8 // FIXME: integer overflows
10 const char *__langinfo(nl_item);
12 static int is_leap(int y)
15 if (y>INT_MAX-1900) y -= 2000;
17 return !(y%4) && ((y%100) || !(y%400));
20 size_t strftime(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm)
26 for (l=0; *f && l<n; f++) {
36 item = ABDAY_1 + tm->tm_wday;
39 item = DAY_1 + tm->tm_wday;
43 item = ABMON_1 + tm->tm_mon;
46 item = MON_1 + tm->tm_mon;
52 val = (1900+tm->tm_year) / 100;
71 val = 0; //week_based_year(tm)%100;
76 val = 0; //week_based_year(tm);
86 else if (val > 12) val -= 12;
105 item = tm->tm_hour >= 12 ? PM_STR : AM_STR;
124 val = tm->tm_wday ? tm->tm_wday : 7;
128 val = (tm->tm_yday + 7 - tm->tm_wday) / 7;
132 val = (tm->tm_yday + 7 - (tm->tm_wday+6)%7) / 7;
136 val = (tm->tm_yday + 7 - (tm->tm_wday+6)%7) / 7;
137 /* If 1 Jan is just 1-3 days past Monday,
138 * the previous week is also in this year. */
139 if ((tm->tm_wday - tm->tm_yday - 2 + 371) % 7 <= 2)
143 /* If 31 December of prev year a Thursday,
144 * or Friday of a leap year, then the
145 * prev year has 53 weeks. */
146 int dec31 = (tm->tm_wday - tm->tm_yday - 1 + 7) % 7;
147 if (dec31 == 4 || (dec31 == 5 && is_leap(tm->tm_year%400-1)))
149 } else if (val == 53) {
150 /* If 1 January is not a Thursday, and not
151 * a Wednesday of a leap year, then this
152 * year has only 52 weeks. */
153 int jan1 = (tm->tm_wday - tm->tm_yday + 371) % 7;
154 if (jan1 != 4 && (jan1 != 3 || !is_leap(tm->tm_year)))
170 val = tm->tm_year % 100;
174 val = tm->tm_year + 1900;
178 if (tm->tm_isdst < 0) continue;
179 val = -__timezone - (tm->tm_isdst ? __dst_offset : 0);
180 l += snprintf(s+l, n-l, "%+.2d%.2d", val/3600, abs(val%3600)/60);
183 if (tm->tm_isdst < 0 || !__tzname[0] || !__tzname[0][0])
185 l += snprintf(s+l, n-l, "%s", __tzname[!!tm->tm_isdst]);
195 l += snprintf(s+l, n-l, fmt, val);
198 l += snprintf(s+l, n-l, "%s", __langinfo(item));
201 fmt = __langinfo(item);
203 l += strftime(s+l, n-l, fmt, tm);
205 if (l >= n) return 0;