1 /* $NetBSD: tm.c,v 1.8 2025/01/26 16:25:39 christos Exp $ */ 2 3 /* 4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC") 5 * 6 * SPDX-License-Identifier: MPL-2.0 AND BSD-2-Clause 7 * 8 * This Source Code Form is subject to the terms of the Mozilla Public 9 * License, v. 2.0. If a copy of the MPL was not distributed with this 10 * file, you can obtain one at https://mozilla.org/MPL/2.0/. 11 * 12 * See the COPYRIGHT file distributed with this work for additional 13 * information regarding copyright ownership. 14 */ 15 16 /*- 17 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc. 18 * All rights reserved. 19 * 20 * This code was contributed to The NetBSD Foundation by Klaus Klein. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 32 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 33 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 34 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 35 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 36 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 37 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 38 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 39 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 41 * POSSIBILITY OF SUCH DAMAGE. 42 */ 43 44 #include <ctype.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <time.h> 49 50 #include <isc/tm.h> 51 #include <isc/util.h> 52 53 /* 54 * Portable conversion routines for struct tm, replacing 55 * timegm() and strptime(), which are not available on all 56 * platforms and don't always behave the same way when they 57 * are. 58 */ 59 60 /* 61 * We do not implement alternate representations. However, we always 62 * check whether a given modifier is allowed for a certain conversion. 63 */ 64 #define ALT_E 0x01 65 #define ALT_O 0x02 66 #define LEGAL_ALT(x) \ 67 { \ 68 if ((alt_format & ~(x)) != 0) \ 69 return ((0)); \ 70 } 71 72 #ifndef TM_YEAR_BASE 73 #define TM_YEAR_BASE 1900 74 #endif /* ifndef TM_YEAR_BASE */ 75 76 static const char *day[7] = { "Sunday", "Monday", "Tuesday", "Wednesday", 77 "Thursday", "Friday", "Saturday" }; 78 static const char *abday[7] = { 79 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" 80 }; 81 static const char *mon[12] = { 82 "January", "February", "March", "April", "May", "June", 83 "July", "August", "September", "October", "November", "December" 84 }; 85 static const char *abmon[12] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", 86 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; 87 static const char *am_pm[2] = { "AM", "PM" }; 88 89 static int 90 conv_num(const char **buf, int *dest, int llim, int ulim) { 91 int result = 0; 92 93 /* The limit also determines the number of valid digits. */ 94 int rulim = ulim; 95 96 if (!isdigit((unsigned char)**buf)) { 97 return 0; 98 } 99 100 do { 101 result = 10 * result + *(*buf)++ - '0'; 102 rulim /= 10; 103 } while ((result * 10 <= ulim) && rulim && 104 isdigit((unsigned char)**buf)); 105 106 if (result < llim || result > ulim) { 107 return 0; 108 } 109 110 *dest = result; 111 return 1; 112 } 113 114 time_t 115 isc_tm_timegm(struct tm *tm) { 116 time_t ret; 117 int i, yday = 0, leapday; 118 int mdays[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30 }; 119 120 leapday = ((((tm->tm_year + 1900) % 4) == 0 && 121 ((tm->tm_year + 1900) % 100) != 0) || 122 ((tm->tm_year + 1900) % 400) == 0) 123 ? 