usr.bin/units/units.c

   1 /*
   2  * units.c   Copyright (c) 1993 by Adrian Mariano (adrian@cam.cornell.edu)
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. The name of the author may not be used to endorse or promote products
  10  *    derived from this software without specific prior written permission.
  11  * Disclaimer:  This software is provided by the author "as is".  The author
  12  * shall not be liable for any damages caused in any way by this software.
  13  *
  14  * I would appreciate (though I do not require) receiving a copy of any
  15  * improvements you might make to this program.
  16  *
  17  * $FreeBSD: src/usr.bin/units/units.c,v 1.6.2.2 2001/03/04 09:22:35 kris Exp $
  18  * $DragonFly: src/usr.bin/units/units.c,v 1.4 2006/08/13 19:19:44 swildner Exp $
  19  */
  20
  21 #include <ctype.h>
  22 #include <err.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27
  28 #include "pathnames.h"
  29
  30 #define VERSION "1.0"
  31
  32 #ifndef UNITSFILE
  33 #define UNITSFILE _PATH_UNITSLIB
  34 #endif
  35
  36 #define MAXUNITS 1000
  37 #define MAXPREFIXES 100
  38
  39 #define MAXSUBUNITS 500
  40
  41 #define PRIMITIVECHAR '!'
  42
  43 const char *powerstring = "^";
  44
  45 struct {
  46         char *uname;
  47         char *uval;
  48 }      unittable[MAXUNITS];
  49
  50 struct unittype {
  51         char *numerator[MAXSUBUNITS];
  52         char *denominator[MAXSUBUNITS];
  53         double factor;
  54 };
  55
  56 struct {
  57         char *prefixname;
  58         char *prefixval;
  59 }      prefixtable[MAXPREFIXES];
  60
  61
  62 char NULLUNIT[] = "";
  63
  64 #ifdef MSDOS
  65 #define SEPARATOR      ";"
  66 #else
  67 #define SEPARATOR      ":"
  68 #endif
  69
  70 int unitcount;
  71 int prefixcount;
  72
  73
  74 static int       addsubunit(char *[], char *);
  75 static int       addunit(struct unittype *, char *, int);
  76 static void      cancelunit(struct unittype *);
  77 static int       compare(const void *, const void *);
  78 static int       compareproducts(char **, char **);
  79 static int       compareunits(struct unittype *, struct unittype *);
  80 static int       completereduce(struct unittype *);
  81 static char     *dupstr(const char *);
  82 static void      initializeunit(struct unittype *);
  83 static char     *lookupunit(const char *);
  84 static void      readunits(const char *);
  85 static int       reduceproduct(struct unittype *, int);
  86 static int       reduceunit(struct unittype *);
  87 static void      showanswer(struct unittype *, struct unittype *);
  88 static void      showunit(struct unittype *);
  89 static void      sortunit(struct unittype *);
  90 static void      usage(void);
  91 static void      zeroerror(void);
  92
  93
  94 char *
  95 dupstr(const char *str)
  96 {
  97         char *ret;
  98
  99         ret = malloc(strlen(str) + 1);
 100         if (!ret)
 101                 errx(3, "memory allocation error");
 102         strcpy(ret, str);
 103         return (ret);
 104 }
 105
 106
 107 void
 108 readunits(const char *userfile)
 109 {
 110         FILE *unitfile;
 111         char line[512], *lineptr;
 112         int len, linenum, i;
 113
 114         unitcount = 0;
 115         linenum = 0;
 116
 117         if (userfile) {
 118                 unitfile = fopen(userfile, "rt");
 119                 if (!unitfile)
 120                         errx(1, "unable to open units file '%s'", userfile);
 121         }
 122         else {
 123                 unitfile = fopen(UNITSFILE, "rt");
 124                 if (!unitfile) {
 125                         char *direc, *env;
 126                         char filename[1000];
 127
 128                         env = getenv("PATH");
 129                         if (env) {
 130                                 direc = strtok(env, SEPARATOR);
 131                                 while (direc) {
 132                                         snprintf(filename, sizeof(filename),
 133                                             "%s/%s", direc, UNITSFILE);
 134                                         unitfile = fopen(filename, "rt");
 135                                         if (unitfile)
 136                                                 break;
 137                                         direc = strtok(NULL, SEPARATOR);
 138                                 }
 139                         }
 140                         if (!unitfile)
 141                                 errx(1, "can't find units file '%s'", UNITSFILE);
 142                 }
 143         }
 144         while (!feof(unitfile)) {
 145                 if (!fgets(line, sizeof(line), unitfile))
 146                         break;
 147                 linenum++;
 148                 lineptr = line;
 149                 if (*lineptr == '/')
 150                         continue;
 151                 lineptr += strspn(lineptr, " \n\t");
 152                 len = strcspn(lineptr, " \n\t");
 153                 lineptr[len] = 0;
 154                 if (!strlen(lineptr))
 155                         continue;
 156                 if (lineptr[strlen(lineptr) - 1] == '-') { /* it's a prefix */
 157                         if (prefixcount == MAXPREFIXES) {
