src/libopts/parse-duration.c

   1 /* Parse a time duration and return a seconds count
   2    Copyright (C) 2008-2012 Free Software Foundation, Inc.
   3    Written by Bruce Korb <bkorb@gnu.org>, 2008.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 /* Specification.  */
  21 #include "parse-duration.h"
  22
  23 #include <ctype.h>
  24 #include <errno.h>
  25 #include <limits.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29
  30 #ifndef NUL
  31 #define NUL '\0'
  32 #endif
  33
  34 #define cch_t char const
  35
  36 typedef enum {
  37   NOTHING_IS_DONE,
  38   YEAR_IS_DONE,
  39   MONTH_IS_DONE,
  40   WEEK_IS_DONE,
  41   DAY_IS_DONE,
  42   HOUR_IS_DONE,
  43   MINUTE_IS_DONE,
  44   SECOND_IS_DONE
  45 } whats_done_t;
  46
  47 #define SEC_PER_MIN     60
  48 #define SEC_PER_HR      (SEC_PER_MIN * 60)
  49 #define SEC_PER_DAY     (SEC_PER_HR  * 24)
  50 #define SEC_PER_WEEK    (SEC_PER_DAY * 7)
  51 #define SEC_PER_MONTH   (SEC_PER_DAY * 30)
  52 #define SEC_PER_YEAR    (SEC_PER_DAY * 365)
  53
  54 #define TIME_MAX        0x7FFFFFFF
  55
  56 /* Wrapper around strtoul that does not require a cast.  */
  57 inline static unsigned long
  58 str_const_to_ul (cch_t * str, cch_t ** ppz, int base)
  59 {
  60   return strtoul (str, (char **)ppz, base);
  61 }
  62
  63 /* Wrapper around strtol that does not require a cast.  */
  64 inline static long
  65 str_const_to_l (cch_t * str, cch_t ** ppz, int base)
  66 {
  67   return strtol (str, (char **)ppz, base);
  68 }
  69
  70 /* Returns BASE + VAL * SCALE, interpreting BASE = BAD_TIME
  71    with errno set as an error situation, and returning BAD_TIME
  72    with errno set in an error situation.  */
  73 inline static time_t
  74 scale_n_add (time_t base, time_t val, int scale)
  75 {
  76   if (base == BAD_TIME)
  77     {
  78       if (errno == 0)
  79         errno = EINVAL;
  80       return BAD_TIME;
  81     }
  82
  83   if (val > TIME_MAX / scale)
  84     {
  85       errno = ERANGE;
  86       return BAD_TIME;
  87     }
  88
  89   val *= scale;
  90   if (base > TIME_MAX - val)
  91     {
  92       errno = ERANGE;
  93       return BAD_TIME;
  94     }
  95
  96   return base + val;
  97 }
  98
  99 /* After a number HH has been parsed, parse subsequent :MM or :MM:SS.  */
 100 static time_t
 101 parse_hr_min_sec (time_t start, cch_t * pz)
 102 {
 103   int lpct = 0;
 104
 105   errno = 0;
 106
 107   /* For as long as our scanner pointer points to a colon *AND*
 108      we've not looped before, then keep looping.  (two iterations max) */
 109   while ((*pz == ':') && (lpct++ <= 1))
 110     {
 111       unsigned long v = str_const_to_ul (pz+1, &pz, 10);
 112
 113       if (errno != 0)
 114         return BAD_TIME;
 115
 116       start = scale_n_add (v, start, 60);
 117
 118       if (errno != 0)
 119         return BAD_TIME;
 120     }
 121
 122   /* allow for trailing spaces */
 123   while (isspace ((unsigned char)*pz))
 124     pz++;
 125   if (*pz != NUL)
 126     {
 127       errno = EINVAL;
 128       return BAD_TIME;
 129     }
 130
 131   return start;
 132 }
 133
 134 /* Parses a value and returns BASE + value * SCALE, interpreting
 135    BASE = BAD_TIME with errno set as an error situation, and returning
 136    BAD_TIME with errno set in an error situation.  */
 137 static time_t
 138 parse_scaled_value (time_t base, cch_t ** ppz, cch_t * endp, int scale)
 139 {
 140   cch_t * pz = *ppz;
 141   time_t val;
 142
 143   if (base == BAD_TIME)
 144     return base;
 145
 146   errno = 0;
 147   val = str_const_to_ul (pz, &pz, 10);
 148   if (errno != 0)
 149     return BAD_TIME;
 150   while (isspace ((unsigned char)*pz))
 151     pz++;
 152   if (pz != endp)
 153     {
 154       errno = EINVAL;
 155       return BAD_TIME;
 156     }
 157
 158   *ppz = pz;
 159   return scale_n_add (base, val, scale);
 160 }
 161
 162 /* Parses the syntax YEAR-MONTH-DAY.
