xref: /freebsd/usr.bin/units/units.c (revision b985c9ca) 
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 #include <ctype.h>
21 #include <err.h>
22 #include <errno.h>
23 #include <histedit.h>
24 #include <getopt.h>
25 #include <stdbool.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30 
31 #include <capsicum_helpers.h>
32 
33 #ifndef UNITSFILE
34 #define UNITSFILE "/usr/share/misc/definitions.units"
35 #endif
36 
37 #define MAXUNITS 1000
38 #define MAXPREFIXES 100
39 
40 #define MAXSUBUNITS 500
41 
42 #define PRIMITIVECHAR '!'
43 
44 static const char *powerstring = "^";
45 static const char *numfmt = "%.8g";
46 
47 static struct {
48 	char *uname;
49 	char *uval;
50 }      unittable[MAXUNITS];
51 
52 struct unittype {
53 	char *numerator[MAXSUBUNITS];
54 	char *denominator[MAXSUBUNITS];
55 	double factor;
56 	double offset;
57 	int quantity;
58 };
59 
60 static struct {
61 	char *prefixname;
62 	char *prefixval;
63 }      prefixtable[MAXPREFIXES];
64 
65 
66 static char NULLUNIT[] = "";
67 
68 #define SEPARATOR      ":"
69 
70 static int unitcount;
71 static int prefixcount;
72 static bool verbose = false;
73 static bool terse = false;
74 static const char * outputformat;
75 static const char * havestr;
76 static const char * wantstr;
77 
78 static int	 addsubunit(char *product[], char *toadd);
79 static int	 addunit(struct unittype *theunit, const char *toadd, int flip, int quantity);
80 static void	 cancelunit(struct unittype * theunit);
81 static int	 compare(const void *item1, const void *item2);
82 static int	 compareproducts(char **one, char **two);
83 static int	 compareunits(struct unittype * first, struct unittype * second);
84 static int	 completereduce(struct unittype * unit);
85 static char	*dupstr(const char *str);
86 static void	 initializeunit(struct unittype * theunit);
87 static char	*lookupunit(const char *unit);
88 static void	 readunits(const char *userfile);
89 static int	 reduceproduct(struct unittype * theunit, int flip);
90 static int	 reduceunit(struct unittype * theunit);
91 static void	 showanswer(struct unittype * have, struct unittype * want);
92 static void	 showunit(struct unittype * theunit);
93 static void	 sortunit(struct unittype * theunit);
94 static void	 usage(void);
95 static void	 zeroerror(void);
96 
97 static const char* promptstr = "";
98 
99 static const char * prompt(EditLine *e __unused) {
100 	return promptstr;
101 }
102 
103 static char *
104 dupstr(const char *str)
105 {
106 	char *ret;
107 
108 	ret = strdup(str);
109 	if (!ret)
110 		err(3, "dupstr");
111 	return (ret);
112 }
113 
114 
115 static void
116 readunits(const char *userfile)
117 {
118 	FILE *unitfile;
119 	char line[512], *lineptr;
120 	int len, linenum, i;
121 	cap_rights_t unitfilerights;
122 
123 	unitcount = 0;
124 	linenum = 0;
125 
126 	if (userfile) {
127 		unitfile = fopen(userfile, "r");
128 		if (!unitfile)
129 			errx(1, "unable to open units file '%s'", userfile);
130 	}
131 	else {
132 		unitfile = fopen(UNITSFILE, "r");
133 		if (!unitfile) {
134 			char *direc, *env;
135 			char filename[1000];
136 
137 			env = getenv("PATH");
138 			if (env) {
139 				direc = strtok(env, SEPARATOR);
