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strtoday.c

/*
 * Copyright 1991 - 1994, Julianne Frances Haugh
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of Julianne F. Haugh nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if !defined(__GLIBC__)
#define _XOPEN_SOURCE 500
#endif

#include <config.h>

#include "rcsid.h"
RCSID("$Id: strtoday.c 6 2005-03-20 15:34:28Z bubulle $")

#include "defines.h"

#ifndef USE_GETDATE
#define USE_GETDATE 1
#endif

#if USE_GETDATE

#include "getdate.h"

/*
 * strtoday() now uses get_date() (borrowed from GNU shellutils)
 * which can handle many date formats, for example:
 *    1970-09-17  # ISO 8601.
 *    70-9-17           # This century assumed by default.
 *    70-09-17    # Leading zeros are ignored.
 *    9/17/72           # Common U.S. writing.
 *    24 September 1972
 *    24 Sept 72  # September has a special abbreviation.
 *    24 Sep 72   # Three-letter abbreviations always allowed.
 *    Sep 24, 1972
 *    24-sep-72
 *    24sep72
 */
long
strtoday(const char *str)
{
      time_t t;

      /*
       * get_date() interprets an empty string as the current date,
       * which is not what we expect, unless you're a BOFH :-).
       * (useradd sets sp_expire = current date for new lusers)
       */
      if (!str || *str == '\0')
            return -1;

      t = get_date(str, (time_t *) 0);
      if (t == (time_t) -1)
            return -1;
      /* convert seconds to days since 1970-01-01 */
      return (t + DAY/2)/DAY;
}

#else /* !USE_GETDATE */
/*
 * Old code, just in case get_date() doesn't work as expected...
 */

#include <stdio.h>

#ifdef HAVE_STRPTIME
/*
 * for now we allow just one format, but we can define more later
 * (we try them all until one succeeds).  --marekm
 */
static char *date_formats[] = {
      "%Y-%m-%d",
      (char *) 0
};
#else
/*
 * days and juldays are used to compute the number of days in the
 * current month, and the cummulative number of days in the preceding
 * months.  they are declared so that january is 1, not 0.
 */

static      short days[13] = { 0,
      31,   28,   31,   30,   31,   30,   /* JAN - JUN */
      31,   31,   30,   31,   30,   31 }; /* JUL - DEC */

static      short juldays[13] = { 0,
      0,    31,   59,   90,   120,  151,  /* JAN - JUN */
      181,  212,  243,  273,  304,  334 };      /* JUL - DEC */
#endif

/*
 * strtoday - compute the number of days since 1970.
 *
 * the total number of days prior to the current date is
 * computed.  january 1, 1970 is used as the origin with
 * it having a day number of 0.
 */

long
strtoday(const char *str)
{
#ifdef HAVE_STRPTIME
      struct tm tp;
      char * const *fmt;
      char *cp;
      time_t result;

      memzero(&tp, sizeof tp);
      for (fmt = date_formats; *fmt; fmt++) {
            cp = strptime((char *) str, *fmt, &tp);
            if (!cp || *cp != '\0')
                  continue;

            result = mktime(&tp);
            if (result == (time_t) -1)
                  continue;

            return result / DAY;  /* success */
      }
      return -1;
#else
      char  slop[2];
      int   month;
      int   day;
      int   year;
      long  total;

      /*
       * start by separating the month, day and year.  the order
       * is compiled in ...
       */

      if (sscanf (str, "%d/%d/%d%c", &year, &month, &day, slop) != 3)
            return -1;

      /*
       * the month, day of the month, and year are checked for
       * correctness and the year adjusted so it falls between
       * 1970 and 2069.
       */

      if (month < 1 || month > 12)
            return -1;

      if (day < 1)
            return -1;

      if ((month != 2 || (year % 4) != 0) && day > days[month])
            return -1;
      else if ((month == 2 && (year % 4) == 0) && day > 29)
            return -1;

      if (year < 0)
            return -1;
      else if (year <= 69)
            year += 2000;
      else if (year <= 99)
            year += 1900;

      /*
       * On systems with 32-bit signed time_t, time wraps around in 2038
       * - for now we just limit the year to 2037 (instead of 2069).
       * This limit can be removed once no one is using 32-bit systems
       * anymore :-).  --marekm
       */
      if (year < 1970 || year > 2037)
            return -1;

      /*
       * the total number of days is the total number of days in all
       * the whole years, plus the number of leap days, plus the
       * number of days in the whole months preceding, plus the number
       * of days so far in the month.
       */

      total = (long) ((year - 1970) * 365L) + (((year + 1) - 1970) / 4);
      total += (long) juldays[month] + (month > 2 && (year % 4) == 0 ? 1:0);
      total += (long) day - 1;

      return total;
#endif /* HAVE_STRPTIME */
}
#endif /* !USE_GETDATE */

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