xref: /freebsd/usr.bin/units/units.c (revision 069ac184) 
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 	}
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 static 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 static 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 static 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++;
624 			two++;
625 		}
626 	}
627 	return 0;
628 }
629 
630 
631 /* Return zero if units are compatible, nonzero otherwise */
632 
633 static int
634 compareunits(struct unittype * first, struct unittype * second)
635 {
636 	return
637 	compareproducts(first->numerator, second->numerator) ||
638 	compareproducts(first->denominator, second->denominator);
639 }
640 
641 
642 static int
643 completereduce(struct unittype * unit)
644 {
645 	if (reduceunit(unit))
646 		return 1;
647 	sortunit(unit);
648 	cancelunit(unit);
649 	return 0;
650 }
651 
652 static void
653 showanswer(struct unittype * have, struct unittype * want)
654 {
655 	double ans;
656 	char* oformat;
657 
658 	if (compareunits(have, want)) {
659 		printf("conformability error\n");
660 		if (verbose)
661 			printf("\t%s = ", havestr);
662 		else if (!terse)
663 			printf("\t");
664 		showunit(have);
665 		if (!terse) {
666 			if (verbose)
667 				printf("\t%s = ", wantstr);
668 			else
669 				printf("\t");
670 			showunit(want);
671 		}
672 	}
673 	else if (have->offset != want->offset) {
674 		if (want->quantity)
675 			printf("WARNING: conversion of non-proportional quantities.\n");
676 		if (have->quantity) {
677 			asprintf(&oformat, "\t%s\n", outputformat);
678 			printf(oformat,
679 			    (have->factor + have->offset-want->offset)/want->factor);
680 			free(oformat);
681 		}
682 		else {
683 			asprintf(&oformat, "\t (-> x*%sg %sg)\n\t (<- y*%sg %sg)\n",
684 			    outputformat, outputformat, outputformat, outputformat);
685 			printf(oformat,
686 			    have->factor / want->factor,
687 			    (have->offset-want->offset)/want->factor,
688 			    want->factor / have->factor,
689 			    (want->offset - have->offset)/have->factor);
690 		}
691 	}
692 	else {
693 		ans = have->factor / want->factor;
694 
695 		if (verbose) {
696 			printf("\t%s = ", havestr);
697 			printf(outputformat, ans);
698 			printf(" * %s", wantstr);
699 			printf("\n");
700 		}
701 		else if (terse) {
702 			printf(outputformat, ans);
703 			printf("\n");
704 		}
705 		else {
706 			printf("\t* ");
707 			printf(outputformat, ans);
708 			printf("\n");
709 		}
710 
711 		if (verbose) {
712 			printf("\t%s = (1 / ", havestr);
713 			printf(outputformat, 1/ans);
714 			printf(") * %s\n", wantstr);
715 		}
716 		else if (!terse) {
717 			printf("\t/ ");
718 			printf(outputformat, 1/ans);
719 			printf("\n");
720 		}
721 	}
722 }
723 
724 
725 static void __dead2
726 usage(void)
727 {
728 	fprintf(stderr,
729 	    "usage: units [-ehqtUVv] [-f unitsfile] [-o format] [from to]\n");
730 	exit(3);
731 }
732 
733 static struct option longopts[] = {
734 	{"exponential", no_argument, NULL, 'e'},
735 	{"file", required_argument, NULL, 'f'},
736 	{"history", required_argument, NULL, 'H'},
737 	{"help", no_argument, NULL, 'h'},
738 	{"output-format", required_argument, NULL, 'o'},
739 	{"quiet", no_argument, NULL, 'q'},
740 	{"terse", no_argument, NULL, 't'},
741 	{"unitsfile", no_argument, NULL, 'U'},
742 	{"version", no_argument, NULL, 'V'},
743 	{"verbose", no_argument, NULL, 'v'},
