2 * units.c Copyright (c) 1993 by Adrian Mariano (adrian@cam.cornell.edu)
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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.
14 * I would appreciate (though I do not require) receiving a copy of any
15 * improvements you might make to this program.
17 * $FreeBSD: src/usr.bin/units/units.c,v 1.6.2.2 2001/03/04 09:22:35 kris Exp $
18 * $DragonFly: src/usr.bin/units/units.c,v 1.4 2006/08/13 19:19:44 swildner Exp $
28 #include "pathnames.h"
33 #define UNITSFILE _PATH_UNITSLIB
37 #define MAXPREFIXES 100
39 #define MAXSUBUNITS 500
41 #define PRIMITIVECHAR '!'
43 const char *powerstring = "^";
48 } unittable[MAXUNITS];
51 char *numerator[MAXSUBUNITS];
52 char *denominator[MAXSUBUNITS];
59 } prefixtable[MAXPREFIXES];
74 static int addsubunit(char *[], char *);
75 static int addunit(struct unittype *, char *, int);
76 static void cancelunit(struct unittype *);
77 static int compare(const void *, const void *);
78 static int compareproducts(char **, char **);
79 static int compareunits(struct unittype *, struct unittype *);
80 static int completereduce(struct unittype *);
81 static char *dupstr(const char *);
82 static void initializeunit(struct unittype *);
83 static char *lookupunit(const char *);
84 static void readunits(const char *);
85 static int reduceproduct(struct unittype *, int);
86 static int reduceunit(struct unittype *);
87 static void showanswer(struct unittype *, struct unittype *);
88 static void showunit(struct unittype *);
89 static void sortunit(struct unittype *);
90 static void usage(void);
91 static void zeroerror(void);
95 dupstr(const char *str)
99 ret = malloc(strlen(str) + 1);
101 errx(3, "memory allocation error");
108 readunits(const char *userfile)
111 char line[512], *lineptr;
118 unitfile = fopen(userfile, "rt");
120 errx(1, "unable to open units file '%s'", userfile);
123 unitfile = fopen(UNITSFILE, "rt");
128 env = getenv("PATH");
130 direc = strtok(env, SEPARATOR);
132 snprintf(filename, sizeof(filename),
133 "%s/%s", direc, UNITSFILE);
134 unitfile = fopen(filename, "rt");
137 direc = strtok(NULL, SEPARATOR);
141 errx(1, "can't find units file '%s'", UNITSFILE);
144 while (!feof(unitfile)) {
145 if (!fgets(line, sizeof(line), unitfile))
151 lineptr += strspn(lineptr, " \n\t");
152 len = strcspn(lineptr, " \n\t");
154 if (!strlen(lineptr))
156 if (lineptr[strlen(lineptr) - 1] == '-') { /* it's a prefix */
157 if (prefixcount == MAXPREFIXES) {
158 warnx("memory for prefixes exceeded in line %d", linenum);
161 lineptr[strlen(lineptr) - 1] = 0;
162 prefixtable[prefixcount].prefixname = dupstr(lineptr);
163 for (i = 0; i < prefixcount; i++)
164 if (!strcmp(prefixtable[i].prefixname, lineptr)) {
165 warnx("redefinition of prefix '%s' on line %d ignored",
170 lineptr += strspn(lineptr, " \n\t");
171 len = strcspn(lineptr, "\n\t");
173 warnx("unexpected end of prefix on line %d",
178 prefixtable[prefixcount++].prefixval = dupstr(lineptr);
180 else { /* it's not a prefix */
181 if (unitcount == MAXUNITS) {
182 warnx("memory for units exceeded in line %d", linenum);
185 unittable[unitcount].uname = dupstr(lineptr);
186 for (i = 0; i < unitcount; i++)
187 if (!strcmp(unittable[i].uname, lineptr)) {
188 warnx("redefinition of unit '%s' on line %d ignored",
193 lineptr += strspn(lineptr, " \n\t");
194 if (!strlen(lineptr)) {
195 warnx("unexpected end of unit on line %d",
199 len = strcspn(lineptr, "\n\t");
201 unittable[unitcount++].uval = dupstr(lineptr);
208 initializeunit(struct unittype * theunit)
210 theunit->factor = 1.0;
211 theunit->numerator[0] = theunit->denominator[0] = NULL;
216 addsubunit(char *product[], char *toadd)
220 for (ptr = product; *ptr && *ptr != NULLUNIT; ptr++);
221 if (ptr >= product + MAXSUBUNITS) {
222 warnx("memory overflow in unit reduction");
227 *ptr = dupstr(toadd);
233 showunit(struct unittype * theunit)
239 printf("\t%.8g", theunit->factor);
240 for (ptr = theunit->numerator; *ptr; ptr++) {
241 if (ptr > theunit->numerator && **ptr &&
242 !strcmp(*ptr, *(ptr - 1)))
246 printf("%s%d", powerstring, counter);
253 printf("%s%d", powerstring, counter);
256 for (ptr = theunit->denominator; *ptr; ptr++) {
257 if (ptr > theunit->denominator && **ptr &&
258 !strcmp(*ptr, *(ptr - 1)))
262 printf("%s%d", powerstring, counter);
273 printf("%s%d", powerstring, counter);
281 warnx("unit reduces to zero");