140 				while (direc) {
141 					snprintf(filename, sizeof(filename),
142 					    "%s/%s", direc, UNITSFILE);
143 					unitfile = fopen(filename, "rt");
144 					if (unitfile)
145 						break;
146 					direc = strtok(NULL, SEPARATOR);
147 				}
148 			}
149 			if (!unitfile)
150 				errx(1, "can't find units file '%s'", UNITSFILE);
151 		}
152 	}
153 	cap_rights_init(&unitfilerights, CAP_READ, CAP_FSTAT);
154 	if (caph_rights_limit(fileno(unitfile), &unitfilerights) < 0)
155 		err(1, "cap_rights_limit() failed");
156 	while (!feof(unitfile)) {
157 		if (!fgets(line, sizeof(line), unitfile))
158 			break;
159 		linenum++;
160 		lineptr = line;
161 		if (*lineptr == '/' || *lineptr == '#')
162 			continue;
163 		lineptr += strspn(lineptr, " \n\t");
164 		len = strcspn(lineptr, " \n\t");
165 		lineptr[len] = 0;
166 		if (!strlen(lineptr))
167 			continue;
168 		if (lineptr[strlen(lineptr) - 1] == '-') { /* it's a prefix */
169 			if (prefixcount == MAXPREFIXES) {
170 				warnx("memory for prefixes exceeded in line %d", linenum);
171 				continue;
172 			}
173 			lineptr[strlen(lineptr) - 1] = 0;
174 			prefixtable[prefixcount].prefixname = dupstr(lineptr);
175 			for (i = 0; i < prefixcount; i++)
176 				if (!strcmp(prefixtable[i].prefixname, lineptr)) {
177 					warnx("redefinition of prefix '%s' on line %d ignored",
178 					    lineptr, linenum);
179 					continue;
180 				}
181 			lineptr += len + 1;
182 			lineptr += strspn(lineptr, " \n\t");
183 			len = strcspn(lineptr, "\n\t");
184 			if (len == 0) {
185 				warnx("unexpected end of prefix on line %d",
186 				    linenum);
187 				continue;
188 			}
189 			lineptr[len] = 0;
190 			prefixtable[prefixcount++].prefixval = dupstr(lineptr);
191 		}
192 		else {		/* it's not a prefix */
193 			if (unitcount == MAXUNITS) {
194 				warnx("memory for units exceeded in line %d", linenum);
195 				continue;
196 			}
197 			unittable[unitcount].uname = dupstr(lineptr);
198 			for (i = 0; i < unitcount; i++)
199 				if (!strcmp(unittable[i].uname, lineptr)) {
200 					warnx("redefinition of unit '%s' on line %d ignored",
201 					    lineptr, linenum);
202 					continue;
203 				}
204 			lineptr += len + 1;
205 			lineptr += strspn(lineptr, " \n\t");
206 			if (!strlen(lineptr)) {
207 				warnx("unexpected end of unit on line %d",
208 				    linenum);
209 				continue;
210 			}
211 			len = strcspn(lineptr, "\n\t");
212 			lineptr[len] = 0;
213 			unittable[unitcount++].uval = dupstr(lineptr);
214 		}
215 	}
216 	fclose(unitfile);
217 }
218 
219 static void
220 initializeunit(struct unittype * theunit)
221 {
222 	theunit->numerator[0] = theunit->denominator[0] = NULL;
223 	theunit->factor = 1.0;
224 	theunit->offset = 0.0;
225 	theunit->quantity = 0;
226 }
227 
228 
229 static int
230 addsubunit(char *product[], char *toadd)
231 {
232 	char **ptr;
233 
234 	for (ptr = product; *ptr && *ptr != NULLUNIT; ptr++);
235 	if (ptr >= product + MAXSUBUNITS) {
236 		warnx("memory overflow in unit reduction");
237 		return 1;
238 	}
239 	if (!*ptr)
240 		*(ptr + 1) = NULL;
241 	*ptr = dupstr(toadd);
242 	return 0;
243 }
244 
245 
246 static void
247 showunit(struct unittype * theunit)
248 {
