Units conversion utility courtesy of NetBSD.

Submitted by:	Jeremy Prior
Obtained from:	NetBSD

1 files changed, 706 insertions, 0 deletions

diff --git a/usr.bin/units/units.c b/usr.bin/units/units.c
new file mode 100644
index 0000000..83e5b42
--- /dev/null
+++ b/usr.bin/units/units.c
@@ -0,0 +1,706 @@
+/*	$Id: units.c,v 1.6 1996/04/06 06:01:03 thorpej Exp $	*/
+
+/*
+ * units.c   Copyright (c) 1993 by Adrian Mariano (adrian@cam.cornell.edu)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ * Disclaimer:  This software is provided by the author "as is".  The author
+ * shall not be liable for any damages caused in any way by this software.
+ *
+ * I would appreciate (though I do not require) receiving a copy of any
+ * improvements you might make to this program.
+ */
+
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "pathnames.h"
+
+#define VERSION "1.0"
+
+#ifndef UNITSFILE
+#define UNITSFILE _PATH_UNITSLIB
+#endif
+
+#define MAXUNITS 1000
+#define MAXPREFIXES 50
+
+#define MAXSUBUNITS 500
+
+#define PRIMITIVECHAR '!'
+
+char *powerstring = "^";
+
+struct {
+	char *uname;
+	char *uval;
+}      unittable[MAXUNITS];
+
+struct unittype {
+	char *numerator[MAXSUBUNITS];
+	char *denominator[MAXSUBUNITS];
+	double factor;
+};
+
+struct {
+	char *prefixname;
+	char *prefixval;
+}      prefixtable[MAXPREFIXES];
+
+
+char *NULLUNIT = "";
+
+int unitcount;
+int prefixcount;
+
+
+char *
+dupstr(char *str)
+{
+	char *ret;
+
+	ret = malloc(strlen(str) + 1);
+	if (!ret) {
+		fprintf(stderr, "Memory allocation error\n");
+		exit(3);
+	}
+	strcpy(ret, str);
+	return (ret);
+}
+
+
+void 
+readerror(int linenum)
+{
+	fprintf(stderr, "Error in units file '%s' line %d\n", UNITSFILE,
+	    linenum);
+}
+
+
+void 
+readunits(char *userfile)
+{
+	FILE *unitfile;
+	char line[80], *lineptr;
+	int len, linenum, i;
+
+	unitcount = 0;
+	linenum = 0;
+
+	if (userfile) {
+		unitfile = fopen(userfile, "rt");
+		if (!unitfile) {
+			fprintf(stderr, "Unable to open units file '%s'\n",
+			    userfile);
+			exit(1);
+		}
+	}
+	else {
+		unitfile = fopen(UNITSFILE, "rt");
+		if (!unitfile) {
+			char *direc, *env;
+			char filename[1000];
+			char separator[2];
+
+			env = getenv("PATH");
+			if (env) {
+				if (strchr(env, ';'))
+					strcpy(separator, ";");
+				else
+					strcpy(separator, ":");
+				direc = strtok(env, separator);
+				while (direc) {
+					strcpy(filename, "");
+					strncat(filename, direc, 999);
+					strncat(filename, "/",
+					    999 - strlen(filename));
+					strncat(filename, UNITSFILE,
+					    999 - strlen(filename));
+					unitfile = fopen(filename, "rt");
+					if (unitfile)
+						break;
+					direc = strtok(NULL, separator);
+				}
+			}
+			if (!unitfile) {
+				fprintf(stderr, "Can't find units file '%s'\n",
+				    UNITSFILE);
+				exit(1);
+			}
+		}
+	}
+	while (!feof(unitfile)) {
+		if (!fgets(line, 79, unitfile))
+			break;
+		linenum++;
+		lineptr = line;
+		if (*lineptr == '/')
+			continue;
+		lineptr += strspn(lineptr, " \n\t");
+		len = strcspn(lineptr, " \n\t");
+		lineptr[len] = 0;