744 	{ 0, 0, 0, 0 }
745 };
746 
747 
748 int
749 main(int argc, char **argv)
750 {
751 
752 	struct unittype have, want;
753 	int optchar;
754 	bool quiet;
755 	bool readfile;
756 	bool quit;
757 	History *inhistory;
758 	EditLine *el;
759 	HistEvent ev;
760 	int inputsz;
761 
762 	quiet = false;
763 	readfile = false;
764 	outputformat = numfmt;
765 	quit = false;
766 	while ((optchar = getopt_long(argc, argv, "+ehf:o:qtvH:UV", longopts, NULL)) != -1) {
767 		switch (optchar) {
768 		case 'e':
769 			outputformat = "%6e";
770 			break;
771 		case 'f':
772 			readfile = true;
773 			if (strlen(optarg) == 0)
774 				readunits(NULL);
775 			else
776 				readunits(optarg);
777 			break;
778 		case 'H':
779 			/* Ignored, for compatibility with GNU units. */
780 			break;
781 		case 'q':
782 			quiet = true;
783 			break;
784 		case 't':
785 			terse = true;
786 			break;
787 		case 'o':
788 			outputformat = optarg;
789 			break;
790 		case 'v':
791 			verbose = true;
792 			break;
793 		case 'V':
794 			fprintf(stderr, "FreeBSD units\n");
795 			/* FALLTHROUGH */
796 		case 'U':
797 			if (access(UNITSFILE, F_OK) == 0)
798 				printf("%s\n", UNITSFILE);
799 			else
800 				printf("Units data file not found");
801 			exit(0);
802 		case 'h':
803 			/* FALLTHROUGH */
804 
805 		default:
806 			usage();
807 		}
808 	}
809 
810 	if (!readfile)
811 		readunits(NULL);
812 
813 	if (optind == argc - 2) {
814 		if (caph_enter() < 0)
815 			err(1, "unable to enter capability mode");
816 
817 		havestr = argv[optind];
818 		wantstr = argv[optind + 1];
819 		initializeunit(&have);
820 		addunit(&have, havestr, 0, 1);
821 		completereduce(&have);
822 		initializeunit(&want);
823 		addunit(&want, wantstr, 0, 1);
824 		completereduce(&want);
825 		showanswer(&have, &want);
826 	} else {
827 		inhistory = history_init();
828 		el = el_init(argv[0], stdin, stdout, stderr);
829 		el_set(el, EL_PROMPT, &prompt);
830 		el_set(el, EL_EDITOR, "emacs");
831 		el_set(el, EL_SIGNAL, 1);
832 		el_set(el, EL_HIST, history, inhistory);
833 		el_source(el, NULL);
834 		history(inhistory, &ev, H_SETSIZE, 800);
835 		if (inhistory == 0)
836 			err(1, "Could not initialize history");
837 
838 		if (caph_enter() < 0)
839 			err(1, "unable to enter capability mode");
840 
841 		if (!quiet)
842 			printf("%d units, %d prefixes\n", unitcount,
843 			    prefixcount);
844 		while (!quit) {
845 			do {
846 				initializeunit(&have);
847 				if (!quiet)
848 					promptstr = "You have: ";
849 				havestr = el_gets(el, &inputsz);
850 				if (havestr == NULL) {
851 					quit = true;
852 					break;
853 				}
854 				if (inputsz > 0)
855 					history(inhistory, &ev, H_ENTER,
856 					havestr);
857 			} while (addunit(&have, havestr, 0, 1) ||
858 			    completereduce(&have));
859 			if (quit) {
860 				break;
861 			}
862 			do {
863 				initializeunit(&want);
864 				if (!quiet)
865 					promptstr = "You want: ";
866 				wantstr = el_gets(el, &inputsz);
867 				if (wantstr == NULL) {
868 					quit = true;
869 					break;
870 				}
871 				if (inputsz > 0)
872 					history(inhistory, &ev, H_ENTER,
873 					wantstr);
874 			} while (addunit(&want, wantstr, 0, 1) ||
875 			    completereduce(&want));
876 			if (quit) {
877 				break;
878 			}
879 			showanswer(&have, &want);
880 		}
881 
882 		history_end(inhistory);
883 		el_end(el);
884 	}
885 
886 	return (0);
887 }
888