nsz Git - musl/blob - src/time/strftime.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <langinfo.h>
   4 #include <time.h>
   5 #include "__time.h"
   6
   7 // FIXME: integer overflows
   8
   9 const char *__langinfo(nl_item);
  10
  11 size_t strftime(char *s, size_t n, const char *f, const struct tm *tm)
  12 {
  13         nl_item item;
  14         int val;
  15         const char *fmt;
  16         size_t l;
  17         for (l=0; *f && l<n; f++) {
  18                 if (*f == '%') {
  19 do_fmt:
  20                 switch (*++f) {
  21                 case '%':
  22                         goto literal;
  23                 case 'E':
  24                 case 'O':
  25                         goto do_fmt;
  26                 case 'a':
  27                         item = ABDAY_1 + tm->tm_wday;
  28                         goto nl_strcat;
  29                 case 'A':
  30                         item = DAY_1 + tm->tm_wday;
  31                         goto nl_strcat;
  32                 case 'h':
  33                 case 'b':
  34                         item = ABMON_1 + tm->tm_mon;
  35                         goto nl_strcat;
  36                 case 'B':
  37                         item = MON_1 + tm->tm_mon;
  38                         goto nl_strcat;
  39                 case 'c':
  40                         item = D_T_FMT;
  41                         goto nl_strftime;
  42                 case 'C':
  43                         val = (1900+tm->tm_year) / 100;
  44                         fmt = "%02d";
  45                         goto number;
  46                 case 'd':
  47                         val = tm->tm_mday;
  48                         fmt = "%02d";
  49                         goto number;
  50                 case 'D':
  51                         fmt = "%m/%d/%y";
  52                         goto recu_strftime;
  53                 case 'e':
  54                         val = tm->tm_mday;
  55                         fmt = "%2d";
  56                         goto number;
  57                 case 'F':
  58                         fmt = "%Y-%m-%d";
  59                         goto recu_strftime;
  60                 case 'g':
  61                         // FIXME
  62                         val = 0; //week_based_year(tm)%100;
  63                         fmt = "%02d";
  64                         goto number;
  65                 case 'G':
  66                         // FIXME
  67                         val = 0; //week_based_year(tm);
  68                         fmt = "%04d";
  69                         goto number;
  70                 case 'H':
  71                         val = tm->tm_hour;
  72                         fmt = "%02d";
  73                         goto number;
  74                 case 'I':
  75                         val = tm->tm_hour;
  76                         if (!val) val = 12;
  77                         else if (val > 12) val -= 12;
  78                         fmt = "%02d";
  79                         goto number;
  80                 case 'j':
  81                         val = tm->tm_yday+1;
  82                         fmt = "%03d";
  83                         goto number;
  84                 case 'm':
  85                         val = tm->tm_mon+1;
  86                         fmt = "%02d";
  87                         goto number;
  88                 case 'M':
  89                         val = tm->tm_min;
  90                         fmt = "%02d";
  91                         goto number;
  92                 case 'n':
  93                         s[l++] = '\n';
  94                         continue;
  95                 case 'p':
  96                         item = tm->tm_hour >= 12 ? PM_STR : AM_STR;
  97                         goto nl_strcat;
  98                 case 'r':
  99                         item = T_FMT_AMPM;
 100                         goto nl_strftime;
 101                 case 'R':
 102                         fmt = "%H:%M";
 103                         goto recu_strftime;
 104                 case 'S':
 105                         val = tm->tm_sec;
 106                         fmt = "%02d";
 107                         goto number;
 108                 case 't':
 109                         s[l++] = '\t';
 110                         continue;
 111                 case 'T':
 112                         fmt = "%H:%M:%S";
 113                         goto recu_strftime;
 114                 case 'u':
 115                         val = tm->tm_wday ? tm->tm_wday : 7;
 116                         fmt = "%d";
 117                         goto number;
 118                 case 'U':
 119                 case 'V':
 120                 case 'W':
 121                         // FIXME: week number mess..
 122                         continue;
 123                 case 'w':
 124                         val = tm->tm_wday;
 125                         fmt = "%d";
 126                         goto number;
 127                 case 'x':
 128                         item = D_FMT;
 129                         goto nl_strftime;
 130                 case 'X':
 131                         item = T_FMT;
 132                         goto nl_strftime;
 133                 case 'y':
 134                         val = tm->tm_year % 100;
 135                         fmt = "%02d";
 136                         goto number;
 137                 case 'Y':
 138                         val = tm->tm_year + 1900;
 139                         fmt = "%04d";
 140                         goto number;
 141                 case 'z':
 142                         if (tm->tm_isdst < 0) continue;
 143                         val = -__timezone - (tm->tm_isdst ? __dst_offset : 0);
 144                         l += snprintf(s+l, n-l, "%+.2d%.2d", val/3600, abs(val%3600)/60);
 145                         continue;
 146                 case 'Z':
 147                         if (tm->tm_isdst < 0 || !__tzname[0] || !__tzname[0][0])
 148                                 continue;
 149                         l += snprintf(s+l, n-l, "%s", __tzname[!!tm->tm_isdst]);
 150                         continue;
 151                 default:
 152                         return 0;
 153                 }
 154                 }
 155 literal:
 156                 s[l++] = *f;
 157                 continue;
 158 number:
 159                 l += snprintf(s+l, n-l, fmt, val);
 160                 continue;
 161 nl_strcat:
 162                 l += snprintf(s+l, n-l, "%s", __langinfo(item));
 163                 continue;
 164 nl_strftime:
 165                 fmt = __langinfo(item);
 166 recu_strftime:
 167                 l += strftime(s+l, n-l, fmt, tm);
 168         }
 169         if (l >= n) return 0;
 170         s[l] = 0;
 171         return l;
 172 }