10 const char *__nl_langinfo_l(nl_item, locale_t);
12 static int is_leap(int y)
15 if (y>INT_MAX-1900) y -= 2000;
17 return !(y%4) && ((y%100) || !(y%400));
20 static int week_num(const struct tm *tm)
22 int val = (tm->tm_yday + 7 - (tm->tm_wday+6)%7) / 7;
23 /* If 1 Jan is just 1-3 days past Monday,
24 * the previous week is also in this year. */
25 if ((tm->tm_wday - tm->tm_yday - 2 + 371) % 7 <= 2)
29 /* If 31 December of prev year a Thursday,
30 * or Friday of a leap year, then the
31 * prev year has 53 weeks. */
32 int dec31 = (tm->tm_wday - tm->tm_yday - 1 + 7) % 7;
33 if (dec31 == 4 || (dec31 == 5 && is_leap(tm->tm_year%400-1)))
35 } else if (val == 53) {
36 /* If 1 January is not a Thursday, and not
37 * a Wednesday of a leap year, then this
38 * year has only 52 weeks. */
39 int jan1 = (tm->tm_wday - tm->tm_yday + 371) % 7;
40 if (jan1 != 4 && (jan1 != 3 || !is_leap(tm->tm_year)))
46 const char *__tm_to_tzname(const struct tm *);
47 size_t __strftime_l(char *restrict, size_t, const char *restrict, const struct tm *restrict, locale_t);
49 const char *__strftime_fmt_1(char (*s)[100], size_t *l, int f, const struct tm *tm, locale_t loc)
58 item = ABDAY_1 + tm->tm_wday;
61 item = DAY_1 + tm->tm_wday;
65 item = ABMON_1 + tm->tm_mon;
68 item = MON_1 + tm->tm_mon;
74 val = (1900LL+tm->tm_year) / 100;
90 val = tm->tm_year + 1900LL;
91 if (tm->tm_yday < 3 && week_num(tm) != 1) val--;
92 else if (tm->tm_yday > 360 && week_num(tm) == 1) val++;
93 if (f=='g') val %= 100;
102 else if (val > 12) val -= 12;
118 item = tm->tm_hour >= 12 ? PM_STR : AM_STR;
136 val = tm->tm_wday ? tm->tm_wday : 7;
140 val = (tm->tm_yday + 7 - tm->tm_wday) / 7;
143 val = (tm->tm_yday + 7 - (tm->tm_wday+6)%7) / 7;
159 val = tm->tm_year % 100;
162 val = tm->tm_year + 1900;
164 *l = snprintf(*s, sizeof *s, "+%lld", val);
170 if (tm->tm_isdst < 0) {
174 *l = snprintf(*s, sizeof *s, "%+.2d%.2d",
175 (-tm->__tm_gmtoff)/3600,
176 abs(tm->__tm_gmtoff%3600)/60);
179 if (tm->tm_isdst < 0) {
183 fmt = __tm_to_tzname(tm);
192 *l = snprintf(*s, sizeof *s, "%0*lld", width, val);
195 fmt = __nl_langinfo_l(item, loc);
200 fmt = __nl_langinfo_l(item, loc);
202 *l = __strftime_l(*s, sizeof *s, fmt, tm, loc);
207 size_t __strftime_l(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm, locale_t loc)
215 for (l=0; l+1<n; f++) {
225 if ((plus = (*f == '+'))) f++;
226 width = strtoul(f, &p, 10);
227 if (*p == 'C' || *p == 'F' || *p == 'G' || *p == 'Y') {
228 if (!width && p!=f) width = 1;
229 if (width >= n-l) return 0;
234 if (*f == 'E' || *f == 'O') f++;
235 t = __strftime_fmt_1(&buf, &k, *f, tm, loc);
238 for (; *t=='+' || *t=='-' || (*t=='0'&&t[1]); t++, k--);
240 if (plus && tm->tm_year >= 10000-1900)
242 else if (tm->tm_year < -1900)
246 if (width >= n-l) return 0;
247 for (; width > k; width--)
250 if (k >= n-l) return 0;
257 size_t strftime(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm)
259 return __strftime_l(s, n, f, tm, 0);
262 weak_alias(__strftime_l, strftime_l);