 158                                 warnx("memory for prefixes exceeded in line %d", linenum);
 159                                 continue;
 160                         }
 161                         lineptr[strlen(lineptr) - 1] = 0;
 162                         prefixtable[prefixcount].prefixname = dupstr(lineptr);
 163                         for (i = 0; i < prefixcount; i++)
 164                                 if (!strcmp(prefixtable[i].prefixname, lineptr)) {
 165                                         warnx("redefinition of prefix '%s' on line %d ignored",
 166                                             lineptr, linenum);
 167                                         continue;
 168                                 }
 169                         lineptr += len + 1;
 170                         lineptr += strspn(lineptr, " \n\t");
 171                         len = strcspn(lineptr, "\n\t");
 172                         if (len == 0) {
 173                                 warnx("unexpected end of prefix on line %d",
 174                                     linenum);
 175                                 continue;
 176                         }
 177                         lineptr[len] = 0;
 178                         prefixtable[prefixcount++].prefixval = dupstr(lineptr);
 179                 }
 180                 else {          /* it's not a prefix */
 181                         if (unitcount == MAXUNITS) {
 182                                 warnx("memory for units exceeded in line %d", linenum);
 183                                 continue;
 184                         }
 185                         unittable[unitcount].uname = dupstr(lineptr);
 186                         for (i = 0; i < unitcount; i++)
 187                                 if (!strcmp(unittable[i].uname, lineptr)) {
 188                                         warnx("redefinition of unit '%s' on line %d ignored",
 189                                             lineptr, linenum);
 190                                         continue;
 191                                 }
 192                         lineptr += len + 1;
 193                         lineptr += strspn(lineptr, " \n\t");
 194                         if (!strlen(lineptr)) {
 195                                 warnx("unexpected end of unit on line %d",
 196                                     linenum);
 197                                 continue;
 198                         }
 199                         len = strcspn(lineptr, "\n\t");
 200                         lineptr[len] = 0;
 201                         unittable[unitcount++].uval = dupstr(lineptr);
 202                 }
 203         }
 204         fclose(unitfile);
 205 }
 206
 207 void
 208 initializeunit(struct unittype * theunit)
 209 {
 210         theunit->factor = 1.0;
 211         theunit->numerator[0] = theunit->denominator[0] = NULL;
 212 }
 213
 214
 215 int
 216 addsubunit(char *product[], char *toadd)
 217 {
 218         char **ptr;
 219
 220         for (ptr = product; *ptr && *ptr != NULLUNIT; ptr++);
 221         if (ptr >= product + MAXSUBUNITS) {
 222                 warnx("memory overflow in unit reduction");
 223                 return 1;
 224         }
 225         if (!*ptr)
 226                 *(ptr + 1) = 0;
 227         *ptr = dupstr(toadd);
 228         return 0;
 229 }
 230
 231
 232 void
 233 showunit(struct unittype * theunit)
 234 {
 235         char **ptr;
 236         int printedslash;
 237         int counter = 1;
 238
 239         printf("\t%.8g", theunit->factor);
 240         for (ptr = theunit->numerator; *ptr; ptr++) {
 241                 if (ptr > theunit->numerator && **ptr &&
 242                     !strcmp(*ptr, *(ptr - 1)))
 243                         counter++;
 244                 else {
 245                         if (counter > 1)
 246                                 printf("%s%d", powerstring, counter);
 247                         if (**ptr)
 248                                 printf(" %s", *ptr);
 249                         counter = 1;
 250                 }
 251         }
 252         if (counter > 1)
 253                 printf("%s%d", powerstring, counter);
 254         counter = 1;
 255         printedslash = 0;
 256         for (ptr = theunit->denominator; *ptr; ptr++) {
 257                 if (ptr > theunit->denominator && **ptr &&
 258                     !strcmp(*ptr, *(ptr - 1)))
 259                         counter++;
 260                 else {
 261                         if (counter > 1)
 262                                 printf("%s%d", powerstring, counter);
 263                         if (**ptr) {
 264                                 if (!printedslash)
 265                                         printf(" /");
 266                                 printedslash = 1;
 267                                 printf(" %s", *ptr);
 268                         }
 269                         counter = 1;
 270                 }
 271         }
 272         if (counter > 1)
 273                 printf("%s%d", powerstring, counter);
 274         printf("\n");
 275 }
 276
 277
 278 void
 279 zeroerror(void)
 280 {
 281         warnx("unit reduces to zero");
