sys/src/cmd/astro/pdate.c

   1 #include "astro.h"
   2
   3
   4 char*   month[] =
   5 {
   6         "January",
   7         "February",
   8         "March",
   9         "April",
  10         "May",
  11         "June",
  12         "July",
  13         "August",
  14         "September",
  15         "October",
  16         "November",
  17         "December",
  18 };
  19
  20 double
  21 dsrc(double d, Tim *t, int i)
  22 {
  23         double y;
  24
  25         do {
  26                 t->ifa[i] += 1.;
  27                 y = convdate(t);
  28         } while(d >= y);
  29         do {
  30                 t->ifa[i] -= 1.;
  31                 y = convdate(t);
  32         } while(d < y);
  33         return d - y;
  34 }
  35
  36 void
  37 dtsetup(double d, Tim *t)
  38 {
  39         double v;
  40
  41         t->ifa[0] = floor(1900 + d/365.24220);
  42         t->ifa[1] = 1;
  43         t->ifa[2] = 1;
  44         t->ifa[3] = 0;
  45         t->ifa[4] = 0;
  46         t->ifa[1] = floor(1 + dsrc(d, t, 0)/30);
  47         t->ifa[2] = floor(1 + dsrc(d, t, 1));
  48         dsrc(d, t, 2);
  49
  50         v = (d - convdate(t)) * 24;
  51         t->ifa[3] = floor(v);
  52         t->ifa[4] = (v - t->ifa[3]) * 60;
  53         convdate(t);    /* to set timezone */
  54 }
  55
  56 void
  57 pdate(double d)
  58 {
  59         int i;
  60         Tim t;
  61
  62         dtsetup(d, &t);
  63         if(flags['s']) {
  64                 i = t.ifa[1];
  65                 print("%s ", month[i-1]);
  66                 i = t.ifa[2];
  67                 numb(i);
  68                 print("...");
  69                 return;
  70         }
  71
  72         /* year month day */
  73         print("%4d %2d %2d",
  74                 (int)t.ifa[0],
  75                 (int)t.ifa[1],
  76                 (int)t.ifa[2]);
  77 }
  78
  79 void
  80 ptime(double d)
  81 {
  82         int h, m, s;
  83         char *mer;
  84         Tim t;
  85
  86         if(flags['s']) {
  87                 /* hour minute */
  88                 dtsetup(d + .5/(24*60), &t);
  89                 h = t.ifa[3];
  90                 m = floor(t.ifa[4]);
  91
  92                 mer = "AM";
  93                 if(h >= 12) {
  94                         mer = "PM";
  95                         h -= 12;
  96                 }
  97                 if(h == 0)
  98                         h = 12;
  99                 numb(h);
 100                 if(m < 10) {
 101                         if(m == 0) {
 102                                 print("%s exactly ...", mer);
 103                                 return;
 104                         }
 105                         print("O ");
 106                 }
 107                 numb(m);
 108                 print("%s ...", mer);
 109                 return;
 110         }
 111         /* hour minute second */
 112         dtsetup(d, &t);
 113         h = t.ifa[3];
 114         m = floor(t.ifa[4]);
 115         s = floor((t.ifa[4]-m) * 60);
 116         print("%.2d:%.2d:%.2d %.*s", h, m, s, utfnlen(t.tz, 3), t.tz);
 117 }
 118
 119 char*   unit[] =
 120 {
 121         "zero",
 122         "one",
 123         "two",
 124         "three",
 125         "four",
 126         "five",
 127         "six",
 128         "seven",
 129         "eight",
 130         "nine",
 131         "ten",
 132         "eleven",
 133         "twelve",
 134         "thirteen",
 135         "fourteen",
 136         "fifteen",
 137         "sixteen",
 138         "seventeen",
 139         "eighteen",
 140         "nineteen"
 141 };
 142 char*   decade[] =
 143 {
 144         "twenty",
 145         "thirty",
 146         "forty",
 147         "fifty",
 148         "sixty",
 149         "seventy",
 150         "eighty",
