xref: /freebsd/usr.bin/units/units.c (revision 535af610) 
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 <capsicum_helpers.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 (caph_rights_limit(fileno(unitfile), &unitfilerights) < 0)
160 		err(1, "cap_rights_limit() failed");
161 	while (!feof(unitfile)) {
162 		if (!fgets(line, sizeof(line), unitfile))
163 			break;
164 		linenum++;
165 		lineptr = line;
166 		if (*lineptr == '/' || *lineptr == '#')
167 			continue;
168 		lineptr += strspn(lineptr, " \n\t");
169 		len = strcspn(lineptr, " \n\t");
170 		lineptr[len] = 0;
171 		if (!strlen(lineptr))
172 			continue;
173 		if (lineptr[strlen(lineptr) - 1] == '-') { /* it's a prefix */
174 			if (prefixcount == MAXPREFIXES) {
175 				warnx("memory for prefixes exceeded in line %d", linenum);
176 				continue;
177 			}
178 			lineptr[strlen(lineptr) - 1] = 0;
179 			prefixtable[prefixcount].prefixname = dupstr(lineptr);
180 			for (i = 0; i < prefixcount; i++)
181 				if (!strcmp(prefixtable[i].prefixname, lineptr)) {
182 					warnx("redefinition of prefix '%s' on line %d ignored",
183 					    lineptr, linenum);
184 					continue;
185 				}
186 			lineptr += len + 1;
187 			lineptr += strspn(lineptr, " \n\t");
188 			len = strcspn(lineptr, "\n\t");
189 			if (len == 0) {
190 				warnx("unexpected end of prefix on line %d",
191 				    linenum);
192 				continue;
193 			}
194 			lineptr[len] = 0;
195 			prefixtable[prefixcount++].prefixval = dupstr(lineptr);
196 		}
197 		else {		/* it's not a prefix */
198 			if (unitcount == MAXUNITS) {
199 				warnx("memory for units exceeded in line %d", linenum);
200 				continue;
201 			}
202 			unittable[unitcount].uname = dupstr(lineptr);
203 			for (i = 0; i < unitcount; i++)
204 				if (!strcmp(unittable[i].uname, lineptr)) {
205 					warnx("redefinition of unit '%s' on line %d ignored",
206 					    lineptr, linenum);
207 					continue;
208 				}
209 			lineptr += len + 1;
210 			lineptr += strspn(lineptr, " \n\t");
211 			if (!strlen(lineptr)) {
212 				warnx("unexpected end of unit on line %d",
213 				    linenum);
214 				continue;
215 			}
216 			len = strcspn(lineptr, "\n\t");
217 			lineptr[len] = 0;
218 			unittable[unitcount++].uval = dupstr(lineptr);
219 		}
220 	}
221 	fclose(unitfile);
222 }
223 
224 static void
225 initializeunit(struct unittype * theunit)
226 {
227 	theunit->numerator[0] = theunit->denominator[0] = NULL;
228 	theunit->factor = 1.0;
229 	theunit->offset = 0.0;
230 	theunit->quantity = 0;
231 }
232 
233 
234 static int
235 addsubunit(char *product[], char *toadd)
236 {
237 	char **ptr;
238 
239 	for (ptr = product; *ptr && *ptr != NULLUNIT; ptr++);
240 	if (ptr >= product + MAXSUBUNITS) {
241 		warnx("memory overflow in unit reduction");
242 		return 1;
243 	}
244 	if (!*ptr)
245 		*(ptr + 1) = NULL;
246 	*ptr = dupstr(toadd);
247 	return 0;
248 }
249 
250 
251 static void
252 showunit(struct unittype * theunit)
253 {
254 	char **ptr;
255 	int printedslash;
256 	int counter = 1;
257 
258 	printf(numfmt, theunit->factor);
259 	if (theunit->offset)
260 		printf("&%.8g", theunit->offset);
261 	for (ptr = theunit->numerator; *ptr; ptr++) {
262 		if (ptr > theunit->numerator && **ptr &&
263 		    !strcmp(*ptr, *(ptr - 1)))
264 			counter++;
265 		else {
266 			if (counter > 1)
267 				printf("%s%d", powerstring, counter);
268 			if (**ptr)
269 				printf(" %s", *ptr);
270 			counter = 1;
271 		}
272 	}
273 	if (counter > 1)
274 		printf("%s%d", powerstring, counter);
275 	counter = 1;
276 	printedslash = 0;
277 	for (ptr = theunit->denominator; *ptr; ptr++) {
278 		if (ptr > theunit->denominator && **ptr &&
279 		    !strcmp(*ptr, *(ptr - 1)))
280 			counter++;
281 		else {
282 			if (counter > 1)
283 				printf("%s%d", powerstring, counter);
284 			if (**ptr) {
285 				if (!printedslash)
286 					printf(" /");
287 				printedslash = 1;
288 				printf(" %s", *ptr);
289 			}
290 			counter = 1;
291 		}
292 	}
293 	if (counter > 1)
294 		printf("%s%d", powerstring, counter);
295 	printf("\n");
296 }
297 
298 
299 void
300 zeroerror(void)
301 {
302 	warnx("unit reduces to zero");
