1 #include "all.h"
2
3 static int sunday(Tm *t, int d);
4 static int dysize(int);
5 static void ct_numb(char*, int);
6 static void klocaltime(long tim, Tm *ct);
7 static void kgmtime(long tim, Tm *ct);
8
9 static char dmsize[12] =
10 {
11 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
12 };
13
14 /*
15 * The following table is used for 1974 and 1975 and
16 * gives the day number of the first day after the Sunday of the
17 * change.
18 */
19 static struct
20 {
21 short yrfrom;
22 short yrto;
23 short daylb;
24 short dayle;
25 } daytab[] =
26 {
27 87, 999, 97, 303,
28 76, 86, 119, 303,
29 75, 75, 58, 303,
30 74, 74, 5, 333,
31 0, 73, 119, 303,
32 };
33
34 static struct
35 {
36 short minuteswest; /* minutes west of Greenwich */
37 short dsttime; /* dst correction */
38 } timezone =
39 {
40 5*60, 1
41 };
42
43 static void
klocaltime(long tim,Tm * ct)44 klocaltime(long tim, Tm *ct)
45 {
46 int daylbegin, daylend, dayno, i;
47 long copyt;
48
49 copyt = tim - timezone.minuteswest*60L;
50 kgmtime(copyt, ct);
51 dayno = ct->yday;
52 for(i=0;; i++)
53 if(ct->year >= daytab[i].yrfrom &&
54 ct->year <= daytab[i].yrto) {
55 daylbegin = sunday(ct, daytab[i].daylb);
56 daylend = sunday(ct, daytab[i].dayle);
57 break;
58 }
59 if(timezone.dsttime &&
60 (dayno>daylbegin || (dayno==daylbegin && ct->hour>=2)) &&
61 (dayno<daylend || (dayno==daylend && ct->hour<1))) {
62 copyt += 60L*60L;
63 kgmtime(copyt, ct);
64 }
65 }
66
67 /*
68 * The argument is a 0-origin day number.
69 * The value is the day number of the last
70 * Sunday before or after the day.
71 */
72 static
sunday(Tm * t,int d)73 sunday(Tm *t, int d)
74 {
75 if(d >= 58)
76 d += dysize(t->year) - 365;
77 return d - (d - t->yday + t->wday + 700) % 7;
78 }
79
80 static void
kgmtime(long tim,Tm * ct)81 kgmtime(long tim, Tm *ct)
82 {
83 int d0, d1;
84 long hms, day;
85
86 /*
87 * break initial number into days
88 */
89 hms = tim % 86400L;
90 day = tim / 86400L;
91 if(hms < 0) {
92 hms += 86400L;
93 day -= 1;
94 }
95
96 /*
97 * generate hours:minutes:seconds
98 */
99 ct->sec = hms % 60;
100 d1 = hms / 60;
101 ct->min = d1 % 60;
102 d1 /= 60;
103 ct->hour = d1;
104
105 /*
106 * day is the day number.
107 * generate day of the week.
108 * The addend is 4 mod 7 (1/1/1970 was Thursday)
109 */
110
111 ct->wday = (day + 7340036L) % 7;
112
113 /*
114 * year number
115 */
116 if(day >= 0)
117 for(d1 = 70; day >= dysize(d1); d1++)
118 day -= dysize(d1);
119 else
120 for (d1 = 70; day < 0; d1--)
121 day += dysize(d1-1);
122 ct->year = d1;
123 ct->yday = d0 = day;
124
125 /*
126 * generate month
127 */
128
129 if(dysize(d1) == 366)
130 dmsize[1] = 29;
131 for(d1 = 0; d0 >= dmsize[d1]; d1++)
132 d0 -= dmsize[d1];
133 dmsize[1] = 28;
134 ct->mday = d0 + 1;
135 ct->mon = d1;
136 }
137
138 void
datestr(char * s,long t)139 datestr(char *s, long t)
140 {
141 Tm tm;
142
143 klocaltime(t, &tm);
144 sprint(s, "%.4d%.2d%.2d", tm.year+1900, tm.mon+1, tm.mday);
145 }
146
147 int
Tfmt(Fmt * f1)148 Tfmt(Fmt *f1)
149 {
150 char s[30];
151 char *cp;
152 long t;
153 Tm tm;
154
155 t = va_arg(f1->args, long);
156 if(t == 0)
157 return fmtstrcpy(f1, "The Epoch");
158
159 klocaltime(t, &tm);
160 strcpy(s, "Day Mon 00 00:00:00 1900");
161 cp = &"SunMonTueWedThuFriSat"[tm.wday*3];
162 s[0] = cp[0];
163 s[1] = cp[1];
164 s[2] = cp[2];
165 cp = &"JanFebMarAprMayJunJulAugSepOctNovDec"[tm.mon*3];
166 s[4] = cp[0];
167 s[5] = cp[1];
168 s[6] = cp[2];
169 ct_numb(s+8, tm.mday);
170 ct_numb(s+11, tm.hour+100);
171 ct_numb(s+14, tm.min+100);
172 ct_numb(s+17, tm.sec+100);
173 if(tm.year >= 100) {
174 s[20] = '2';
175 s[21] = '0';
176 }
177 ct_numb(s+22, tm.year+100);
178
179 return fmtstrcpy(f1, s);
180 }
181
182 static
dysize(int y)183 dysize(int y)
184 {
185
186 if((y%4) == 0)
187 return 366;
188 return 365;
189 }
190
191 static
192 void
ct_numb(char * cp,int n)193 ct_numb(char *cp, int n)
194 {
195
196 if(n >= 10)
197 cp[0] = (n/10)%10 + '0';
198 else
199 cp[0] = ' ';
200 cp[1] = n%10 + '0';
201 }
202
203 /*
204 * compute the next time after t
205 * that has hour hr and is not on
206 * day in bitpattern --
207 * for automatic dumps
208 */
209 long
nextime(long t,int hr,int day)210 nextime(long t, int hr, int day)
211 {
212 Tm tm;
213 int nhr;
214
215 if(hr < 0 || hr >= 24)
216 hr = 5;
217 if((day&0x7f) == 0x7f)
218 day = 0;
219
220 loop:
221 klocaltime(t, &tm);
222 t -= tm.sec;
223 t -= tm.min*60;
224 nhr = tm.hour;
225 do {
226 t += 60*60;
227 nhr++;
228 } while(nhr%24 != hr);
229 klocaltime(t, &tm);
230 if(tm.hour != hr) {
231 t += 60*60;
232 klocaltime(t, &tm);
233 if(tm.hour != hr) {
234 t -= 60*60;
235 klocaltime(t, &tm);
236 }
237 }
238 if(day & (1<<tm.wday)) {
239 t += 12*60*60;
240 goto loop;
241 }
242 return t;
243 }
244