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