+		if (!strlen(lineptr))
+			continue;
+		if (lineptr[strlen(lineptr) - 1] == '-') { /* it's a prefix */
+			if (prefixcount == MAXPREFIXES) {
+				fprintf(stderr, "Memory for prefixes exceeded in line %d\n",
+				    linenum);
+				continue;
+			}
+			lineptr[strlen(lineptr) - 1] = 0;
+			prefixtable[prefixcount].prefixname = dupstr(lineptr);
+			for (i = 0; i < prefixcount; i++)
+				if (!strcmp(prefixtable[i].prefixname, lineptr)) {
+					fprintf(stderr, "Redefinition of prefix '%s' on line %d ignored\n",
+					    lineptr, linenum);
+					continue;
+				}
+			lineptr += len + 1;
+			if (!strlen(lineptr)) {
+				readerror(linenum);
+				continue;
+			}
+			lineptr += strspn(lineptr, " \n\t");
+			len = strcspn(lineptr, "\n\t");
+			lineptr[len] = 0;
+			prefixtable[prefixcount++].prefixval = dupstr(lineptr);
+		}
+		else {		/* it's not a prefix */
+			if (unitcount == MAXUNITS) {
+				fprintf(stderr, "Memory for units exceeded in line %d\n",
+				    linenum);
+				continue;
+			}
+			unittable[unitcount].uname = dupstr(lineptr);
+			for (i = 0; i < unitcount; i++)
+				if (!strcmp(unittable[i].uname, lineptr)) {
+					fprintf(stderr, "Redefinition of unit '%s' on line %d ignored\n",
+					    lineptr, linenum);
+					continue;
+				}
+			lineptr += len + 1;
+			lineptr += strspn(lineptr, " \n\t");
+			if (!strlen(lineptr)) {
+				readerror(linenum);
+				continue;
+			}
+			len = strcspn(lineptr, "\n\t");
+			lineptr[len] = 0;
+			unittable[unitcount++].uval = dupstr(lineptr);
+		}
+	}
+	fclose(unitfile);
+}
+
+void 
+initializeunit(struct unittype * theunit)
+{
+	theunit->factor = 1.0;
+	theunit->numerator[0] = theunit->denominator[0] = NULL;
+}
+
+
+int 
+addsubunit(char *product[], char *toadd)
+{
+	char **ptr;
+
+	for (ptr = product; *ptr && *ptr != NULLUNIT; ptr++);
+	if (ptr >= product + MAXSUBUNITS) {
+		fprintf(stderr, "Memory overflow in unit reduction\n");
+		return 1;
+	}
+	if (!*ptr)
+		*(ptr + 1) = 0;
+	*ptr = dupstr(toadd);
+	return 0;
+}
+
+
+void 
+showunit(struct unittype * theunit)
+{
+	char **ptr;
+	int printedslash;
+	int counter = 1;
+
+	printf("\t%.8g", theunit->factor);
+	for (ptr = theunit->numerator; *ptr; ptr++) {
+		if (ptr > theunit->numerator && **ptr &&
+		    !strcmp(*ptr, *(ptr - 1)))
+			counter++;
+		else {
+			if (counter > 1)
+				printf("%s%d", powerstring, counter);
+			if (**ptr)
+				printf(" %s", *ptr);
+			counter = 1;
+		}
+	}
+	if (counter > 1)
+		printf("%s%d", powerstring, counter);
+	counter = 1;
+	printedslash = 0;
+	for (ptr = theunit->denominator; *ptr; ptr++) {
+		if (ptr > theunit->denominator && **ptr &&
+		    !strcmp(*ptr, *(ptr - 1)))
+			counter++;
+		else {
+			if (counter > 1)
+				printf("%s%d", powerstring, counter);
+			if (**ptr) {
+				if (!printedslash)
+					printf(" /");
+				printedslash = 1;
+				printf(" %s", *ptr);
+			}
+			counter = 1;
+		}
+	}
+	if (counter > 1)
+		printf("%s%d", powerstring, counter);
+	printf("\n");
+}
+
+
+void 
+zeroerror()
+{
+	fprintf(stderr, "Unit reduces to zero\n");
+}
+
+/*
+   Adds the specified string to the unit.
