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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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