 163    PS points into the string, after "YEAR", before "-MONTH-DAY".  */
 164 static time_t
 165 parse_year_month_day (cch_t * pz, cch_t * ps)
 166 {
 167   time_t res = 0;
 168
 169   res = parse_scaled_value (0, &pz, ps, SEC_PER_YEAR);
 170
 171   pz++; /* over the first '-' */
 172   ps = strchr (pz, '-');
 173   if (ps == NULL)
 174     {
 175       errno = EINVAL;
 176       return BAD_TIME;
 177     }
 178   res = parse_scaled_value (res, &pz, ps, SEC_PER_MONTH);
 179
 180   pz++; /* over the second '-' */
 181   ps = pz + strlen (pz);
 182   return parse_scaled_value (res, &pz, ps, SEC_PER_DAY);
 183 }
 184
 185 /* Parses the syntax YYYYMMDD.  */
 186 static time_t
 187 parse_yearmonthday (cch_t * in_pz)
 188 {
 189   time_t res = 0;
 190   char   buf[8];
 191   cch_t * pz;
 192
 193   if (strlen (in_pz) != 8)
 194     {
 195       errno = EINVAL;
 196       return BAD_TIME;
 197     }
 198
 199   memcpy (buf, in_pz, 4);
 200   buf[4] = NUL;
 201   pz = buf;
 202   res = parse_scaled_value (0, &pz, buf + 4, SEC_PER_YEAR);
 203
 204   memcpy (buf, in_pz + 4, 2);
 205   buf[2] = NUL;
 206   pz =   buf;
 207   res = parse_scaled_value (res, &pz, buf + 2, SEC_PER_MONTH);
 208
 209   memcpy (buf, in_pz + 6, 2);
 210   buf[2] = NUL;
 211   pz =   buf;
 212   return parse_scaled_value (res, &pz, buf + 2, SEC_PER_DAY);
 213 }
 214
 215 /* Parses the syntax yy Y mm M ww W dd D.  */
 216 static time_t
 217 parse_YMWD (cch_t * pz)
 218 {
 219   time_t res = 0;
 220   cch_t * ps = strchr (pz, 'Y');
 221   if (ps != NULL)
 222     {
 223       res = parse_scaled_value (0, &pz, ps, SEC_PER_YEAR);
 224       pz++;
 225     }
 226
 227   ps = strchr (pz, 'M');
 228   if (ps != NULL)
 229     {
 230       res = parse_scaled_value (res, &pz, ps, SEC_PER_MONTH);
 231       pz++;
 232     }
 233
 234   ps = strchr (pz, 'W');
 235   if (ps != NULL)
 236     {
 237       res = parse_scaled_value (res, &pz, ps, SEC_PER_WEEK);
 238       pz++;
 239     }
 240
 241   ps = strchr (pz, 'D');
 242   if (ps != NULL)
 243     {
 244       res = parse_scaled_value (res, &pz, ps, SEC_PER_DAY);
 245       pz++;
 246     }
 247
 248   while (isspace ((unsigned char)*pz))
 249     pz++;
 250   if (*pz != NUL)
 251     {
 252       errno = EINVAL;
 253       return BAD_TIME;
 254     }
 255
 256   return res;
 257 }
 258
 259 /* Parses the syntax HH:MM:SS.