+   Flip is 0 for adding normally, 1 for adding reciprocal.
+
+   Returns 0 for successful addition, nonzero on error.
+*/
+
+int 
+addunit(struct unittype * theunit, char *toadd, int flip)
+{
+	char *scratch, *savescr;
+	char *item;
+	char *divider, *slash;
+	int doingtop;
+
+	savescr = scratch = dupstr(toadd);
+	for (slash = scratch + 1; *slash; slash++)
+		if (*slash == '-' &&
+		    (tolower(*(slash - 1)) != 'e' ||
+		    !strchr(".0123456789", *(slash + 1))))
+			*slash = ' ';
+	slash = strchr(scratch, '/');
+	if (slash)
+		*slash = 0;
+	doingtop = 1;
+	do {
+		item = strtok(scratch, " *\t\n/");
+		while (item) {
+			if (strchr("0123456789.", *item)) { /* item is a number */
+				double num;
+
+				divider = strchr(item, '|');
+				if (divider) {
+					*divider = 0;
+					num = atof(item);
+					if (!num) {
+						zeroerror();
+						return 1;
+					}
+					if (doingtop ^ flip)
+						theunit->factor *= num;
+					else
+						theunit->factor /= num;
+					num = atof(divider + 1);
+					if (!num) {
+						zeroerror();
+						return 1;
+					}
+					if (doingtop ^ flip)
+						theunit->factor /= num;
+					else
+						theunit->factor *= num;
+				}
+				else {
+					num = atof(item);
+					if (!num) {
+						zeroerror();
+						return 1;
+					}
+					if (doingtop ^ flip)
+						theunit->factor *= num;
+					else
+						theunit->factor /= num;
+
+				}
+			}
+			else {	/* item is not a number */
+				int repeat = 1;
+
+				if (strchr("23456789",
+				    item[strlen(item) - 1])) {
+					repeat = item[strlen(item) - 1] - '0';
+					item[strlen(item) - 1] = 0;
+				}
+				for (; repeat; repeat--)
+					if (addsubunit(doingtop ^ flip ? theunit->numerator : theunit->denominator, item))
+						return 1;
+			}
+			item = strtok(NULL, " *\t/\n");
+		}
+		doingtop--;
+		if (slash) {
+			scratch = slash + 1;
+		}
+		else
+			doingtop--;
+	} while (doingtop >= 0);
+	free(savescr);
+	return 0;
+}
+
+
+int 
+compare(const void *item1, const void *item2)
+{
+	return strcmp(*(char **) item1, *(char **) item2);
+}
+
+
+void 
+sortunit(struct unittype * theunit)
+{
+	char **ptr;
+	int count;
+
+	for (count = 0, ptr = theunit->numerator; *ptr; ptr++, count++);
+	qsort(theunit->numerator, count, sizeof(char *), compare);
+	for (count = 0, ptr = theunit->denominator; *ptr; ptr++, count++);
+	qsort(theunit->denominator, count, sizeof(char *), compare);
+}
+
+
+void 
+cancelunit(struct unittype * theunit)
+{
+	char **den, **num;
+	int comp;
+
+	den = theunit->denominator;
+	num = theunit->numerator;
+
+	while (*num && *den) {
+		comp = strcmp(*den, *num);
+		if (!comp) {
+/*      if (*den!=NULLUNIT) free(*den);
+      if (*num!=NULLUNIT) free(*num);*/
+			*den++ = NULLUNIT;
+			*num++ = NULLUNIT;
+		}
+		else if (comp < 0)
+			den++;
+		else
+			num++;
+	}
+}
+
+
+
+
+/*
+   Looks up the definition for the specified unit.