285 Adds the specified string to the unit.
286 Flip is 0 for adding normally, 1 for adding reciprocal.
288 Returns 0 for successful addition, nonzero on error.
292 addunit(struct unittype * theunit, char *toadd, int flip)
294 char *scratch, *savescr;
296 char *divider, *slash;
302 savescr = scratch = dupstr(toadd);
303 for (slash = scratch + 1; *slash; slash++)
305 (tolower(*(slash - 1)) != 'e' ||
306 !strchr(".0123456789", *(slash + 1))))
308 slash = strchr(scratch, '/');
313 item = strtok(scratch, " *\t\n/");
315 if (strchr("0123456789.", *item)) { /* item is a number */
318 divider = strchr(item, '|');
327 theunit->factor *= num;
329 theunit->factor /= num;
330 num = atof(divider + 1);
336 theunit->factor /= num;
338 theunit->factor *= num;
347 theunit->factor *= num;
349 theunit->factor /= num;
353 else { /* item is not a number */
356 if (strchr("23456789",
357 item[strlen(item) - 1])) {
358 repeat = item[strlen(item) - 1] - '0';
359 item[strlen(item) - 1] = 0;
361 for (; repeat; repeat--)
362 if (addsubunit(doingtop ^ flip ? theunit->numerator : theunit->denominator, item))
365 item = strtok(NULL, " *\t/\n");
373 } while (doingtop >= 0);
380 compare(const void *item1, const void *item2)
382 return strcmp(*(const char * const *)item1, *(const char * const *)item2);
387 sortunit(struct unittype * theunit)
392 for (count = 0, ptr = theunit->numerator; *ptr; ptr++, count++);
393 qsort(theunit->numerator, count, sizeof(char *), compare);
394 for (count = 0, ptr = theunit->denominator; *ptr; ptr++, count++);
395 qsort(theunit->denominator, count, sizeof(char *), compare);
400 cancelunit(struct unittype * theunit)
405 den = theunit->denominator;
406 num = theunit->numerator;
408 while (*num && *den) {
409 comp = strcmp(*den, *num);
411 /* if (*den!=NULLUNIT) free(*den);
412 if (*num!=NULLUNIT) free(*num);*/
427 Looks up the definition for the specified unit.
428 Returns a pointer to the definition or a null pointer
429 if the specified unit does not appear in the units table.
