1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <string.h>
4 #include <langinfo.h>
5 #include <locale.h>
6 #include <ctype.h>
7 #include <time.h>
8 #include <limits.h>
9 #include "locale_impl.h"
10 #include "time_impl.h"
11
is_leap(int y)12 static int is_leap(int y)
13 {
14 /* Avoid overflow */
15 if (y>INT_MAX-1900) y -= 2000;
16 y += 1900;
17 return !(y%4) && ((y%100) || !(y%400));
18 }
19
week_num(const struct tm * tm)20 static int week_num(const struct tm *tm)
21 {
22 int val = (tm->tm_yday + 7U - (tm->tm_wday+6U)%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 + 371U - tm->tm_yday - 2) % 7 <= 2)
26 val++;
27 if (!val) {
28 val = 52;
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 + 7U - tm->tm_yday - 1) % 7;
33 if (dec31 == 4 || (dec31 == 5 && is_leap(tm->tm_year%400-1)))
34 val++;
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 + 371U - tm->tm_yday) % 7;
40 if (jan1 != 4 && (jan1 != 3 || !is_leap(tm->tm_year)))
41 val = 1;
42 }
43 return val;
44 }
45
__strftime_fmt_1(char (* s)[100],size_t * l,int f,const struct tm * tm,locale_t loc,int pad)46 const char *__strftime_fmt_1(char (*s)[100], size_t *l, int f, const struct tm *tm, locale_t loc, int pad)
47 {
48 nl_item item;
49 long long val;
50 const char *fmt = "-";
51 int width = 2, def_pad = '0';
52
53 switch (f) {
54 case 'a':
55 if (tm->tm_wday > 6U) goto string;
56 item = ABDAY_1 + tm->tm_wday;
57 goto nl_strcat;
58 case 'A':
59 if (tm->tm_wday > 6U) goto string;
60 item = DAY_1 + tm->tm_wday;
61 goto nl_strcat;
62 case 'h':
63 case 'b':
64 if (tm->tm_mon > 11U) goto string;
65 item = ABMON_1 + tm->tm_mon;
66 goto nl_strcat;
67 case 'B':
68 if (tm->tm_mon > 11U) goto string;
69 item = MON_1 + tm->tm_mon;
70 goto nl_strcat;
71 case 'c':
72 item = D_T_FMT;
73 goto nl_strftime;
74 case 'C':
75 val = (1900LL+tm->tm_year) / 100;
76 goto number;
77 case 'e':
78 def_pad = '_';
79 case 'd':
80 val = tm->tm_mday;
81 goto number;
82 case 'D':
83 fmt = "%m/%d/%y";
84 goto recu_strftime;
85 case 'F':
86 fmt = "%Y-%m-%d";
87 goto recu_strftime;
88 case 'g':
89 case 'G':
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;
94 else width = 4;
95 goto number;
96 case 'H':
97 val = tm->tm_hour;
98 goto number;
99 case 'I':
100 val = tm->tm_hour;
101 if (!val) val = 12;
102 else if (val > 12) val -= 12;
103 goto number;
104 case 'j':
105 val = tm->tm_yday+1;
106 width = 3;
107 goto number;
108 case 'm':
109 val = tm->tm_mon+1;
110 goto number;
111 case 'M':
112 val = tm->tm_min;
113 goto number;
114 case 'n':
115 *l = 1;
116 return "\n";
117 case 'p':
118 item = tm->tm_hour >= 12 ? PM_STR : AM_STR;
119 goto nl_strcat;
120 case 'r':
121 item = T_FMT_AMPM;
122 goto nl_strftime;
123 case 'R':
124 fmt = "%H:%M";
125 goto recu_strftime;
126 case 's':
127 val = __tm_to_secs(tm) - tm->__tm_gmtoff;
128 width = 1;
129 goto number;
130 case 'S':
131 val = tm->tm_sec;
132 goto number;
133 case 't':
134 *l = 1;
135 return "\t";
136 case 'T':
137 fmt = "%H:%M:%S";
138 goto recu_strftime;
139 case 'u':
140 val = tm->tm_wday ? tm->tm_wday : 7;
141 width = 1;
142 goto number;
143 case 'U':
144 val = (tm->tm_yday + 7U - tm->tm_wday) / 7;
145 goto number;
146 case 'W':
147 val = (tm->tm_yday + 7U - (tm->tm_wday+6U)%7) / 7;
148 goto number;
149 case 'V':
150 val = week_num(tm);
