git.zerfleddert.de Git - micropolis/blob - src/tclx/ossupp/strftime.c

1 /*

2 * strftime.c

3 *

4 * Public-domain relatively quick-and-dirty implemenation of

5 * ANSI library routine for System V Unix systems.

6 *

7 * It's written in old-style C for maximal portability.

8 *

9 * The code for %c, %x, and %X is my best guess as to what's "appropriate".

10 * This version ignores LOCALE information.

11 * It also doesn't worry about multi-byte characters.

12 * So there.

13 *

14 * Arnold Robbins

15 * January, February, 1991

16 *

17 * Fixes from ado@elsie.nci.nih.gov

18 * February 1991

19 *-----------------------------------------------------------------------------

20 * $Id: strftime.c,v 2.0 1992/10/16 04:52:16 markd Rel $

21 *-----------------------------------------------------------------------------

22 */

24 /*

25 * To avoid Unix version problems, this code has been simplified to avoid

26 * const and size_t, however this can cause an incompatible definition on

27 * ansi-C systems, so a game is played with defines to ignore a strftime

28 * declaration in time.h

29 */

31 #define strftime ___srtftime

33 #include <stdio.h>

34 #include <string.h>

35 #include <time.h>

36 #include <sys/types.h>

38 #undef strftime

 extern char *strchr();

41 static int weeknumber();

43 #ifndef TCL_HAS_TM_ZONE

 extern char *tzname[2];

45 extern int daylight;

46 #endif

48 /* strftime --- produce formatted time */

50 int

 strftime(s, maxsize, format, timeptr)

52 char *s;

53 int maxsize;

54 char *format;

55 struct tm *timeptr;

56 {

         char *endp = s + maxsize;

58 char *start = s;

59 char tbuf[100];

60 int i;

62 /* various tables, useful in North America */

63 static char *days_a[] = {

                 "Sun", "Mon", "Tue", "Wed",

                 "Thu", "Fri", "Sat",

66 };

67 static char *days_l[] = {

                 "Sunday", "Monday", "Tuesday", "Wednesday",

                 "Thursday", "Friday", "Saturday",

70 };

71 static char *months_a[] = {

                 "Jan", "Feb", "Mar", "Apr", "May", "Jun",

                 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",

74 };

75 static char *months_l[] = {

                 "January", "February", "March", "April",

                 "May", "June", "July", "August", "September",

                 "October", "November", "December",

79 };

         static char *ampm[] = { "AM", "PM", };

         if (s == NULL || format == NULL || timeptr == NULL || maxsize == 0)

83 return 0;

         if (strchr(format, '%') == NULL && strlen(format) + 1 >= maxsize)

86 return 0;

         for (; *format && s < endp - 1; format++) {

                 tbuf[0] = '\0';

                 if (*format != '%') {

91 *s++ = *format;

92 continue;

93 }

94 switch (*++format) {

95 case '\0':

96 *s++ = '%';

97 goto out;

99 case '%':

100 *s++ = '%';

101 continue;

102

103 case 'a': /* abbreviated weekday name */

                         if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6)

                                 strcpy(tbuf, "?");

106 else

                                 strcpy(tbuf, days_a[timeptr->tm_wday]);

108 break;

109

110 case 'A': /* full weekday name */

                         if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6)

                                 strcpy(tbuf, "?");

113 else

                                 strcpy(tbuf, days_l[timeptr->tm_wday]);

115 break;

116

117 case 'h': /* abbreviated month name */

118 case 'b': /* abbreviated month name */

                         if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11)

                                 strcpy(tbuf, "?");

121 else

                                 strcpy(tbuf, months_a[timeptr->tm_mon]);

123 break;

124

125 case 'B': /* full month name */

                         if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11)

                                 strcpy(tbuf, "?");

128 else

                                 strcpy(tbuf, months_l[timeptr->tm_mon]);

130 break;

131

132 case 'c': /* appropriate date and time representation */

                         sprintf(tbuf, "%s %s %2d %02d:%02d:%02d %d",

134 days_a[timeptr->tm_wday],

135 months_a[timeptr->tm_mon],

136 timeptr->tm_mday,

137 timeptr->tm_hour,

138 timeptr->tm_min,

139 timeptr->tm_sec,

140 timeptr->tm_year + 1900);

141 break;

142

143 case 'd': /* day of the month, 01 - 31 */

                         sprintf(tbuf, "%02d", timeptr->tm_mday);

145 break;

146

147 case 'H': /* hour, 24-hour clock, 00 - 23 */

                         sprintf(tbuf, "%02d", timeptr->tm_hour);

149 break;

150

151 case 'I': /* hour, 12-hour clock, 01 - 12 */

152 i = timeptr->tm_hour;

                         if (i == 0)

