sys/src/libhttpd/date.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <httpd.h>
   4
   5 /*
   6  * print dates in the format
   7  * Wkd, DD Mon YYYY HH:MM:SS GMT
   8  * parse dates of formats
   9  * Wkd, DD Mon YYYY HH:MM:SS GMT
  10  * Weekday, DD-Mon-YY HH:MM:SS GMT
  11  * Wkd Mon ( D|DD) HH:MM:SS YYYY
  12  * plus anything similar
  13  */
  14 static char *
  15 weekdayname[7] =
  16 {
  17         "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
  18 };
  19 static char *
  20 wdayname[7] =
  21 {
  22         "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
  23 };
  24
  25 static char *
  26 monname[12] =
  27 {
  28         "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
  29 };
  30
  31 static  int     dateindex(char*, char**, int);
  32
  33 static int
  34 dtolower(int c)
  35 {
  36         if(c >= 'A' && c <= 'Z')
  37                 return c - 'A' + 'a';
  38         return c;
  39 }
  40
  41 static int
  42 disalpha(int c)
  43 {
  44         return c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z';
  45 }
  46
  47 static int
  48 disdig(int c)
  49 {
  50         return c >= '0' && c <= '9';
  51 }
  52
  53 int
  54 hdatefmt(Fmt *f)
  55 {
  56         Tm *tm;
  57         ulong t;
  58
  59         t = va_arg(f->args, ulong);
  60         tm = gmtime(t);
  61         return fmtprint(f, "%s, %.2d %s %.4d %.2d:%.2d:%.2d GMT",
  62                 wdayname[tm->wday], tm->mday, monname[tm->mon], tm->year+1900,
  63                 tm->hour, tm->min, tm->sec);
  64 }
  65
  66 static char*
  67 dateword(char *date, char *buf)
  68 {
  69         char *p;
  70         int c;
  71
  72         p = buf;
  73         while(!disalpha(c = *date) && !disdig(c) && c)
  74                 date++;
  75         while(disalpha(c = *date)){
  76                 if(p - buf < 30)
  77                         *p++ = dtolower(c);
  78                 date++;
  79         }
  80         *p = 0;
  81         return date;
  82 }
  83
  84 static int
  85 datenum(char **d)
  86 {
  87         char *date;
  88         int c, n;
  89
  90         date = *d;
  91         while(!disdig(c = *date) && c)
  92                 date++;
  93         if(c == 0){
  94                 *d = date;
  95                 return -1;
  96         }
  97         n = 0;
  98         while(disdig(c = *date)){
  99                 n = n * 10 + c - '0';
 100                 date++;
 101         }
 102         *d = date;
 103         return n;
 104 }
 105
 106 /*
 107  * parse a date and return the seconds since the epoch
 108  * return 0 for a failure
 109  */
 110 ulong
 111 hdate2sec(char *date)
 112 {
 113         Tm tm;
 114         char buf[32];
 115
 116         /*
 117          * Weekday|Wday
 118          */
 119         date = dateword(date, buf);
 120         tm.wday = dateindex(buf, wdayname, 7);
 121         if(tm.wday < 0)
 122                 tm.wday = dateindex(buf, weekdayname, 7);
 123         if(tm.wday < 0)
 124                 return 0;
 125
 126         /*
 127          * check for the two major formats
 128          */
 129         date = dateword(date, buf);
 130         tm.mon = dateindex(buf, monname, 12);
 131         if(tm.mon >= 0){
 132                 /*
 133                  * MM
 134                  */
 135                 tm.mday = datenum(&date);
 136                 if(tm.mday < 1 || tm.mday > 31)
 137                         return 0;
 138
 139                 /*
 140                  * HH:MM:SS
 141                  */
 142                 tm.hour = datenum(&date);
 143                 if(tm.hour < 0 || tm.hour >= 24)
 144                         return 0;
 145                 tm.min = datenum(&date);
 146                 if(tm.min < 0 || tm.min >= 60)
 147                         return 0;
 148                 tm.sec = datenum(&date);
 149                 if(tm.sec < 0 || tm.sec >= 60)
 150                         return 0;
 151
 152                 /*
 153                  * YYYY
 154                  */
 155                 tm.year = datenum(&date);
 156                 if(tm.year < 70 || tm.year > 99 && tm.year < 1970)
 157                         return 0;
 158                 if(tm.year >= 1970)
 159                         tm.year -= 1900;
 160         }else{
 161                 /*
 162                  * MM-Mon-(YY|YYYY)
 163                  */
 164                 tm.mday = datenum(&date);
 165                 if(tm.mday < 1 || tm.mday > 31)
 166                         return 0;
 167                 date = dateword(date, buf);
 168                 tm.mon = dateindex(buf, monname, 12);
 169                 if(tm.mon < 0 || tm.mon >= 12)
 170                         return 0;
 171                 tm.year = datenum(&date);
 172                 if(tm.year < 70 || tm.year > 99 && tm.year < 1970)
 173                         return 0;
 174                 if(tm.year >= 1970)
 175                         tm.year -= 1900;
 176
 177                 /*
 178                  * HH:MM:SS
 179                  */
 180                 tm.hour = datenum(&date);
 181                 if(tm.hour < 0 || tm.hour >= 24)
 182                         return 0;
 183                 tm.min = datenum(&date);
 184                 if(tm.min < 0 || tm.min >= 60)
 185                         return 0;
 186                 tm.sec = datenum(&date);
 187                 if(tm.sec < 0 || tm.sec >= 60)
 188                         return 0;
 189
 190                 /*
 191                  * timezone
 192                  */
 193                 dateword(date, buf);
 194                 if(strncmp(buf, "gmt", 3) != 0)
 195                         return 0;
 196         }
 197
 198         strcpy(tm.zone, "GMT");
 199         tm.tzoff = 0;
 200         tm.yday = 0;
 201         return tm2sec(&tm);
 202 }
 203
 204 static int
 205 dateindex(char *d, char **tab, int n)
 206 {
 207         int i;
 208
 209         for(i = 0; i < n; i++)
 210                 if(cistrcmp(d, tab[i]) == 0)
 211                         return i;
 212         return -1;
 213 }