1 /* $OpenBSD: units.c,v 1.23 2022/12/26 18:52:10 florian Exp $ */
2 /* $NetBSD: units.c,v 1.6 1996/04/06 06:01:03 thorpej Exp $ */
3
4 /*
5 * units.c Copyright (c) 1993 by Adrian Mariano (adrian@cam.cornell.edu)
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. The name of the author may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
14 * Disclaimer: This software is provided by the author "as is". The author
15 * shall not be liable for any damages caused in any way by this software.
16 *
17 * I would appreciate (though I do not require) receiving a copy of any
18 * improvements you might make to this program.
19 */
20
21 #include <ctype.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <stdlib.h>
25 #include <unistd.h>
26 #include <err.h>
27
28 #define UNITSFILE "/usr/share/misc/units.lib"
29
30 #define VERSION "1.0"
31
32 #define MAXUNITS 1000
33 #define MAXPREFIXES 100
34
35 #define MAXSUBUNITS 500
36
37 #define PRIMITIVECHAR '!'
38
39 char *powerstring = "^";
40
41 struct {
42 char *uname;
43 char *uval;
44 } unittable[MAXUNITS];
45
46 struct unittype {
47 char *numerator[MAXSUBUNITS];
48 char *denominator[MAXSUBUNITS];
49 double factor;
50 };
51
52 struct {
53 char *prefixname;
54 char *prefixval;
55 } prefixtable[MAXPREFIXES];
56
57
58 char *NULLUNIT = "";
59
60 int unitcount;
61 int prefixcount;
62
63 char *dupstr(char *);
64 void readunits(char *);
65 void initializeunit(struct unittype *);
66 int addsubunit(char *[], char *);
67 void showunit(struct unittype *);
68 void zeroerror(void);
69 int addunit(struct unittype *, char *, int);
70 int compare(const void *, const void *);
71 void sortunit(struct unittype *);
72 void cancelunit(struct unittype *);
73 char *lookupunit(char *);
74 int reduceproduct(struct unittype *, int);
75 int reduceunit(struct unittype *);
76 int compareproducts(char **, char **);
77 int compareunits(struct unittype *, struct unittype *);
78 int completereduce(struct unittype *);
79 void showanswer(struct unittype *, struct unittype *);
80 void usage(void);
81
82 char *
dupstr(char * str)83 dupstr(char *str)
84 {
85 char *ret;
86
87 ret = strdup(str);
88 if (!ret) {
89 fprintf(stderr, "Memory allocation error\n");
90 exit(3);
91 }
92 return (ret);
93 }
94
95
96 void
readunits(char * userfile)97 readunits(char *userfile)
98 {
99 char line[512], *lineptr;
100 int len, linenum, i;
101 FILE *unitfile;
102
103 linenum = 0;
104
105 if (userfile) {
106 unitfile = fopen(userfile, "r");
107 if (!unitfile) {
108 fprintf(stderr, "Unable to open units file '%s'\n",
109 userfile);
110 exit(1);
111 }
112 } else {
113 unitfile = fopen(UNITSFILE, "r");
114 if (!unitfile) {
115 fprintf(stderr, "Can't find units file '%s'\n",
116 UNITSFILE);
117 exit(1);
118 }
119 }
120 while (!feof(unitfile)) {
121 if (!fgets(line, sizeof(line), unitfile))
122 break;
123 linenum++;
124 lineptr = line;
125 if (*lineptr == '/')
126 continue;
127 lineptr += strspn(lineptr, " \n\t");
128 len = strcspn(lineptr, " \n\t");
129 lineptr[len] = 0;
130 if (!strlen(lineptr))
131 continue;
132 if (lineptr[strlen(lineptr) - 1] == '-') { /* it's a prefix */
133 if (prefixcount == MAXPREFIXES) {
134 fprintf(stderr,
135 "Memory for prefixes exceeded in line %d\n",
136 linenum);
137 continue;
138 }
139
140 lineptr[strlen(lineptr) - 1] = 0;
