+++ /dev/null
-
-/*
- *
- * Purpose:
- *
- * Manipulate character strings representing dates.
- *
- * Usage:
- *
- * #include <parsedate.h>
- *
- * char date;
- * struct parseddate *pd;
- *
- * pd = parsedate (date);
- *
- * compute_unixtime (pd);
- *
- * break_down_unixtime (pd);
- *
- * date = mail_date_string (pd);
- *
- * date = uucp_date_string (pd);
- *
- * Notes:
- *
- * The returned value from "parsedate", "mail_date_string", or
- * "uucp_date_string" points to static data whose contents are
- * overwritten by the next call to the same routine.
- *
- * "compute_unixtime" is implicitly called by "parsedate".
- *
- * Global contents:
- *
- * struct parseddate *parsedate (date) char *date;
- * Parse a character string representing a date and time into
- * individual values in a "struct parseddate" data structure.
- *
- * compute_unixtime (pd) struct parseddate *pd;
- * Given a mostly filled-in "struct parseddate", compute the day
- * of the week and the internal UNIX representation of the date.
- *
- * break_down_unixtime (pd) struct parseddate *pd;
- * Compute the date and time corresponding to the "unixtime" and
- * "zone" values in a "struct parseddate".
- *
- * char *mail_date_string (pd) struct parseddate *pd;
- * Generate a character string representing a date and time in
- * the RFC822 (ARPANET mail standard) format.
- *
- * char *uucp_date_string (pd) struct parseddate *pd;
- * Generate a character string representing a date and time in
- * the UUCP mail format.
- *
- * Local contents:
- *
- * None.
- */
-
-#include <stdio.h>
-#include <string.h>
-#include "parsedate.h"
-
-static char *RCSID = "$Id: parsedate.c,v 1.2 2002-09-28 06:58:45 arjen Exp $";
-
-extern int yyparse();
-
-void compute_unixtime (register struct parseddate *pd);
-
-/* Number of seconds in various time intervals. */
-#define SEC_PER_MIN 60
-#define SEC_PER_HOUR (60*SEC_PER_MIN)
-#define SEC_PER_DAY (24*SEC_PER_HOUR)
-#define SEC_PER_YEAR (365*SEC_PER_DAY)
-
-/* Number of days in each month. */
-static int monthsize[] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };
-
-/* Three-letter abbreviations of month and day names. */
-static char monthname[] = "JanFebMarAprMayJunJulAugSepOctNovDec";
-static char dayname[] = "SunMonTueWedThuFriSat";
-
-/* struct parseddate *parsedate (date) char *date;
- * Analyze a character string representing a date and time. The
- * returned value points to a data structure with the desired
- * information. (NOTE: The returned value points to static data
- * whose contents are overwritten by each call.)
- */
-struct parseddate * parsedate (char *date)
-{ register char *c;
- register int year_save;
- extern struct parseddate yyans;
- extern char *yyinbuf;
-
- /* Initialize the returned-value structure. */
- yyans.unixtime = -1;
- yyans.year = -1;
- yyans.month = -1;
- yyans.day = -1;
- yyans.hour = -1;
- yyans.minute = -1;
- yyans.second = -1;
- yyans.zone = -1;
- yyans.dst = -1;
- yyans.weekday = -1;
- yyans.c_weekday = -1;
- yyans.error = NULL;
-
- /* Parse the argument string. */
- yyinbuf = date;
-
- if (yyparse () != 0 && yyans.error == NULL)
- yyans.error = yyinbuf;
-
- /* Validate the day of the month, compute/validate the day of the
- * week, and compute the internal UNIX form of the time. See if
- * "compute_unixtime" found fault with the year or the day of the
- * month. (Note that we have to remember the original "year" value
- * because it might legitimately have been -1 to begin with.)
- */
- year_save = yyans.year; compute_unixtime (&yyans);
- if (yyans.error == NULL
- && (yyans.year != year_save
- || (yyans.month > 0 && yyans.day < 0)
- || (yyans.month < 0 && yyans.day > 0)))
- yyans.error = yyinbuf;
-
- return &yyans;
-}
-
-/* compute_unixtime (pd) struct parseddate *pd;
- * Given a mostly filled-in "struct parseddate", compute the day of
- * the week and the internal UNIX representation of the date.
- *
- * A year before 1600 will be rejected and replaced with -1. A
- * date from 1600 on which falls outside the range representable in
- * internal UNIX form will still have the correct day of the week
- * computed.
- *
- * The day of the week is always computed on the assumption that the
- * Gregorian calendar is in use. Days of the week for dates in the
- * far future may turn out to be incorrect if any changes are made
- * to the calendar between now and then.
- */
-void compute_unixtime (register struct parseddate *pd)
-{
- register int weekday, n, l, a;
-
- /* Validate the year. */
- if (pd->year >= 0 && pd->year < 1600) pd->year = -1;
-
- /* Validate the day of the month. Also calculate the number of days
- * in February (even if this is not February, we will need the num-
- * ber of days in February later on when computing the UNIX time).
