xref: /freebsd/usr.bin/units/units.c (revision 56e53cb8ef000c3ef72337a4095987a932cdedef) 
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * units.c   Copyright (c) 1993 by Adrian Mariano (adrian@cam.cornell.edu)
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. The name of the author may not be used to endorse or promote products
12  *    derived from this software without specific prior written permission.
13  * Disclaimer:  This software is provided by the author "as is".  The author
14  * shall not be liable for any damages caused in any way by this software.
15  *
16  * I would appreciate (though I do not require) receiving a copy of any
17  * improvements you might make to this program.
18  */
19 
20 #ifndef lint
21 static const char rcsid[] =
22   "$FreeBSD$";
23 #endif /* not lint */
24 
25 #include <ctype.h>
26 #include <err.h>
27 #include <errno.h>
28 #include <histedit.h>
29 #include <getopt.h>
30 #include <stdbool.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35 
36 #include <sys/capsicum.h>
37 
38 #ifndef UNITSFILE
39 #define UNITSFILE "/usr/share/misc/definitions.units"
40 #endif
41 
42 #define MAXUNITS 1000
43 #define MAXPREFIXES 100
44 
45 #define MAXSUBUNITS 500
46 
47 #define PRIMITIVECHAR '!'
48 
49 static const char *powerstring = "^";
50 static const char *numfmt = "%.8g";
51 
52 static struct {
53 	char *uname;
54 	char *uval;
55 }      unittable[MAXUNITS];
56 
57 struct unittype {
58 	char *numerator[MAXSUBUNITS];
59 	char *denominator[MAXSUBUNITS];
60 	double factor;
61 	double offset;
62 	int quantity;
63 };
64 
65 static struct {
66 	char *prefixname;
67 	char *prefixval;
68 }      prefixtable[MAXPREFIXES];
69 
70 
71 static char NULLUNIT[] = "";
72 
73 #define SEPARATOR      ":"
74 
75 static int unitcount;
76 static int prefixcount;
77 static bool verbose = false;
78 static bool terse = false;
79 static const char * outputformat;
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 static 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 static 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, "r");
133 		if (!unitfile)
134 			errx(1, "unable to open units file '%s'", userfile);
135 	}
136 	else {
137 		unitfile = fopen(UNITSFILE, "r");
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 == '/' || *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 static 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 static 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 static void
253 showunit(struct unittype * theunit)
254 {
255 	char **ptr;
256 	int printedslash;
257 	int counter = 1;
258 
259 	printf(numfmt, 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 static 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 						free(savescr);
358 						return 1;
359 					}
360 					if (doingtop ^ flip) {
361 						theunit->factor *= num;
362 						theunit->offset *= num;
363 					} else {
364 						theunit->factor /= num;
365 						theunit->offset /= num;
366 					}
367 					num = atof(divider + 1);
368 					if (!num) {
369 						zeroerror();
370 						free(savescr);
371 						return 1;
372 					}
373 					if (doingtop ^ flip) {
374 						theunit->factor /= num;
375 						theunit->offset /= num;
376 					} else {
377 						theunit->factor *= num;
378 						theunit->offset *= num;
379 					}
380 				}
381 				else {
382 					num = atof(item);
383 					if (!num) {
384 						zeroerror();
385 						free(savescr);
386 						return 1;
387 					}
388 					if (doingtop ^ flip) {
389 						theunit->factor *= num;
390 						theunit->offset *= num;
391 					} else {
392 						theunit->factor /= num;
393 						theunit->offset /= num;
394 					}
395 				}
396 				if (doingtop ^ flip)
397 					theunit->offset += offsetnum;
398 			}
399 			else {	/* item is not a number */
400 				int repeat = 1;
401 
402 				if (strchr("23456789",
403 				    item[strlen(item) - 1])) {
404 					repeat = item[strlen(item) - 1] - '0';
405 					item[strlen(item) - 1] = 0;
406 				}
407 				for (; repeat; repeat--) {
408 					if (addsubunit(doingtop ^ flip ? theunit->numerator : theunit->denominator, item)) {
409 						free(savescr);
410 						return 1;
411 					}
412 				}
413 			}
414 			item = strtok(NULL, " *\t/\n");
415 		}
416 		doingtop--;
417 		if (slash) {
418 			scratch = slash + 1;
419 		}
420 		else
421 			doingtop--;
422 	} while (doingtop >= 0);
423 	free(savescr);
424 	return 0;
425 }
426 
427 
428 static int
429 compare(const void *item1, const void *item2)
430 {
431 	return strcmp(*(const char * const *)item1, *(const char * const *)item2);
432 }
433 
434 
435 static void
436 sortunit(struct unittype * theunit)
437 {
438 	char **ptr;
439 	unsigned int count;
440 
441 	for (count = 0, ptr = theunit->numerator; *ptr; ptr++, count++);
442 	qsort(theunit->numerator, count, sizeof(char *), compare);
443 	for (count = 0, ptr = theunit->denominator; *ptr; ptr++, count++);
444 	qsort(theunit->denominator, count, sizeof(char *), compare);
445 }
446 
447 
448 void
449 cancelunit(struct unittype * theunit)
450 {
451 	char **den, **num;
452 	int comp;
453 
454 	den = theunit->denominator;
455 	num = theunit->numerator;
456 
457 	while (*num && *den) {
458 		comp = strcmp(*den, *num);
459 		if (!comp) {
460 /*      if (*den!=NULLUNIT) free(*den);
461       if (*num!=NULLUNIT) free(*num);*/
462 			*den++ = NULLUNIT;
463 			*num++ = NULLUNIT;
464 		}
465 		else if (comp < 0)
466 			den++;
467 		else
468 			num++;