249 	char **ptr;
250 	int printedslash;
251 	int counter = 1;
252 
253 	printf(numfmt, theunit->factor);
254 	if (theunit->offset)
255 		printf("&%.8g", theunit->offset);
256 	for (ptr = theunit->numerator; *ptr; ptr++) {
257 		if (ptr > theunit->numerator && **ptr &&
258 		    !strcmp(*ptr, *(ptr - 1)))
259 			counter++;
260 		else {
261 			if (counter > 1)
262 				printf("%s%d", powerstring, counter);
263 			if (**ptr)
264 				printf(" %s", *ptr);
265 			counter = 1;
266 		}
267 	}
268 	if (counter > 1)
269 		printf("%s%d", powerstring, counter);
270 	counter = 1;
271 	printedslash = 0;
272 	for (ptr = theunit->denominator; *ptr; ptr++) {
273 		if (ptr > theunit->denominator && **ptr &&
274 		    !strcmp(*ptr, *(ptr - 1)))
275 			counter++;
276 		else {
277 			if (counter > 1)
278 				printf("%s%d", powerstring, counter);
279 			if (**ptr) {
280 				if (!printedslash)
281 					printf(" /");
282 				printedslash = 1;
283 				printf(" %s", *ptr);
284 			}
285 			counter = 1;
286 		}
287 	}
288 	if (counter > 1)
289 		printf("%s%d", powerstring, counter);
290 	printf("\n");
291 }
292 
293 
294 void
295 zeroerror(void)
296 {
297 	warnx("unit reduces to zero");
298 }
299 
300 /*
301    Adds the specified string to the unit.
302    Flip is 0 for adding normally, 1 for adding reciprocal.
303    Quantity is 1 if this is a quantity to be converted rather than a pure unit.
304 
305    Returns 0 for successful addition, nonzero on error.
306 */
307 
308 static int
309 addunit(struct unittype * theunit, const char *toadd, int flip, int quantity)
310 {
311 	char *scratch, *savescr;
312 	char *item;
313 	char *divider, *slash, *offset;
314 	int doingtop;
315 
316 	if (!strlen(toadd))
317 		return 1;
318 
319 	savescr = scratch = dupstr(toadd);
320 	for (slash = scratch + 1; *slash; slash++)
321 		if (*slash == '-' &&
322 		    (tolower(*(slash - 1)) != 'e' ||
323 		    !strchr(".0123456789", *(slash + 1))))
324 			*slash = ' ';
325 	slash = strchr(scratch, '/');
326 	if (slash)
327 		*slash = 0;
328 	doingtop = 1;
329 	do {
330 		item = strtok(scratch, " *\t\n/");
331 		while (item) {
332 			if (strchr("0123456789.", *item)) { /* item is a number */
333 				double num, offsetnum;
334 
335 				if (quantity)
336 					theunit->quantity = 1;
337 
338 				offset = strchr(item, '&');
339 				if (offset) {
340 					*offset = 0;
341 					offsetnum = atof(offset+1);
342 				} else
343 					offsetnum = 0.0;
344 
345 				divider = strchr(item, '|');
346 				if (divider) {
347 					*divider = 0;
348 					num = atof(item);
349 					if (!num) {
350 						zeroerror();
351 						free(savescr);
352 						return 1;
353 					}
354 					if (doingtop ^ flip) {
355 						theunit->factor *= num;
356 						theunit->offset *= num;
357 					} else {
358 						theunit->factor /= num;
359 						theunit->offset /= num;
360 					}
361 					num = atof(divider + 1);
362 					if (!num) {
363 						zeroerror();
364 						free(savescr);
365 						return 1;
366 					}
367 					if (doingtop ^ flip) {
368 						theunit->factor /= num;
369 						theunit->offset /= num;
370 					} else {
371 						theunit->factor *= num;
372 						theunit->offset *= num;
373 					}
374 				}