154 i = 12;

                         else if (i > 12)

156 i -= 12;

                         sprintf(tbuf, "%02d", i);

158 break;

159

160 case 'j': /* day of the year, 001 - 366 */

                         sprintf(tbuf, "%03d", timeptr->tm_yday + 1);

162 break;

163

164 case 'm': /* month, 01 - 12 */

                         sprintf(tbuf, "%02d", timeptr->tm_mon + 1);

166 break;

167

168 case 'M': /* minute, 00 - 59 */

                         sprintf(tbuf, "%02d", timeptr->tm_min);

170 break;

171

172 case 'p': /* am or pm based on 12-hour clock */

                         if (timeptr->tm_hour < 12)

                                 strcpy(tbuf, ampm[0]);

175 else

                                 strcpy(tbuf, ampm[1]);

177 break;

178

179 case 'S': /* second, 00 - 61 */

                         sprintf(tbuf, "%02d", timeptr->tm_sec);

181 break;

182

183 case 'U': /* week of year, Sunday is first day of week */

                         sprintf(tbuf, "%d", weeknumber(timeptr, 0));

185 break;

186

187 case 'w': /* weekday, Sunday == 0, 0 - 6 */

                         sprintf(tbuf, "%d", timeptr->tm_wday);

189 break;

190

191 case 'W': /* week of year, Monday is first day of week */

                         sprintf(tbuf, "%d", weeknumber(timeptr, 1));

193 break;

194

195 case 'x': /* appropriate date representation */

                         sprintf(tbuf, "%s %s %2d %d",

197 days_a[timeptr->tm_wday],

198 months_a[timeptr->tm_mon],

199 timeptr->tm_mday,

200 timeptr->tm_year + 1900);

201 break;

202

203 case 'X': /* appropriate time representation */

                         sprintf(tbuf, "%02d:%02d:%02d",

205 timeptr->tm_hour,

206 timeptr->tm_min,

207 timeptr->tm_sec);

208 break;

209

210 case 'y': /* year without a century, 00 - 99 */

                         i = timeptr->tm_year % 100;

                         sprintf(tbuf, "%d", i);

213 break;

214

215 case 'Y': /* year with century */

                         sprintf(tbuf, "%d", 1900 + timeptr->tm_year);

217 break;

218

219 case 'Z': /* time zone name or abbrevation */

220 #ifdef TCL_HAS_TM_ZONE

                         strcpy(tbuf, timeptr->tm_zone);

222 #else

223 i = 0;

                         if (daylight && timeptr->tm_isdst)

225 i = 1;

                         strcpy(tbuf, tzname[i]);

227 #endif

228 break;

229

230 case 'n': /* same as \n */

                         tbuf[0] = '\n';

                         tbuf[1] = '\0';

233 break;

234

235 case 't': /* same as \t */

                         tbuf[0] = '\t';

                         tbuf[1] = '\0';

238 break;

239

240 case 'D': /* date as %m/%d/%y */

                         strftime(tbuf, sizeof tbuf, "%m/%d/%y", timeptr);

242 break;

243

244 case 'e': /* day of month, blank padded */

                         sprintf(tbuf, "%2d", timeptr->tm_mday);

246 break;

247

248 case 'r': /* time as %I:%M:%S %p */

                         strftime(tbuf, sizeof tbuf, "%I:%M:%S %p", timeptr);

250 break;

251

252 case 'R': /* time as %H:%M */

                         strftime(tbuf, sizeof tbuf, "%H:%M", timeptr);

254 break;

255

256 case 'T': /* time as %H:%M:%S */

                         strftime(tbuf, sizeof tbuf, "%H:%M:%S", timeptr);

258 break;

259

260 default:

                         tbuf[0] = '%';

262 tbuf[1] = *format;

                         tbuf[2] = '\0';

264 break;

265 }

266 i = strlen(tbuf);

267 if (i)

                         if (s + i < endp - 1) {

269 strcpy(s, tbuf);

270 s += i;

271 } else

272 return 0;

273 }

274 out:

         if (s < endp && *format == '\0') {

276 *s = '\0';

277 return (s - start);

278 } else

279 return 0;

280 }

281

282 /* weeknumber --- figure how many weeks into the year */

283

284 /* With thanks and tip of the hatlo to ado@elsie.nci.nih.gov */

285

286 static int

287 weeknumber(timeptr, firstweekday)

288 struct tm *timeptr;

289 int firstweekday;

290 {

         if (firstweekday == 0)

                 return (timeptr->tm_yday + 7 - timeptr->tm_wday) / 7;

293 else

                 return (timeptr->tm_yday + 7 -

                         (timeptr->tm_wday ? (timeptr->tm_wday - 1) : 6)) / 7;

296 }