469 	}
470 }
471 
472 
473 
474 
475 /*
476    Looks up the definition for the specified unit.
477    Returns a pointer to the definition or a null pointer
478    if the specified unit does not appear in the units table.
479 */
480 
481 static char buffer[100];	/* buffer for lookupunit answers with
482 				   prefixes */
483 
484 char *
485 lookupunit(const char *unit)
486 {
487 	int i;
488 	char *copy;
489 
490 	for (i = 0; i < unitcount; i++) {
491 		if (!strcmp(unittable[i].uname, unit))
492 			return unittable[i].uval;
493 	}
494 
495 	if (unit[strlen(unit) - 1] == '^') {
496 		copy = dupstr(unit);
497 		copy[strlen(copy) - 1] = 0;
498 		for (i = 0; i < unitcount; i++) {
499 			if (!strcmp(unittable[i].uname, copy)) {
500 				strlcpy(buffer, copy, sizeof(buffer));
501 				free(copy);
502 				return buffer;
503 			}
504 		}
505 		free(copy);
506 	}
507 	if (unit[strlen(unit) - 1] == 's') {
508 		copy = dupstr(unit);
509 		copy[strlen(copy) - 1] = 0;
510 		for (i = 0; i < unitcount; i++) {
511 			if (!strcmp(unittable[i].uname, copy)) {
512 				strlcpy(buffer, copy, sizeof(buffer));
513 				free(copy);
514 				return buffer;
515 			}
516 		}
517 		if (copy[strlen(copy) - 1] == 'e') {
518 			copy[strlen(copy) - 1] = 0;
519 			for (i = 0; i < unitcount; i++) {
520 				if (!strcmp(unittable[i].uname, copy)) {
521 					strlcpy(buffer, copy, sizeof(buffer));
522 					free(copy);
523 					return buffer;
524 				}
525 			}
526 		}
527 		free(copy);
528 	}
529 	for (i = 0; i < prefixcount; i++) {
530 		size_t len = strlen(prefixtable[i].prefixname);
531 		if (!strncmp(prefixtable[i].prefixname, unit, len)) {
532 			if (!strlen(unit + len) || lookupunit(unit + len)) {
533 				snprintf(buffer, sizeof(buffer), "%s %s",
534 				    prefixtable[i].prefixval, unit + len);
535 				return buffer;
536 			}
537 		}
538 	}
539 	return 0;
540 }
541 
542 
543 
544 /*
545    reduces a product of symbolic units to primitive units.
546    The three low bits are used to return flags:
547 
548      bit 0 (1) set on if reductions were performed without error.
549      bit 1 (2) set on if no reductions are performed.
550      bit 2 (4) set on if an unknown unit is discovered.
551 */
552 
553 
554 #define ERROR 4
555 
556 static int
557 reduceproduct(struct unittype * theunit, int flip)
558 {
559 
560 	char *toadd;
561 	char **product;
562 	int didsomething = 2;
563 
564 	if (flip)
565 		product = theunit->denominator;
566 	else
567 		product = theunit->numerator;
568 
569 	for (; *product; product++) {
570 
571 		for (;;) {
572 			if (!strlen(*product))
573 				break;
574 			toadd = lookupunit(*product);
575 			if (!toadd) {
576 				printf("unknown unit '%s'\n", *product);
577 				return ERROR;
578 			}
579 			if (strchr(toadd, PRIMITIVECHAR))
580 				break;
581 			didsomething = 1;
582 			if (*product != NULLUNIT) {
583 				free(*product);
584 				*product = NULLUNIT;
585 			}
586 			if (addunit(theunit, toadd, flip, 0))
587 				return ERROR;
588 		}
589 	}
590 	return didsomething;
