tin  2.6.1
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strftime.c
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1/*
2 * Project : tin - a Usenet reader
3 * Module : strftime.c
4 * Author : A. Robbins & I. Lea
5 * Created : 1991-02-01
6 * Updated : 2018-04-04
7 * Notes : Relatively quick-and-dirty implementation of ANSI library
8 * routine for System V Unix systems.
9 * If target system already has strftime() call the #define
10 * HAVE_STRFTIME can be set to use it.
11 * Example : time(&secs);
12 * tm = localtime(&secs);
13 * num = strftime(buf, sizeof(buf), "%a %d-%m-%y %H:%M:%S", tm);
14 *
15 * Copyright (c) 1991-2022 Arnold Robbins <arnold@skeeve.com>
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 *
22 * 1. Redistributions of source code must retain the above copyright notice,
23 * this list of conditions and the following disclaimer.
24 *
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
28 *
29 * 3. Neither the name of the copyright holder nor the names of its
30 * contributors may be used to endorse or promote products derived from
31 * this software without specific prior written permission.
32 *
33 * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
34 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
35 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
36 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
37 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
38 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
39 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
40 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
41 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
43 * POSSIBILITY OF SUCH DAMAGE.
44 */
45
46
47#ifndef TIN_H
48# include "tin.h"
49#endif /* !TIN_H */
50
51#ifdef SYSV
52extern int daylight;
53#endif /* SYSV */
54
55#ifndef HAVE_STRFTIME
56# define SYSV_EXT 1 /* stuff in System V ascftime routine */
57#endif /* !HAVE_STRFTIME */
58
59/*
60 * strftime --- produce formatted time
61 */
62
63size_t
65 char *s,
66 size_t maxsize,
67 const char *format,
68 struct tm *timeptr)
69{
70#ifdef HAVE_STRFTIME
71 return strftime(s, maxsize, format, timeptr);
72#else
73 char *endp;
74 char *start = s;
75 char tbuf[100];
76 int i;
77
78 /*
79 * various tables, useful in North America
80 */
81 static const char *days_a[] = {
82 "Sun", "Mon", "Tue", "Wed",
83 "Thu", "Fri", "Sat",
84 };
85 static const char *days_l[] = {
86 "Sunday", "Monday", "Tuesday", "Wednesday",
87 "Thursday", "Friday", "Saturday",
88 };
89 static const char *months_a[] = {
90 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
91 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
92 };
93 static const char *months_l[] = {
94 "January", "February", "March", "April",
95 "May", "June", "July", "August", "September",
96 "October", "November", "December",
97 };
98 static const char *ampm[] = { "AM", "PM", };
99
100 if (s == NULL || format == NULL || timeptr == NULL || maxsize == 0)
101 return 0;
102
103 if (strchr(format, '%') == NULL && strlen(format) + 1 >= maxsize)
104 return 0;
105
106# ifdef HAVE_TZSET
107 tzset();
108# else
109# ifdef HAVE_SETTZ
110 settz();
111# endif /* HAVE_SETTZ */
112# endif /* HAVE_TZSET */
113
114 endp = s + maxsize;
115 for (; *format && s < endp - 1; format++) {
116 tbuf[0] = '\0';
117 if (*format != '%') {
118 *s++ = *format;
119 continue;
120 }
121 switch (*++format) {
122 case '\0':
123 *s++ = '%';
124 goto out;
125
126 case '%':
127 *s++ = '%';
128 continue;
129
130 case 'a': /* abbreviated weekday name */
131 strcpy(tbuf, days_a[timeptr->tm_wday]);
132 break;
133
134 case 'A': /* full weekday name */
135 strcpy(tbuf, days_l[timeptr->tm_wday]);
136 break;
137
138# ifdef SYSV_EXT