+   Returns a pointer to the definition or a null pointer
+   if the specified unit does not appear in the units table.
+*/
+
+static char buffer[100];	/* buffer for lookupunit answers with
+				   prefixes */
+
+char *
+lookupunit(char *unit)
+{
+	int i;
+	char *copy;
+
+	for (i = 0; i < unitcount; i++) {
+		if (!strcmp(unittable[i].uname, unit))
+			return unittable[i].uval;
+	}
+
+	if (unit[strlen(unit) - 1] == '^') {
+		copy = dupstr(unit);
+		copy[strlen(copy) - 1] = 0;
+		for (i = 0; i < unitcount; i++) {
+			if (!strcmp(unittable[i].uname, copy)) {
+				strcpy(buffer, copy);
+				free(copy);
+				return buffer;
+			}
+		}
+		free(copy);
+	}
+	if (unit[strlen(unit) - 1] == 's') {
+		copy = dupstr(unit);
+		copy[strlen(copy) - 1] = 0;
+		for (i = 0; i < unitcount; i++) {
+			if (!strcmp(unittable[i].uname, copy)) {
+				strcpy(buffer, copy);
+				free(copy);
+				return buffer;
+			}
+		}
+		if (copy[strlen(copy) - 1] == 'e') {
+			copy[strlen(copy) - 1] = 0;
+			for (i = 0; i < unitcount; i++) {
+				if (!strcmp(unittable[i].uname, copy)) {
+					strcpy(buffer, copy);
+					free(copy);
+					return buffer;
+				}
+			}
+		}
+		free(copy);
+	}
+	for (i = 0; i < prefixcount; i++) {
+		if (!strncmp(prefixtable[i].prefixname, unit,
+			strlen(prefixtable[i].prefixname))) {
+			unit += strlen(prefixtable[i].prefixname);
+			if (!strlen(unit) || lookupunit(unit)) {
+				strcpy(buffer, prefixtable[i].prefixval);
+				strcat(buffer, " ");
+				strcat(buffer, unit);
+				return buffer;
+			}
+		}
+	}
+	return 0;
+}
+
+
+
+/*
+   reduces a product of symbolic units to primitive units.
+   The three low bits are used to return flags:
+
+     bit 0 (1) set on if reductions were performed without error.
+     bit 1 (2) set on if no reductions are performed.
+     bit 2 (4) set on if an unknown unit is discovered.
+*/
+
+
+#define ERROR 4
+
+int 
+reduceproduct(struct unittype * theunit, int flip)
+{
+
+	char *toadd;
+	char **product;
+	int didsomething = 2;
+
+	if (flip)
+		product = theunit->denominator;
+	else
+		product = theunit->numerator;
+
+	for (; *product; product++) {
+
+		for (;;) {
+			if (!strlen(*product))
+				break;
+			toadd = lookupunit(*product);
+			if (!toadd) {
+				printf("unknown unit '%s'\n", *product);
+				return ERROR;
+			}
+			if (strchr(toadd, PRIMITIVECHAR))
+				break;
+			didsomething = 1;
+			if (*product != NULLUNIT) {
+				free(*product);
+				*product = NULLUNIT;
+			}
+			if (addunit(theunit, toadd, flip))
+				return ERROR;
+		}
+	}
+	return didsomething;
+}
+
+
+/*
+   Reduces numerator and denominator of the specified unit.
+   Returns 0 on success, or 1 on unknown unit error.