141 for (i = 0; i < prefixcount; i++) {
142 if (!strcmp(prefixtable[i].prefixname, lineptr))
143 break;
144 }
145 if (i < prefixcount) {
146 fprintf(stderr, "Redefinition of prefix '%s' "
147 "on line %d ignored\n", lineptr, linenum);
148 continue; /* skip duplicate prefix */
149 }
150
151 prefixtable[prefixcount].prefixname = dupstr(lineptr);
152 lineptr += len + 1;
153 lineptr += strspn(lineptr, " \n\t");
154 len = strcspn(lineptr, "\n\t");
155 if (len == 0) {
156 fprintf(stderr, "Unexpected end of prefix on "
157 "line %d\n", linenum);
158 free(prefixtable[prefixcount].prefixname);
159 continue;
160 }
161 lineptr[len] = 0;
162 prefixtable[prefixcount++].prefixval = dupstr(lineptr);
163 } else { /* it's not a prefix */
164 if (unitcount == MAXUNITS) {
165 fprintf(stderr,
166 "Memory for units exceeded in line %d\n",
167 linenum);
168 continue;
169 }
170
171 for (i = 0; i < unitcount; i++) {
172 if (!strcmp(unittable[i].uname, lineptr))
173 break;
174 }
175 if (i < unitcount) {
176 fprintf(stderr, "Redefinition of unit '%s' "
177 "on line %d ignored\n", lineptr, linenum);
178 continue; /* skip duplicate unit */
179 }
180
181 unittable[unitcount].uname = dupstr(lineptr);
182 lineptr += len + 1;
183 lineptr += strspn(lineptr, " \n\t");
184 if (!strlen(lineptr)) {
185 fprintf(stderr, "Unexpected end of unit on "
186 "line %d\n", linenum);
187 free(unittable[unitcount].uname);
188 continue;
189 }
190 len = strcspn(lineptr, "\n\t");
191 lineptr[len] = 0;
192 unittable[unitcount++].uval = dupstr(lineptr);
193 }
194 }
195 fclose(unitfile);
196 }
197
198 void
initializeunit(struct unittype * theunit)199 initializeunit(struct unittype *theunit)
200 {
201 theunit->factor = 1.0;
202 theunit->numerator[0] = theunit->denominator[0] = NULL;
203 }
204
205
206 int
addsubunit(char * product[],char * toadd)207 addsubunit(char *product[], char *toadd)
208 {
209 char **ptr;
210
211 for (ptr = product; *ptr && *ptr != NULLUNIT; ptr++);
212 if (ptr >= product + MAXSUBUNITS) {
213 fprintf(stderr, "Memory overflow in unit reduction\n");
214 return 1;
215 }
216 if (!*ptr)
217 *(ptr + 1) = 0;
218 *ptr = dupstr(toadd);
219 return 0;
220 }
221
222
223 void
showunit(struct unittype * theunit)224 showunit(struct unittype *theunit)
225 {
226 char **ptr;
227 int printedslash;
228 int counter = 1;
229
230 printf("\t%.8g", theunit->factor);
231 for (ptr = theunit->numerator; *ptr; ptr++) {
232 if (ptr > theunit->numerator && **ptr &&
233 !strcmp(*ptr, *(ptr - 1)))
234 counter++;
235 else {
236 if (counter > 1)
237 printf("%s%d", powerstring, counter);
238 if (**ptr)
239 printf(" %s", *ptr);
240 counter = 1;
241 }
242 }
243 if (counter > 1)
244 printf("%s%d", powerstring, counter);
245 counter = 1;
246 printedslash = 0;
247 for (ptr = theunit->denominator; *ptr; ptr++) {
248 if (ptr > theunit->denominator && **ptr &&
249 !strcmp(*ptr, *(ptr - 1)))
250 counter++;
251 else {
252 if (counter > 1)
253 printf("%s%d", powerstring, counter);
254 if (**ptr) {
255 if (!printedslash)
256 printf(" /");
257 printedslash = 1;
258 printf(" %s", *ptr);
259 }
260 counter = 1;
261 }
262 }
263 if (counter > 1)
264 printf("%s%d", powerstring, counter);
265 printf("\n");
266 }
267
268
269 void
zeroerror(void)270 zeroerror(void)
271 {
272 fprintf(stderr, "Unit reduces to zero\n");
