xref: /freebsd/usr.bin/units/units.c (revision db9def8b) 
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 
18 #ifndef lint
19 static const char rcsid[] =
20   "$FreeBSD$";
21 #endif /* not lint */
22 
23 #include <ctype.h>
24 #include <err.h>
25 #include <errno.h>
26 #include <histedit.h>
27 #include <stdbool.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include <sys/capsicum.h>
34 
35 #include "pathnames.h"
36 
37 #ifndef UNITSFILE
38 #define UNITSFILE _PATH_UNITSLIB
39 #endif
40 
41 #define MAXUNITS 1000
42 #define MAXPREFIXES 100
43 
44 #define MAXSUBUNITS 500
45 
46 #define PRIMITIVECHAR '!'
47 
48 static const char *powerstring = "^";
49 
50 static struct {
51 	char *uname;
52 	char *uval;
53 }      unittable[MAXUNITS];
54 
55 struct unittype {
56 	char *numerator[MAXSUBUNITS];
57 	char *denominator[MAXSUBUNITS];
58 	double factor;
59 	double offset;
60 	int quantity;
61 };
62 
63 static struct {
64 	char *prefixname;
65 	char *prefixval;
66 }      prefixtable[MAXPREFIXES];
67 
68 
69 static char NULLUNIT[] = "";
70 
71 #ifdef MSDOS
72 #define SEPARATOR      ";"
73 #else
74 #define SEPARATOR      ":"
75 #endif
76 
77 static int unitcount;
78 static int prefixcount;
79 static bool verbose = false;
80 static const char * havestr;
81 static const char * wantstr;
82 
83 static int	 addsubunit(char *product[], char *toadd);
84 static int	 addunit(struct unittype *theunit, const char *toadd, int flip, int quantity);
85 static void	 cancelunit(struct unittype * theunit);
86 static int	 compare(const void *item1, const void *item2);
87 static int	 compareproducts(char **one, char **two);
88 static int	 compareunits(struct unittype * first, struct unittype * second);
89 static int	 completereduce(struct unittype * unit);
90 static char	*dupstr(const char *str);
91 static void	 initializeunit(struct unittype * theunit);
92 static char	*lookupunit(const char *unit);
93 static void	 readunits(const char *userfile);
94 static int	 reduceproduct(struct unittype * theunit, int flip);
95 static int	 reduceunit(struct unittype * theunit);
96 static void	 showanswer(struct unittype * have, struct unittype * want);
97 static void	 showunit(struct unittype * theunit);
98 static void	 sortunit(struct unittype * theunit);
99 static void	 usage(void);
100 static void	 zeroerror(void);
101 
102 static const char* promptstr = "";
103 
104 static const char * prompt(EditLine *e __unused) {
105 	return promptstr;
106 }
107 
108 char *
109 dupstr(const char *str)
110 {
111 	char *ret;
112 
113 	ret = strdup(str);
114 	if (!ret)
115 		err(3, "dupstr");
116 	return (ret);
117 }
118 
119 
120 void
121 readunits(const char *userfile)
122 {
123 	FILE *unitfile;
124 	char line[512], *lineptr;
125 	int len, linenum, i;
126 	cap_rights_t unitfilerights;
127 
128 	unitcount = 0;
129 	linenum = 0;
130 
131 	if (userfile) {
132 		unitfile = fopen(userfile, "rt");
133 		if (!unitfile)
134 			errx(1, "unable to open units file '%s'", userfile);
135 	}
136 	else {
137 		unitfile = fopen(UNITSFILE, "rt");
138 		if (!unitfile) {
139 			char *direc, *env;
140 			char filename[1000];
141 
142 			env = getenv("PATH");
143 			if (env) {
144 				direc = strtok(env, SEPARATOR);
145 				while (direc) {
146 					snprintf(filename, sizeof(filename),
147 					    "%s/%s", direc, UNITSFILE);
148 					unitfile = fopen(filename, "rt");
149 					if (unitfile)
150 						break;
151 					direc = strtok(NULL, SEPARATOR);
152 				}
153 			}
154 			if (!unitfile)
155 				errx(1, "can't find units file '%s'", UNITSFILE);
156 		}
157 	}
158 	cap_rights_init(&unitfilerights, CAP_READ, CAP_FSTAT);
159 	if (cap_rights_limit(fileno(unitfile), &unitfilerights) < 0
160 		&& errno != ENOSYS)
161 		err(1, "cap_rights_limit() failed");
162 	while (!feof(unitfile)) {
