src/time/strptime.c

   1 #include <stdlib.h>
   2 #include <langinfo.h>
   3 #include <time.h>
   4 #include <ctype.h>
   5 #include <stddef.h>
   6 #include <string.h>
   7 #include <strings.h>
   8
   9 char *strptime(const char *restrict s, const char *restrict f, struct tm *restrict tm)
  10 {
  11         int i, w, neg, adj, min, range, *dest, dummy;
  12         const char *ex;
  13         size_t len;
  14         int want_century = 0, century = 0;
  15         while (*f) {
  16                 if (*f != '%') {
  17                         if (isspace(*f)) for (; *s && isspace(*s); s++);
  18                         else if (*s != *f) return 0;
  19                         else s++;
  20                         f++;
  21                         continue;
  22                 }
  23                 f++;
  24                 if (*f == '+') f++;
  25                 if (isdigit(*f)) w=strtoul(f, (void *)&f, 10);
  26                 else w=-1;
  27                 adj=0;
  28                 switch (*f++) {
  29                 case 'a': case 'A':
  30                         dest = &tm->tm_wday;
  31                         min = ABDAY_1;
  32                         range = 7;
  33                         goto symbolic_range;
  34                 case 'b': case 'B': case 'h':
  35                         dest = &tm->tm_mon;
  36                         min = ABMON_1;
  37                         range = 12;
  38                         goto symbolic_range;
  39                 case 'c':
  40                         s = strptime(s, nl_langinfo(D_T_FMT), tm);
  41                         if (!s) return 0;
  42                         break;
  43                 case 'C':
  44                         dest = &century;
  45                         if (w<0) w=2;
  46                         want_century |= 2;
  47                         goto numeric_digits;
  48                 case 'd': case 'e':
  49                         dest = &tm->tm_mday;
  50                         min = 1;
  51                         range = 31;
  52                         goto numeric_range;
  53                 case 'D':
  54                         s = strptime(s, "%m/%d/%y", tm);
  55                         if (!s) return 0;
  56                         break;
  57                 case 'H':
  58                         dest = &tm->tm_hour;
  59                         min = 0;
  60                         range = 24;
  61                         goto numeric_range;
  62                 case 'I':
  63                         dest = &tm->tm_hour;
  64                         min = 1;
  65                         range = 12;
  66                         goto numeric_range;
  67                 case 'j':
  68                         dest = &tm->tm_yday;
  69                         min = 1;
  70                         range = 366;
  71                         goto numeric_range;
  72                 case 'm':
  73                         dest = &tm->tm_mon;
  74                         min = 1;
  75                         range = 12;
  76                         adj = 1;
  77                         goto numeric_range;
  78                 case 'M':
  79                         dest = &tm->tm_min;
  80                         min = 0;
  81                         range = 60;
  82                         goto numeric_range;
  83                 case 'n': case 't':
  84                         for (; *s && isspace(*s); s++);
  85                         break;
  86                 case 'p':
  87                         ex = nl_langinfo(AM_STR);
  88                         len = strlen(ex);
  89                         if (!strncasecmp(s, ex, len)) {
  90                                 tm->tm_hour %= 12;
  91                                 break;
  92                         }
  93                         ex = nl_langinfo(PM_STR);
  94                         len = strlen(ex);
  95                         if (!strncasecmp(s, ex, len)) {
  96                                 tm->tm_hour %= 12;
  97                                 tm->tm_hour += 12;
  98                                 break;
  99                         }
 100                         return 0;
 101                 case 'r':
 102                         s = strptime(s, nl_langinfo(T_FMT_AMPM), tm);
 103                         if (!s) return 0;
 104                         break;
 105                 case 'R':
 106                         s = strptime(s, "%H:%M", tm);
 107                         if (!s) return 0;
 108                         break;
 109                 case 'S':
 110                         dest = &tm->tm_sec;
 111                         min = 0;
 112                         range = 61;
 113                         goto numeric_range;
 114                 case 'T':
 115                         s = strptime(s, "%H:%M:%S", tm);
 116                         if (!s) return 0;
 117                         break;
 118                 case 'U':
 119                 case 'W':
 120                         /* Throw away result, for now. (FIXME?) */
 121                         dest = &dummy;
 122                         min = 0;
 123                         range = 54;
 124                         goto numeric_range;
 125                 case 'w':
 126                         dest = &tm->tm_wday;
 127                         min = 0;
 128                         range = 7;
 129                         goto numeric_range;
 130                 case 'x':
 131                         s = strptime(s, nl_langinfo(D_FMT), tm);
 132                         if (!s) return 0;
 133                         break;
 134                 case 'X':
 135                         s = strptime(s, nl_langinfo(T_FMT), tm);
 136                         if (!s) return 0;
 137                         break;
 138                 case 'y':
 139                         dest = &tm->tm_year;
 140                         w = 2;
 141                         want_century |= 1;
 142                         goto numeric_digits;
 143                 case 'Y':
 144                         dest = &tm->tm_year;
 145                         if (w<0) w=4;
 146                         adj = 1900;
 147                         want_century = 0;
 148                         goto numeric_digits;
 149                 case '%':
 150                         if (*s++ != '%') return 0;
 151                         break;
 152                 default:
 153                         return 0;
 154                 numeric_range:
 155                         if (!isdigit(*s)) return 0;
 156                         *dest = 0;
 157                         for (i=1; i<=min+range && isdigit(*s); i*=10)
 158                                 *dest = *dest * 10 + *s++ - '0';
 159                         if (*dest - min >= (unsigned)range) return 0;
 160                         *dest -= adj;
 161                         switch((char *)dest - (char *)tm) {
 162                         case offsetof(struct tm, tm_yday):
 163                                 ;
 164                         }
 165                         goto update;
 166                 numeric_digits:
 167                         neg = 0;
 168                         if (*s == '+') s++;
 169                         else if (*s == '-') neg=1, s++;
 170                         if (!isdigit(*s)) return 0;
 171                         for (*dest=i=0; i<w && isdigit(*s); i++)
 172                                 *dest = *dest * 10 + *s++ - '0';
 173                         if (neg) *dest = -*dest;
 174                         *dest -= adj;
 175                         goto update;
 176                 symbolic_range:
 177                         for (i=2*range-1; i>=0; i--) {
 178                                 ex = nl_langinfo(min+i);
 179                                 len = strlen(ex);
 180                                 if (strncasecmp(s, ex, len)) continue;
 181                                 s += len;
 182                                 *dest = i % range;
 183                                 break;
 184                         }
 185                         if (i<0) return 0;
 186                         goto update;
 187                 update:
 188                         //FIXME
 189                         ;
 190                 }
 191         }
 192         if (want_century) {
 193                 if (want_century & 2) tm->tm_year += century * 100 - 1900;
 194                 else if (tm->tm_year <= 68) tm->tm_year += 100;
 195         }
 196         return (char *)s;
 197 }