 260    PS points into the string, after "HH", before ":MM:SS".  */
 261 static time_t
 262 parse_hour_minute_second (cch_t * pz, cch_t * ps)
 263 {
 264   time_t res = 0;
 265
 266   res = parse_scaled_value (0, &pz, ps, SEC_PER_HR);
 267
 268   pz++;
 269   ps = strchr (pz, ':');
 270   if (ps == NULL)
 271     {
 272       errno = EINVAL;
 273       return BAD_TIME;
 274     }
 275
 276   res = parse_scaled_value (res, &pz, ps, SEC_PER_MIN);
 277
 278   pz++;
 279   ps = pz + strlen (pz);
 280   return parse_scaled_value (res, &pz, ps, 1);
 281 }
 282
 283 /* Parses the syntax HHMMSS.  */
 284 static time_t
 285 parse_hourminutesecond (cch_t * in_pz)
 286 {
 287   time_t res = 0;
 288   char   buf[4];
 289   cch_t * pz;
 290
 291   if (strlen (in_pz) != 6)
 292     {
 293       errno = EINVAL;
 294       return BAD_TIME;
 295     }
 296
 297   memcpy (buf, in_pz, 2);
 298   buf[2] = NUL;
 299   pz = buf;
 300   res = parse_scaled_value (0, &pz, buf + 2, SEC_PER_HR);
 301
 302   memcpy (buf, in_pz + 2, 2);
 303   buf[2] = NUL;
 304   pz =   buf;
 305   res = parse_scaled_value (res, &pz, buf + 2, SEC_PER_MIN);
 306
 307   memcpy (buf, in_pz + 4, 2);
 308   buf[2] = NUL;
 309   pz =   buf;
 310   return parse_scaled_value (res, &pz, buf + 2, 1);
 311 }
 312
 313 /* Parses the syntax hh H mm M ss S.  */
 314 static time_t
 315 parse_HMS (cch_t * pz)
 316 {
 317   time_t res = 0;
 318   cch_t * ps = strchr (pz, 'H');
 319   if (ps != NULL)
 320     {
 321       res = parse_scaled_value (0, &pz, ps, SEC_PER_HR);
 322       pz++;
 323     }
 324
 325   ps = strchr (pz, 'M');
 326   if (ps != NULL)
 327     {
 328       res = parse_scaled_value (res, &pz, ps, SEC_PER_MIN);
 329       pz++;
 330     }
 331
 332   ps = strchr (pz, 'S');
 333   if (ps != NULL)
 334     {
 335       res = parse_scaled_value (res, &pz, ps, 1);
 336       pz++;
 337     }
 338
 339   while (isspace ((unsigned char)*pz))
 340     pz++;
 341   if (*pz != NUL)
 342     {
 343       errno = EINVAL;
 344       return BAD_TIME;
 345     }
 346
 347   return res;
 348 }
 349
 350 /* Parses a time (hours, minutes, seconds) specification in either syntax.  */
 351 static time_t
 352 parse_time (cch_t * pz)
 353 {
 354   cch_t * ps;
 355   time_t  res = 0;
 356
 357   /*
 358    *  Scan for a hyphen
 359    */
 360   ps = strchr (pz, ':');
 361   if (ps != NULL)
 362     {
 363       res = parse_hour_minute_second (pz, ps);
 364     }
 365
 366   /*
 367    *  Try for a 'H', 'M' or 'S' suffix
 368    */
 369   else if (ps = strpbrk (pz, "HMS"),
 370            ps == NULL)
 371     {
 372       /* Its a YYYYMMDD format: */
 373       res = parse_hourminutesecond (pz);
 374     }
 375
 376   else
 377     res = parse_HMS (pz);
 378
 379   return res;
 380 }
 381
 382 /* Returns a substring of the given string, with spaces at the beginning and at
 383    the end destructively removed, per SNOBOL.  */
 384 static char *
 385 trim (char * pz)
 386 {
 387   /* trim leading white space */
 388   while (isspace ((unsigned char)*pz))
 389     pz++;
 390
 391   /* trim trailing white space */
 392   {
 393     char * pe = pz + strlen (pz);
 394     while ((pe > pz) && isspace ((unsigned char)pe[-1]))
 395       pe--;
 396     *pe = NUL;
 397   }
 398
 399   return pz;
 400 }
 401
 402 /*
 403  *  Parse the year/months/days of a time period
 404  */
 405 static time_t
 406 parse_period (cch_t * in_pz)
 407 {
 408   char * pT;
 409   char * ps;
 410   char * pz   = strdup (in_pz);
 411   void * fptr = pz;
 412   time_t res  = 0;
 413
 414   if (pz == NULL)
 415     {
 416       errno = ENOMEM;
 417       return BAD_TIME;
 418     }
 419
 420   pT = strchr (pz, 'T');
 421   if (pT != NULL)
 422     {
 423       *(pT++) = NUL;
 424       pz = trim (pz);
 425       pT = trim (pT);
 426     }
 427
 428   /*
 429    *  Scan for a hyphen
 430    */
 431   ps = strchr (pz, '-');
 432   if (ps != NULL)
 433     {
 434       res = parse_year_month_day (pz, ps);
 435     }
 436
 437   /*
 438    *  Try for a 'Y', 'M' or 'D' suffix
 439    */
 440   else if (ps = strpbrk (pz, "YMWD"),
 441            ps == NULL)
 442     {
 443       /* Its a YYYYMMDD format: */
 444       res = parse_yearmonthday (pz);
 445     }
 446
 447   else
 448     res = parse_YMWD (pz);
 449
 450   if ((errno == 0) && (pT != NULL))
 451     {
 452       time_t val = parse_time (pT);
 453       res = scale_n_add (res, val, 1);
 454     }
 455
 456   free (fptr);
 457   return res;
 458 }
 459
 460 static time_t
 461 parse_non_iso8601 (cch_t * pz)
 462 {
 463   whats_done_t whatd_we_do = NOTHING_IS_DONE;
 464
 465   time_t res = 0;
 466
 467   do  {
 468     time_t val;
 469
 470     errno = 0;
 471     val = str_const_to_l (pz, &pz, 10);
 472     if (errno != 0)
 473       goto bad_time;
 474
 475     /*  IF we find a colon, then we're going to have a seconds value.