163 		if (!fgets(line, sizeof(line), unitfile))
164 			break;
165 		linenum++;
166 		lineptr = line;
167 		if (*lineptr == '/')
168 			continue;
169 		lineptr += strspn(lineptr, " \n\t");
170 		len = strcspn(lineptr, " \n\t");
171 		lineptr[len] = 0;
172 		if (!strlen(lineptr))
173 			continue;
174 		if (lineptr[strlen(lineptr) - 1] == '-') { /* it's a prefix */
175 			if (prefixcount == MAXPREFIXES) {
176 				warnx("memory for prefixes exceeded in line %d", linenum);
177 				continue;
178 			}
179 			lineptr[strlen(lineptr) - 1] = 0;
180 			prefixtable[prefixcount].prefixname = dupstr(lineptr);
181 			for (i = 0; i < prefixcount; i++)
182 				if (!strcmp(prefixtable[i].prefixname, lineptr)) {
183 					warnx("redefinition of prefix '%s' on line %d ignored",
184 					    lineptr, linenum);
185 					continue;
186 				}
187 			lineptr += len + 1;
188 			lineptr += strspn(lineptr, " \n\t");
189 			len = strcspn(lineptr, "\n\t");
190 			if (len == 0) {
191 				warnx("unexpected end of prefix on line %d",
192 				    linenum);
193 				continue;
194 			}
195 			lineptr[len] = 0;
196 			prefixtable[prefixcount++].prefixval = dupstr(lineptr);
197 		}
198 		else {		/* it's not a prefix */
199 			if (unitcount == MAXUNITS) {
200 				warnx("memory for units exceeded in line %d", linenum);
201 				continue;
202 			}
203 			unittable[unitcount].uname = dupstr(lineptr);
204 			for (i = 0; i < unitcount; i++)
205 				if (!strcmp(unittable[i].uname, lineptr)) {
206 					warnx("redefinition of unit '%s' on line %d ignored",
207 					    lineptr, linenum);
208 					continue;
209 				}
210 			lineptr += len + 1;
211 			lineptr += strspn(lineptr, " \n\t");
212 			if (!strlen(lineptr)) {
213 				warnx("unexpected end of unit on line %d",
214 				    linenum);
215 				continue;
216 			}
217 			len = strcspn(lineptr, "\n\t");
218 			lineptr[len] = 0;
219 			unittable[unitcount++].uval = dupstr(lineptr);
220 		}
221 	}
222 	fclose(unitfile);
223 }
224 
225 void
226 initializeunit(struct unittype * theunit)
227 {
228 	theunit->numerator[0] = theunit->denominator[0] = NULL;
229 	theunit->factor = 1.0;
230 	theunit->offset = 0.0;
231 	theunit->quantity = 0;
232 }
233 
234 
235 int
236 addsubunit(char *product[], char *toadd)
237 {
238 	char **ptr;
239 
240 	for (ptr = product; *ptr && *ptr != NULLUNIT; ptr++);
241 	if (ptr >= product + MAXSUBUNITS) {
242 		warnx("memory overflow in unit reduction");
243 		return 1;
244 	}
245 	if (!*ptr)
246 		*(ptr + 1) = NULL;
247 	*ptr = dupstr(toadd);
248 	return 0;
249 }
250 
251 
252 void
253 showunit(struct unittype * theunit)
254 {
255 	char **ptr;
256 	int printedslash;
257 	int counter = 1;
258 
259 	printf("%.8g", theunit->factor);
260 	if (theunit->offset)
261 		printf("&%.8g", theunit->offset);
262 	for (ptr = theunit->numerator; *ptr; ptr++) {
263 		if (ptr > theunit->numerator && **ptr &&
264 		    !strcmp(*ptr, *(ptr - 1)))
265 			counter++;
266 		else {
267 			if (counter > 1)
268 				printf("%s%d", powerstring, counter);
269 			if (**ptr)
270 				printf(" %s", *ptr);
271 			counter = 1;
272 		}
273 	}
274 	if (counter > 1)
275 		printf("%s%d", powerstring, counter);
276 	counter = 1;
277 	printedslash = 0;
278 	for (ptr = theunit->denominator; *ptr; ptr++) {
279 		if (ptr > theunit->denominator && **ptr &&
280 		    !strcmp(*ptr, *(ptr - 1)))
281 			counter++;
282 		else {
283 			if (counter > 1)
284 				printf("%s%d", powerstring, counter);
285 			if (**ptr) {
286 				if (!printedslash)
287 					printf(" /");
288 				printedslash = 1;
289 				printf(" %s", *ptr);
290 			}
291 			counter = 1;
292 		}
293 	}
294 	if ( counter > 1)
295 		printf("%s%d", powerstring, counter);
296 	printf("\n");
297 }
298 
299 
300 void
301 zeroerror(void)
302 {
303 	warnx("unit reduces to zero");
