sys/src/cmd/cal.c

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