139 case 'h': /* abbreviated month name */
140# endif /* SYSV_EXT */
141 case 'b': /* abbreviated month name */
142 strcpy(tbuf, months_a[timeptr->tm_mon]);
143 break;
144
145 case 'B': /* full month name */
146 strcpy(tbuf, months_l[timeptr->tm_mon]);
147 break;
148
149 case 'c': /* appropriate date and time representation */
150 snprintf(tbuf, sizeof(tbuf), "%s %s %2d %02d:%02d:%02d %d",
151 days_a[timeptr->tm_wday],
152 months_a[timeptr->tm_mon],
153 timeptr->tm_mday,
154 timeptr->tm_hour,
155 timeptr->tm_min,
156 timeptr->tm_sec,
157 timeptr->tm_year + 1900);
158 break;
159
160 case 'd': /* day of the month, 01 - 31 */
161 snprintf(tbuf, sizeof(tbuf), "%02d", timeptr->tm_mday);
162 break;
163
164 case 'H': /* hour, 24-hour clock, 00 - 23 */
165 snprintf(tbuf, sizeof(tbuf), "%02d", timeptr->tm_hour);
166 break;
167
168 case 'I': /* hour, 12-hour clock, 01 - 12 */
169 i = timeptr->tm_hour;
170 if (i == 0)
171 i = 12;
172 else if (i > 12)
173 i -= 12;
174 snprintf(tbuf, sizeof(tbuf), "%02d", i);
175 break;
176
177 case 'j': /* day of the year, 001 - 366 */
178 snprintf(tbuf, sizeof(tbuf), "%03d", timeptr->tm_yday + 1);
179 break;
180
181 case 'm': /* month, 01 - 12 */
182 snprintf(tbuf, sizeof(tbuf), "%02d", timeptr->tm_mon + 1);
183 break;
184
185 case 'M': /* minute, 00 - 59 */
186 snprintf(tbuf, sizeof(tbuf), "%02d", timeptr->tm_min);
187 break;
188
189 case 'p': /* am or pm based on 12-hour clock */
190 strcpy(tbuf, ampm[((timeptr->tm_hour < 12) ? 0 : 1)]);
191 break;
192
193 case 'S': /* second, 00 - 61 */
194 snprintf(tbuf, sizeof(tbuf), "%02d", timeptr->tm_sec);
195 break;
196
197 case 'w': /* weekday, Sunday == 0, 0 - 6 */
198 snprintf(tbuf, sizeof(tbuf), "%d", timeptr->tm_wday);
199 break;
200
201 case 'x': /* appropriate date representation */
202 snprintf(tbuf, sizeof(tbuf), "%s %s %2d %d",
203 days_a[timeptr->tm_wday],
204 months_a[timeptr->tm_mon],
205 timeptr->tm_mday,
206 timeptr->tm_year + 1900);
207 break;
208
209 case 'X': /* appropriate time representation */
210 snprintf(tbuf, sizeof(tbuf), "%02d:%02d:%02d",
211 timeptr->tm_hour,
212 timeptr->tm_min,
213 timeptr->tm_sec);
214 break;
215
216 case 'y': /* year without a century, 00 - 99 */
217 i = timeptr->tm_year % 100;
218 snprintf(tbuf, sizeof(tbuf), "%d", i);
219 break;
220
221 case 'Y': /* year with century */
222 snprintf(tbuf, sizeof(tbuf), "%d", timeptr->tm_year + 1900);
223 break;
224
225# ifdef SYSV_EXT
226 case 'n': /* same as \n */
227 tbuf[0] = '\n';
228 tbuf[1] = '\0';
229 break;
230
231 case 't': /* same as \t */
232 tbuf[0] = '\t';
233 tbuf[1] = '\0';
234 break;
235
236 case 'D': /* date as %m/%d/%y */
237 my_strftime(tbuf, sizeof(tbuf), "%m/%d/%y", timeptr);
238 break;
239
240 case 'e': /* day of month, blank padded */
241 snprintf(tbuf, sizeof(tbuf), "%2d", timeptr->tm_mday);
242 break;
243
244 case 'r': /* time as %I:%M:%S %p */
245 my_strftime(tbuf, sizeof(tbuf), "%I:%M:%S %p", timeptr);
246 break;
247
248 case 'R': /* time as %H:%M */
249 my_strftime(tbuf, sizeof(tbuf), "%H:%M", timeptr);
250 break;
251
252 case 'T': /* time as %H:%M:%S */
253 my_strftime(tbuf, sizeof(tbuf), "%H:%M:%S", timeptr);
254 break;
255# endif /* SYSV_EXT */
256
257 default:
258 tbuf[0] = '%';
259 tbuf[1] = *format;
260 tbuf[2] = '\0';
261 break;
262 }
263 if ((i = strlen(tbuf))) {
264 if (s + i < endp - 1) {
265 strcpy(s, tbuf);
266 s += i;
267 } else
268 return 0;
269 }
270 }
271out:
272 if (s < endp && *format == '\0') {
273 *s = '\0';
274 return (size_t) (s - start);
275 } else
276 return 0;
277
278#endif /* HAVE_STRFTIME */
279}
size_t my_strftime(char *s, size_t maxsize, const char *format, struct tm *timeptr)
Definition: strftime.c:64
#define snprintf
Definition: tin.h:2464