 282 }
 283
 284 /*
 285    Adds the specified string to the unit.
 286    Flip is 0 for adding normally, 1 for adding reciprocal.
 287
 288    Returns 0 for successful addition, nonzero on error.
 289 */
 290
 291 int
 292 addunit(struct unittype * theunit, char *toadd, int flip)
 293 {
 294         char *scratch, *savescr;
 295         char *item;
 296         char *divider, *slash;
 297         int doingtop;
 298
 299         if (!strlen(toadd))
 300                 return 1;
 301
 302         savescr = scratch = dupstr(toadd);
 303         for (slash = scratch + 1; *slash; slash++)
 304                 if (*slash == '-' &&
 305                     (tolower(*(slash - 1)) != 'e' ||
 306                     !strchr(".0123456789", *(slash + 1))))
 307                         *slash = ' ';
 308         slash = strchr(scratch, '/');
 309         if (slash)
 310                 *slash = 0;
 311         doingtop = 1;
 312         do {
 313                 item = strtok(scratch, " *\t\n/");
 314                 while (item) {
 315                         if (strchr("0123456789.", *item)) { /* item is a number */
 316                                 double num;
 317
 318                                 divider = strchr(item, '|');
 319                                 if (divider) {
 320                                         *divider = 0;
 321                                         num = atof(item);
 322                                         if (!num) {
 323                                                 zeroerror();
 324                                                 return 1;
 325                                         }
 326                                         if (doingtop ^ flip)
 327                                                 theunit->factor *= num;
 328                                         else
 329                                                 theunit->factor /= num;
 330                                         num = atof(divider + 1);
 331                                         if (!num) {
 332                                                 zeroerror();
 333                                                 return 1;
 334                                         }
 335                                         if (doingtop ^ flip)
 336                                                 theunit->factor /= num;
 337                                         else
 338                                                 theunit->factor *= num;
 339                                 }
 340                                 else {
 341                                         num = atof(item);
 342                                         if (!num) {
 343                                                 zeroerror();
 344                                                 return 1;
 345                                         }
 346                                         if (doingtop ^ flip)
 347                                                 theunit->factor *= num;
 348                                         else
 349                                                 theunit->factor /= num;
 350
 351                                 }
 352                         }
 353                         else {  /* item is not a number */
 354                                 int repeat = 1;
 355
 356                                 if (strchr("23456789",
 357                                     item[strlen(item) - 1])) {
 358                                         repeat = item[strlen(item) - 1] - '0';
 359                                         item[strlen(item) - 1] = 0;
 360                                 }
 361                                 for (; repeat; repeat--)
 362                                         if (addsubunit(doingtop ^ flip ? theunit->numerator : theunit->denominator, item))
 363                                                 return 1;
 364                         }
 365                         item = strtok(NULL, " *\t/\n");
 366                 }
 367                 doingtop--;
 368                 if (slash) {
 369                         scratch = slash + 1;
 370                 }
 371                 else
 372                         doingtop--;
 373         } while (doingtop >= 0);
 374         free(savescr);
 375         return 0;
 376 }
 377
 378
 379 int
 380 compare(const void *item1, const void *item2)
 381 {
 382         return strcmp(*(const char * const *)item1, *(const char * const *)item2);
 383 }
 384
 385
 386 void
 387 sortunit(struct unittype * theunit)
 388 {
 389         char **ptr;
 390         unsigned int count;
 391
 392         for (count = 0, ptr = theunit->numerator; *ptr; ptr++, count++);
 393         qsort(theunit->numerator, count, sizeof(char *), compare);
 394         for (count = 0, ptr = theunit->denominator; *ptr; ptr++, count++);
 395         qsort(theunit->denominator, count, sizeof(char *), compare);
 396 }
 397
 398
 399 void
 400 cancelunit(struct unittype * theunit)
 401 {
 402         char **den, **num;
 403         int comp;
 404
 405         den = theunit->denominator;
 406         num = theunit->numerator;
 407
 408         while (*num && *den) {
 409                 comp = strcmp(*den, *num);
 410                 if (!comp) {
 411 /*      if (*den!=NULLUNIT) free(*den);
 412       if (*num!=NULLUNIT) free(*num);*/
 413                         *den++ = NULLUNIT;
 414                         *num++ = NULLUNIT;
 415                 }
 416                 else if (comp < 0)
 417                         den++;
 418                 else
 419                         num++;
 420         }
 421 }
 422
 423
 424
 425
 426 /*
 427    Looks up the definition for the specified unit.
 428    Returns a pointer to the definition or a null pointer
 429    if the specified unit does not appear in the units table.
