->tokenp[1].token == tUNUMBER) {
/* "19:14:12-0530" */
gds->HaveZone++;
gds->DSTmode = DSToff;
gds->Timezone = + ((gds->tokenp[1].value / 100) * HOUR
+ (gds->tokenp[1].value % 100) * MINUTE);
gds->tokenp += 2;
}
return 1;
}
/*
* Timezone name, possibly including DST.
*/
static int
zonephrase(struct gdstate *gds)
{
if (gds->tokenp[0].token == tZONE
&& gds->tokenp[1].token == tDST) {
gds->HaveZone++;
gds->Timezone = gds->tokenp[0].value;
gds->DSTmode = DSTon;
gds->tokenp += 1;
return 1;
}
if (gds->tokenp[0].token == tZONE) {
gds->HaveZone++;
gds->Timezone = gds->tokenp[0].value;
gds->DSTmode = DSToff;
gds->tokenp += 1;
return 1;
}
if (gds->tokenp[0].token == tDAYZONE) {
gds->HaveZone++;
gds->Timezone = gds->tokenp[0].value;
gds->DSTmode = DSTon;
gds->tokenp += 1;
return 1;
}
return 0;
}
/*
* Year/month/day in various combinations.
*/
static int
datephrase(struct gdstate *gds)
{
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == '/'
&& gds->tokenp[2].token == tUNUMBER
&& gds->tokenp[3].token == '/'
&& gds->tokenp[4].token == tUNUMBER) {
gds->HaveYear++;
gds->HaveMonth++;
gds->HaveDay++;
if (gds->tokenp[0].value >= 13) {
/* First number is big: 2004/01/29, 99/02/17 */
gds->Year = gds->tokenp[0].value;
gds->Month = gds->tokenp[2].value;
gds->Day = gds->tokenp[4].value;
} else if ((gds->tokenp[4].value >= 13)
|| (gds->tokenp[2].value >= 13)) {
/* Last number is big: 01/07/98 */
/* Middle number is big: 01/29/04 */
gds->Month = gds->tokenp[0].value;
gds->Day = gds->tokenp[2].value;
gds->Year = gds->tokenp[4].value;
} else {
/* No significant clues: 02/03/04 */
gds->Month = gds->tokenp[0].value;
gds->Day = gds->tokenp[2].value;
gds->Year = gds->tokenp[4].value;
}
gds->tokenp += 5;
return 1;
}
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == '/'
&& gds->tokenp[2].token == tUNUMBER) {
/* "1/15" */
gds->HaveMonth++;
gds->HaveDay++;
gds->Month = gds->tokenp[0].value;
gds->Day = gds->tokenp[2].value;
gds->tokenp += 3;
return 1;
}
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == '-'
&& gds->tokenp[2].token == tUNUMBER
&& gds->tokenp[3].token == '-'
&& gds->tokenp[4].token == tUNUMBER) {
/* ISO 8601 format. yyyy-mm-dd. */
gds->HaveYear++;
gds->HaveMonth++;
gds->HaveDay++;
gds->Year = gds->tokenp[0].value;
gds->Month = gds->tokenp[2].value;
gds->Day = gds->tokenp[4].value;
gds->tokenp += 5;
return 1;
}
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == '-'
&& gds->tokenp[2].token == tMONTH
&& gds->tokenp[3].token == '-'
&& gds->tokenp[4].token == tUNUMBER) {
gds->HaveYear++;
gds->HaveMonth++;
gds->HaveDay++;
if (gds->tokenp[0].value > 31) {
/* e.g. 1992-Jun-17 */
gds->Year = gds->tokenp[0].value;
gds->Month = gds->tokenp[2].value;
gds->Day = gds->tokenp[4].value;
} else {
/* e.g. 17-JUN-1992. */
gds->Day = gds->tokenp[0].value;
gds->Month = gds->tokenp[2].value;
gds->Year = gds->tokenp[4].value;
}
gds->tokenp += 5;
return 1;
}