- */
- if (pd->month > 0)
- { if (pd->year < 0) monthsize[2] = 29;
- else if (pd->year % 4 != 0) monthsize[2] = 28;
- else if (pd->year % 100 != 0) monthsize[2] = 29;
- else if (pd->year % 400 != 0) monthsize[2] = 28;
- else monthsize[2] = 29;
- if (pd->day <= 0 || pd->day > monthsize[pd->month])
- pd->day = -1;
- }
-
- /* Compute the day of the week. The next several lines constitute a
- * perpetual-calendar formula. Note, of course, that the "claimed"
- * day of the week (pd->c_weekday) is ignored here.
- */
- if (pd->year > 0 && pd->month > 0 && pd->day > 0)
- { if (pd->month >= 3) n = pd->year / 100,
- l = pd->year % 100;
- else n = (pd->year-1) / 100,
- l = (pd->year-1) % 100;
- a = (26 * ((pd->month+9)%12 + 1) - 2) / 10;
- weekday = (a+(l>>2)+(n>>2)+l-(n+n)+pd->day);
- while (weekday < 0) weekday += 7;
- pd->weekday = weekday % 7;
- }
-
- /* Figure out the internal UNIX form of the date. */
- if (pd->year >= 1969 && pd->year <= 2038
- && pd->month > 0 && pd->day > 0
- && pd->hour >= 0 && pd->minute >= 0
- && pd->zone != -1 && pd->zone > -1440 && pd->zone < 1440)
- { pd->unixtime =
- SEC_PER_YEAR * (pd->year - 1970)
- + SEC_PER_DAY * ((pd->year - 1969) / 4)
- /* month is taken care of later */
- + SEC_PER_DAY * (pd->day - 1)
- + SEC_PER_HOUR * pd->hour
- + SEC_PER_MIN * pd->minute
- /* seconds are taken care of later */
- - SEC_PER_MIN * pd->zone;
- if (pd->second >= 0)
- pd->unixtime += pd->second;
- for (n = pd->month - 1; n > 0; n--)
- pd->unixtime += SEC_PER_DAY * monthsize[n];
- if (pd->unixtime < 0) pd->unixtime = -1;
- }
- else pd->unixtime = -1;
-}
-
-/* break_down_unixtime (pd) struct parseddate *pd;
- * Given the "unixtime" and "zone" fields of a "struct parseddate",
- * compute the values of the "year", "month", "day", "hour", "min-
- * ute", "second", and "weekday" fields. The "dst" and "error"
- * fields of the structure are not used or modified.
- */
-void break_down_unixtime (pd)
- register struct parseddate *pd;
-{ register unsigned long timevalue;
- register int m, n;
-
- /* Validate the "unixtime" and "zone" fields. */
- if (pd->unixtime < 0
- || pd->zone == -1 || pd->zone <= -1440 || pd->zone >= 1440)
- { /* Sorry, can't do it. */
- pd->year = -1; pd->month = -1; pd->day = -1;
- pd->hour = -1; pd->minute = -1; pd->second = -1;
- pd->weekday = -1;
- return;
- }
-
- /* Even though "pd->unixtime" must be non-negative, and thus cannot
- * indicate a time earlier than 1970, a negative "pd->zone" could
- * cause the local date to be Wednesday, 31 December 1969. Such a
- * date requires special handling.
- *
- * A local date earlier than 31 December 1969 is impossible because
- * "pd->zone" must represent a time-zone shift of less than a day.
- */
- if (pd->zone < 0 && pd->unixtime + SEC_PER_MIN * pd->zone < 0)
- { pd->year = 1969; pd->month = 12; pd->day = 31;
- pd->weekday = 3; /* Wednesday */
- timevalue = pd->unixtime + SEC_PER_MIN * pd->zone + SEC_PER_DAY;
- /* Note: 0 <= timevalue < SEC_PER_DAY */
- pd->hour = timevalue / SEC_PER_HOUR;
- pd->minute = (timevalue % SEC_PER_HOUR) / SEC_PER_MIN;
- pd->second = timevalue % SEC_PER_MIN;
- return;
- }
-
- /* Handle the general case (local time is 1970 or later). */
- timevalue = pd->unixtime + SEC_PER_MIN * pd->zone;
-
- /* day of the week (1 January 1970 was a Thursday) . . . */
- pd->weekday = (timevalue/SEC_PER_DAY + 4 /* Thursday */) % 7;
-
- /* year (note that the only possible century year here is 2000,
- * a leap year -- hence no special tests for century years are
- * needed) . . .