273 }
274
275 /*
276 Adds the specified string to the unit.
277 Flip is 0 for adding normally, 1 for adding reciprocal.
278
279 Returns 0 for successful addition, nonzero on error.
280 */
281
282 int
addunit(struct unittype * theunit,char * toadd,int flip)283 addunit(struct unittype *theunit, char *toadd, int flip)
284 {
285 char *scratch, *savescr;
286 char *item;
287 char *divider, *slash;
288 int doingtop;
289
290 savescr = scratch = dupstr(toadd);
291 for (slash = scratch + 1; *slash; slash++)
292 if (*slash == '-' &&
293 (tolower((unsigned char)*(slash - 1)) != 'e' ||
294 !strchr(".0123456789", *(slash + 1))))
295 *slash = ' ';
296 slash = strchr(scratch, '/');
297 if (slash)
298 *slash = 0;
299 doingtop = 1;
300 do {
301 item = strtok(scratch, " *\t\n/");
302 while (item) {
303 if (strchr("0123456789.", *item)) { /* item is a number */
304 double num;
305
306 divider = strchr(item, '|');
307 if (divider) {
308 *divider = 0;
309 num = atof(item);
310 if (!num) {
311 zeroerror();
312 free(savescr);
313 return 1;
314 }
315 if (doingtop ^ flip)
316 theunit->factor *= num;
317 else
318 theunit->factor /= num;
319 num = atof(divider + 1);
320 if (!num) {
321 zeroerror();
322 free(savescr);
323 return 1;
324 }
325 if (doingtop ^ flip)
326 theunit->factor /= num;
327 else
328 theunit->factor *= num;
329 } else {
330 num = atof(item);
331 if (!num) {
332 zeroerror();
333 free(savescr);
334 return 1;
335 }
336 if (doingtop ^ flip)
337 theunit->factor *= num;
338 else
339 theunit->factor /= num;
340
341 }
342 } else { /* item is not a number */
343 int repeat = 1;
344
345 if (strchr("23456789",
346 item[strlen(item) - 1])) {
347 repeat = item[strlen(item) - 1] - '0';
348 item[strlen(item) - 1] = 0;
349 }
350 for (; repeat; repeat--)
351 if (addsubunit(doingtop ^ flip
352 ? theunit->numerator
353 : theunit->denominator, item)) {
354 free(savescr);
355 return 1;
356 }
357 }
358 item = strtok(NULL, " *\t/\n");
359 }
360 doingtop--;
361 if (slash) {
362 scratch = slash + 1;
363 } else
364 doingtop--;
365 } while (doingtop >= 0);
366 free(savescr);
367 return 0;
368 }
369
370
371 int
compare(const void * item1,const void * item2)372 compare(const void *item1, const void *item2)
373 {
374 return strcmp(*(char **) item1, *(char **) item2);
375 }
376
377
378 void
sortunit(struct unittype * theunit)379 sortunit(struct unittype *theunit)
380 {
381 char **ptr;
382 int count;
383
384 for (count = 0, ptr = theunit->numerator; *ptr; ptr++, count++);
385 qsort(theunit->numerator, count, sizeof(char *), compare);
386 for (count = 0, ptr = theunit->denominator; *ptr; ptr++, count++);
387 qsort(theunit->denominator, count, sizeof(char *), compare);
388 }
389
390
391 void
cancelunit(struct unittype * theunit)392 cancelunit(struct unittype *theunit)
393 {
394 char **den, **num;
395 int comp;
396
397 den = theunit->denominator;
398 num = theunit->numerator;
399
400 while (*num && *den) {
401 comp = strcmp(*den, *num);
402 if (!comp) {
403 *den++ = NULLUNIT;
404 *num++ = NULLUNIT;
405 } else if (comp < 0)
406 den++;
407 else
408 num++;
409 }
410 }
411
412
413
414
415 /*
416 Looks up the definition for the specified unit.
417 Returns a pointer to the definition or a null pointer
418 if the specified unit does not appear in the units table.
