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Annotation of 43BSD/contrib/rcs/src/maketime.c, revision 1.1

1.1     ! root        1: #
        !             2: /*
        !             3:  * MAKETIME            derive 32-bit time value from TM structure.
        !             4:  *
        !             5:  * Usage:
        !             6:  *     long t,maketime();
        !             7:  *     struct tm *tp;  Pointer to TM structure from <time.h>
        !             8:  *                     NOTE: this must be extended version!!!
        !             9:  *     t = maketime(tp);
        !            10:  *
        !            11:  * Returns:
        !            12:  *     0 if failure; parameter out of range or nonsensical.
        !            13:  *     else long time-value.
        !            14:  * Notes:
        !            15:  *     This code is quasi-public; it may be used freely in like software.
        !            16:  *     It is not to be sold, nor used in licensed software without
        !            17:  *     permission of the author.
        !            18:  *     For everyone's benefit, please report bugs and improvements!
        !            19:  *     Copyright 1981 by Ken Harrenstien, SRI International.
        !            20:  *     (ARPANET: KLH @ SRI)
        !            21:  */
        !            22: 
        !            23: static char rcsid[]= "$Id: maketime.c,v 1.1 82/05/06 11:38:00 wft Exp $";
        !            24: 
        !            25: /* $Log:       maketime.c,v $
        !            26:  * Revision 1.1  82/05/06  11:38:00  wft
        !            27:  * Initial revision
        !            28:  * 
        !            29:  */
        !            30: 
        !            31: 
        !            32: #include "time.h"
        !            33: 
        !            34: int daytb[] = {   /* # days in year thus far, indexed by month (0-12!!) */
        !            35:        0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365
        !            36: };
        !            37: 
        !            38: struct tm *localtime();
        !            39: 
        !            40: long maketime(atm)
        !            41: struct tm *atm;
        !            42: {      register struct tm *tp;
        !            43:        register int i;
        !            44:        int year, yday, mon, day, hour, min, sec, zone, dst, leap;
        !            45:        long tres, curtim;
        !            46: 
        !            47:        time(&curtim);
        !            48:        tp = localtime(&curtim);        /* Get breakdowns of current time */
        !            49:        year = tp->tm_year;             /* Use to set up defaults */
        !            50:        mon = tp->tm_mon;
        !            51:        day = tp->tm_mday;
        !            52: 
        !            53: 
        !            54: #ifdef DEBUG
        !            55: printf("first YMD: %d %d %d, T=%ld\n",year,mon,day,tres);
        !            56: #endif DEBUG
        !            57:        tp = atm;
        !            58: 
        !            59:        /* First must find date, using specified year, month, day.
        !            60:         * If one of these is unspecified, it defaults either to the
        !            61:         * current date (if no more global spec was given) or to the
        !            62:         * zero-value for that spec (i.e. a more global spec was seen).
        !            63:         * Start with year... note 32 bits can only handle 135 years.
        !            64:         */
        !            65:        if(tp->tm_year != TMNULL)
        !            66:          {     if((year = tp->tm_year) >= 1900)        /* Allow full yr # */
        !            67:                        year -= 1900;                   /* by making kosher */
        !            68:                mon = 0;                /* Since year was given, default */
        !            69:                day = 1;                /* for remaining specs is zero */
        !            70:          }
        !            71:        if(year < 70 || 70+134 < year ) /* Check range */
        !            72:                return(0);              /* ERR: year out of range */
        !            73:        leap = year&03 ? 0 : 1;         /* See if leap year */
        !            74:        year -= 70;                     /* UNIX time starts at 1970 */
        !            75: 
        !            76:        /*
        !            77:         * Find day of year.
        !            78:         * YDAY is used only if it exists and either the month or day-of-month
        !            79:         * is missing.