if (gds->tokenp[0].token == tMONTH
&& gds->tokenp[1].token == tUNUMBER
&& gds->tokenp[2].token == ','
&& gds->tokenp[3].token == tUNUMBER) {
/* "June 17, 2001" */
gds->HaveYear++;
gds->HaveMonth++;
gds->HaveDay++;
gds->Month = gds->tokenp[0].value;
gds->Day = gds->tokenp[1].value;
gds->Year = gds->tokenp[3].value;
gds->tokenp += 4;
return 1;
}
if (gds->tokenp[0].token == tMONTH
&& gds->tokenp[1].token == tUNUMBER) {
/* "May 3" */
gds->HaveMonth++;
gds->HaveDay++;
gds->Month = gds->tokenp[0].value;
gds->Day = gds->tokenp[1].value;
gds->tokenp += 2;
return 1;
}
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == tMONTH
&& gds->tokenp[2].token == tUNUMBER) {
/* "12 Sept 1997" */
gds->HaveYear++;
gds->HaveMonth++;
gds->HaveDay++;
gds->Day = gds->tokenp[0].value;
gds->Month = gds->tokenp[1].value;
gds->Year = gds->tokenp[2].value;
gds->tokenp += 3;
return 1;
}
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == tMONTH) {
/* "12 Sept" */
gds->HaveMonth++;
gds->HaveDay++;
gds->Day = gds->tokenp[0].value;
gds->Month = gds->tokenp[1].value;
gds->tokenp += 2;
return 1;
}
return 0;
}
/*
* Relative time phrase: "tomorrow", "yesterday", "+1 hour", etc.
*/
static int
relunitphrase(struct gdstate *gds)
{
if (gds->tokenp[0].token == '-'
&& gds->tokenp[1].token == tUNUMBER
&& gds->tokenp[2].token == tSEC_UNIT) {
/* "-3 hours" */
gds->HaveRel++;
gds->RelSeconds -= gds->tokenp[1].value * gds->tokenp[2].value;
gds->tokenp += 3;
return 1;
}
if (gds->tokenp[0].token == '+'
&& gds->tokenp[1].token == tUNUMBER
&& gds->tokenp[2].token == tSEC_UNIT) {
/* "+1 minute" */
gds->HaveRel++;
gds->RelSeconds += gds->tokenp[1].value * gds->tokenp[2].value;
gds->tokenp += 3;
return 1;
}
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == tSEC_UNIT) {
/* "1 day" */
gds->HaveRel++;
gds->RelSeconds += gds->tokenp[1].value * gds->tokenp[2].value;
gds->tokenp += 3;
return 1;
}
if (gds->tokenp[0].token == '-'
&& gds->tokenp[1].token == tUNUMBER
&& gds->tokenp[2].token == tMONTH_UNIT) {
/* "-3 months" */
gds->HaveRel++;
gds->RelMonth -= gds->tokenp[1].value * gds->tokenp[2].value;
gds->tokenp += 3;
return 1;
}
if (gds->tokenp[0].token == '+'
&& gds->tokenp[1].token == tUNUMBER
&& gds->tokenp[2].token == tMONTH_UNIT) {
/* "+5 years" */
gds->HaveRel++;
gds->RelMonth += gds->tokenp[1].value * gds->tokenp[2].value;
gds->tokenp += 3;
return 1;
}
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == tMONTH_UNIT) {
/* "2 years" */
gds->HaveRel++;
gds->RelMonth += gds->tokenp[0].value * gds->tokenp[1].value;
gds->tokenp += 2;
return 1;
}
if (gds->tokenp[0].token == tSEC_UNIT) {
/* "now", "tomorrow" */
gds->HaveRel++;
gds->RelSeconds += gds->tokenp[0].value;
++gds->tokenp;
return 1;
}
if (gds->tokenp[0].token == tMONTH_UNIT) {
/* "month" */
gds->HaveRel++;
gds->RelMonth += gds->tokenp[0].value;
gds->tokenp += 1;
return 1;
}
return 0;
}
/*
* Day of the week specification.