419 */
420
421 static char buffer[500]; /* buffer for lookupunit answers with
422 prefixes */
423
424 char *
lookupunit(char * unit)425 lookupunit(char *unit)
426 {
427 size_t len;
428 int i;
429 char *copy;
430
431 for (i = 0; i < unitcount; i++) {
432 if (!strcmp(unittable[i].uname, unit))
433 return unittable[i].uval;
434 }
435
436 len = strlen(unit);
437 if (len == 0)
438 return NULL;
439 if (unit[len - 1] == '^') {
440 copy = dupstr(unit);
441 copy[len - 1] = '\0';
442 for (i = 0; i < unitcount; i++) {
443 if (!strcmp(unittable[i].uname, copy)) {
444 strlcpy(buffer, copy, sizeof(buffer));
445 free(copy);
446 return buffer;
447 }
448 }
449 free(copy);
450 }
451 if (unit[len - 1] == 's') {
452 copy = dupstr(unit);
453 copy[len - 1] = '\0';
454 --len;
455 for (i = 0; i < unitcount; i++) {
456 if (!strcmp(unittable[i].uname, copy)) {
457 strlcpy(buffer, copy, sizeof(buffer));
458 free(copy);
459 return buffer;
460 }
461 }
462 if (len != 0 && copy[len - 1] == 'e') {
463 copy[len - 1] = 0;
464 for (i = 0; i < unitcount; i++) {
465 if (!strcmp(unittable[i].uname, copy)) {
466 strlcpy(buffer, copy, sizeof(buffer));
467 free(copy);
468 return buffer;
469 }
470 }
471 }
472 free(copy);
473 }
474 for (i = 0; i < prefixcount; i++) {
475 len = strlen(prefixtable[i].prefixname);
476 if (!strncmp(prefixtable[i].prefixname, unit, len)) {
477 if (!strlen(unit + len) || lookupunit(unit + len)) {
478 snprintf(buffer, sizeof(buffer), "%s %s",
479 prefixtable[i].prefixval, unit + len);
480 return buffer;
481 }
482 }
483 }
484 return NULL;
485 }
486
487
488
489 /*
490 reduces a product of symbolic units to primitive units.
491 The three low bits are used to return flags:
492
493 bit 0 (1) set on if reductions were performed without error.
494 bit 1 (2) set on if no reductions are performed.
495 bit 2 (4) set on if an unknown unit is discovered.
496 */
497
498
499 #define ERROR 4
500
501 int
reduceproduct(struct unittype * theunit,int flip)502 reduceproduct(struct unittype *theunit, int flip)
503 {
504 char *toadd, **product;
505 int didsomething = 2;
506
507 if (flip)
508 product = theunit->denominator;
509 else
510 product = theunit->numerator;
511
512 for (; *product; product++) {
513
514 for (;;) {
515 if (!strlen(*product))
516 break;
517 toadd = lookupunit(*product);
518 if (!toadd) {
519 printf("unknown unit '%s'\n", *product);
520 return ERROR;
521 }
522 if (strchr(toadd, PRIMITIVECHAR))
523 break;
524 didsomething = 1;
525 if (*product != NULLUNIT) {
526 free(*product);
527 *product = NULLUNIT;
528 }
529 if (addunit(theunit, toadd, flip))
530 return ERROR;
531 }
532 }
533 return didsomething;