304 }
305 
306 /*
307    Adds the specified string to the unit.
308    Flip is 0 for adding normally, 1 for adding reciprocal.
309    Quantity is 1 if this is a quantity to be converted rather than a pure unit.
310 
311    Returns 0 for successful addition, nonzero on error.
312 */
313 
314 int
315 addunit(struct unittype * theunit, const char *toadd, int flip, int quantity)
316 {
317 	char *scratch, *savescr;
318 	char *item;
319 	char *divider, *slash, *offset;
320 	int doingtop;
321 
322 	if (!strlen(toadd))
323 		return 1;
324 
325 	savescr = scratch = dupstr(toadd);
326 	for (slash = scratch + 1; *slash; slash++)
327 		if (*slash == '-' &&
328 		    (tolower(*(slash - 1)) != 'e' ||
329 		    !strchr(".0123456789", *(slash + 1))))
330 			*slash = ' ';
331 	slash = strchr(scratch, '/');
332 	if (slash)
333 		*slash = 0;
334 	doingtop = 1;
335 	do {
336 		item = strtok(scratch, " *\t\n/");
337 		while (item) {
338 			if (strchr("0123456789.", *item)) { /* item is a number */
339 				double num, offsetnum;
340 
341 				if (quantity)
342 					theunit->quantity = 1;
343 
344 				offset = strchr(item, '&');
345 				if (offset) {
346 					*offset = 0;
347 					offsetnum = atof(offset+1);
348 				} else
349 					offsetnum = 0.0;
350 
351 				divider = strchr(item, '|');
352 				if (divider) {
353 					*divider = 0;
354 					num = atof(item);
355 					if (!num) {
356 						zeroerror();
357 						return 1;
358 					}
359 					if (doingtop ^ flip) {
360 						theunit->factor *= num;
361 						theunit->offset *= num;
362 					} else {
363 						theunit->factor /= num;
364 						theunit->offset /= num;
365 					}
366 					num = atof(divider + 1);
367 					if (!num) {
368 						zeroerror();
369 						return 1;
370 					}
371 					if (doingtop ^ flip) {
372 						theunit->factor /= num;
373 						theunit->offset /= num;
374 					} else {
375 						theunit->factor *= num;
376 						theunit->offset *= num;
377 					}
378 				}
379 				else {
380 					num = atof(item);
381 					if (!num) {
382 						zeroerror();
383 						return 1;
384 					}
385 					if (doingtop ^ flip) {
386 						theunit->factor *= num;
387 						theunit->offset *= num;
388 					} else {
389 						theunit->factor /= num;
390 						theunit->offset /= num;
391 					}
392 				}
393 				if (doingtop ^ flip)
394 					theunit->offset += offsetnum;
395 			}
396 			else {	/* item is not a number */
397 				int repeat = 1;
398 
399 				if (strchr("23456789",
400 				    item[strlen(item) - 1])) {
401 					repeat = item[strlen(item) - 1] - '0';
402 					item[strlen(item) - 1] = 0;
403 				}
404 				for (; repeat; repeat--)
405 					if (addsubunit(doingtop ^ flip ? theunit->numerator : theunit->denominator, item))
406 						return 1;
407 			}
408 			item = strtok(NULL, " *\t/\n");
409 		}
410 		doingtop--;
411 		if (slash) {
412 			scratch = slash + 1;
413 		}
414 		else
415 			doingtop--;
416 	} while (doingtop >= 0);
417 	free(savescr);
418 	return 0;
419 }
420 