*/
static int
dayphrase(struct gdstate *gds)
{
if (gds->tokenp[0].token == tDAY) {
/* "tues", "wednesday," */
gds->HaveWeekDay++;
gds->DayOrdinal = 1;
gds->DayNumber = gds->tokenp[0].value;
gds->tokenp += 1;
if (gds->tokenp[0].token == ',')
gds->tokenp += 1;
return 1;
}
if (gds->tokenp[0].token == tUNUMBER
&& gds->tokenp[1].token == tDAY) {
/* "second tues" "3 wed" */
gds->HaveWeekDay++;
gds->DayOrdinal = gds->tokenp[0].value;
gds->DayNumber = gds->tokenp[1].value;
gds->tokenp += 2;
return 1;
}
return 0;
}
/*
* Try to match a phrase using one of the above functions.
* This layer also deals with a couple of generic issues.
*/
static int
phrase(struct gdstate *gds)
{
if (timephrase(gds))
return 1;
if (zonephrase(gds))
return 1;
if (datephrase(gds))
return 1;
if (dayphrase(gds))
return 1;
if (relunitphrase(gds)) {
if (gds->tokenp[0].token == tAGO) {
gds->RelSeconds = -gds->RelSeconds;
gds->RelMonth = -gds->RelMonth;
gds->tokenp += 1;
}
return 1;
}
/* Bare numbers sometimes have meaning. */
if (gds->tokenp[0].token == tUNUMBER) {
if (gds->HaveTime && !gds->HaveYear && !gds->HaveRel) {
gds->HaveYear++;
gds->Year = gds->tokenp[0].value;
gds->tokenp += 1;
return 1;
}
if(gds->tokenp[0].value > 10000) {
/* "20040301" */
gds->HaveYear++;
gds->HaveMonth++;
gds->HaveDay++;
gds->Day= (gds->tokenp[0].value)%100;
gds->Month= (gds->tokenp[0].value/100)%100;
gds->Year = gds->tokenp[0].value/10000;
gds->tokenp += 1;
return 1;
}
if (gds->tokenp[0].value < 24) {
gds->HaveTime++;
gds->Hour = gds->tokenp[0].value;
gds->Minutes = 0;
gds->Seconds = 0;
gds->tokenp += 1;
return 1;
}
if ((gds->tokenp[0].value / 100 < 24)
&& (gds->tokenp[0].value % 100 < 60)) {
/* "513" is same as "5:13" */
gds->Hour = gds->tokenp[0].value / 100;
gds->Minutes = gds->tokenp[0].value % 100;
gds->Seconds = 0;
gds->tokenp += 1;
return 1;
}
}
return 0;
}
/*
* A dictionary of time words.
*/
static struct LEXICON {
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 seconds. */
{ 0, "gmt", tZONE, 0*HOUR }, /* Greenwich Mean */
{ 0, "ut", tZONE, 0*HOUR }, /* Universal (Coordinated) */
{ 0, "utc", tZONE, 0*HOUR },
{ 0, "wet", tZONE, 0*HOUR }, /* Western European */
{ 0, "bst", tDAYZONE, 0*HOUR }, /* British Summer */
{ 0, "wat", tZONE, 1*HOUR }, /* West Africa */
{ 0, "at", tZONE, 2*HOUR }, /* Azores */
/* { 0, "bst", tZONE, 3*HOUR }, */ /* Brazil Standard: Conflict */
/* { 0, "gst", tZONE, 3*HOUR }, */ /* Greenland Standard: Conflict*/
{ 0, "nft", tZONE, 3*HOUR+30*MINUTE }, /* Newfoundland */
{ 0, "nst", tZONE, 3*HOUR+30*MINUTE }, /* Newfoundland Standard */
{ 0, "ndt", tDAYZONE, 3*HOUR+30*MINUTE }, /* Newfoundland Daylight */
{ 0, "ast", tZONE, 4*HOUR }, /* Atlantic Standard */
{ 0, "adt", tDAYZONE, 4*HOUR }, /* Atlantic Daylight */
{ 0, "est", tZONE, 5*HOUR }, /* Eastern Standard */
{ 0, "edt", tDAYZONE, 5*HOUR }, /* Eastern Daylight */
{ 0, "cst", tZONE, 6*HOUR }, /* Central Standard */