 430 */
 431
 432 static char buffer[100];        /* buffer for lookupunit answers with
 433                                    prefixes */
 434
 435 char *
 436 lookupunit(const char *unit)
 437 {
 438         int i;
 439         char *copy;
 440
 441         for (i = 0; i < unitcount; i++) {
 442                 if (!strcmp(unittable[i].uname, unit))
 443                         return unittable[i].uval;
 444         }
 445
 446         if (unit[strlen(unit) - 1] == '^') {
 447                 copy = dupstr(unit);
 448                 copy[strlen(copy) - 1] = 0;
 449                 for (i = 0; i < unitcount; i++) {
 450                         if (!strcmp(unittable[i].uname, copy)) {
 451                                 strlcpy(buffer, copy, sizeof(buffer));
 452                                 free(copy);
 453                                 return buffer;
 454                         }
 455                 }
 456                 free(copy);
 457         }
 458         if (unit[strlen(unit) - 1] == 's') {
 459                 copy = dupstr(unit);
 460                 copy[strlen(copy) - 1] = 0;
 461                 for (i = 0; i < unitcount; i++) {
 462                         if (!strcmp(unittable[i].uname, copy)) {
 463                                 strlcpy(buffer, copy, sizeof(buffer));
 464                                 free(copy);
 465                                 return buffer;
 466                         }
 467                 }
 468                 if (copy[strlen(copy) - 1] == 'e') {
 469                         copy[strlen(copy) - 1] = 0;
 470                         for (i = 0; i < unitcount; i++) {
 471                                 if (!strcmp(unittable[i].uname, copy)) {
 472                                         strlcpy(buffer, copy, sizeof(buffer));
 473                                         free(copy);
 474                                         return buffer;
 475                                 }
 476                         }
 477                 }
 478                 free(copy);
 479         }
 480         for (i = 0; i < prefixcount; i++) {
 481                 size_t len = strlen(prefixtable[i].prefixname);
 482                 if (!strncmp(prefixtable[i].prefixname, unit, len)) {
 483                         if (!strlen(unit + len) || lookupunit(unit + len)) {
 484                                 snprintf(buffer, sizeof(buffer), "%s %s",
 485                                     prefixtable[i].prefixval, unit + len);
 486                                 return buffer;
 487                         }
 488                 }
 489         }
 490         return 0;
 491 }
 492
 493
 494
 495 /*
 496    reduces a product of symbolic units to primitive units.
 497    The three low bits are used to return flags:
 498
 499      bit 0 (1) set on if reductions were performed without error.
 500      bit 1 (2) set on if no reductions are performed.
 501      bit 2 (4) set on if an unknown unit is discovered.
 502 */
 503
 504
 505 #define ERROR 4
 506
 507 int
 508 reduceproduct(struct unittype * theunit, int flip)
 509 {
 510
 511         char *toadd;
 512         char **product;
 513         int didsomething = 2;
 514
 515         if (flip)
 516                 product = theunit->denominator;
 517         else
 518                 product = theunit->numerator;
 519
 520         for (; *product; product++) {
 521
 522                 for (;;) {
 523                         if (!strlen(*product))
 524                                 break;
 525                         toadd = lookupunit(*product);
 526                         if (!toadd) {
 527                                 printf("unknown unit '%s'\n", *product);
 528                                 return ERROR;
 529                         }
 530                         if (strchr(toadd, PRIMITIVECHAR))
 531                                 break;
 532                         didsomething = 1;
 533                         if (*product != NULLUNIT) {
 534                                 free(*product);
 535                                 *product = NULLUNIT;
 536                         }
 537                         if (addunit(theunit, toadd, flip))
 538                                 return ERROR;
 539                 }
 540         }
 541         return didsomething;