421 
422 int
423 compare(const void *item1, const void *item2)
424 {
425 	return strcmp(*(const char * const *)item1, *(const char * const *)item2);
426 }
427 
428 
429 void
430 sortunit(struct unittype * theunit)
431 {
432 	char **ptr;
433 	unsigned int count;
434 
435 	for (count = 0, ptr = theunit->numerator; *ptr; ptr++, count++);
436 	qsort(theunit->numerator, count, sizeof(char *), compare);
437 	for (count = 0, ptr = theunit->denominator; *ptr; ptr++, count++);
438 	qsort(theunit->denominator, count, sizeof(char *), compare);
439 }
440 
441 
442 void
443 cancelunit(struct unittype * theunit)
444 {
445 	char **den, **num;
446 	int comp;
447 
448 	den = theunit->denominator;
449 	num = theunit->numerator;
450 
451 	while (*num && *den) {
452 		comp = strcmp(*den, *num);
453 		if (!comp) {
454 /*      if (*den!=NULLUNIT) free(*den);
455       if (*num!=NULLUNIT) free(*num);*/
456 			*den++ = NULLUNIT;
457 			*num++ = NULLUNIT;
458 		}
459 		else if (comp < 0)
460 			den++;
461 		else
462 			num++;
463 	}
464 }
465 
466 
467 
468 
469 /*
470    Looks up the definition for the specified unit.
471    Returns a pointer to the definition or a null pointer
472    if the specified unit does not appear in the units table.
473 */
474 
475 static char buffer[100];	/* buffer for lookupunit answers with
476 				   prefixes */
477 
478 char *
479 lookupunit(const char *unit)
480 {
481 	int i;
482 	char *copy;
483 
484 	for (i = 0; i < unitcount; i++) {
485 		if (!strcmp(unittable[i].uname, unit))
486 			return unittable[i].uval;
487 	}
488 
489 	if (unit[strlen(unit) - 1] == '^') {
490 		copy = dupstr(unit);
491 		copy[strlen(copy) - 1] = 0;
492 		for (i = 0; i < unitcount; i++) {
493 			if (!strcmp(unittable[i].uname, copy)) {
494 				strlcpy(buffer, copy, sizeof(buffer));
495 				free(copy);
496 				return buffer;
497 			}
498 		}
499 		free(copy);
500 	}
501 	if (unit[strlen(unit) - 1] == 's') {
502 		copy = dupstr(unit);
503 		copy[strlen(copy) - 1] = 0;
504 		for (i = 0; i < unitcount; i++) {
505 			if (!strcmp(unittable[i].uname, copy)) {
506 				strlcpy(buffer, copy, sizeof(buffer));
507 				free(copy);
508 				return buffer;
509 			}
510 		}
511 		if (copy[strlen(copy) - 1] == 'e') {
512 			copy[strlen(copy) - 1] = 0;
513 			for (i = 0; i < unitcount; i++) {
514 				if (!strcmp(unittable[i].uname, copy)) {
515 					strlcpy(buffer, copy, sizeof(buffer));
516 					free(copy);
517 					return buffer;
518 				}
519 			}
520 		}
521 		free(copy);
522 	}
523 	for (i = 0; i < prefixcount; i++) {
524 		size_t len = strlen(prefixtable[i].prefixname);
525 		if (!strncmp(prefixtable[i].prefixname, unit, len)) {
526 			if (!strlen(unit + len) || lookupunit(unit + len)) {
527 				snprintf(buffer, sizeof(buffer), "%s %s",
528 				    prefixtable[i].prefixval, unit + len);
529 				return buffer;
530 			}
531 		}
532 	}
533 	return 0;
534 }
535 
536 
537 
538 /*
539    reduces a product of symbolic units to primitive units.