1 124 : 0; 125 mdays[1] += leapday; 126 127 yday = tm->tm_mday - 1; 128 for (i = 1; i <= tm->tm_mon; i++) { 129 yday += mdays[i - 1]; 130 } 131 ret = tm->tm_sec + (60 * tm->tm_min) + (3600 * tm->tm_hour) + 132 (86400 * 133 (yday + ((tm->tm_year - 70) * 365) + ((tm->tm_year - 69) / 4) - 134 ((tm->tm_year - 1) / 100) + ((tm->tm_year + 299) / 400))); 135 return ret; 136 } 137 138 char * 139 isc_tm_strptime(const char *buf, const char *fmt, struct tm *tm) { 140 char c; 141 const char *bp; 142 size_t len = 0; 143 int alt_format, i, split_year = 0; 144 145 REQUIRE(buf != NULL); 146 REQUIRE(fmt != NULL); 147 REQUIRE(tm != NULL); 148 149 memset(tm, 0, sizeof(struct tm)); 150 151 bp = buf; 152 153 while ((c = *fmt) != '\0') { 154 /* Clear `alternate' modifier prior to new conversion. */ 155 alt_format = 0; 156 157 /* Eat up white-space. */ 158 if (isspace((unsigned char)c)) { 159 while (isspace((unsigned char)*bp)) { 160 bp++; 161 } 162 163 fmt++; 164 continue; 165 } 166 167 if ((c = *fmt++) != '%') { 168 goto literal; 169 } 170 171 again: 172 switch (c = *fmt++) { 173 case '%': /* "%%" is converted to "%". */ 174 literal: 175 if (c != *bp++) { 176 return 0; 177 } 178 break; 179 180 /* 181 * "Alternative" modifiers. Just set the appropriate flag 182 * and start over again. 183 */ 184 case 'E': /* "%E?" alternative conversion modifier. */ 185 LEGAL_ALT(0); 186 alt_format |= ALT_E; 187 goto again; 188 189 case 'O': /* "%O?" alternative conversion modifier. */ 190 LEGAL_ALT(0); 191 alt_format |= ALT_O; 192 goto again; 193 194 /* 195 * "Complex" conversion rules, implemented through recursion. 196 */ 197 case 'c': /* Date and time, using the locale's format. */ 198 LEGAL_ALT(ALT_E); 199 if (!(bp = isc_tm_strptime(bp, "%x %X", tm))) { 200 return 0; 201 } 202 break; 203 204 case 'D': /* The date as "%m/%d/%y". */ 205 LEGAL_ALT(0); 206 if (!(bp = isc_tm_strptime(bp, "%m/%d/%y", tm))) { 207 return 0; 208 } 209 break; 210 211 case 'R': /* The time as "%H:%M". */ 212 LEGAL_ALT(0); 213 if (!(bp = isc_tm_strptime(bp, "%H:%M", tm))) { 214 return 0; 215 } 216 break; 217 218 case 'r': /* The time in 12-hour clock representation. */ 219 LEGAL_ALT(0); 220 if (!(bp = isc_tm_strptime(bp, "%I:%M:%S %p", tm))) { 221 return 0; 222 } 223 break; 224 225 case 'T': /* The time as "%H:%M:%S". */ 226 LEGAL_ALT(0); 227 if (!(bp = isc_tm_strptime(bp, "%H:%M:%S", tm))) { 228 return 0; 229 } 230 break; 231 232 case 'X': /* The time, using the locale's format. */ 233 LEGAL_ALT(ALT_E); 234 if (!(bp = isc_tm_strptime(bp, "%H:%M:%S", tm))) { 235 return 0; 236 } 237 break; 238 239 case 'x': /* The date, using the locale's format. */ 240 LEGAL_ALT(ALT_E); 241 if (!(bp = isc_tm_strptime(bp, "%m/%d/%y", tm))) { 242 return 0; 243 } 244 break; 245 246 /* 247 * "Elementary" conversion rules. 248 */ 249 case 'A': /* The day of week, using the locale's form. */ 250 case 'a': 251 LEGAL_ALT(0); 252 for (i = 0; i < 7; i++) { 253 /* Full name. */ 254 len = strlen(day[i]); 255 if (strncasecmp(day[i], bp, len) == 0) { 256 break; 257 } 258 259 /* Abbreviated name. */ 260 len = strlen(abday[i]); 261 if (strncasecmp(abday[i], bp, len) == 0) { 262 break; 263 } 264 } 265 266 /* Nothing matched. */ 267 if (i == 7) { 268 return 0; 269 } 270 271 tm->tm_wday = i; 272 bp += len; 273 break; 274 275 case 'B': /* The month, using the locale's form. */ 276 case 'b': 277 case 'h': 278 LEGAL_ALT(0); 279 for (i = 0; i < 12; i++) { 280 /* Full name. */ 281 len = strlen(mon[i]); 282 if (strncasecmp(mon[i], bp, len) == 0) { 283 break; 284 } 285 286 /* Abbreviated name. */ 287 len = strlen(abmon[i]); 288 if (strncasecmp(abmon[i], bp, len) == 0) { 289 break; 290 } 291 } 292 293 /* Nothing matched. */ 294 if (i == 12) { 295 return 0; 296 } 297 298 tm->tm_mon = i; 299 bp += len; 300 break; 301 302 case 'C': /* The century number. */ 303 LEGAL_ALT(ALT_E); 304 if (!