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, relyear = 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)) {
  26                         char *new_f;
  27                         w=strtoul(f, &new_f, 10);
  28                         f = new_f;
  29                 } else {
  30                         w=-1;
  31                 }
  32                 adj=0;
  33                 switch (*f++) {
  34                 case 'a': case 'A':
  35                         dest = &tm->tm_wday;
  36                         min = ABDAY_1;
  37                         range = 7;
  38                         goto symbolic_range;
  39                 case 'b': case 'B': case 'h':
  40                         dest = &tm->tm_mon;
  41                         min = ABMON_1;
  42                         range = 12;
  43                         goto symbolic_range;
  44                 case 'c':
  45                         s = strptime(s, nl_langinfo(D_T_FMT), tm);
  46                         if (!s) return 0;
  47                         break;
  48                 case 'C':
  49                         dest = &century;
  50                         if (w<0) w=2;
  51                         want_century |= 2;
  52                         goto numeric_digits;
  53                 case 'd': case 'e':
  54                         dest = &tm->tm_mday;
  55                         min = 1;
  56                         range = 31;
  57                         goto numeric_range;
  58                 case 'D':
  59                         s = strptime(s, "%m/%d/%y", tm);
  60                         if (!s) return 0;
  61                         break;
  62                 case 'H':
  63                         dest = &tm->tm_hour;
  64                         min = 0;
  65                         range = 24;
  66                         goto numeric_range;
  67                 case 'I':
  68                         dest = &tm->tm_hour;
  69                         min = 1;
  70                         range = 12;
  71                         goto numeric_range;
  72                 case 'j':
  73                         dest = &tm->tm_yday;
  74                         min = 1;
  75                         range = 366;
  76                         adj = 1;
  77                         goto numeric_range;
  78                 case 'm':
  79                         dest = &tm->tm_mon;
  80                         min = 1;
  81                         range = 12;
  82                         adj = 1;
  83                         goto numeric_range;
  84                 case 'M':
  85                         dest = &tm->tm_min;
  86                         min = 0;
  87                         range = 60;
  88                         goto numeric_range;
  89                 case 'n': case 't':
  90                         for (; *s && isspace(*s); s++);
  91                         break;
  92                 case 'p':
  93                         ex = nl_langinfo(AM_STR);
  94                         len = strlen(ex);
  95                         if (!strncasecmp(s, ex, len)) {
  96                                 tm->tm_hour %= 12;
  97                                 s += len;
  98                                 break;
  99                         }
 100                         ex = nl_langinfo(PM_STR);
 101                         len = strlen(ex);
 102                         if (!strncasecmp(s, ex, len)) {
 103                                 tm->tm_hour %= 12;
 104                                 tm->tm_hour += 12;
 105                                 s += len;
 106                                 break;
 107                         }
 108                         return 0;
 109                 case 'r':
 110                         s = strptime(s, nl_langinfo(T_FMT_AMPM), tm);
 111                         if (!s) return 0;
 112                         break;
 113                 case 'R':
 114                         s = strptime(s, "%H:%M", tm);
 115                         if (!s) return 0;
 116                         break;
 117                 case 'S':
 118                         dest = &tm->tm_sec;
 119                         min = 0;
 120                         range = 61;
 121                         goto numeric_range;
 122                 case 'T':
 123                         s = strptime(s, "%H:%M:%S", tm);
 124                         if (!s) return 0;
 125                         break;
 126                 case 'U':
 127                 case 'W':
 128                         /* Throw away result, for now. (FIXME?) */
 129                         dest = &dummy;
 130                         min = 0;
 131                         range = 54;
 132                         goto numeric_range;
 133                 case 'w':
 134                         dest = &tm->tm_wday;
 135                         min = 0;
 136                         range = 7;
 137                         goto numeric_range;
 138                 case 'x':
 139                         s = strptime(s, nl_langinfo(D_FMT), tm);
 140                         if (!s) return 0;
 141                         break;
 142                 case 'X':
 143                         s = strptime(s, nl_langinfo(T_FMT), tm);
 144                         if (!s) return 0;
 145                         break;
 146                 case 'y':
 147                         dest = &relyear;
 148                         w = 2;
 149                         want_century |= 1;
 150                         goto numeric_digits;
 151                 case 'Y':
 152                         dest = &tm->tm_year;
 153                         if (w<0) w=4;
 154                         adj = 1900;
 155                         want_century = 0;
 156                         goto numeric_digits;
 157                 case '%':
 158                         if (*s++ != '%') return 0;
 159                         break;
 160                 default:
 161                         return 0;
 162                 numeric_range:
 163                         if (!isdigit(*s)) return 0;
 164                         *dest = 0;
 165                         for (i=1; i<=min+range && isdigit(*s); i*=10)
 166                                 *dest = *dest * 10 + *s++ - '0';
 167                         if (*dest - min >= (unsigned)range) return 0;
 168                         *dest -= adj;
 169                         switch((char *)dest - (char *)tm) {
 170                         case offsetof(struct tm, tm_yday):
 171                                 ;
 172                         }
 173                         goto update;
 174                 numeric_digits:
 175                         neg = 0;
 176                         if (*s == '+') s++;
 177                         else if (*s == '-') neg=1, s++;
 178                         if (!isdigit(*s)) return 0;
 179                         for (*dest=i=0; i<w && isdigit(*s); i++)
 180                                 *dest = *dest * 10 + *s++ - '0';
 181                         if (neg) *dest = -*dest;
 182                         *dest -= adj;
 183                         goto update;
 184                 symbolic_range:
 185                         for (i=2*range-1; i>=0; i--) {
 186                                 ex = nl_langinfo(min+i);
 187                                 len = strlen(ex);
 188                                 if (strncasecmp(s, ex, len)) continue;
 189                                 s += len;
 190                                 *dest = i % range;
 191                                 break;
 192                         }
 193                         if (i<0) return 0;
 194                         goto update;
 195                 update:
 196                         //FIXME
 197                         ;
 198                 }
 199         }
 200         if (want_century) {
 201                 tm->tm_year = relyear;
 202                 if (want_century & 2) tm->tm_year += century * 100 - 1900;
 203                 else if (tm->tm_year <= 68) tm->tm_year += 100;
 204         }
 205         return (char *)s;
 206 }