        !            80:         */
        !            81:        if (tp->tm_yday != TMNULL
        !            82:         && (tp->tm_mon == TMNULL || tp->tm_mday == TMNULL))
        !            83:                yday = tp->tm_yday;
        !            84:        else
        !            85:          {     if(tp->tm_mon  != TMNULL)
        !            86:                  {     mon = tp->tm_mon;       /* Month was specified */
        !            87:                        day = 1;                /* so set remaining default */
        !            88:                  }
        !            89:                if(mon < 0 || 11 < mon) return(0);      /* ERR: bad month */
        !            90:                if(tp->tm_mday != TMNULL) day = tp->tm_mday;
        !            91:                if(day < 1
        !            92:                 || (((daytb[mon+1]-daytb[mon]) < day)
        !            93:                        && (day!=29 || mon!=1 || !leap) ))
        !            94:                                return(0);              /* ERR: bad day */
        !            95:                yday = daytb[mon]       /* Add # of days in months so far */
        !            96:                  + ((leap              /* Leap year, and past Feb?  If */
        !            97:                      && mon>1)? 1:0)   /* so, add leap day for this year */
        !            98:                  + day-1;              /* And finally add # days this mon */
        !            99: 
        !           100:                 if (tp->tm_yday != TMNULL       /* Confirm that YDAY correct */
        !           101:                  && tp->tm_yday != yday) return(0);     /* ERR: conflict */
        !           102:          }
        !           103:        if(yday < 0 || (leap?366:365) <= yday)
        !           104:                return(0);              /* ERR: bad YDAY or maketime bug */
        !           105: 
        !           106:        tres = year*365                 /* Get # days of years so far */
        !           107:                + ((year+1)>>2)         /* plus # of leap days since 1970 */
        !           108:                + yday;                 /* and finally add # days this year */
        !           109: 
        !           110:         if((i = tp->tm_wday) != TMNULL) /* Check WDAY if present */
        !           111:                 if(i < 0 || 6 < i       /* Ensure within range */
        !           112:                   || i != (tres+4)%7)   /* Matches? Jan 1,1970 was Thu = 4 */
        !           113:                         return(0);      /* ERR: bad WDAY */
        !           114: 
        !           115: #ifdef DEBUG
        !           116: printf("YMD: %d %d %d, T=%ld\n",year,mon,day,tres);
        !           117: #endif DEBUG
        !           118:        /*
        !           119:         * Now determine time.  If not given, default to zeros
        !           120:         * (since time is always the least global spec)
        !           121:         */
        !           122:        tres *= 86400L;                 /* Get # seconds (24*60*60) */
        !           123:        hour = min = sec = 0;
        !           124:        if(tp->tm_hour != TMNULL) hour = tp->tm_hour;
        !           125:        if(tp->tm_min  != TMNULL) min  = tp->tm_min;
        !           126:        if(tp->tm_sec  != TMNULL) sec  = tp->tm_sec;
        !           127:        if( min < 0 || 60 <= min
        !           128:         || sec < 0 || 60 <= sec) return(0);    /* ERR: MS out of range */
        !           129:        if(hour < 0 || 24 <= hour)
        !           130:                if(hour != 24 || (min+sec) !=0) /* Allow 24:00 */
        !           131:                        return(0);              /* ERR: H out of range */
        !           132: 
        !           133:        /* confirm AM/PM if there */
        !           134:        switch(tp->tm_ampm)
        !           135:          {     case 0: case TMNULL:    /* Ignore these values */
        !           136:                        break;
        !           137:                case 1:                 /* AM */
        !           138:                case 2:                 /* PM */
        !           139:                        if(hour > 12) return(0);  /* ERR: hrs 13-23 bad */
        !           140:                        if(hour ==12) hour = 0; /* Modulo 12 */
        !           141:                        if(tp->tm_ampm == 2)    /* If PM, then */
        !           142:                                hour += 12;     /*   get 24-hour time */
        !           143:                        break;
        !           144:                default: return(0);     /* ERR: illegal TM_AMPM value */
        !           145:          }
        !           146: 
        !           147:        tres += sec + 60L*(min + 60L*hour);     /* Add in # secs of time */
        !           148: 
        !           149: #ifdef DEBUG
        !           150: printf("HMS: %d %d %d T=%ld\n",hour,min,sec,tres);
        !           151: #endif DEBUG
        !           152:        /*
        !           153:         * We now have the GMT date/time and must make final
        !           154:         * adjustment for the specified time zone.  If none is specified,
        !           155:         * the local time-zone is assumed.
        !           156:         */
        !           157:        if((zone = tp->tm_zon) == TMNULL        /* If unspecified */
        !           158:         || (zone == 1))                        /* or local-zone requested */
        !           159:                zone = localzone();             /* then set to local zone */
        !           160:        if(zone < 0 || 24*60 <= zone)
        !           161:                return(0);                      /* ERR: zone out of range */
        !           162: 
        !           163:        /* See if must apply Daylight Saving Time shift.
        !           164:         * Note that if DST is specified, validity is not checked.
        !           165:         */
        !           166:        if((dst = tp->tm_isdst) == TMNULL)      /* Must we figure it out? */
        !           167:          {     curtim = tres +localzone()*60L; /* Yuck.  Get equiv local */
        !           168:                dst = localtime(&curtim)->tm_isdst;     /* time, and ask. */
        !           169:          }
        !           170:        tres += zone*60L -(dst?3600:0); /* Add in # seconds of zone adj */
        !           171: 
        !           172:        return(tres);
        !           173: }
        !           174: 
        !           175: 
        !           176: /* LOCALZONE           return local timezone in # mins west of GMT
        !           177:  *
        !           178:  */
        !           179: 
        !           180: #ifdef V6
        !           181: extern timezone;
        !           182: #else /* V7 */
        !           183: #include <sys/types.h>
        !           184: #include <sys/timeb.h>
        !           185: #endif V6/7
        !           186: 
        !           187: int _lclzon = -1;
        !           188: localzone()
        !           189: {
        !           190: #ifdef V6
        !           191:        return(_lclzon >= 0 ? _lclzon : (_lclzon = timezone/60));
        !           192: #else /* V7 */
        !           193:        struct timeb tb;
        !           194: 
        !           195:        if(_lclzon < 0)
        !           196:          {     ftime(&tb);
        !           197:                _lclzon = tb.timezone;
        !           198:          }
        !           199:        return(_lclzon);
        !           200: 
        !           201: #endif V6/7
        !           202: }

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