sys/src/cmd/cal.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <bio.h>
   4
   5 char    dayws[] =
   6 {
   7         "Su  M Tu  W Th  F Sa Su  M Tu  W Th  F Sa",
   8 };
   9 char    *smon[] =
  10 {
  11         "January", "February", "March", "April",
  12         "May", "June", "July", "August",
  13         "September", "October", "November", "December",
  14 };
  15 char    mon[] =
  16 {
  17         0,
  18         31, 29, 31, 30,
  19         31, 30, 31, 31,
  20         30, 31, 30, 31,
  21 };
  22 char    string[432];
  23 Biobuf  bout;
  24 int     wstart;
  25
  26 void    main(int argc, char *argv[]);
  27 int     number(char *str);
  28 void    pstr(char *str, int n);
  29 void    cal(int m, int y, char *p, int w);
  30 int     jan1(int yr);
  31 int     curmo(void);
  32 int     curyr(void);
  33
  34 static void
  35 usage(void)
  36 {
  37         fprint(2, "usage: cal [-s 1..7] [month] [year]\n");
  38         exits("usage");
  39 }
  40
  41 void
  42 main(int argc, char *argv[])
  43 {
  44         int y, i, j, m;
  45         char *dayw;
  46
  47         ARGBEGIN{
  48         case 's':
  49                 wstart = atoi(EARGF(usage()));
  50                 if(wstart < 0 || wstart > 7)
  51                         usage();
  52                 wstart %= 7;
  53                 break;
  54         default:
  55                 usage();
  56         }ARGEND
  57
  58         if(argc > 2)
  59                 usage();
  60         Binit(&bout, 1, OWRITE);
  61
  62         dayw = dayws + 3*wstart;
  63         dayw[(3*7)-1] = '\0';
  64
  65 /*
  66  * no arg, print current month
  67  */
  68         if(argc == 0) {
  69                 m = curmo();
  70                 y = curyr();
  71                 goto xshort;
  72         }
  73
  74 /*
  75  * one arg
  76  *      if looks like a month, print month
  77  *      else print year
  78  */
  79         if(argc == 1) {
  80                 y = number(argv[0]);
  81                 if(y < 0)
  82                         y = -y;
  83                 if(y >= 1 && y <= 12) {
  84                         m = y;
  85                         y = curyr();
  86                         goto xshort;
  87                 }
  88                 goto xlong;
  89         }
  90
  91 /*
  92  * two arg, month and year
  93  */
  94         m = number(argv[0]);
  95         if(m < 0)
  96                 m = -m;
  97         y = number(argv[1]);
  98         goto xshort;
  99
 100 /*
 101  *      print out just month
 102  */
 103 xshort:
 104         if(m < 1 || m > 12)
 105                 goto badarg;
 106         if(y < 1 || y > 9999)
 107                 goto badarg;
 108         Bprint(&bout, "   %s %ud\n", smon[m-1], y);
 109         Bprint(&bout, "%s\n", dayw);
 110         cal(m, y, string, 24);
 111         for(i=0; i<6*24; i+=24)
 112                 pstr(string+i, 24);
 113         exits(nil);
 114
 115 /*
 116  *      print out complete year
 117  */
 118 xlong:
 119         if(y<1 || y>9999)
 120                 goto badarg;
 121         Bprint(&bout, "\n\n\n");
 122         Bprint(&bout, "                                %ud\n", y);
 123         Bprint(&bout, "\n");
 124         for(i=0; i<12; i+=3) {
 125                 for(j=0; j<6*72; j++)
 126                         string[j] = '\0';
 127                 Bprint(&bout, "         %.3s", smon[i]);
 128                 Bprint(&bout, "                    %.3s", smon[i+1]);
 129                 Bprint(&bout, "                    %.3s\n", smon[i+2]);
 130                 Bprint(&bout, "%s   %s   %s\n", dayw, dayw, dayw);
 131                 cal(i+1, y, string, 72);
 132                 cal(i+2, y, string+23, 72);
 133                 cal(i+3, y, string+46, 72);
 134                 for(j=0; j<6*72; j+=72)
 135                         pstr(string+j, 72);
 136         }
 137         Bprint(&bout, "\n\n\n");
 138         exits(nil);
 139
 140 badarg:
 141         Bprint(&bout, "cal: bad argument\n");
 142 }
 143
 144 struct
 145 {
 146         char*   word;
 147         int     val;
 148 } dict[] =
 149 {
 150         "jan",          1,
 151         "january",      1,
 152         "feb",          2,
 153         "february",     2,
 154         "mar",          3,
 155         "march",        3,
 156         "apr",          4,
 157         "april",        4,
 158         "may",          5,
 159         "jun",          6,
 160         "june",         6,
 161         "jul",          7,
 162         "july",         7,
 163         "aug",          8,
 164         "august",       8,
 165         "sep",          9,
 166         "sept",         9,
 167         "september",    9,
 168         "oct",          10,
 169         "october",      10,
 170         "nov",          11,
 171         "november",     11,
 172         "dec",          12,
 173         "december",     12,
 174         0
 175 };
 176
 177 /*
 178  * convert to a number.