- */
- for (m = 1970; ; m++)
- { n = (m%4==0) ? SEC_PER_YEAR+SEC_PER_DAY : SEC_PER_YEAR;
- if (n > timevalue) break;
- timevalue -= n;
- }
- pd->year = m;
- monthsize[2] = (m%4==0) ? 29 : 28;
-
- /* month . . . */
- for (m = 1; ; m++)
- { n = SEC_PER_DAY * monthsize[m];
- if (n > timevalue) break;
- timevalue -= n;
- }
- pd->month = m;
-
- /* day, hour, minute, and second . . . */
- pd->day = (timevalue / SEC_PER_DAY) + 1;
- pd->hour = (timevalue % SEC_PER_DAY) / SEC_PER_HOUR;
- pd->minute = (timevalue % SEC_PER_HOUR) / SEC_PER_MIN;
- pd->second = timevalue % SEC_PER_MIN;
-}
-
-/* char *mail_date_string (pd) struct parseddate *pd;
- * Generate a character string representing a date and time in the
- * RFC822 (ARPANET mail standard) format. A value of NULL is re-
- * turned if "pd" does not contain all necessary data fields.
- * (NOTE: The returned value points to static data whose contents
- * are overwritten by each call.)
- */
-char *
-mail_date_string (pd)
- register struct parseddate *pd;
-{ register char *c;
- static char answer[50];
-
- /* Check the day of the month and compute the day of the week. */
- compute_unixtime (pd);
-
- /* Make sure all required fields are present. */
- if (pd->year < 0 || pd->month < 0 || pd->day < 0
- || pd->hour < 0 || pd->minute < 0
- || pd->zone == -1 || pd->zone <= -1440 || pd->zone >= 1440)
- return NULL; /* impossible to generate string */
-
- /* Generate the answer string. */
- sprintf (answer,
- "%.3s, %d %.3s %d %02d:%02d",
- dayname + 3*pd->weekday,
- pd->day, monthname + 3*(pd->month-1),
- (pd->year >= 1960 && pd->year <= 1999)
- ? pd->year - 1900 : pd->year,
- pd->hour, pd->minute);
- c = answer + strlen (answer);
- if (pd->second >= 0) sprintf (c, ":%02d", pd->second), c += 3;
- *c++ = ' ';
- switch (pd->zone)
- { /* NOTE: Only zone abbreviations in RFC822 are used here. */
- case 0: strcpy (c, pd->dst ? "+0000" : "GMT"); break;
- case -240: strcpy (c, pd->dst ? "EDT" : "-0400"); break;
- case -300: strcpy (c, pd->dst ? "CDT" : "EST"); break;
- case -360: strcpy (c, pd->dst ? "MDT" : "CST"); break;
- case -420: strcpy (c, pd->dst ? "PDT" : "MST"); break;
- case -480: strcpy (c, pd->dst ? "-0800" : "PST"); break;
- default:
- if (pd->zone >= 0)
- sprintf (c, "+%02d%02d", pd->zone/60, pd->zone%60);
- else sprintf (c, "-%02d%02d", -pd->zone/60, -pd->zone%60);
- }
-
- return answer;
-}
-
-/* char *uucp_date_string (pd) struct parseddate *pd;
- * Generate a character string representing a date and time in the
- * UUCP mail format. A value of NULL is returned if "pd" does not
- * contain all necessary data fields. (NOTE: The returned value
- * points to static data whose contents are overwritten by each
- * call.)
- */
-char *
-uucp_date_string (pd)
- register struct parseddate *pd;
-{ register char *c;
- static char answer[50];
-
- /* Check the day of the month and compute the day of the week. */
- compute_unixtime (pd);
-
- /* Make sure all required fields are present. */
- if (pd->year < 0 || pd->month < 0 || pd->day < 0
- || pd->hour < 0 || pd->minute < 0
- || pd->zone == -1 || pd->zone <= -1440 || pd->zone >= 1440)
- return NULL; /* impossible to generate string */
-
- /* Generate the answer string. */
- sprintf (answer,
- "%.3s %.3s %d %02d:%02d",
- dayname + 3*pd->weekday,
- monthname + 3*(pd->month-1), pd->day,
- pd->hour, pd->minute);
- c = answer + strlen (answer);
- if (pd->second >= 0) sprintf (c, ":%02d", pd->second), c += 3;
- switch (pd->zone)
- { /* NOTE: Only zone abbreviations in RFC822 are used here. */
- case 0: strcpy (c, pd->dst ? "+0000" : "-GMT"); break;
- case -240: strcpy (c, pd->dst ? "-EDT" : "-0400"); break;
- case -300: strcpy (c, pd->dst ? "-CDT" : "-EST"); break;
- case -360: strcpy (c, pd->dst ? "-MDT" : "-CST"); break;
- case -420: strcpy (c, pd->dst ? "-PDT" : "-MST"); break;
- case -480: strcpy (c, pd->dst ? "-0800" : "-PST"); break;
- default:
- if (pd->zone >= 0)
- sprintf (c, "+%02d%02d", pd->zone/60, pd->zone%60);
- else sprintf (c, "-%02d%02d", -pd->zone/60, -pd->zone%60);
- }
- c = answer + strlen (answer);
- sprintf (c, " %d", pd->year);
-
- return answer;
-}
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