303 }
304 
305 /*
306    Adds the specified string to the unit.
307    Flip is 0 for adding normally, 1 for adding reciprocal.
308    Quantity is 1 if this is a quantity to be converted rather than a pure unit.
309 
310    Returns 0 for successful addition, nonzero on error.
311 */
312 
313 static int
314 addunit(struct unittype * theunit, const char *toadd, int flip, int quantity)
315 {
316 	char *scratch, *savescr;
317 	char *item;
318 	char *divider, *slash, *offset;
319 	int doingtop;
320 
321 	if (!strlen(toadd))
322 		return 1;
323 
324 	savescr = scratch = dupstr(toadd);
325 	for (slash = scratch + 1; *slash; slash++)
326 		if (*slash == '-' &&
327 		    (tolower(*(slash - 1)) != 'e' ||
328 		    !strchr(".0123456789", *(slash + 1))))
329 			*slash = ' ';
330 	slash = strchr(scratch, '/');
331 	if (slash)
332 		*slash = 0;
333 	doingtop = 1;
334 	do {
335 		item = strtok(scratch, " *\t\n/");
336 		while (item) {
337 			if (strchr("0123456789.", *item)) { /* item is a number */
338 				double num, offsetnum;
339 
340 				if (quantity)
341 					theunit->quantity = 1;
342 
343 				offset = strchr(item, '&');
344 				if (offset) {
345 					*offset = 0;
346 					offsetnum = atof(offset+1);
347 				} else
348 					offsetnum = 0.0;
349 
350 				divider = strchr(item, '|');
351 				if (divider) {
352 					*divider = 0;
353 					num = atof(item);
354 					if (!num) {
355 						zeroerror();
356 						free(savescr);
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 						free(savescr);
370 						return 1;
371 					}
372 					if (doingtop ^ flip) {
373 						theunit->factor /= num;
374 						theunit->offset /= num;
375 					} else {
376 						theunit->factor *= num;
377 						theunit->offset *= num;
378 					}
379 				}
380 				else {
381 					num = atof(item);
382 					if (!num) {
383 						zeroerror();
384 						free(savescr);
385 						return 1;
386 					}
387 					if (doingtop ^ flip) {
388 						theunit->factor *= num;
389 						theunit->offset *= num;
390 					} else {
391 						theunit->factor /= num;
392 						theunit->offset /= num;
393 					}
394 				}
395 				if (doingtop ^ flip)
396 					theunit->offset += offsetnum;
397 			}
398 			else {	/* item is not a number */
399 				int repeat = 1;
400 
401 				if (strchr("23456789",
402 				    item[strlen(item) - 1])) {
403 					repeat = item[strlen(item) - 1] - '0';
404 					item[strlen(item) - 1] = 0;
405 				}
406 				for (; repeat; repeat--) {
407 					if (addsubunit(doingtop ^ flip ? theunit->numerator : theunit->denominator, item)) {
408 						free(savescr);
409 						return 1;
410 					}
411 				}
412 			}
413 			item = strtok(NULL, " *\t/\n");
414 		}
415 		doingtop--;
416 		if (slash) {
417 			scratch = slash + 1;
418 		}
419 		else
420 			doingtop--;
421 	} while (doingtop >= 0);
422 	free(savescr);
423 	return 0;
424 }
425 
426 
427 static int
428 compare(const void *item1, const void *item2)
429 {
430 	return strcmp(*(const char * const *)item1, *(const char * const *)item2);
431 }
432 
433 
434 static void
435 sortunit(struct unittype * theunit)
436 {
437 	char **ptr;
438 	unsigned int count;
439 
440 	for (count = 0, ptr = theunit->numerator; *ptr; ptr++, count++);
441 	qsort(theunit->numerator, count, sizeof(char *), compare);
442 	for (count = 0, ptr = theunit->denominator; *ptr; ptr++, count++);
443 	qsort(theunit->denominator, count, sizeof(char *), compare);
444 }
445 
446 
447 void
448 cancelunit(struct unittype * theunit)
449 {
450 	char **den, **num;
451 	int comp;
452 
453 	den = theunit->denominator;
454 	num = theunit->numerator;
455 
456 	while (*num && *den) {
457 		comp = strcmp(*den, *num);
458 		if (!comp) {
459 /*      if (*den!=NULLUNIT) free(*den);
460       if (*num!=NULLUNIT) free(*num);*/
461 			*den++ = NULLUNIT;
462 			*num++ = NULLUNIT;
463 		}
464 		else if (comp < 0)
465 			den++;
466 		else
467 			num++;