{ 0, "cdt", tDAYZONE, 6*HOUR }, /* Central Daylight */
{ 0, "mst", tZONE, 7*HOUR }, /* Mountain Standard */
{ 0, "mdt", tDAYZONE, 7*HOUR }, /* Mountain Daylight */
{ 0, "pst", tZONE, 8*HOUR }, /* Pacific Standard */
{ 0, "pdt", tDAYZONE, 8*HOUR }, /* Pacific Daylight */
{ 0, "yst", tZONE, 9*HOUR }, /* Yukon Standard */
{ 0, "ydt", tDAYZONE, 9*HOUR }, /* Yukon Daylight */
{ 0, "hst", tZONE, 10*HOUR }, /* Hawaii Standard */
{ 0, "hdt", tDAYZONE, 10*HOUR }, /* Hawaii Daylight */
{ 0, "cat", tZONE, 10*HOUR }, /* Central Alaska */
{ 0, "ahst", tZONE, 10*HOUR }, /* Alaska-Hawaii Standard */
{ 0, "nt", tZONE, 11*HOUR }, /* Nome */
{ 0, "idlw", tZONE, 12*HOUR }, /* Intl Date Line West */
{ 0, "cet", tZONE, -1*HOUR }, /* Central European */
{ 0, "met", tZONE, -1*HOUR }, /* Middle European */
{ 0, "mewt", tZONE, -1*HOUR }, /* Middle European Winter */
{ 0, "mest", tDAYZONE, -1*HOUR }, /* Middle European Summer */
{ 0, "swt", tZONE, -1*HOUR }, /* Swedish Winter */
{ 0, "sst", tDAYZONE, -1*HOUR }, /* Swedish Summer */
{ 0, "fwt", tZONE, -1*HOUR }, /* French Winter */
{ 0, "fst", tDAYZONE, -1*HOUR }, /* French Summer */
{ 0, "eet", tZONE, -2*HOUR }, /* Eastern Eur, USSR Zone 1 */
{ 0, "bt", tZONE, -3*HOUR }, /* Baghdad, USSR Zone 2 */
{ 0, "it", tZONE, -3*HOUR-30*MINUTE },/* Iran */
{ 0, "zp4", tZONE, -4*HOUR }, /* USSR Zone 3 */
{ 0, "zp5", tZONE, -5*HOUR }, /* USSR Zone 4 */
{ 0, "ist", tZONE, -5*HOUR-30*MINUTE },/* Indian Standard */
{ 0, "zp6", tZONE, -6*HOUR }, /* USSR Zone 5 */
/* { 0, "nst", tZONE, -6.5*HOUR }, */ /* North Sumatra: Conflict */
/* { 0, "sst", tZONE, -7*HOUR }, */ /* So Sumatra, USSR 6: Conflict */
{ 0, "wast", tZONE, -7*HOUR }, /* West Australian Standard */
{ 0, "wadt", tDAYZONE, -7*HOUR }, /* West Australian Daylight */
{ 0, "jt", tZONE, -7*HOUR-30*MINUTE },/* Java (3pm in Cronusland!)*/
{ 0, "cct", tZONE, -8*HOUR }, /* China Coast, USSR Zone 7 */
{ 0, "jst", tZONE, -9*HOUR }, /* Japan Std, USSR Zone 8 */
{ 0, "cast", tZONE, -9*HOUR-30*MINUTE },/* Ctrl Australian Std */
{ 0, "cadt", tDAYZONE, -9*HOUR-30*MINUTE },/* Ctrl Australian Daylt */
{ 0, "east", tZONE, -10*HOUR }, /* Eastern Australian Std */
{ 0, "eadt", tDAYZONE, -10*HOUR }, /* Eastern Australian Daylt */
{ 0, "gst", tZONE, -10*HOUR }, /* Guam Std, USSR Zone 9 */
{ 0, "nzt", tZONE, -12*HOUR }, /* New Zealand */
{ 0, "nzst", tZONE, -12*HOUR }, /* New Zealand Standard */
{ 0, "nzdt", tDAYZONE, -12*HOUR }, /* New Zealand Daylight */
{ 0, "idle", tZONE, -12*HOUR }, /* 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 * DAY },
{ 4, "weeks", tSEC_UNIT, 7 * DAY },
{ 3, "days", tSEC_UNIT, DAY },
{ 4, "hours", tSEC_UNIT, HOUR },
{ 3, "minutes", tSEC_UNIT, MINUTE },
{ 3, "seconds", tSEC_UNIT, 1 },
/* Relative-time words. */
{ 0, "tomorrow", tSEC_UNIT, DAY },
{ 0, "yesterday", tSEC_UNIT, -DAY },
{ 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, 1*HOUR },
{ 0, "b", tZONE, 2*HOUR },
{ 0, "c", tZONE, 3*HOUR },
