diplodocus.org Git - nmh/blob - docs/historical/mh-6.8.5/miscellany/mem/promptdate.c

   1 #ifndef lint
   2 static char Id[] = "$Id: promptdate.c,v 1.2 1996/02/09 17:38:07 jromine Exp $";
   3 #endif
   4
   5 #include        <stdio.h>
   6 #include        <sys/time.h>
   7 #include        <ctype.h>
   8
   9 /*
  10 **      promptdate
  11 **      prompt user for a date specification which can be quite minimal
  12 **      and print it in a form suitable for parsing by MH
  13 */
  14
  15 #define         MAXLINE         128
  16
  17 char            *mname[12]      ={
  18                 "Jan","Feb","Mar","Apr","May","Jun",
  19                 "Jul","Aug","Sep","Oct","Nov","Dec"};
  20 char            *dname[7]       ={
  21                 "Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
  22 struct tm       now;
  23 int             dayspast        = 0;
  24 int             monthlen[2][12] ={
  25                 31,28,31,30,31,30,31,31,30,31,30,31,
  26                 31,29,31,30,31,30,31,31,30,31,30,31};
  27 char            *defaultformat  = "%d %N %y 00:00";
  28
  29 main(argc, argv)
  30         int             argc;
  31         char            **argv;
  32 {
  33         register int    c;
  34         struct tm       then;
  35         extern int      optind;         /* defined in getopt */
  36         extern char     *optarg;        /* defined in getopt */
  37         int             getopt();
  38         long            secsfr70();
  39
  40         while ((c = getopt (argc, argv, "f:")) != EOF)
  41         {
  42                 switch (c)
  43                 {
  44                 case 'f':
  45                         defaultformat = optarg;
  46                         break;
  47                 default:
  48                         fprintf(stderr, "usage: %s [-f format] [datespec]\n", argv[0]);
  49                         exit (1);
  50                 }
  51         }
  52         argc -= optind;
  53         argv += optind;
  54
  55         finddate(&now, dayspast = (int)(secsfr70()/86400L));
  56
  57         if (argc <= 0)                  /* get from user */
  58         {
  59                 if (!promptdate(&then))
  60                         exit(1);
  61                 printdate(&then, defaultformat);
  62         }
  63         else                            /* get from command line */
  64         {
  65                 if (!decodedate(argv[0], &then))
  66                         exit(1);
  67                 printdate(&then, defaultformat);
  68         }
  69         exit(0);
  70 }
  71
  72 int promptdate(when)
  73         struct tm       *when;
  74 {
  75         char            line[MAXLINE];
  76         int             decodedate();
  77         char            *p;
  78
  79         for (;;)
  80         {
  81                 fprintf(stderr, "When? ");
  82                 if (fgets(line, sizeof(line), stdin) == NULL)
  83                 {
  84                         fprintf(stderr, "\n");
  85                         return (0);
  86                 }
  87                 p = line + strlen (line) - 1;
  88                 if (*p == '\n')
  89                         *p = '\0';
  90                 if (decodedate(line, when))
  91                         return (1);
  92         }
  93 /*NOTREACHED*/
  94 }
  95
  96 int decodedate(line, when)
  97         char            *line;
  98         struct tm       *when;
  99 /*
 100 **      accept spec for date in several forms
 101 **      legal are: sun,mon,tue,wed,thu,fri,sat,today,tomorrow,
 102 **      <date><month>,+<relative number of days>
 103 **      <month> should be alpha
 104 **      upper case accepted too
 105 */
 106 {
 107         char            s[4];
 108         register int    i,targetdate;
 109         int             tem;
 110         register char   *lptr;
 111
 112         when->tm_year = now.tm_year;
 113         when->tm_mon = now.tm_mon;
 114         targetdate = dayspast;
 115         for (lptr = line; isspace(*lptr); lptr++)
 116                 ;
 117         if (isdigit(*lptr))
 118         {
 119                 i = sscanf(lptr, "%d%3s%d", &when->tm_mday, s, &tem);
 120                 switch(i)
 121                 {
 122                     case 3:
 123                         when->tm_year = tem;
 124                     case 2:
 125                         fold(s);
 126                         when->tm_mon = monthofyear(s);
 127                         if (i == 3)
 128                                 break;
 129                         if (when->tm_mday != 0 && when->tm_mon != 0 && daysfr70(when) < dayspast)
 130                                 when->tm_year++;
 131                         break;
 132                     case 1:
 133                         if (when->tm_mday != 0 && when->tm_mday < now.tm_mday)
 134                         {
 135                                 if (++when->tm_mon > 12)
 136                                 {
 137                                         when->tm_mon = 1;