(conv_num(&bp, &i, 0, 99))) { 305 return 0; 306 } 307 308 if (split_year) { 309 tm->tm_year = (tm->tm_year % 100) + (i * 100); 310 } else { 311 tm->tm_year = i * 100; 312 split_year = 1; 313 } 314 break; 315 316 case 'd': /* The day of month. */ 317 case 'e': 318 LEGAL_ALT(ALT_O); 319 if (!(conv_num(&bp, &tm->tm_mday, 1, 31))) { 320 return 0; 321 } 322 break; 323 324 case 'k': /* The hour (24-hour clock representation). */ 325 LEGAL_ALT(0); 326 FALLTHROUGH; 327 case 'H': 328 LEGAL_ALT(ALT_O); 329 if (!(conv_num(&bp, &tm->tm_hour, 0, 23))) { 330 return 0; 331 } 332 break; 333 334 case 'l': /* The hour (12-hour clock representation). */ 335 LEGAL_ALT(0); 336 FALLTHROUGH; 337 case 'I': 338 LEGAL_ALT(ALT_O); 339 if (!(conv_num(&bp, &tm->tm_hour, 1, 12))) { 340 return 0; 341 } 342 if (tm->tm_hour == 12) { 343 tm->tm_hour = 0; 344 } 345 break; 346 347 case 'j': /* The day of year. */ 348 LEGAL_ALT(0); 349 if (!(conv_num(&bp, &i, 1, 366))) { 350 return 0; 351 } 352 tm->tm_yday = i - 1; 353 break; 354 355 case 'M': /* The minute. */ 356 LEGAL_ALT(ALT_O); 357 if (!(conv_num(&bp, &tm->tm_min, 0, 59))) { 358 return 0; 359 } 360 break; 361 362 case 'm': /* The month. */ 363 LEGAL_ALT(ALT_O); 364 if (!(conv_num(&bp, &i, 1, 12))) { 365 return 0; 366 } 367 tm->tm_mon = i - 1; 368 break; 369 370 case 'p': /* The locale's equivalent of AM/PM. */ 371 LEGAL_ALT(0); 372 /* AM? */ 373 if (strcasecmp(am_pm[0], bp) == 0) { 374 if (tm->tm_hour > 11) { 375 return 0; 376 } 377 378 bp += strlen(am_pm[0]); 379 break; 380 } 381 /* PM? */ 382 else if (strcasecmp(am_pm[1], bp) == 0) 383 { 384 if (tm->tm_hour > 11) { 385 return 0; 386 } 387 388 tm->tm_hour += 12; 389 bp += strlen(am_pm[1]); 390 break; 391 } 392 393 /* Nothing matched. */ 394 return 0; 395 396 case 'S': /* The seconds. */ 397 LEGAL_ALT(ALT_O); 398 if (!(conv_num(&bp, &tm->tm_sec, 0, 61))) { 399 return 0; 400 } 401 break; 402 403 case 'U': /* The week of year, beginning on sunday. */ 404 case 'W': /* The week of year, beginning on monday. */ 405 LEGAL_ALT(ALT_O); 406 /* 407 * XXX This is bogus, as we can not assume any valid 408 * information present in the tm structure at this 409 * point to calculate a real value, so just check the 410 * range for now. 411 */ 412 if (!(conv_num(&bp, &i, 0, 53))) { 413 return 0; 414 } 415 break; 416 417 case 'w': /* The day of week, beginning on sunday. */ 418 LEGAL_ALT(ALT_O); 419 if (!(conv_num(&bp, &tm->tm_wday, 0, 6))) { 420 return 0; 421 } 422 break; 423 424 case 'Y': /* The year. */ 425 LEGAL_ALT(ALT_E); 426 if (!(conv_num(&bp, &i, 0, 9999))) { 427 return 0; 428 } 429 430 tm->tm_year = i - TM_YEAR_BASE; 431 break; 432 433 case 'y': /* The year within 100 years of the epoch. */ 434 LEGAL_ALT(ALT_E | ALT_O); 435 if (!(conv_num(&bp, &i, 0, 99))) { 436 return 0; 437 } 438 439 if (split_year) { 440 tm->tm_year = ((tm->tm_year / 100) * 100) + i; 441 break; 442 } 443 split_year = 1; 444 if (i <= 68) { 445 tm->tm_year = i + 2000 - TM_YEAR_BASE; 446 } else { 447 tm->tm_year = i + 1900 - TM_YEAR_BASE; 448 } 449 break; 450 451 /* 452 * Miscellaneous conversions. 453 */ 454 case 'n': /* Any kind of white-space. */ 455 case 't': 456 LEGAL_ALT(0); 457 while (isspace((unsigned char)*bp)) { 458 bp++; 459 } 460 break; 461 462 default: /* Unknown/unsupported conversion. */ 463 return 0; 464 } 465 } 466 467 /* LINTED functional specification */ 468 return UNCONST(bp); 469 } 470
Indexes created Sat Feb 28 05:31:39 UTC 2026