591 }
592 
593 
594 /*
595    Reduces numerator and denominator of the specified unit.
596    Returns 0 on success, or 1 on unknown unit error.
597 */
598 
599 static int
600 reduceunit(struct unittype * theunit)
601 {
602 	int ret;
603 
604 	ret = 1;
605 	while (ret & 1) {
606 		ret = reduceproduct(theunit, 0) | reduceproduct(theunit, 1);
607 		if (ret & 4)
608 			return 1;
609 	}
610 	return 0;
611 }
612 
613 
614 static int
615 compareproducts(char **one, char **two)
616 {
617 	while (*one || *two) {
618 		if (!*one && *two != NULLUNIT)
619 			return 1;
620 		if (!*two && *one != NULLUNIT)
621 			return 1;
622 		if (*one == NULLUNIT)
623 			one++;
624 		else if (*two == NULLUNIT)
625 			two++;
626 		else if (strcmp(*one, *two))
627 			return 1;
628 		else
629 			one++, two++;
630 	}
631 	return 0;
632 }
633 
634 
635 /* Return zero if units are compatible, nonzero otherwise */
636 
637 static int
638 compareunits(struct unittype * first, struct unittype * second)
639 {
640 	return
641 	compareproducts(first->numerator, second->numerator) ||
642 	compareproducts(first->denominator, second->denominator);
643 }
644 
645 
646 static int
647 completereduce(struct unittype * unit)
648 {
649 	if (reduceunit(unit))
650 		return 1;
651 	sortunit(unit);
652 	cancelunit(unit);
653 	return 0;
654 }
655 
656 static void
657 showanswer(struct unittype * have, struct unittype * want)
658 {
659 	double ans;
660 	char* oformat;
661 
662 	if (compareunits(have, want)) {
663 		printf("conformability error\n");
664 		if (verbose)
665 			printf("\t%s = ", havestr);
666 		else if (!terse)
667 			printf("\t");
668 		showunit(have);
669 		if (!terse) {
670 			if (verbose)
671 				printf("\t%s = ", wantstr);
672 			else
673 				printf("\t");
674 			showunit(want);
675 		}
676 	}
677 	else if (have->offset != want->offset) {
678 		if (want->quantity)
679 			printf("WARNING: conversion of non-proportional quantities.\n");
680 		if (have->quantity) {
681 			asprintf(&oformat, "\t%s\n", outputformat);
682 			printf(oformat,
683 			    (have->factor + have->offset-want->offset)/want->factor);
684 			free(oformat);
685 		}
686 		else {
687 			asprintf(&oformat, "\t (-> x*%sg %sg)\n\t (<- y*%sg %sg)\n",
688 			    outputformat, outputformat, outputformat, outputformat);
689 			printf(oformat,
690 			    have->factor / want->factor,
691 			    (have->offset-want->offset)/want->factor,
692 			    want->factor / have->factor,
693 			    (want->offset - have->offset)/have->factor);
694 		}
695 	}
696 	else {
697 		ans = have->factor / want->factor;
698 
699 		if (verbose) {
700 			printf("\t%s = ", havestr);
701 			printf(outputformat, ans);
702 			printf(" * %s", wantstr);
703 			printf("\n");
704 		}
705 		else if (terse) {
706 			printf(outputformat, ans);
707 			printf("\n");
708 		}
709 		else {
710 			printf("\t* ");
711 			printf(outputformat, ans);
712 			printf("\n");
713 		}
714 
715 		if (verbose) {
716 			printf("\t%s = (1 / ", havestr);
717 			printf(outputformat, 1/ans);
718 			printf(") * %s\n", wantstr);
719 		}
720 		else if (!terse) {
721 			printf("\t/ ");
722 			printf(outputformat, 1/ans);
723 			printf("\n");
724 		}
725 	}
726 }
727 
728 
729 static void
730 usage(void)
731 {
732 	fprintf(stderr,
733 		"usage: units [-f unitsfile] [-H historyfile] [-UVq] [from-unit to-unit]\n");
734 	exit(3);
735 }
736 
737 static struct option longopts[] = {
738 	{"help", no_argument, NULL, 'h'},
739 	{"exponential", no_argument, NULL, 'e'},
740 	{"file", required_argument, NULL, 'f'},
741 	{"history", required_argument, NULL, 'H'},
742 	{"output-format", required_argument, NULL, 'o'},
743 	{"quiet", no_argument, NULL, 'q'},