 179  * if its a dictionary word,
 180  * return negative  number
 181  */
 182 int
 183 number(char *str)
 184 {
 185         int n, c;
 186         char *s;
 187
 188         for(n=0; s=dict[n].word; n++)
 189                 if(strcmp(s, str) == 0)
 190                         return -dict[n].val;
 191         n = 0;
 192         s = str;
 193         while(c = *s++) {
 194                 if(c<'0' || c>'9')
 195                         return 0;
 196                 n = n*10 + c-'0';
 197         }
 198         return n;
 199 }
 200
 201 void
 202 pstr(char *str, int n)
 203 {
 204         int i;
 205         char *s;
 206
 207         s = str;
 208         i = n;
 209         while(i--)
 210                 if(*s++ == '\0')
 211                         s[-1] = ' ';
 212         i = n+1;
 213         while(i--)
 214                 if(*--s != ' ')
 215                         break;
 216         s[1] = '\0';
 217         Bprint(&bout, "%s\n", str);
 218 }
 219
 220 void
 221 cal(int m, int y, char *p, int w)
 222 {
 223         int d, i;
 224         char *s;
 225
 226         s = p;
 227         d = jan1(y);
 228         mon[2] = 29;
 229         mon[9] = 30;
 230
 231         switch((jan1(y+1)+7-d)%7) {
 232
 233         /*
 234          *      non-leap year
 235          */
 236         case 1:
 237                 mon[2] = 28;
 238                 break;
 239
 240         /*
 241          *      1752
 242          */
 243         default:
 244                 mon[9] = 19;
 245                 break;
 246
 247         /*
 248          *      leap year
 249          */
 250         case 2:
 251                 ;
 252         }
 253         for(i=1; i<m; i++)
 254                 d += mon[i];
 255         d += 7 - wstart;
 256         d %= 7;
 257         s += 3*d;
 258         for(i=1; i<=mon[m]; i++) {
 259                 if(i==3 && mon[m]==19) {
 260                         i += 11;
 261                         mon[m] += 11;
 262                 }
 263                 if(i > 9)
 264                         *s = i/10+'0';
 265                 s++;
 266                 *s++ = i%10+'0';
 267                 s++;
 268                 if(++d == 7) {
 269                         d = 0;
 270                         s = p+w;
 271                         p = s;
 272                 }
 273         }
 274 }
 275
 276 /*
 277  *      return day of the week
 278  *      of jan 1 of given year
 279  */
 280 int
 281 jan1(int yr)
 282 {
 283         int y, d;
 284
 285 /*
 286  *      normal gregorian calendar
 287  *      one extra day per four years
 288  */
 289
 290         y = yr;
 291         d = 4+y+(y+3)/4;
 292
 293 /*
 294  *      julian calendar
 295  *      regular gregorian
 296  *      less three days per 400
 297  */
 298
 299         if(y > 1800) {
 300                 d -= (y-1701)/100;
 301                 d += (y-1601)/400;
 302         }
 303
 304 /*
 305  *      great calendar changeover instant
 306  */
 307
 308         if(y > 1752)
 309                 d += 3;
 310
 311         return d%7;
 312 }
 313
 314 /*
 315  * system dependent
 316  * get current month and year
 317  */
 318 int
 319 curmo(void)
 320 {
 321         Tm *tm;
 322
 323         tm = localtime(time(0));
 324         return tm->mon+1;
 325 }
 326
 327 int
 328 curyr(void)
 329 {
 330         Tm *tm;
 331
 332         tm = localtime(time(0));
 333         return tm->year+1900;
 334 }