 138                                         when->tm_year++;
 139                                 }
 140                         }
 141                 }
 142                 return (validate(when));
 143         }
 144         if (isalpha(*lptr))
 145         {
 146                 sscanf(lptr, "%3s", s);
 147                 fold(s);
 148                 if ((tem = dayofweek(s)) >= 0)
 149                         targetdate += (tem -= now.tm_wday) <= 0 ? tem + 7 : tem;
 150                 else if (strcmp(s, "Tom") == 0)
 151                         targetdate++;
 152                 else if (strcmp(s, "Tod") == 0)
 153                         ;
 154                 else    /* mistake */
 155                         return (0);
 156         }
 157         else if (*lptr == '+')
 158         {
 159                 if (sscanf(++lptr, "%d", &tem) == 0 || tem < 0) /* mistake */
 160                         return (0);
 161                 targetdate += tem;
 162         }
 163         else    /* mistake by default */
 164                 return (0);
 165         finddate(when, targetdate);
 166         return (when->tm_mday != 0);
 167 }
 168
 169 int validate(datetm)
 170 /*
 171 **      check that a given date and month combination is legal
 172 **      datetm->tm_year must hold the year in question
 173 */
 174         register struct tm      *datetm;
 175 {
 176
 177         return (datetm->tm_mday <= monthlen[leapyear(datetm->tm_year)]
 178                 [datetm->tm_mon] && datetm->tm_mday > 0);
 179 }
 180
 181 finddate(datetm, df70)
 182 /*
 183 **      convert days from 1 jan 1970 to a date in struct datetm
 184 */
 185         register int            df70;
 186         register struct tm      *datetm;
 187 {
 188         register struct tm      *tdtm;
 189         long                    longtime;
 190         struct tm               *gmtime();
 191
 192         longtime = df70 * 86400L;
 193         tdtm = gmtime(&longtime);
 194         datetm->tm_yday = tdtm->tm_yday;
 195         datetm->tm_wday = tdtm->tm_wday;
 196         datetm->tm_year = tdtm->tm_year + 1900;
 197         datetm->tm_mon = tdtm->tm_mon;
 198         datetm->tm_mday = tdtm->tm_mday;
 199         datetm->tm_hour = tdtm->tm_hour;
 200         datetm->tm_min = tdtm->tm_min;
 201         datetm->tm_sec = tdtm->tm_sec;
 202 }
 203
 204 fold(s)
 205 /*
 206 **      convert first character to uppercase
 207 **      convert rest of string from uppercase to lower case
 208 */
 209         register char   *s;
 210 {
 211         register char   c;
 212
 213         if ((c = *s) != '\0')
 214                 *s++ += islower(c) ? 'A' - 'a' : 0;
 215         while ((c = *s) != '\0')
 216                 *s++ += isupper(c) ? 'a' - 'A' : 0;
 217 }
 218
 219 int leapyear(y)
 220 /*
 221 **      returns 1 if leapyear 0 otherwise
 222 */
 223         register int    y;
 224 {
 225
 226         return (((y % 4) == 0 && (y % 100) != 0) || (y % 400) == 0);
 227 }
 228
 229 int daysfr70(datetm)
 230 /*
 231 **      returns the number of days from 1 Jan 1970
 232 **      no checking for illegal date at all
 233 */
 234         register struct tm      *datetm;
 235 {
 236         register int            i, totdays;
 237
 238
 239         totdays = 0;
 240         for (i = 1970; i <= 2050 && i < datetm->tm_year; i++)   /* prevent overflow */
 241                 totdays += 365 + leapyear(i);
 242         for (i = 0; i < 12 && i < datetm->tm_mon; i++)
 243                 totdays += monthlen[leapyear(datetm->tm_year)][i];
 244         totdays += datetm->tm_mday - 1;
 245         return (totdays);
 246 }
 247
 248 int monthofyear(s)
 249 /*
 250 **      returns month of year in numeric form when given
 251 **      the first three letters
 252 */
 253         register char   *s;
 254 {
 255         register int    i;
 256
 257         fold(s);
 258         for (i = 12; i-- && strcmp(s,mname[i]); )
 259                 ;
 260         return (i);
 261 }
 262
 263 int dayofweek(s)
 264 /*
 265 **      sunday = 0,...,saturday = 6, nomatch = -1
 266 */
 267         register char   *s;
 268 {
 269         register int    i;
 270
 271         fold(s);
 272         for (i = 7; i-- && strcmp(s,dname[i]); )
 273                 ;
 274         return (i);
 275 }
 276
 277 printdate(date, format)
 278 /*
 279 **      print date in MH acceptable format
 280 **      kludge - general formats are not implemented
 281 */
 282         struct tm       *date;
 283         char            *format;
 284 {
 285         printf("%d %s %d 00:00\n",
 286                 date->tm_mday, mname[date->tm_mon], date->tm_year);
 287 }
 288
 289 long secsfr70()
 290 /*
 291 **      This is system dependent
 292 */
 293 {
 294         register int            dst;
 295         struct timeval          tv;
 296         struct timezone         tz;
 297         struct tm               *localtime();
 298
 299         gettimeofday(&tv, &tz);
 300         dst = localtime(&tv.tv_sec)->tm_isdst;
 301         return (tv.tv_sec - tz.tz_minuteswest * 60 + (dst ? 3600 : 0));
 302 }