744 	{"terse", no_argument, NULL, 't'},
745 	{"unitsfile", no_argument, NULL, 'U'},
746 	{"verbose", no_argument, NULL, 'v'},
747 	{"version", no_argument, NULL, 'V'},
748 	{ 0, 0, 0, 0 }
749 };
750 
751 
752 int
753 main(int argc, char **argv)
754 {
755 
756 	struct unittype have, want;
757 	int optchar;
758 	bool quiet;
759 	bool readfile;
760 	bool quit;
761 	History *inhistory;
762 	EditLine *el;
763 	HistEvent ev;
764 	int inputsz;
765 	char const * history_file;
766 
767 	quiet = false;
768 	readfile = false;
769 	history_file = NULL;
770 	outputformat = numfmt;
771 	quit = false;
772 	while ((optchar = getopt_long(argc, argv, "+ehf:o:qtvH:UV", longopts, NULL)) != -1) {
773 		switch (optchar) {
774 		case 'e':
775 			outputformat = "%6e";
776 			break;
777 		case 'f':
778 			readfile = true;
779 			if (strlen(optarg) == 0)
780 				readunits(NULL);
781 			else
782 				readunits(optarg);
783 			break;
784 		case 'H':
785 			history_file = optarg;
786 			break;
787 		case 'q':
788 			quiet = true;
789 			break;
790 		case 't':
791 			terse = true;
792 			break;
793 		case 'o':
794 			outputformat = optarg;
795 			break;
796 		case 'v':
797 			verbose = true;
798 			break;
799 		case 'V':
800 			fprintf(stderr, "FreeBSD units\n");
801 			/* FALLTHROUGH */
802 		case 'U':
803 			if (access(UNITSFILE, F_OK) == 0)
804 				printf("%s\n", UNITSFILE);
805 			else
806 				printf("Units data file not found");
807 			exit(0);
808 			break;
809 		case 'h':
810 			/* FALLTHROUGH */
811 
812 		default:
813 			usage();
814 		}
815 	}
816 
817 	if (!readfile)
818 		readunits(NULL);
819 
820 	if (optind == argc - 2) {
821 		if (cap_enter() < 0 && errno != ENOSYS)
822 			err(1, "unable to enter capability mode");
823 
824 		havestr = argv[optind];
825 		wantstr = argv[optind + 1];
826 		initializeunit(&have);
827 		addunit(&have, havestr, 0, 1);
828 		completereduce(&have);
829 		initializeunit(&want);
830 		addunit(&want, wantstr, 0, 1);
831 		completereduce(&want);
832 		showanswer(&have, &want);
833 	} else {
834 		inhistory = history_init();
835 		el = el_init(argv[0], stdin, stdout, stderr);
836 		el_set(el, EL_PROMPT, &prompt);
837 		el_set(el, EL_EDITOR, "emacs");
838 		el_set(el, EL_SIGNAL, 1);
839 		el_set(el, EL_HIST, history, inhistory);
840 		el_source(el, NULL);
841 		history(inhistory, &ev, H_SETSIZE, 800);
842 		if (inhistory == 0)
843 			err(1, "Could not initialize history");
844 
845 		if (cap_enter() < 0 && errno != ENOSYS)
846 			err(1, "unable to enter capability mode");
847 
848 		if (!quiet)
849 			printf("%d units, %d prefixes\n", unitcount,
850 			    prefixcount);
851 		while (!quit) {
852 			do {
853 				initializeunit(&have);
854 				if (!quiet)
855 					promptstr = "You have: ";
856 				havestr = el_gets(el, &inputsz);
857 				if (havestr == NULL) {
858 					quit = true;
859 					break;
860 				}
861 				if (inputsz > 0)
862 					history(inhistory, &ev, H_ENTER,
863 					havestr);
864 			} while (addunit(&have, havestr, 0, 1) ||
865 			    completereduce(&have));
866 			if (quit) {
867 				break;
868 			}
869 			do {
870 				initializeunit(&want);
871 				if (!quiet)
872 					promptstr = "You want: ";
873 				wantstr = el_gets(el, &inputsz);
874 				if (wantstr == NULL) {
875 					quit = true;
876 					break;
877 				}
878 				if (inputsz > 0)
879 					history(inhistory, &ev, H_ENTER,
880 					wantstr);
881 			} while (addunit(&want, wantstr, 0, 1) ||
882 			    completereduce(&want));
883 			if (quit) {
884 				break;
885 			}
886 			showanswer(&have, &want);
887 		}
888 
889 		history_end(inhistory);
890 		el_end(el);
891 	}
892 
893 	return (0);
894 }
895