540    The three low bits are used to return flags:
541 
542      bit 0 (1) set on if reductions were performed without error.
543      bit 1 (2) set on if no reductions are performed.
544      bit 2 (4) set on if an unknown unit is discovered.
545 */
546 
547 
548 #define ERROR 4
549 
550 int
551 reduceproduct(struct unittype * theunit, int flip)
552 {
553 
554 	char *toadd;
555 	char **product;
556 	int didsomething = 2;
557 
558 	if (flip)
559 		product = theunit->denominator;
560 	else
561 		product = theunit->numerator;
562 
563 	for (; *product; product++) {
564 
565 		for (;;) {
566 			if (!strlen(*product))
567 				break;
568 			toadd = lookupunit(*product);
569 			if (!toadd) {
570 				printf("unknown unit '%s'\n", *product);
571 				return ERROR;
572 			}
573 			if (strchr(toadd, PRIMITIVECHAR))
574 				break;
575 			didsomething = 1;
576 			if (*product != NULLUNIT) {
577 				free(*product);
578 				*product = NULLUNIT;
579 			}
580 			if (addunit(theunit, toadd, flip, 0))
581 				return ERROR;
582 		}
583 	}
584 	return didsomething;
585 }
586 
587 
588 /*
589    Reduces numerator and denominator of the specified unit.
590    Returns 0 on success, or 1 on unknown unit error.
591 */
592 
593 int
594 reduceunit(struct unittype * theunit)
595 {
596 	int ret;
597 
598 	ret = 1;
599 	while (ret & 1) {
600 		ret = reduceproduct(theunit, 0) | reduceproduct(theunit, 1);
601 		if (ret & 4)
602 			return 1;
603 	}
604 	return 0;
605 }
606 
607 
608 int
609 compareproducts(char **one, char **two)
610 {
611 	while (*one || *two) {
612 		if (!*one && *two != NULLUNIT)
613 			return 1;
614 		if (!*two && *one != NULLUNIT)
615 			return 1;
616 		if (*one == NULLUNIT)
617 			one++;
618 		else if (*two == NULLUNIT)
619 			two++;
620 		else if (strcmp(*one, *two))
621 			return 1;
622 		else
623 			one++, two++;
624 	}
625 	return 0;
626 }
627 
628 
629 /* Return zero if units are compatible, nonzero otherwise */
630 
631 int
632 compareunits(struct unittype * first, struct unittype * second)
633 {
634 	return
635 	compareproducts(first->numerator, second->numerator) ||
636 	compareproducts(first->denominator, second->denominator);
637 }
638 
639 
640 int
641 completereduce(struct unittype * unit)
642 {
643 	if (reduceunit(unit))
644 		return 1;
645 	sortunit(unit);
646 	cancelunit(unit);
647 	return 0;
648 }
649 
650 void
651 showanswer(struct unittype * have, struct unittype * want)
652 {
653 	double ans;
654 
655 	if (compareunits(have, want)) {
656 		printf("conformability error\n");
657 		if (verbose)
658 			printf("\t%s = ", havestr);
659 		else
660 			printf("\t");
661 		showunit(have);
662 		if (verbose)
663 			printf("\t%s = ", wantstr);
664 		else
665 			printf("\t");
666 		showunit(want);
667 	}
668 	else if (have->offset != want->offset) {
669 		if (want->quantity)
670 			printf("WARNING: conversion of non-proportional quantities.\n");
671 		if (have->quantity)
672 			printf("\t%.8g\n",
673 			    (have->factor + have->offset-want->offset)/want->factor);
674 		else {
675 			printf("\t (-> x*%.8g %+.8g)\n\t (<- y*%.8g %+.8g)\n",
676 			    have->factor / want->factor,
677 			    (have->offset-want->offset)/want->factor,
678 			    want->factor / have->factor,
