707 lines
14 KiB
C
707 lines
14 KiB
C
/*
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* units.c Copyright (c) 1993 by Adrian Mariano (adrian@cam.cornell.edu)
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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* Disclaimer: This software is provided by the author "as is". The author
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* shall not be liable for any damages caused in any way by this software.
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*
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* I would appreciate (though I do not require) receiving a copy of any
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* improvements you might make to this program.
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*
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* $Id: units.c,v 1.3 1994/12/21 07:22:00 jtc Exp $
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*/
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#include <ctype.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include "pathnames.h"
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#define VERSION "1.0"
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#ifndef UNITSFILE
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#define UNITSFILE _PATH_UNITSLIB
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#endif
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#define MAXUNITS 1000
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#define MAXPREFIXES 50
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#define MAXSUBUNITS 500
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#define PRIMITIVECHAR '!'
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char *powerstring = "^";
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struct {
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char *uname;
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char *uval;
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} unittable[MAXUNITS];
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struct unittype {
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char *numerator[MAXSUBUNITS];
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char *denominator[MAXSUBUNITS];
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double factor;
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};
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struct {
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char *prefixname;
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char *prefixval;
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} prefixtable[MAXPREFIXES];
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char *NULLUNIT = "";
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int unitcount;
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int prefixcount;
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char *
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dupstr(char *str)
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{
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char *ret;
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ret = malloc(strlen(str) + 1);
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if (!ret) {
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fprintf(stderr, "Memory allocation error\n");
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exit(3);
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}
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strcpy(ret, str);
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return (ret);
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}
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void
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readerror(int linenum)
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{
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fprintf(stderr, "Error in units file '%s' line %d\n", UNITSFILE,
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linenum);
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}
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void
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readunits(char *userfile)
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{
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FILE *unitfile;
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char line[80], *lineptr;
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int len, linenum, i;
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unitcount = 0;
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linenum = 0;
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if (userfile) {
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unitfile = fopen(userfile, "rt");
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if (!unitfile) {
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fprintf(stderr, "Unable to open units file '%s'\n",
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userfile);
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exit(1);
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}
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}
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else {
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unitfile = fopen(UNITSFILE, "rt");
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if (!unitfile) {
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char *direc, *env;
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char filename[1000];
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char separator[2];
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env = getenv("PATH");
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if (env) {
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if (strchr(env, ';'))
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strcpy(separator, ";");
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else
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strcpy(separator, ":");
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direc = strtok(env, separator);
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while (direc) {
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strcpy(filename, "");
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strncat(filename, direc, 999);
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strncat(filename, "/",
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999 - strlen(filename));
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strncat(filename, UNITSFILE,
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999 - strlen(filename));
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unitfile = fopen(filename, "rt");
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if (unitfile)
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break;
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direc = strtok(NULL, separator);
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}
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}
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if (!unitfile) {
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fprintf(stderr, "Can't find units file '%s'\n",
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UNITSFILE);
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exit(1);
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}
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}
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}
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while (!feof(unitfile)) {
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if (!fgets(line, 79, unitfile))
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break;
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linenum++;
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lineptr = line;
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if (*lineptr == '/')
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continue;
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lineptr += strspn(lineptr, " \n\t");
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len = strcspn(lineptr, " \n\t");
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lineptr[len] = 0;
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if (!strlen(lineptr))
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continue;
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if (lineptr[strlen(lineptr) - 1] == '-') { /* it's a prefix */
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if (prefixcount == MAXPREFIXES) {
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fprintf(stderr, "Memory for prefixes exceeded in line %d\n",
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linenum);
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continue;
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}
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lineptr[strlen(lineptr) - 1] = 0;
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prefixtable[prefixcount].prefixname = dupstr(lineptr);
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for (i = 0; i < prefixcount; i++)
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if (!strcmp(prefixtable[i].prefixname, lineptr)) {
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fprintf(stderr, "Redefinition of prefix '%s' on line %d ignored\n",
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lineptr, linenum);
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continue;
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}
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lineptr += len + 1;
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if (!strlen(lineptr)) {
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readerror(linenum);
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continue;
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}
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lineptr += strspn(lineptr, " \n\t");
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len = strcspn(lineptr, "\n\t");
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lineptr[len] = 0;
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prefixtable[prefixcount++].prefixval = dupstr(lineptr);
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}
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else { /* it's not a prefix */
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if (unitcount == MAXUNITS) {
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fprintf(stderr, "Memory for units exceeded in line %d\n",
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linenum);
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continue;
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}
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unittable[unitcount].uname = dupstr(lineptr);
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for (i = 0; i < unitcount; i++)
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if (!strcmp(unittable[i].uname, lineptr)) {
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fprintf(stderr, "Redefinition of unit '%s' on line %d ignored\n",
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lineptr, linenum);
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continue;
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}
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lineptr += len + 1;
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lineptr += strspn(lineptr, " \n\t");
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if (!strlen(lineptr)) {
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readerror(linenum);
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continue;
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}
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len = strcspn(lineptr, "\n\t");
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lineptr[len] = 0;
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unittable[unitcount++].uval = dupstr(lineptr);
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}
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}
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fclose(unitfile);
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}
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void