375 				else {
376 					num = atof(item);
377 					if (!num) {
378 						zeroerror();
379 						free(savescr);
380 						return 1;
381 					}
382 					if (doingtop ^ flip) {
383 						theunit->factor *= num;
384 						theunit->offset *= num;
385 					} else {
386 						theunit->factor /= num;
387 						theunit->offset /= num;
388 					}
389 				}
390 				if (doingtop ^ flip)
391 					theunit->offset += offsetnum;
392 			}
393 			else {	/* item is not a number */
394 				int repeat = 1;
395 
396 				if (strchr("23456789",
397 				    item[strlen(item) - 1])) {
398 					repeat = item[strlen(item) - 1] - '0';
399 					item[strlen(item) - 1] = 0;
400 				}
401 				for (; repeat; repeat--) {
402 					if (addsubunit(doingtop ^ flip ? theunit->numerator : theunit->denominator, item)) {
403 						free(savescr);
404 						return 1;
405 					}
406 				}
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 static 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 static 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 	} else if (unit[strlen(unit) - 1] == 's') {
501 		copy = dupstr(unit);
502 		copy[strlen(copy) - 1] = 0;
503 		for (i = 0; i < unitcount; i++) {
504 			if (!strcmp(unittable[i].uname, copy)) {
505 				strlcpy(buffer, copy, sizeof(buffer));
506 				free(copy);
507 				return buffer;
508 			}
509 		}
510 		if (copy[strlen(copy) - 1] == 'e') {
511 			copy[strlen(copy) - 1] = 0;
512 			for (i = 0; i < unitcount; i++) {
513 				if (!strcmp(unittable[i].uname, copy)) {
514 					strlcpy(buffer, copy, sizeof(buffer));
515 					free(copy);
516 					return buffer;
517 				}
518 			}
519 		}
520 		free(copy);
521 	}
522 	for (i = 0; i < prefixcount; i++) {
523 		size_t len = strlen(prefixtable[i].prefixname);
524 		if (!strncmp(prefixtable[i].prefixname, unit, len)) {
525 			if (!strlen(unit + len) || lookupunit(unit + len)) {
526 				snprintf(buffer, sizeof(buffer), "%s %s",
527 				    prefixtable[i].prefixval, unit + len);
528 				return buffer;
529 			}
530 		}
531 	}
532 	return 0;
533 }
534 
535 
536 
537 /*
538    reduces a product of symbolic units to primitive units.
539    The three low bits are used to return flags:
540 
541      bit 0 (1) set on if reductions were performed without error.
542      bit 1 (2) set on if no reductions are performed.
543      bit 2 (4) set on if an unknown unit is discovered.
544 */
545 
546 
547 #define ERROR 4
548 
549 static int
550 reduceproduct(struct unittype * theunit, int flip)
551 {
552 
553 	char *toadd;
554 	char **product;
555 	int didsomething = 2;
556 
557 	if (flip)
558 		product = theunit->denominator;
559 	else
560 		product = theunit->numerator;
561 
562 	for (; *product; product++) {
563 
564 		for (;;) {
565 			if (!strlen(*product))
566 				break;
567 			toadd = lookupunit(*product);
568 			if (!toadd) {
569 				printf("unknown unit '%s'\n", *product);
570 				return ERROR;
571 			}
572 			if (strchr(toadd, PRIMITIVECHAR))
573 				break;
574 			didsomething = 1;
575 			if (*product != NULLUNIT) {
576 				free(*product);
577 				*product = NULLUNIT;
578 			}
579 			if (addunit(theunit, toadd, flip, 0))
580 				return ERROR;
581 		}
582 	}
583 	return didsomething;