151 goto number;
152 case 'w':
153 val = tm->tm_wday;
154 width = 1;
155 goto number;
156 case 'x':
157 item = D_FMT;
158 goto nl_strftime;
159 case 'X':
160 item = T_FMT;
161 goto nl_strftime;
162 case 'y':
163 val = (tm->tm_year + 1900LL) % 100;
164 if (val < 0) val = -val;
165 goto number;
166 case 'Y':
167 val = tm->tm_year + 1900LL;
168 if (val >= 10000) {
169 *l = snprintf(*s, sizeof *s, "+%lld", val);
170 return *s;
171 }
172 width = 4;
173 goto number;
174 case 'z':
175 if (tm->tm_isdst < 0) {
176 *l = 0;
177 return "";
178 }
179 *l = snprintf(*s, sizeof *s, "%+.4ld",
180 tm->__tm_gmtoff/3600*100 + tm->__tm_gmtoff%3600/60);
181 return *s;
182 case 'Z':
183 if (tm->tm_isdst < 0) {
184 *l = 0;
185 return "";
186 }
187 fmt = __tm_to_tzname(tm);
188 goto string;
189 case '%':
190 *l = 1;
191 return "%";
192 default:
193 return 0;
194 }
195 number:
196 switch (pad ? pad : def_pad) {
197 case '-': *l = snprintf(*s, sizeof *s, "%lld", val); break;
198 case '_': *l = snprintf(*s, sizeof *s, "%*lld", width, val); break;
199 case '0':
200 default: *l = snprintf(*s, sizeof *s, "%0*lld", width, val); break;
201 }
202 return *s;
203 nl_strcat:
204 fmt = __nl_langinfo_l(item, loc);
205 string:
206 *l = strlen(fmt);
207 return fmt;
208 nl_strftime:
209 fmt = __nl_langinfo_l(item, loc);
210 recu_strftime:
211 *l = __strftime_l(*s, sizeof *s, fmt, tm, loc);
212 if (!*l) return 0;
213 return *s;
214 }
215
__strftime_l(char * restrict s,size_t n,const char * restrict f,const struct tm * restrict tm,locale_t loc)216 size_t __strftime_l(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm, locale_t loc)
217 {
218 size_t l, k;
219 char buf[100];
220 char *p;
221 const char *t;
222 int pad, plus;
223 unsigned long width;
224 for (l=0; l<n; f++) {
225 if (!*f) {
226 s[l] = 0;
227 return l;
228 }
229 if (*f != '%') {
230 s[l++] = *f;
231 continue;
232 }
233 f++;
234 pad = 0;
235 if (*f == '-' || *f == '_' || *f == '0') pad = *f++;
236 if ((plus = (*f == '+'))) f++;
237 if (isdigit(*f)) {
238 width = strtoul(f, &p, 10);
239 } else {
240 width = 0;
241 p = (void *)f;
242 }
243 if (*p == 'C' || *p == 'F' || *p == 'G' || *p == 'Y') {
244 if (!width && p!=f) width = 1;
245 } else {
246 width = 0;
247 }
248 f = p;
249 if (*f == 'E' || *f == 'O') f++;
250 t = __strftime_fmt_1(&buf, &k, *f, tm, loc, pad);
251 if (!t) break;
252 if (width) {
253 /* Trim off any sign and leading zeros, then
254 * count remaining digits to determine behavior
255 * for the + flag. */
256 if (*t=='+' || *t=='-') t++, k--;
257 for (; *t=='0' && t[1]-'0'<10U; t++, k--);
258 if (width < k) width = k;
259 size_t d;
260 for (d=0; t[d]-'0'<10U; d++);
261 if (tm->tm_year < -1900) {
262 s[l++] = '-';
263 width--;
264 } else if (plus && d+(width-k) >= (*p=='C'?3:5)) {
265 s[l++] = '+';
266 width--;
267 }
268 for (; width > k && l < n; width--)
269 s[l++] = '0';
270 }
271 if (k > n-l) k = n-l;
272 memcpy(s+l, t, k);
273 l += k;
274 }
275 if (n) {
276 if (l==n) l=n-1;
277 s[l] = 0;
278 }
279 return 0;
280 }
281
strftime(char * restrict s,size_t n,const char * restrict f,const struct tm * restrict tm)282 size_t strftime(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm)
283 {
284 return __strftime_l(s, n, f, tm, CURRENT_LOCALE);
285 }
286
287 weak_alias(__strftime_l, strftime_l);
288