468 	}
469 }
470 
471 
472 
473 
474 /*
475    Looks up the definition for the specified unit.
476    Returns a pointer to the definition or a null pointer
477    if the specified unit does not appear in the units table.
478 */
479 
480 static char buffer[100];	/* buffer for lookupunit answers with
481 				   prefixes */
482 
483 char *
484 lookupunit(const char *unit)
485 {
486 	int i;
487 	char *copy;
488 
489 	for (i = 0; i < unitcount; i++) {
490 		if (!strcmp(unittable[i].uname, unit))
491 			return unittable[i].uval;
492 	}
493 
494 	if (unit[strlen(unit) - 1] == '^') {
495 		copy = dupstr(unit);
496 		copy[strlen(copy) - 1] = 0;
497 		for (i = 0; i < unitcount; i++) {
498 			if (!strcmp(unittable[i].uname, copy)) {
499 				strlcpy(buffer, copy, sizeof(buffer));
500 				free(copy);
501 				return buffer;
502 			}
503 		}
504 		free(copy);
505 	}
506 	if (unit[strlen(unit) - 1] == 's') {
507 		copy = dupstr(unit);
508 		copy[strlen(copy) - 1] = 0;
509 		for (i = 0; i < unitcount; i++) {
510 			if (!strcmp(unittable[i].uname, copy)) {
511 				strlcpy(buffer, copy, sizeof(buffer));
512 				free(copy);
513 				return buffer;
514 			}
515 		}
516 		if (copy[strlen(copy) - 1] == 'e') {
517 			copy[strlen(copy) - 1] = 0;
518 			for (i = 0; i < unitcount; i++) {
519 				if (!strcmp(unittable[i].uname, copy)) {
520 					strlcpy(buffer, copy, sizeof(buffer));
521 					free(copy);
522 					return buffer;
523 				}
524 			}
525 		}
526 		free(copy);
527 	}
528 	for (i = 0; i < prefixcount; i++) {
529 		size_t len = strlen(prefixtable[i].prefixname);
530 		if (!strncmp(prefixtable[i].prefixname, unit, len)) {
531 			if (!strlen(unit + len) || lookupunit(unit + len)) {
532 				snprintf(buffer, sizeof(buffer), "%s %s",
533 				    prefixtable[i].prefixval, unit + len);
534 				return buffer;
535 			}
536 		}
537 	}
538 	return 0;
539 }
540 
541 
542 
543 /*
544    reduces a product of symbolic units to primitive units.
545    The three low bits are used to return flags:
546 
547      bit 0 (1) set on if reductions were performed without error.
548      bit 1 (2) set on if no reductions are performed.
549      bit 2 (4) set on if an unknown unit is discovered.
550 */
551 
552 
553 #define ERROR 4
554 
555 static int
556 reduceproduct(struct unittype * theunit, int flip)
557 {
558 
559 	char *toadd;
560 	char **product;
561 	int didsomething = 2;
562 
563 	if (flip)
564 		product = theunit->denominator;
565 	else
566 		product = theunit->numerator;
567 
568 	for (; *product; product++) {
569 
570 		for (;;) {
571 			if (!strlen(*product))
572 				break;
573 			toadd = lookupunit(*product);
574 			if (!toadd) {
575 				printf("unknown unit '%s'\n", *product);
576 				return ERROR;
577 			}
578 			if (strchr(toadd, PRIMITIVECHAR))
579 				break;
580 			didsomething = 1;
581 			if (*product != NULLUNIT) {
582 				free(*product);
583 				*product = NULLUNIT;
584 			}
585 			if (addunit(theunit, toadd, flip, 0))
586 				return ERROR;
587 		}
588 	}
589 	return didsomething;