 476         We will not loop here any more.  We cannot already have parsed
 477         a minute value and if we've parsed an hour value, then the result
 478         value has to be less than an hour. */
 479     if (*pz == ':')
 480       {
 481         if (whatd_we_do >= MINUTE_IS_DONE)
 482           break;
 483
 484         val = parse_hr_min_sec (val, pz);
 485
 486         if ((whatd_we_do == HOUR_IS_DONE) && (val >= SEC_PER_HR))
 487           break;
 488
 489         return scale_n_add (res, val, 1);
 490       }
 491
 492     {
 493       unsigned int mult;
 494
 495       /*  Skip over white space following the number we just parsed. */
 496       while (isspace ((unsigned char)*pz))
 497         pz++;
 498
 499       switch (*pz)
 500         {
 501         default:  goto bad_time;
 502         case NUL:
 503           return scale_n_add (res, val, 1);
 504
 505         case 'y': case 'Y':
 506           if (whatd_we_do >= YEAR_IS_DONE)
 507             goto bad_time;
 508           mult = SEC_PER_YEAR;
 509           whatd_we_do = YEAR_IS_DONE;
 510           break;
 511
 512         case 'M':
 513           if (whatd_we_do >= MONTH_IS_DONE)
 514             goto bad_time;
 515           mult = SEC_PER_MONTH;
 516           whatd_we_do = MONTH_IS_DONE;
 517           break;
 518
 519         case 'W':
 520           if (whatd_we_do >= WEEK_IS_DONE)
 521             goto bad_time;
 522           mult = SEC_PER_WEEK;
 523           whatd_we_do = WEEK_IS_DONE;
 524           break;
 525
 526         case 'd': case 'D':
 527           if (whatd_we_do >= DAY_IS_DONE)
 528             goto bad_time;
 529           mult = SEC_PER_DAY;
 530           whatd_we_do = DAY_IS_DONE;
 531           break;
 532
 533         case 'h':
 534           if (whatd_we_do >= HOUR_IS_DONE)
 535             goto bad_time;
 536           mult = SEC_PER_HR;
 537           whatd_we_do = HOUR_IS_DONE;
 538           break;
 539
 540         case 'm':
 541           if (whatd_we_do >= MINUTE_IS_DONE)
 542             goto bad_time;
 543           mult = SEC_PER_MIN;
 544           whatd_we_do = MINUTE_IS_DONE;
 545           break;
 546
 547         case 's':
 548           mult = 1;
 549           whatd_we_do = SECOND_IS_DONE;
 550           break;
 551         }
 552
 553       res = scale_n_add (res, val, mult);
 554
 555       pz++;
 556       while (isspace ((unsigned char)*pz))
 557         pz++;
 558       if (*pz == NUL)
 559         return res;
 560
 561       if (! isdigit ((unsigned char)*pz))
 562         break;
 563     }
 564
 565   } while (whatd_we_do < SECOND_IS_DONE);
 566
 567  bad_time:
 568   errno = EINVAL;
 569   return BAD_TIME;
 570 }
 571
 572 time_t
 573 parse_duration (char const * pz)
 574 {
 575   while (isspace ((unsigned char)*pz))
 576     pz++;
 577
 578   switch (*pz)
 579     {
 580     case 'P':
 581       return parse_period (pz + 1);
 582
 583     case 'T':
 584       return parse_time (pz + 1);
 585
 586     default:
 587       if (isdigit ((unsigned char)*pz))
 588         return parse_non_iso8601 (pz);
 589
 590       errno = EINVAL;
 591       return BAD_TIME;
 592     }
 593 }
 594
 595 /*
 596  * Local Variables:
 597  * mode: C
 598  * c-file-style: "gnu"
 599  * indent-tabs-mode: nil
 600  * End:
 601  * end of parse-duration.c */