584 }
585 
586 
587 /*
588    Reduces numerator and denominator of the specified unit.
589    Returns 0 on success, or 1 on unknown unit error.
590 */
591 
592 static int
593 reduceunit(struct unittype * theunit)
594 {
595 	int ret;
596 
597 	ret = 1;
598 	while (ret & 1) {
599 		ret = reduceproduct(theunit, 0) | reduceproduct(theunit, 1);
600 		if (ret & 4)
601 			return 1;
602 	}
603 	return 0;
604 }
605 
606 
607 static int
608 compareproducts(char **one, char **two)
609 {
610 	while (*one || *two) {
611 		if (!*one && *two != NULLUNIT)
612 			return 1;
613 		if (!*two && *one != NULLUNIT)
614 			return 1;
615 		if (*one == NULLUNIT)
616 			one++;
617 		else if (*two == NULLUNIT)
618 			two++;
619 		else if (strcmp(*one, *two))
620 			return 1;
621 		else {
622 			one++;
623 			two++;
624 		}
625 	}
626 	return 0;
627 }
628 
629 
630 /* Return zero if units are compatible, nonzero otherwise */
631 
632 static int
633 compareunits(struct unittype * first, struct unittype * second)
634 {
635 	return
636 	compareproducts(first->numerator, second->numerator) ||
637 	compareproducts(first->denominator, second->denominator);
638 }
639 
640 
641 static int
642 completereduce(struct unittype * unit)
643 {
644 	if (reduceunit(unit))
645 		return 1;
646 	sortunit(unit);
647 	cancelunit(unit);
648 	return 0;
649 }
650 
651 static void
652 showanswer(struct unittype * have, struct unittype * want)
653 {
654 	double ans;
655 	char* oformat;
656 
657 	if (compareunits(have, want)) {
658 		printf("conformability error\n");
659 		if (verbose)
660 			printf("\t%s = ", havestr);
661 		else if (!terse)
662 			printf("\t");
663 		showunit(have);
664 		if (!terse) {
665 			if (verbose)
666 				printf("\t%s = ", wantstr);
667 			else
668 				printf("\t");
669 			showunit(want);
670 		}
671 	}
672 	else if (have->offset != want->offset) {
673 		if (want->quantity)
674 			printf("WARNING: conversion of non-proportional quantities.\n");
675 		if (have->quantity) {
676 			asprintf(&oformat, "\t%s\n", outputformat);
677 			printf(oformat,
678 			    (have->factor + have->offset-want->offset)/want->factor);
679 			free(oformat);
680 		}
681 		else {
682 			asprintf(&oformat, "\t (-> x*%sg %sg)\n\t (<- y*%sg %sg)\n",
683 			    outputformat, outputformat, outputformat, outputformat);
684 			printf(oformat,
685 			    have->factor / want->factor,
686 			    (have->offset-want->offset)/want->factor,
687 			    want->factor / have->factor,
688 			    (want->offset - have->offset)/have->factor);
689 		}
690 	}
691 	else {
692 		ans = have->factor / want->factor;
693 
694 		if (verbose) {
695 			printf("\t%s = ", havestr);
696 			printf(outputformat, ans);
697 			printf(" * %s", wantstr);
698 			printf("\n");
699 		}
700 		else if (terse) {
701 			printf(outputformat, ans);
702 			printf("\n");
703 		}
704 		else {
705 			printf("\t* ");
706 			printf(outputformat, ans);
707 			printf("\n");
708 		}
709 
710 		if (verbose) {
711 			printf("\t%s = (1 / ", havestr);
712 			printf(outputformat, 1/ans);
713 			printf(") * %s\n", wantstr);
714 		}
715 		else if (!terse) {
716 			printf("\t/ ");
717 			printf(outputformat, 1/ans);
718 			printf("\n");
719 		}
720 	}
721 }
722 
723 
724 static void __dead2
725 usage(void)
726 {
727 	fprintf(stderr,
728 	    "usage: units [-ehqtUVv] [-f unitsfile] [-o format] [from to]\n");
729 	exit(3);
730 }
731 
732 static struct option longopts[] = {
733 	{"exponential", no_argument, NULL, 'e'},
734 	{"file", required_argument, NULL, 'f'},
735 	{"history", required_argument, NULL, 'H'},
736 	{"help", no_argument, NULL, 'h'},
737 	{"output-format", required_argument, NULL, 'o'},