 542 }
 543
 544
 545 /*
 546    Reduces numerator and denominator of the specified unit.
 547    Returns 0 on success, or 1 on unknown unit error.
 548 */
 549
 550 int
 551 reduceunit(struct unittype * theunit)
 552 {
 553         int ret;
 554
 555         ret = 1;
 556         while (ret & 1) {
 557                 ret = reduceproduct(theunit, 0) | reduceproduct(theunit, 1);
 558                 if (ret & 4)
 559                         return 1;
 560         }
 561         return 0;
 562 }
 563
 564
 565 int
 566 compareproducts(char **one, char **two)
 567 {
 568         while (*one || *two) {
 569                 if (!*one && *two != NULLUNIT)
 570                         return 1;
 571                 if (!*two && *one != NULLUNIT)
 572                         return 1;
 573                 if (*one == NULLUNIT)
 574                         one++;
 575                 else if (*two == NULLUNIT)
 576                         two++;
 577                 else if (strcmp(*one, *two))
 578                         return 1;
 579                 else
 580                         one++, two++;
 581         }
 582         return 0;
 583 }
 584
 585
 586 /* Return zero if units are compatible, nonzero otherwise */
 587
 588 int
 589 compareunits(struct unittype * first, struct unittype * second)
 590 {
 591         return
 592         compareproducts(first->numerator, second->numerator) ||
 593         compareproducts(first->denominator, second->denominator);
 594 }
 595
 596
 597 int
 598 completereduce(struct unittype * unit)
 599 {
 600         if (reduceunit(unit))
 601                 return 1;
 602         sortunit(unit);
 603         cancelunit(unit);
 604         return 0;
 605 }
 606
 607
 608 void
 609 showanswer(struct unittype * have, struct unittype * want)
 610 {
 611         if (compareunits(have, want)) {
 612                 printf("conformability error\n");
 613                 showunit(have);
 614                 showunit(want);
 615         }
 616         else
 617                 printf("\t* %.8g\n\t/ %.8g\n", have->factor / want->factor,
 618                     want->factor / have->factor);
 619 }
 620
 621
 622 void
 623 usage(void)
 624 {
 625         fprintf(stderr,
 626                 "usage: units [-f unitsfile] [-q] [-v] [from-unit to-unit]\n");
 627         exit(3);
 628 }
 629
 630
 631 int
 632 main(int argc, char **argv)
 633 {
 634
 635         struct unittype have, want;
 636         char havestr[81], wantstr[81];
 637         int optchar;
 638         char *userfile = 0;
 639         int quiet = 0;
 640
 641         while ((optchar = getopt(argc, argv, "vqf:")) != -1) {
 642                 switch (optchar) {
 643                 case 'f':
 644                         userfile = optarg;
 645                         break;
 646                 case 'q':
 647                         quiet = 1;
 648                         break;
 649                 case 'v':
 650                         fprintf(stderr, "\n  units version %s  Copyright (c) 1993 by Adrian Mariano\n",
 651                             VERSION);
 652                         fprintf(stderr, "                    This program may be freely distributed\n");
 653                         usage();
 654                 default:
 655                         usage();
 656                         break;
 657                 }
 658         }
 659
 660         if (optind != argc - 2 && optind != argc)
 661                 usage();
 662
 663         readunits(userfile);
 664
 665         if (optind == argc - 2) {
 666                 strlcpy(havestr, argv[optind], sizeof(havestr));
 667                 strlcpy(wantstr, argv[optind + 1], sizeof(wantstr));
 668                 initializeunit(&have);
 669                 addunit(&have, havestr, 0);
 670                 completereduce(&have);
 671                 initializeunit(&want);
 672                 addunit(&want, wantstr, 0);
 673                 completereduce(&want);
 674                 showanswer(&have, &want);
 675         }
 676         else {
 677                 if (!quiet)
 678                         printf("%d units, %d prefixes\n", unitcount,
 679                             prefixcount);
 680                 for (;;) {
 681                         do {
 682                                 initializeunit(&have);
 683                                 if (!quiet)
 684                                         printf("You have: ");
 685                                 if (!fgets(havestr, sizeof(havestr), stdin)) {
 686                                         if (!quiet)
 687                                                 putchar('\n');
 688                                         exit(0);
 689                                 }
 690                         } while (addunit(&have, havestr, 0) ||
 691                             completereduce(&have));
 692                         do {
 693                                 initializeunit(&want);
 694                                 if (!quiet)
 695                                         printf("You want: ");
 696                                 if (!fgets(wantstr, sizeof(wantstr), stdin)) {
 697                                         if (!quiet)
 698                                                 putchar('\n');
 699                                         exit(0);
 700                                 }
 701                         } while (addunit(&want, wantstr, 0) ||
 702                             completereduce(&want));
 703                         showanswer(&have, &want);
 704                 }
 705         }
 706
 707         return(0);
 708 }