590 }
591 
592 
593 /*
594    Reduces numerator and denominator of the specified unit.
595    Returns 0 on success, or 1 on unknown unit error.
596 */
597 
598 static int
599 reduceunit(struct unittype * theunit)
600 {
601 	int ret;
602 
603 	ret = 1;
604 	while (ret & 1) {
605 		ret = reduceproduct(theunit, 0) | reduceproduct(theunit, 1);
606 		if (ret & 4)
607 			return 1;
608 	}
609 	return 0;
610 }
611 
612 
613 static int
614 compareproducts(char **one, char **two)
615 {
616 	while (*one || *two) {
617 		if (!*one && *two != NULLUNIT)
618 			return 1;
619 		if (!*two && *one != NULLUNIT)
620 			return 1;
621 		if (*one == NULLUNIT)
622 			one++;
623 		else if (*two == NULLUNIT)
624 			two++;
625 		else if (strcmp(*one, *two))
626 			return 1;
627 		else {
628 			one++;
629 			two++;
630 		}
631 	}
632 	return 0;
633 }
634 
635 
636 /* Return zero if units are compatible, nonzero otherwise */
637 
638 static int
639 compareunits(struct unittype * first, struct unittype * second)
640 {
641 	return
642 	compareproducts(first->numerator, second->numerator) ||
643 	compareproducts(first->denominator, second->denominator);
644 }
645 
646 
647 static int
648 completereduce(struct unittype * unit)
649 {
650 	if (reduceunit(unit))
651 		return 1;
652 	sortunit(unit);
653 	cancelunit(unit);
654 	return 0;
655 }
656 
657 static void
658 showanswer(struct unittype * have, struct unittype * want)
659 {
660 	double ans;
661 	char* oformat;
662 
663 	if (compareunits(have, want)) {
664 		printf("conformability error\n");
665 		if (verbose)
666 			printf("\t%s = ", havestr);
667 		else if (!terse)
668 			printf("\t");
669 		showunit(have);
670 		if (!terse) {
671 			if (verbose)
672 				printf("\t%s = ", wantstr);
673 			else
674 				printf("\t");
675 			showunit(want);
676 		}
677 	}
678 	else if (have->offset != want->offset) {
679 		if (want->quantity)
680 			printf("WARNING: conversion of non-proportional quantities.\n");
681 		if (have->quantity) {
682 			asprintf(&oformat, "\t%s\n", outputformat);
683 			printf(oformat,
684 			    (have->factor + have->offset-want->offset)/want->factor);
685 			free(oformat);
686 		}
687 		else {
688 			asprintf(&oformat, "\t (-> x*%sg %sg)\n\t (<- y*%sg %sg)\n",
689 			    outputformat, outputformat, outputformat, outputformat);
690 			printf(oformat,
691 			    have->factor / want->factor,
692 			    (have->offset-want->offset)/want->factor,
693 			    want->factor / have->factor,
694 			    (want->offset - have->offset)/have->factor);
695 		}
696 	}
697 	else {
698 		ans = have->factor / want->factor;
699 
700 		if (verbose) {
701 			printf("\t%s = ", havestr);
702 			printf(outputformat, ans);
703 			printf(" * %s", wantstr);
704 			printf("\n");
705 		}
706 		else if (terse) {
707 			printf(outputformat, ans);
708 			printf("\n");
709 		}
710 		else {
711 			printf("\t* ");
712 			printf(outputformat, ans);
713 			printf("\n");
714 		}
715 
716 		if (verbose) {
717 			printf("\t%s = (1 / ", havestr);
718 			printf(outputformat, 1/ans);
719 			printf(") * %s\n", wantstr);
720 		}
721 		else if (!terse) {
722 			printf("\t/ ");
723 			printf(outputformat, 1/ans);
724 			printf("\n");
725 		}
726 	}
727 }
728 
729 
730 static void __dead2
731 usage(void)
732 {
733 	fprintf(stderr,
734 	    "usage: units [-ehqtUVv] [-f unitsfile] [-o format] [from to]\n");
735 	exit(3);
736 }
737 
738 static struct option longopts[] = {
739 	{"exponential", no_argument, NULL, 'e'},
740 	{"file", required_argument, NULL, 'f'},
741 	{"history", required_argument, NULL, 'H'},
742 	{"help", no_argument, NULL, 'h'},
743 	{"output-format", required_argument, NULL, 'o'},