{ 0, "d", tZONE, 4*HOUR },
{ 0, "e", tZONE, 5*HOUR },
{ 0, "f", tZONE, 6*HOUR },
{ 0, "g", tZONE, 7*HOUR },
{ 0, "h", tZONE, 8*HOUR },
{ 0, "i", tZONE, 9*HOUR },
{ 0, "k", tZONE, 10*HOUR },
{ 0, "l", tZONE, 11*HOUR },
{ 0, "m", tZONE, 12*HOUR },
{ 0, "n", tZONE, -1*HOUR },
{ 0, "o", tZONE, -2*HOUR },
{ 0, "p", tZONE, -3*HOUR },
{ 0, "q", tZONE, -4*HOUR },
{ 0, "r", tZONE, -5*HOUR },
{ 0, "s", tZONE, -6*HOUR },
{ 0, "t", tZONE, -7*HOUR },
{ 0, "u", tZONE, -8*HOUR },
{ 0, "v", tZONE, -9*HOUR },
{ 0, "w", tZONE, -10*HOUR },
{ 0, "x", tZONE, -11*HOUR },
{ 0, "y", tZONE, -12*HOUR },
{ 0, "z", tZONE, 0*HOUR },
/* End of table. */
{ 0, NULL, 0, 0 }
};
/*
* 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,
time_t Timezone, enum DSTMODE DSTmode)
{
static int DaysInMonth[12] = {
31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
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]
|| Hours < 0 || Hours > 23
|| Minutes < 0 || Minutes > 59
|| Seconds < 0 || Seconds > 59)
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 *= DAY;
Julian += Timezone;
Julian += Hours * HOUR + Minutes * MINUTE + Seconds;
if (DSTmode == DSTon
|| (DSTmode == DSTmaybe && localtime(&Julian)->tm_isdst))
Julian -= HOUR;
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) * HOUR;
}
static time_t
RelativeDate(time_t Start, time_t zone, int dstmode,
time_t DayOrdinal, time_t DayNumber)
{
struct tm *tm;
time_t t, now;
t = Start - zone;
tm = gmtime(&t);
now = Start;
now += DAY * ((DayNumber - tm->tm_wday + 7) % 7);
now += 7 * DAY * (DayOrdinal <= 0 ? DayOrdinal : DayOrdinal - 1);
if (dstmode == DSTmaybe)
return DSTcorrect(Start, now);
return now - Start;
}
static time_t
RelativeMonth(time_t Start, time_t Timezone, 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,
Timezone, DSTmaybe));
}
/*
* Tokenizer.
*/
static int
nexttoken(char **in, time_t *value)
{
char c;
char buff[64];
for ( ; ; ) {
while (isspace((unsigned char)**in))
++*in;
/* Skip parenthesized comments. */
if (**in == '(') {
int Count = 0;
do {
c = *(*in)++;
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 = *in;
const struct LEXICON *tp;
unsigned i = 0;
/* Force to lowercase and strip '.' characters. */
while (*src != '\0'
&& (isalnum((unsigned char)*src) || *src == '.')
&& i < sizeof(buff)-1) {
if (*src != '.') {
if (isupper((unsigned char)*src))
buff[i++] = tolower((unsigned char)*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. */
*in = src;
/* Return the match. */
*value = 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((unsigned char)(c = **in))) {
for (*value = 0; isdigit((unsigned char)(c = *(*in)++)); )
*value = 10 * *value + c - '0';
(*in)--;
return (tUNUMBER);
}
return *(*in)++;
}
}
#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 (days * DAY + (a->tm_hour - b->tm_hour) * HOUR
+ (a->tm_min - b->tm_min) * MINUTE
+ (a->tm_sec - b->tm_sec));
}
/*
*
* The public function.
