#include <stdlib.h>
#include <langinfo.h>
#include <time.h>
#include <ctype.h>
#include <stddef.h>
#include <string.h>
#include <strings.h>
char *strptime(const char *restrict s, const char *restrict f, struct tm *restrict tm)
{
int i, w, neg, adj, min, range, *dest, dummy;
const char *ex;
size_t len;
int want_century = 0, century = 0, relyear = 0;
while (*f) {
if (*f != '%') {
if (isspace(*f)) for (; *s && isspace(*s); s++);
else if (*s != *f) return 0;
else s++;
f++;
continue;
}
f++;
if (*f == '+') f++;
if (isdigit(*f)) {
char *new_f;
w=strtoul(f, &new_f, 10);
f = new_f;
} else {
w=-1;
}
adj=0;
switch (*f++) {
case 'a': case 'A':
dest = &tm->tm_wday;
min = ABDAY_1;
range = 7;
goto symbolic_range;
case 'b': case 'B': case 'h':
dest = &tm->tm_mon;
min = ABMON_1;
range = 12;
goto symbolic_range;
case 'c':
s = strptime(s, nl_langinfo(D_T_FMT), tm);
if (!s) return 0;
break;
case 'C':
dest = ¢ury;
if (w<0) w=2;
want_century |= 2;
goto numeric_digits;
case 'd': case 'e':
dest = &tm->tm_mday;
min = 1;
range = 31;
goto numeric_range;
case 'D':
s = strptime(s, "%m/%d/%y", tm);
if (!s) return 0;
break;
case 'F':
/* Use temp buffer to implement the odd requirement
* that entire field be width-limited but the year
* subfield not itself be limited. */
i = 0;
char tmp[20];
if (*s == '-' || *s == '+') tmp[i++] = *s++;
while (*s=='0' && isdigit(s[1])) s++;
for (; *s && i<(size_t)w && i+1<sizeof tmp; i++) {
tmp[i] = *s++;
}
tmp[i] = 0;
char *p = strptime(tmp, "%12Y-%m-%d", tm);
if (!p) return 0;
s -= tmp+i-p;
break;
case 'H':
dest = &tm->tm_hour;
min = 0;
range = 24;
goto numeric_range;
case 'I':
dest = &tm->tm_hour;
min = 1;
range = 12;
goto numeric_range;
case 'j':
dest = &tm->tm_yday;
min = 1;
range = 366;
adj = 1;
goto numeric_range;
case 'm':
dest = &tm->tm_mon;
min = 1;
range = 12;
adj = 1;
goto numeric_range;
case 'M':
dest = &tm->tm_min;
min = 0;
range = 60;
goto numeric_range;
case 'n': case 't':
for (; *s && isspace(*s); s++);
break;
case 'p':
ex = nl_langinfo(AM_STR);
len = strlen(ex);
if (!strncasecmp(s, ex, len)) {
tm->tm_hour %= 12;
s += len;
break;
}
ex = nl_langinfo(PM_STR);
len = strlen(ex);
if (!strncasecmp(s, ex, len)) {
tm->tm_hour %= 12;
tm->tm_hour += 12;
s += len;
break;
}
return 0;
case 'r':
s = strptime(s, nl_langinfo(T_FMT_AMPM), tm);
if (!s) return 0;
break;
case 'R':
s = strptime(s, "%H:%M", tm);
if (!s) return 0;
break;
case 's':
/* Parse only. Effect on tm is unspecified
* and presently no effect is implemented.. */
if (*s == '-') s++;
if (!isdigit(*s)) return 0;
while (isdigit(*s)) s++;
break;
case 'S':
dest = &tm->tm_sec;
min = 0;
range = 61;
goto numeric_range;
case 'T':
s = strptime(s, "%H:%M:%S", tm);
if (!s) return 0;
break;
case 'U':
case 'W':
/* Throw away result of %U, %V, %W, %g, and %G. Effect
* is unspecified and there is no clear right choice. */
dest = &dummy;
min = 0;
range = 54;
goto numeric_range;
case 'V':
dest = &dummy;
min = 1;
range = 53;
goto numeric_range;
case 'g':
dest = &dummy;
w = 2;
goto numeric_digits;
case 'G':
dest = &dummy;
if (w<0) w=4;
goto numeric_digits;
case 'u':
dest = &tm->tm_wday;
min = 1;
range = 7;
goto numeric_range;
case 'w':
dest = &tm->tm_wday;
min = 0;
range = 7;
goto numeric_range;
case 'x':
s = strptime(s, nl_langinfo(D_FMT), tm);
if (!s) return 0;
break;
case 'X':
s = strptime(s, nl_langinfo(T_FMT), tm);
if (!s) return 0;
break;
case 'y':
dest = &relyear;
w = 2;
want_century |= 1;
goto numeric_digits;
case 'Y':
dest = &tm->tm_year;
if (w<0) w=4;
adj = 1900;
want_century = 0;
goto numeric_digits;
case 'z':
if (*s == '+') neg = 0;
else if (*s == '-') neg = 1;
else return 0;
for (i=0; i<4; i++) if (!isdigit(s[1+i])) return 0;
tm->__tm_gmtoff = (s[1]-'0')*36000+(s[2]-'0')*3600
+ (s[3]-'0')*600 + (s[4]-'0')*60;
if (neg) tm->__tm_gmtoff = -tm->__tm_gmtoff;
s += 5;
break;
case 'Z':
if (!strncmp(s, tzname[0], len = strlen(tzname[0]))) {
tm->tm_isdst = 0;
s += len;
} else if (!strncmp(s, tzname[1], len=strlen(tzname[1]))) {
tm->tm_isdst = 1;
s += len;
} else {
/* FIXME: is this supposed to be an error? */
while ((*s|32)-'a' <= 'z'-'a') s++;
}
break;
case '%':
if (*s++ != '%') return 0;
break;
default:
return 0;
numeric_range:
if (!isdigit(*s)) return 0;
*dest = 0;
for (i=1; i<=min+range && isdigit(*s); i*=10)
*dest = *dest * 10 + *s++ - '0';
if (*dest - min >= (unsigned)range) return 0;
*dest -= adj;
switch((char *)dest - (char *)tm) {
case offsetof(struct tm, tm_yday):
;
}
goto update;
numeric_digits:
neg = 0;
if (*s == '+') s++;
else if (*s == '-') neg=1, s++;
if (!isdigit(*s)) return 0;
for (*dest=i=0; i<w && isdigit(*s); i++)
*dest = *dest * 10 + *s++ - '0';
if (neg) *dest = -*dest;
*dest -= adj;
goto update;
symbolic_range:
for (i=2*range-1; i>=0; i--) {
ex = nl_langinfo(min+i);
len = strlen(ex);
if (strncasecmp(s, ex, len)) continue;
s += len;
*dest = i % range;
break;
}
if (i<0) return 0;
goto update;
update:
//FIXME
;
}
}
if (want_century) {
tm->tm_year = relyear;
if (want_century & 2) tm->tm_year += century * 100 - 1900;
else if (tm->tm_year <= 68) tm->tm_year += 100;
}
return (char *)s;
}