+*/
+
+int 
+reduceunit(struct unittype * theunit)
+{
+	int ret;
+
+	ret = 1;
+	while (ret & 1) {
+		ret = reduceproduct(theunit, 0) | reduceproduct(theunit, 1);
+		if (ret & 4)
+			return 1;
+	}
+	return 0;
+}
+
+
+int 
+compareproducts(char **one, char **two)
+{
+	while (*one || *two) {
+		if (!*one && *two != NULLUNIT)
+			return 1;
+		if (!*two && *one != NULLUNIT)
+			return 1;
+		if (*one == NULLUNIT)
+			one++;
+		else if (*two == NULLUNIT)
+			two++;
+		else if (strcmp(*one, *two))
+			return 1;
+		else
+			one++, two++;
+	}
+	return 0;
+}
+
+
+/* Return zero if units are compatible, nonzero otherwise */
+
+int 
+compareunits(struct unittype * first, struct unittype * second)
+{
+	return
+	compareproducts(first->numerator, second->numerator) ||
+	compareproducts(first->denominator, second->denominator);
+}
+
+
+int 
+completereduce(struct unittype * unit)
+{
+	if (reduceunit(unit))
+		return 1;
+	sortunit(unit);
+	cancelunit(unit);
+	return 0;
+}
+
+
+void 
+showanswer(struct unittype * have, struct unittype * want)
+{
+	if (compareunits(have, want)) {
+		printf("conformability error\n");
+		showunit(have);
+		showunit(want);
+	}
+	else
+		printf("\t* %.8g\n\t/ %.8g\n", have->factor / want->factor,
+		    want->factor / have->factor);
+}
+
+
+void 
+usage()
+{
+	fprintf(stderr, "\nunits [-f unitsfile] [-q] [-v] [from-unit to-unit]\n");
+	fprintf(stderr, "\n    -f specify units file\n");
+	fprintf(stderr, "    -q supress prompting (quiet)\n");
+	fprintf(stderr, "    -v print version number\n");
+	exit(3);
+}
+
+
+int
+main(int argc, char **argv)
+{
+
+	struct unittype have, want;
+	char havestr[81], wantstr[81];
+	int optchar;
+	char *userfile = 0;
+	int quiet = 0;
+
+	extern char *optarg;
+	extern int optind;
+
+	while ((optchar = getopt(argc, argv, "vqf:")) != -1) {
+		switch (optchar) {
+		case 'f':
+			userfile = optarg;
+			break;
+		case 'q':
+			quiet = 1;
+			break;
+		case 'v':
+			fprintf(stderr, "\n  units version %s  Copyright (c) 1993 by Adrian Mariano\n",
+			    VERSION);
+			fprintf(stderr, "                    This program may be freely distributed\n");
+			usage();
+		default:
+			usage();
+			break;
+		}
+	}
+
+	if (optind != argc - 2 && optind != argc)
+		usage();
+
+	readunits(userfile);
+
+	if (optind == argc - 2) {
+		strcpy(havestr, argv[optind]);
+		strcpy(wantstr, argv[optind + 1]);
+		initializeunit(&have);
+		addunit(&have, havestr, 0);
+		completereduce(&have);
+		initializeunit(&want);
+		addunit(&want, wantstr, 0);
+		completereduce(&want);
+		showanswer(&have, &want);
+	}
+	else {
+		if (!quiet)
+			printf("%d units, %d prefixes\n\n", unitcount,
+			    prefixcount);
+		for (;;) {
+			do {
+				initializeunit(&have);
+				if (!quiet)
+					printf("You have: ");
+				if (!fgets(havestr, 80, stdin)) {
+					if (!quiet);
+					putchar('\n');
+					exit(0);
+				}
+			} while (addunit(&have, havestr, 0) ||
+			    completereduce(&have));
+			do {
+				initializeunit(&want);
+				if (!quiet)
+					printf("You want: ");
+				if (!fgets(wantstr, 80, stdin)) {
+					if (!quiet)
+						putchar('\n');
+					exit(0);
+				}
+			} while (addunit(&want, wantstr, 0) ||
+			    completereduce(&want));
+			showanswer(&have, &want);
+		}
+	}
+}