534 }
535
536
537 /*
538 Reduces numerator and denominator of the specified unit.
539 Returns 0 on success, or 1 on unknown unit error.
540 */
541
542 int
reduceunit(struct unittype * theunit)543 reduceunit(struct unittype *theunit)
544 {
545 int ret;
546
547 ret = 1;
548 while (ret & 1) {
549 ret = reduceproduct(theunit, 0) | reduceproduct(theunit, 1);
550 if (ret & 4)
551 return 1;
552 }
553 return 0;
554 }
555
556
557 int
compareproducts(char ** one,char ** two)558 compareproducts(char **one, char **two)
559 {
560 while (*one || *two) {
561 if (!*one && *two != NULLUNIT)
562 return 1;
563 if (!*two && *one != NULLUNIT)
564 return 1;
565 if (*one == NULLUNIT)
566 one++;
567 else if (*two == NULLUNIT)
568 two++;
569 else if (strcmp(*one, *two))
570 return 1;
571 else
572 one++, two++;
573 }
574 return 0;
575 }
576
577
578 /* Return zero if units are compatible, nonzero otherwise */
579
580 int
compareunits(struct unittype * first,struct unittype * second)581 compareunits(struct unittype *first, struct unittype *second)
582 {
583 return compareproducts(first->numerator, second->numerator) ||
584 compareproducts(first->denominator, second->denominator);
585 }
586
587
588 int
completereduce(struct unittype * unit)589 completereduce(struct unittype *unit)
590 {
591 if (reduceunit(unit))
592 return 1;
593 sortunit(unit);
594 cancelunit(unit);
595 return 0;
596 }
597
598
599 void
showanswer(struct unittype * have,struct unittype * want)600 showanswer(struct unittype *have, struct unittype *want)
601 {
602 if (compareunits(have, want)) {
603 printf("conformability error\n");
604 showunit(have);
605 showunit(want);
606 } else
607 printf("\t* %.8g\n\t/ %.8g\n", have->factor / want->factor,
608 want->factor / have->factor);
609 }
610
611
612 void
usage(void)613 usage(void)
614 {
615 fprintf(stderr,
616 "usage: units [-qv] [-f filename] [[count] from-unit to-unit]\n");
617 exit(3);
618 }
619
620
621 int
main(int argc,char ** argv)622 main(int argc, char **argv)
623 {
624
625 struct unittype have, want;
626 char havestr[81], wantstr[81];
627 int optchar;
628 int quiet = 0, units_read = 0;
629
630 extern char *optarg;
631 extern int optind;
632
633 if (pledge("stdio rpath", NULL) == -1)
634 err(1, "pledge");
635
636 while ((optchar = getopt(argc, argv, "vqf:")) != -1) {
637 switch (optchar) {
638 case 'f':
639 units_read = 1;
640 readunits(*optarg == '\0' ? NULL : optarg);
641 break;
642 case 'q':
643 quiet = 1;
644 break;
645 case 'v':
646 fprintf(stderr,
647 "units version %s Copyright (c) 1993 by Adrian Mariano\n",
648 VERSION);
649 fprintf(stderr,
650 "This program may be freely distributed\n");
651 usage();
652 default:
653 usage();
654 break;
655 }
656 }
657
658 argc -= optind;
659 argv += optind;
660
661 if (argc != 3 && argc != 2 && argc != 0)
662 usage();
663
664 if (!units_read)
665 readunits(NULL);
666
667 if (pledge("stdio", NULL) == -1)
668 err(1, "pledge");
669
670 if (argc == 3) {
671 strlcpy(havestr, argv[0], sizeof(havestr));
672 strlcat(havestr, " ", sizeof(havestr));
673 strlcat(havestr, argv[1], sizeof(havestr));
674 argc--;
675 argv++;
676 argv[0] = havestr;
677 }
678
679 if (argc == 2) {
680 strlcpy(havestr, argv[0], sizeof(havestr));
681 strlcpy(wantstr, argv[1], sizeof(wantstr));
682 initializeunit(&have);
683 addunit(&have, havestr, 0);
684 completereduce(&have);
685 initializeunit(&want);
686 addunit(&want, wantstr, 0);
687 completereduce(&want);
688 showanswer(&have, &want);
689 } else {
690 if (!quiet)
691 printf("%d units, %d prefixes\n", unitcount,
692 prefixcount);
693 for (;;) {
694 do {
695 initializeunit(&have);
696 if (!quiet)
697 printf("You have: ");
698 if (!fgets(havestr, sizeof(havestr), stdin)) {
699 if (!quiet)
700 putchar('\n');
701 exit(0);
702 }
703 } while (addunit(&have, havestr, 0) ||
704 completereduce(&have));
705 do {
706 initializeunit(&want);
707 if (!quiet)
708 printf("You want: ");
709 if (!fgets(wantstr, sizeof(wantstr), stdin)) {
710 if (!quiet)
711 putchar('\n');
712 exit(0);
713 }
714 } while (addunit(&want, wantstr, 0) ||
715 completereduce(&want));
716 showanswer(&have, &want);
717 }
718 }
719 return (0);
720 }
721