 151         "ninety"
 152 };
 153
 154 void
 155 pstime(double d)
 156 {
 157
 158         setime(d);
 159
 160         semi = 0;
 161         motion = 0;
 162         rad = 1.e9;
 163         lambda = 0;
 164         beta = 0;
 165
 166 // uses lambda, beta, rad, motion
 167 // sets alpha, delta, rp
 168
 169         helio();
 170
 171 // uses alpha, delta, rp
 172 // sets ra, decl, lha, decl2, az, el
 173
 174         geo();
 175
 176         print(" %R %D %D %4.0f", lha, nlat, awlong, elev/3.28084);
 177 }
 178
 179 void
 180 numb(int n)
 181 {
 182
 183         if(n >= 100) {
 184                 print("%d ", n);
 185                 return;
 186         }
 187         if(n >= 20) {
 188                 print("%s ", decade[n/10 - 2]);
 189                 n %= 10;
 190                 if(n == 0)
 191                         return;
 192         }
 193         print("%s ", unit[n]);
 194 }
 195
 196 double
 197 tzone(double y, Tim *z)
 198 {
 199         double t, l1, l2;
 200         Tm t1, t2;
 201
 202         /*
 203          * get a rough approximation to unix mean time
 204          */
 205         t = (y - 25567.5) * 86400;
 206
 207         /*
 208          * if outside unix conversions,
 209          * just call it GMT
 210          */
 211         if(t < 0 || t > 2.1e9)
 212                 return y;
 213
 214         /*
 215          * convert by both local and gmt
 216          */
 217         t1 = *localtime((long)t);
 218         t2 = *gmtime((long)t);
 219
 220         /*
 221          * pick up year crossings
 222          */
 223         if(t1.yday == 0 && t2.yday > 1)
 224                 t1.yday = t2.yday+1;
 225         if(t2.yday == 0 && t1.yday > 1)
 226                 t2.yday = t1.yday+1;
 227
 228         /*
 229          * convert times to days
 230          */
 231         l1 = t1.yday + t1.hour/24. + t1.min/1440. + t1.sec/86400.;
 232         l2 = t2.yday + t2.hour/24. + t2.min/1440. + t2.sec/86400.;
 233
 234         /*
 235          * return difference
 236          */
 237         strncpy(z->tz, t1.zone, sizeof(z->tz));
 238         return y + (l2 - l1);
 239 }
 240
 241 int     dmo[12] =
 242 {
 243         0,
 244         31,
 245         59,
 246         90,
 247         120,
 248         151,
 249         181,
 250         212,
 251         243,
 252         273,
 253         304,
 254         334
 255 };
 256
 257 /*
 258  * input date conversion
 259  * output is done by zero crossing
 260  * on this input conversion.
 261  */
 262 double
 263 convdate(Tim *t)
 264 {
 265         double y, d;
 266         int m;
 267
 268         y = t->ifa[0];
 269         m = t->ifa[1];
 270         d = t->ifa[2];
 271
 272         /*
 273          * normalize the month
 274          */
 275         while(m < 1) {
 276                 m += 12;
 277                 y -= 1;
 278         }
 279         while(m > 12) {
 280                 m -= 12;
 281                 y += 1;
 282         }
 283
 284         /*
 285          * bc correction
 286          */
 287         if(y < 0)
 288                 y += 1;
 289
 290         /*
 291          * normal conversion
 292          */
 293         y += 4712;
 294         if(fmod(y, 4) == 0 && m > 2)
 295                 d += 1;
 296         y = y*365 + floor((y+3)/4) + dmo[m-1] + d - 1;
 297
 298         /*
 299          * gregorian change
 300          */
 301         if(y > 2361232)
 302                 y -= floor((y-1794167)/36524.220) -
 303                         floor((y-1721117)/146100);
 304         y += t->ifa[3]/24 + t->ifa[4]/1440 - 2415020.5;
 305
 306         /*
 307          * kitchen clock correction
 308          */
 309         strncpy(t->tz, "GMT", sizeof(t->tz));
 310         if(flags['k'])
 311                 y = tzone(y, t);
 312         return y;
 313 }