744 	{"quiet", no_argument, NULL, 'q'},
745 	{"terse", no_argument, NULL, 't'},
746 	{"unitsfile", no_argument, NULL, 'U'},
747 	{"version", no_argument, NULL, 'V'},
748 	{"verbose", no_argument, NULL, 'v'},
749 	{ 0, 0, 0, 0 }
750 };
751 
752 
753 int
754 main(int argc, char **argv)
755 {
756 
757 	struct unittype have, want;
758 	int optchar;
759 	bool quiet;
760 	bool readfile;
761 	bool quit;
762 	History *inhistory;
763 	EditLine *el;
764 	HistEvent ev;
765 	int inputsz;
766 
767 	quiet = false;
768 	readfile = false;
769 	outputformat = numfmt;
770 	quit = false;
771 	while ((optchar = getopt_long(argc, argv, "+ehf:o:qtvH:UV", longopts, NULL)) != -1) {
772 		switch (optchar) {
773 		case 'e':
774 			outputformat = "%6e";
775 			break;
776 		case 'f':
777 			readfile = true;
778 			if (strlen(optarg) == 0)
779 				readunits(NULL);
780 			else
781 				readunits(optarg);
782 			break;
783 		case 'H':
784 			/* Ignored, for compatibility with GNU units. */
785 			break;
786 		case 'q':
787 			quiet = true;
788 			break;
789 		case 't':
790 			terse = true;
791 			break;
792 		case 'o':
793 			outputformat = optarg;
794 			break;
795 		case 'v':
796 			verbose = true;
797 			break;
798 		case 'V':
799 			fprintf(stderr, "FreeBSD units\n");
800 			/* FALLTHROUGH */
801 		case 'U':
802 			if (access(UNITSFILE, F_OK) == 0)
803 				printf("%s\n", UNITSFILE);
804 			else
805 				printf("Units data file not found");
806 			exit(0);
807 		case 'h':
808 			/* FALLTHROUGH */
809 
810 		default:
811 			usage();
812 		}
813 	}
814 
815 	if (!readfile)
816 		readunits(NULL);
817 
818 	if (optind == argc - 2) {
819 		if (caph_enter() < 0)
820 			err(1, "unable to enter capability mode");
821 
822 		havestr = argv[optind];
823 		wantstr = argv[optind + 1];
824 		initializeunit(&have);
825 		addunit(&have, havestr, 0, 1);
826 		completereduce(&have);
827 		initializeunit(&want);
828 		addunit(&want, wantstr, 0, 1);
829 		completereduce(&want);
830 		showanswer(&have, &want);
831 	} else {
832 		inhistory = history_init();
833 		el = el_init(argv[0], stdin, stdout, stderr);
834 		el_set(el, EL_PROMPT, &prompt);
835 		el_set(el, EL_EDITOR, "emacs");
836 		el_set(el, EL_SIGNAL, 1);
837 		el_set(el, EL_HIST, history, inhistory);
838 		el_source(el, NULL);
839 		history(inhistory, &ev, H_SETSIZE, 800);
840 		if (inhistory == 0)
841 			err(1, "Could not initialize history");
842 
843 		if (caph_enter() < 0)
844 			err(1, "unable to enter capability mode");
845 
846 		if (!quiet)
847 			printf("%d units, %d prefixes\n", unitcount,
848 			    prefixcount);
849 		while (!quit) {
850 			do {
851 				initializeunit(&have);
852 				if (!quiet)
853 					promptstr = "You have: ";
854 				havestr = el_gets(el, &inputsz);
855 				if (havestr == NULL) {
856 					quit = true;
857 					break;
858 				}
859 				if (inputsz > 0)
860 					history(inhistory, &ev, H_ENTER,
861 					havestr);
862 			} while (addunit(&have, havestr, 0, 1) ||
863 			    completereduce(&have));
864 			if (quit) {
865 				break;
866 			}
867 			do {
868 				initializeunit(&want);
869 				if (!quiet)
870 					promptstr = "You want: ";
871 				wantstr = el_gets(el, &inputsz);
872 				if (wantstr == NULL) {
873 					quit = true;
874 					break;
875 				}
876 				if (inputsz > 0)
877 					history(inhistory, &ev, H_ENTER,
878 					wantstr);
879 			} while (addunit(&want, wantstr, 0, 1) ||
880 			    completereduce(&want));
881 			if (quit) {
882 				break;
883 			}
884 			showanswer(&have, &want);
885 		}
886 
887 		history_end(inhistory);
888 		el_end(el);
889 	}
890 
891 	return (0);
892 }
893