src/time/strptime.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <langinfo.h>
   4 #include <time.h>
   5 #include <ctype.h>
   6 #include <stddef.h>
   7 #include <string.h>
   8 #include <strings.h>
   9
  10 char *strptime(const char *restrict s, const char *restrict f, struct tm *restrict tm)
  11 {
  12         int i, w, neg, adj, min, range, *dest;
  13         const char *ex;
  14         size_t len;
  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                 case 'd': case 'e':
  45                         dest = &tm->tm_mday;
  46                         min = 1;
  47                         range = 31;
  48                         goto numeric_range;
  49                 case 'D':
  50                         s = strptime(s, "%m/%d/%y", tm);
  51                         if (!s) return 0;
  52                         break;
  53                 case 'H':
  54                         dest = &tm->tm_hour;
  55                         min = 0;
  56                         range = 24;
  57                         goto numeric_range;
  58                 case 'I':
  59                         dest = &tm->tm_hour;
  60                         min = 1;
  61                         range = 12;
  62                         goto numeric_range;
  63                 case 'j':
  64                         dest = &tm->tm_yday;
  65                         min = 1;
  66                         range = 366;
  67                         goto numeric_range;
  68                 case 'm':
  69                         dest = &tm->tm_mon;
  70                         min = 1;
  71                         range = 12;
  72                         adj = 1;
  73                         goto numeric_range;
  74                 case 'M':
  75                         dest = &tm->tm_min;
  76                         min = 0;
  77                         range = 60;
  78                         goto numeric_range;
  79                 case 'n': case 't':
  80                         for (; *s && isspace(*s); s++);
  81                         break;
  82                 case 'p':
  83                         ex = nl_langinfo(AM_STR);
  84                         len = strlen(ex);
  85                         if (!strncasecmp(s, ex, len)) {
  86                                 tm->tm_hour %= 12;
  87                                 break;
  88                         }
  89                         ex = nl_langinfo(PM_STR);
  90                         len = strlen(ex);
  91                         if (!strncasecmp(s, ex, len)) {
  92                                 tm->tm_hour %= 12;
  93                                 tm->tm_hour += 12;
  94                                 break;
  95                         }
  96                         return 0;
  97                 case 'r':
  98                         s = strptime(s, nl_langinfo(T_FMT_AMPM), tm);
  99                         if (!s) return 0;
 100                         break;
 101                 case 'R':
 102                         s = strptime(s, "%H:%M", tm);
 103                         if (!s) return 0;
 104                         break;
 105                 case 'S':
 106                         dest = &tm->tm_sec;
 107                         min = 0;
 108                         range = 61;
 109                         goto numeric_range;
 110                 case 'T':
 111                         s = strptime(s, "%H:%M:%S", tm);
 112                         if (!s) return 0;
 113                         break;
 114                 case 'U':
 115                 case 'W':
 116                         //FIXME
 117                         return 0;
 118                 case 'w':
 119                         dest = &tm->tm_wday;
 120                         min = 0;
 121                         range = 7;
 122                         goto numeric_range;
 123                 case 'x':
 124                         s = strptime(s, nl_langinfo(D_FMT), tm);
 125                         if (!s) return 0;
 126                         break;
 127                 case 'X':
 128                         s = strptime(s, nl_langinfo(T_FMT), tm);
 129                         if (!s) return 0;
 130                         break;
 131                 case 'y':
 132                         //FIXME
 133                         return 0;
 134                 case 'Y':
 135                         dest = &tm->tm_year;
 136                         if (w<0) w=4;
 137                         adj = 1900;
 138                         goto numeric_digits;
 139                 case '%':
 140                         if (*s++ != '%') return 0;
 141                         break;
 142                 numeric_range:
 143                         if (!isdigit(*s)) return 0;
 144                         *dest = 0;
 145                         for (i=1; i<=min+range && isdigit(*s); i*=10)
 146                                 *dest = *dest * 10 + *s++ - '0';
 147                         if (*dest - min >= (unsigned)range) return 0;
 148                         *dest -= adj;
 149                         switch((char *)dest - (char *)tm) {
 150                         case offsetof(struct tm, tm_yday):
 151                                 ;
 152                         }
 153                         goto update;
 154                 numeric_digits:
 155                         neg = 0;
 156                         if (*s == '+') s++;
 157                         else if (*s == '-') neg=1, s++;
 158                         if (!isdigit(*s)) return 0;
 159                         for (*dest=i=0; i<w && isdigit(*s); i++)
 160                                 *dest = *dest * 10 + *s++ - '0';
 161                         if (neg) *dest = -*dest;
 162                         *dest -= adj;
 163                         goto update;
 164                 symbolic_range:
 165                         for (i=2*range-1; i>=0; i--) {
 166                                 ex = nl_langinfo(min+i);
 167                                 len = strlen(ex);
 168                                 if (strncasecmp(s, ex, len)) continue;
 169                                 s += len;
 170                                 *dest = i % range;
 171                                 break;
 172                         }
 173                         if (i<0) return 0;
 174                         goto update;
 175                 update:
 176                         //FIXME
 177                         ;
 178                 }
 179         }
 180         return (char *)s;
 181 }