679 			    (want->offset - have->offset)/have->factor);
680 		}
681 	}
682 	else {
683 		ans = have->factor / want->factor;
684 		if (verbose)
685 			printf("\t%s = %.8g * %s\n", havestr, ans, wantstr);
686 		else
687 			printf("\t* %.8g\n", ans);
688 
689 		if (verbose)
690 			printf("\t%s = (1 / %.8g) * %s\n", havestr, 1/ans,  wantstr);
691 		else
692 			printf("\t/ %.8g\n", 1/ans);
693 	}
694 }
695 
696 
697 void
698 usage(void)
699 {
700 	fprintf(stderr,
701 		"usage: units [-f unitsfile] [-UVq] [from-unit to-unit]\n");
702 	exit(3);
703 }
704 
705 
706 int
707 main(int argc, char **argv)
708 {
709 
710 	struct unittype have, want;
711 	int optchar;
712 	bool quiet;
713 	bool readfile;
714 	History *inhistory;
715 	EditLine *el;
716 	HistEvent ev;
717 	int inputsz;
718 
719 	quiet = false;
720 	readfile = false;
721 	while ((optchar = getopt(argc, argv, "f:qvUV")) != -1) {
722 		switch (optchar) {
723 		case 'f':
724 			readfile = true;
725 			if (strlen(optarg) == 0)
726 				readunits(NULL);
727 			else
728 				readunits(optarg);
729 			break;
730 		case 'q':
731 			quiet = true;
732 			break;
733 		case 'v':
734 			verbose = true;
735 			break;
736 		case 'V':
737 			fprintf(stderr, "FreeBSD units\n");
738 			/* FALLTHROUGH */
739 		case 'U':
740 			if (access(UNITSFILE, F_OK) == 0)
741 				printf("%s\n", UNITSFILE);
742 			else
743 				printf("Units data file not found");
744 			exit(0);
745 			break;
746 		default:
747 			usage();
748 		}
749 	}
750 
751 	if (!readfile)
752 		readunits(NULL);
753 
754 	inhistory = history_init();
755 	el = el_init(argv[0], stdin, stdout, stderr);
756 	el_set(el, EL_PROMPT, &prompt);
757 	el_set(el, EL_EDITOR, "emacs");
758 	el_set(el, EL_SIGNAL, 1);
759 	el_set(el, EL_HIST, history, inhistory);
760 	el_source(el, NULL);
761 	history(inhistory, &ev, H_SETSIZE, 800);
762 	if (inhistory == 0)
763 		err(1, "Could not initalize history");
764 
765 	if (cap_enter() < 0 && errno != ENOSYS)
766 		err(1, "unable to enter capability mode");
767 
768 	if (optind == argc - 2) {
769 		havestr = argv[optind];
770 		wantstr = argv[optind + 1];
771 		initializeunit(&have);
772 		addunit(&have, havestr, 0, 1);
773 		completereduce(&have);
774 		initializeunit(&want);
775 		addunit(&want, wantstr, 0, 1);
776 		completereduce(&want);
777 		showanswer(&have, &want);
778 	}
779 	else {
780 		if (!quiet)
781 			printf("%d units, %d prefixes\n", unitcount,
782 			    prefixcount);
783 		for (;;) {
784 			do {
785 				initializeunit(&have);
786 				if (!quiet)
787 					promptstr = "You have: ";
788 				havestr = el_gets(el, &inputsz);
789 				if (havestr == NULL)
790 					exit(0);
791 				if (inputsz > 0)
792 					history(inhistory, &ev, H_ENTER,
793 					havestr);
794 			} while (addunit(&have, havestr, 0, 1) ||
795 			    completereduce(&have));
796 			do {
797 				initializeunit(&want);
798 				if (!quiet)
799 					promptstr = "You want: ";
800 				wantstr = el_gets(el, &inputsz);
801 				if (wantstr == NULL)
802 					exit(0);
803 				if (inputsz > 0)
804 					history(inhistory, &ev, H_ENTER,
805 					wantstr);
806 			} while (addunit(&want, wantstr, 0, 1) ||
807 			    completereduce(&want));
808 			showanswer(&have, &want);
809 		}
810 	}
811 
812 	history_end(inhistory);
813 	return(0);
814 }
815