InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/bsd_srcs/usr.sbin/sendmail/src/arpadate.c

C/C++ Source or Header | 1991-04-20 | 4.5 KB | 178 lines

/*
 * Copyright (c) 1983 Eric P. Allman
 * Copyright (c) 1988 Regents of the University of California.
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the University of
 *    California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 THE REGENTS 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 THE REGENTS 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.
 */

#ifndef lint
static char sccsid[] = "@(#)arpadate.c    5.11 (Berkeley) 6/1/90";
#endif /* not lint */

# include "conf.h"
# include <time.h>
# include <sys/types.h>
# include "useful.h"

/*
**  ARPADATE -- Create date in ARPANET format
**
**    Parameters:
**        ud -- unix style date string.  if NULL, one is created.
**
**    Returns:
**        pointer to an ARPANET date field
**
**    Side Effects:
**        none
**
**    WARNING:
**        date is stored in a local buffer -- subsequent
**        calls will overwrite.
**
**    Bugs:
**        Timezone is computed from local time, rather than
**        from whereever (and whenever) the message was sent.
**        To do better is very hard.
**
**        Some sites are now inserting the timezone into the
**        local date.  This routine should figure out what
**        the format is and work appropriately.
*/

char *
arpadate(ud)
    register char *ud;
{
    register char *p;
    register char *q;
    register int off;
    register int i;
    register struct tm *lt;
    time_t t;
    struct tm gmt;
    static char b[40];
    extern struct tm *localtime(), *gmtime();
    extern char *ctime();
    extern time_t time();

    /*
    **  Get current time.
    **    This will be used if a null argument is passed and
    **    to resolve the timezone.
    */

    (void) time(&t);
    if (ud == NULL)
        ud = ctime(&t);

    /*
    **  Crack the UNIX date line in a singularly unoriginal way.
    */

    q = b;

    p = &ud[0];        /* Mon */
    *q++ = *p++;
    *q++ = *p++;
    *q++ = *p++;
    *q++ = ',';
    *q++ = ' ';

    p = &ud[8];        /* 16 */
    if (*p == ' ')
        p++;
    else
        *q++ = *p++;
    *q++ = *p++;
    *q++ = ' ';

    p = &ud[4];        /* Sep */
    *q++ = *p++;
    *q++ = *p++;
    *q++ = *p++;
    *q++ = ' ';

    p = &ud[22];        /* 79 */
    *q++ = *p++;
    *q++ = *p++;
    *q++ = ' ';

    p = &ud[11];        /* 01:03:52 */
    for (i = 8; i > 0; i--)
        *q++ = *p++;

    /*
     * should really get the timezone from the time in "ud" (which
     * is only different if a non-null arg was passed which is different
     * from the current time), but for all practical purposes, returning
     * the current local zone will do (its all that is ever needed).
     */
    gmt = *gmtime(&t);
    lt = localtime(&t);

    off = (lt->tm_hour - gmt.tm_hour) * 60 + lt->tm_min - gmt.tm_min;

    /* assume that offset isn't more than a day ... */
    if (lt->tm_year < gmt.tm_year)
        off -= 24 * 60;
    else if (lt->tm_year > gmt.tm_year)
        off += 24 * 60;
    else if (lt->tm_yday < gmt.tm_yday)
        off -= 24 * 60;
    else if (lt->tm_yday > gmt.tm_yday)
        off += 24 * 60;

    *q++ = ' ';
    if (off == 0) {
        *q++ = 'G';
        *q++ = 'M';
        *q++ = 'T';
    } else {
        if (off < 0) {
            off = -off;
            *q++ = '-';
        } else
            *q++ = '+';

        if (off >= 24*60)        /* should be impossible */
            off = 23*60+59;        /* if not, insert silly value */

        *q++ = (off / 600) + '0';
        *q++ = (off / 60) % 10 + '0';
        off %= 60;
        *q++ = (off / 10) + '0';
        *q++ = (off % 10) + '0';
    }
    *q = '\0';

    return (b);
}