*
* TODO: tokens[] array should be dynamically sized.
*/
time_t
get_date(time_t now, char *p)
{
struct token tokens[256];
struct gdstate _gds;
struct token *lasttoken;
struct gdstate *gds;
struct tm local, *tm;
struct tm gmt, *gmt_ptr;
time_t Start;
time_t tod;
long tzone;
/* Clear out the parsed token array. */
memset(tokens, 0, sizeof(tokens));
/* Initialize the parser state. */
memset(&_gds, 0, sizeof(_gds));
gds = &_gds;
/* Look up the current time. */
memset(&local, 0, sizeof(local));
tm = localtime (&now);
if (tm == NULL)
return -1;
local = *tm;
/* Look up UTC if we can and use that to determine the current
* timezone offset. */
memset(&gmt, 0, sizeof(gmt));
gmt_ptr = gmtime (&now);
if (gmt_ptr != NULL) {
/* Copy, in case localtime and gmtime use the same buffer. */
gmt = *gmt_ptr;
}
if (gmt_ptr != NULL)
tzone = difftm (&gmt, &local);
else
/* This system doesn't understand timezones; fake it. */
tzone = 0;
if(local.tm_isdst)
tzone += HOUR;
/* Tokenize the input string. */
lasttoken = tokens;
while ((lasttoken->token = nexttoken(&p, &lasttoken->value)) != 0) {
++lasttoken;
if (lasttoken > tokens + 255)
return -1;
}
gds->tokenp = tokens;
/* Match phrases until we run out of input tokens. */
while (gds->tokenp < lasttoken) {
if (!phrase(gds))
return -1;
}
/* Use current local timezone if none was specified. */
if (!gds->HaveZone) {
gds->Timezone = tzone;
gds->DSTmode = DSTmaybe;
}
/* If a timezone was specified, use that for generating the default
* time components instead of the local timezone. */
if (gds->HaveZone && gmt_ptr != NULL) {
now -= gds->Timezone;
gmt_ptr = gmtime (&now);
if (gmt_ptr != NULL)
local = *gmt_ptr;
now += gds->Timezone;
}
if (!gds->HaveYear)
gds->Year = local.tm_year + 1900;
if (!gds->HaveMonth)
gds->Month = local.tm_mon + 1;
if (!gds->HaveDay)
gds->Day = local.tm_mday;
/* Note: No default for hour/min/sec; a specifier that just
* gives date always refers to 00:00 on that date. */
/* If we saw more than one time, timezone, weekday, year, month,
* or day, then give up. */
if (gds->HaveTime > 1 || gds->HaveZone > 1 || gds->HaveWeekDay > 1
|| gds->HaveYear > 1 || gds->HaveMonth > 1 || gds->HaveDay > 1)
return -1;
/* Compute an absolute time based on whatever absolute information
* we collected. */
if (gds->HaveYear || gds->HaveMonth || gds->HaveDay
|| gds->HaveTime || gds->HaveWeekDay) {
Start = Convert(gds->Month, gds->Day, gds->Year,
gds->Hour, gds->Minutes, gds->Seconds,
gds->Timezone, gds->DSTmode);
if (Start < 0)
return -1;
} else {
Start = now;
if (!gds->HaveRel)
Start -= local.tm_hour * HOUR + local.tm_min * MINUTE
+ local.tm_sec;
}
/* Add the relative offset. */
Start += gds->RelSeconds;
Start += RelativeMonth(Start, gds->Timezone, gds->RelMonth);
/* Adjust for day-of-week offsets. */
if (gds->HaveWeekDay
&& !(gds->HaveYear || gds->HaveMonth || gds->HaveDay)) {
tod = RelativeDate(Start, gds->Timezone,
gds->DSTmode, gds->DayOrdinal, gds->DayNumber);
Start += tod;
}
/* -1 is an error indicator, so return 0 instead of -1 if
* that's the actual time. */
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) */
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