432 static char buffer[100]; /* buffer for lookupunit answers with
436 lookupunit(const char *unit)
441 for (i = 0; i < unitcount; i++) {
442 if (!strcmp(unittable[i].uname, unit))
443 return unittable[i].uval;
446 if (unit[strlen(unit) - 1] == '^') {
448 copy[strlen(copy) - 1] = 0;
449 for (i = 0; i < unitcount; i++) {
450 if (!strcmp(unittable[i].uname, copy)) {
451 strlcpy(buffer, copy, sizeof(buffer));
458 if (unit[strlen(unit) - 1] == 's') {
460 copy[strlen(copy) - 1] = 0;
461 for (i = 0; i < unitcount; i++) {
462 if (!strcmp(unittable[i].uname, copy)) {
463 strlcpy(buffer, copy, sizeof(buffer));
468 if (copy[strlen(copy) - 1] == 'e') {
469 copy[strlen(copy) - 1] = 0;
470 for (i = 0; i < unitcount; i++) {
471 if (!strcmp(unittable[i].uname, copy)) {
472 strlcpy(buffer, copy, sizeof(buffer));
480 for (i = 0; i < prefixcount; i++) {
481 size_t len = strlen(prefixtable[i].prefixname);
482 if (!strncmp(prefixtable[i].prefixname, unit, len)) {
483 if (!strlen(unit + len) || lookupunit(unit + len)) {
484 snprintf(buffer, sizeof(buffer), "%s %s",
485 prefixtable[i].prefixval, unit + len);
496 reduces a product of symbolic units to primitive units.
497 The three low bits are used to return flags:
499 bit 0 (1) set on if reductions were performed without error.
500 bit 1 (2) set on if no reductions are performed.
501 bit 2 (4) set on if an unknown unit is discovered.
508 reduceproduct(struct unittype * theunit, int flip)
513 int didsomething = 2;
516 product = theunit->denominator;
518 product = theunit->numerator;
520 for (; *product; product++) {
523 if (!strlen(*product))
525 toadd = lookupunit(*product);
527 printf("unknown unit '%s'\n", *product);
530 if (strchr(toadd, PRIMITIVECHAR))
533 if (*product != NULLUNIT) {
537 if (addunit(theunit, toadd, flip))
546 Reduces numerator and denominator of the specified unit.
547 Returns 0 on success, or 1 on unknown unit error.
551 reduceunit(struct unittype * theunit)
557 ret = reduceproduct(theunit, 0) | reduceproduct(theunit, 1);
566 compareproducts(char **one, char **two)
568 while (*one || *two) {
569 if (!*one && *two != NULLUNIT)
571 if (!*two && *one != NULLUNIT)
573 if (*one == NULLUNIT)
575 else if (*two == NULLUNIT)
577 else if (strcmp(*one, *two))
586 /* Return zero if units are compatible, nonzero otherwise */
589 compareunits(struct unittype * first, struct unittype * second)
592 compareproducts(first->numerator, second->numerator) ||
593 compareproducts(first->denominator, second->denominator);
598 completereduce(struct unittype * unit)
600 if (reduceunit(unit))
609 showanswer(struct unittype * have, struct unittype * want)
611 if (compareunits(have, want)) {
612 printf("conformability error\n");
617 printf("\t* %.8g\n\t/ %.8g\n", have->factor / want->factor,
618 want->factor / have->factor);
626 "usage: units [-f unitsfile] [-q] [-v] [from-unit to-unit]\n");
632 main(int argc, char **argv)
635 struct unittype have, want;
636 char havestr[81], wantstr[81];
641 while ((optchar = getopt(argc, argv, "vqf:")) != -1) {
650 fprintf(stderr, "\n units version %s Copyright (c) 1993 by Adrian Mariano\n",
652 fprintf(stderr, " This program may be freely distributed\n");
660 if (optind != argc - 2 && optind != argc)
665 if (optind == argc - 2) {
666 strlcpy(havestr, argv[optind], sizeof(havestr));
667 strlcpy(wantstr, argv[optind + 1], sizeof(wantstr));
668 initializeunit(&have);
669 addunit(&have, havestr, 0);
670 completereduce(&have);
671 initializeunit(&want);
672 addunit(&want, wantstr, 0);
673 completereduce(&want);
674 showanswer(&have, &want);
678 printf("%d units, %d prefixes\n", unitcount,
682 initializeunit(&have);
684 printf("You have: ");
685 if (!fgets(havestr, sizeof(havestr), stdin)) {
690 } while (addunit(&have, havestr, 0) ||
691 completereduce(&have));
693 initializeunit(&want);
695 printf("You want: ");
696 if (!fgets(wantstr, sizeof(wantstr), stdin)) {
701 } while (addunit(&want, wantstr, 0) ||
702 completereduce(&want));
703 showanswer(&have, &want);