738 	{"quiet", no_argument, NULL, 'q'},
739 	{"terse", no_argument, NULL, 't'},
740 	{"unitsfile", no_argument, NULL, 'U'},
741 	{"version", no_argument, NULL, 'V'},
742 	{"verbose", no_argument, NULL, 'v'},
743 	{ 0, 0, 0, 0 }
744 };
745 
746 
747 int
748 main(int argc, char **argv)
749 {
750 
751 	struct unittype have, want;
752 	int optchar;
753 	bool quiet;
754 	bool readfile;
755 	bool quit;
756 	History *inhistory;
757 	EditLine *el;
758 	HistEvent ev;
759 	int inputsz;
760 
761 	quiet = false;
762 	readfile = false;
763 	outputformat = numfmt;
764 	quit = false;
765 	while ((optchar = getopt_long(argc, argv, "+ehf:o:qtvH:UV", longopts, NULL)) != -1) {
766 		switch (optchar) {
767 		case 'e':
768 			outputformat = "%6e";
769 			break;
770 		case 'f':
771 			readfile = true;
772 			if (strlen(optarg) == 0)
773 				readunits(NULL);
774 			else
775 				readunits(optarg);
776 			break;
777 		case 'H':
778 			/* Ignored, for compatibility with GNU units. */
779 			break;
780 		case 'q':
781 			quiet = true;
782 			break;
783 		case 't':
784 			terse = true;
785 			break;
786 		case 'o':
787 			outputformat = optarg;
788 			break;
789 		case 'v':
790 			verbose = true;
791 			break;
792 		case 'V':
793 			fprintf(stderr, "FreeBSD units\n");
794 			/* FALLTHROUGH */
795 		case 'U':
796 			if (access(UNITSFILE, F_OK) == 0)
797 				printf("%s\n", UNITSFILE);
798 			else
799 				printf("Units data file not found");
800 			exit(0);
801 		case 'h':
802 			/* FALLTHROUGH */
803 
804 		default:
805 			usage();
806 		}
807 	}
808 
809 	if (!readfile)
810 		readunits(NULL);
811 
812 	if (optind == argc - 2) {
813 		if (caph_enter() < 0)
814 			err(1, "unable to enter capability mode");
815 
816 		havestr = argv[optind];
817 		wantstr = argv[optind + 1];
818 		initializeunit(&have);
819 		addunit(&have, havestr, 0, 1);
820 		completereduce(&have);
821 		initializeunit(&want);
822 		addunit(&want, wantstr, 0, 1);
823 		completereduce(&want);
824 		showanswer(&have, &want);
825 	} else {
826 		inhistory = history_init();
827 		el = el_init(argv[0], stdin, stdout, stderr);
828 		el_set(el, EL_PROMPT, &prompt);
829 		el_set(el, EL_EDITOR, "emacs");
830 		el_set(el, EL_SIGNAL, 1);
831 		el_set(el, EL_HIST, history, inhistory);
832 		el_source(el, NULL);
833 		history(inhistory, &ev, H_SETSIZE, 800);
834 		if (inhistory == 0)
835 			err(1, "Could not initialize history");
836 
837 		if (caph_enter() < 0)
838 			err(1, "unable to enter capability mode");
839 
840 		if (!quiet)
841 			printf("%d units, %d prefixes\n", unitcount,
842 			    prefixcount);
843 		while (!quit) {
844 			do {
845 				initializeunit(&have);
846 				if (!quiet)
847 					promptstr = "You have: ";
848 				havestr = el_gets(el, &inputsz);
849 				if (havestr == NULL) {
850 					quit = true;
851 					break;
852 				}
853 				if (inputsz > 0)
854 					history(inhistory, &ev, H_ENTER,
855 					havestr);
856 			} while (addunit(&have, havestr, 0, 1) ||
857 			    completereduce(&have));
858 			if (quit) {
859 				break;
860 			}
861 			do {
862 				initializeunit(&want);
863 				if (!quiet)
864 					promptstr = "You want: ";
865 				wantstr = el_gets(el, &inputsz);
866 				if (wantstr == NULL) {
867 					quit = true;
868 					break;
869 				}
870 				if (inputsz > 0)
871 					history(inhistory, &ev, H_ENTER,
872 					wantstr);
873 			} while (addunit(&want, wantstr, 0, 1) ||
874 			    completereduce(&want));
875 			if (quit) {
876 				break;
877 			}
878 			showanswer(&have, &want);
879 		}
880 
881 		history_end(inhistory);
882 		el_end(el);
883 	}
884 
885 	return (0);
886 }
887