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initializeunit(struct unittype * theunit)
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{
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theunit->factor = 1.0;
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theunit->numerator[0] = theunit->denominator[0] = NULL;
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}
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int
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addsubunit(char *product[], char *toadd)
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{
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char **ptr;
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for (ptr = product; *ptr && *ptr != NULLUNIT; ptr++);
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if (ptr >= product + MAXSUBUNITS) {
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fprintf(stderr, "Memory overflow in unit reduction\n");
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return 1;
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}
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if (!*ptr)
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*(ptr + 1) = 0;
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*ptr = dupstr(toadd);
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return 0;
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}
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void
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showunit(struct unittype * theunit)
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{
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char **ptr;
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int printedslash;
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int counter = 1;
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printf("\t%.8g", theunit->factor);
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for (ptr = theunit->numerator; *ptr; ptr++) {
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if (ptr > theunit->numerator && **ptr &&
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!strcmp(*ptr, *(ptr - 1)))
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counter++;
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else {
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if (counter > 1)
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printf("%s%d", powerstring, counter);
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if (**ptr)
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printf(" %s", *ptr);
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counter = 1;
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}
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}
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if (counter > 1)
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printf("%s%d", powerstring, counter);
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counter = 1;
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printedslash = 0;
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for (ptr = theunit->denominator; *ptr; ptr++) {
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if (ptr > theunit->denominator && **ptr &&
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!strcmp(*ptr, *(ptr - 1)))
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counter++;
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else {
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if (counter > 1)
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printf("%s%d", powerstring, counter);
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if (**ptr) {
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if (!printedslash)
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printf(" /");
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printedslash = 1;
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printf(" %s", *ptr);
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}
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counter = 1;
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}
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}
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if (counter > 1)
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printf("%s%d", powerstring, counter);
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printf("\n");
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}
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void
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zeroerror()
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{
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fprintf(stderr, "Unit reduces to zero\n");
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}
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/*
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Adds the specified string to the unit.
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Flip is 0 for adding normally, 1 for adding reciprocal.
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Returns 0 for successful addition, nonzero on error.
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*/
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int
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addunit(struct unittype * theunit, char *toadd, int flip)
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{
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char *scratch, *savescr;
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char *item;
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char *divider, *slash;
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int doingtop;
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savescr = scratch = dupstr(toadd);
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for (slash = scratch + 1; *slash; slash++)
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if (*slash == '-' &&
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(tolower(*(slash - 1)) != 'e' ||
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!strchr(".0123456789", *(slash + 1))))
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*slash = ' ';
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slash = strchr(scratch, '/');
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if (slash)
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*slash = 0;
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doingtop = 1;
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do {
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item = strtok(scratch, " *\t\n/");
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while (item) {
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if (strchr("0123456789.", *item)) { /* item is a number */
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double num;
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divider = strchr(item, '|');
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if (divider) {
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*divider = 0;
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num = atof(item);
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if (!num) {
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zeroerror();
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return 1;
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}
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if (doingtop ^ flip)
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theunit->factor *= num;
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else
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theunit->factor /= num;
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num = atof(divider + 1);
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if (!num) {
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zeroerror();
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return 1;
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}
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if (doingtop ^ flip)
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theunit->factor /= num;
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else
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theunit->factor *= num;
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}
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else {
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num = atof(item);
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if (!num) {
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zeroerror();
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return 1;
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}
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if (doingtop ^ flip)
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theunit->factor *= num;
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else
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theunit->factor /= num;
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}
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}
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else { /* item is not a number */
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int repeat = 1;
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if (strchr("23456789",
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item[strlen(item) - 1])) {
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repeat = item[strlen(item) - 1] - '0';
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item[strlen(item) - 1] = 0;
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}
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for (; repeat; repeat--)
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if (addsubunit(doingtop ^ flip ? theunit->numerator : theunit->denominator, item))
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return 1;
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}
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item = strtok(NULL, " *\t/\n");
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}
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doingtop--;
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if (slash) {
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scratch = slash + 1;
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}
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else
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doingtop--;
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} while (doingtop >= 0);
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free(savescr);
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return 0;
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}
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int
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compare(const void *item1, const void *item2)
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{
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return strcmp(*(char **) item1, *(char **) item2);
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}
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void
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sortunit(struct unittype * theunit)
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{
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char **ptr;
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int count;
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for (count = 0, ptr = theunit->numerator; *ptr; ptr++, count++);
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qsort(theunit->numerator, count, sizeof(char *), compare);
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for (count = 0, ptr = theunit->denominator; *ptr; ptr++, count++);
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qsort(theunit->denominator, count, sizeof(char *), compare);
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}
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void
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cancelunit(struct unittype * theunit)
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{
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char **den, **num;
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int comp;
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den = theunit->denominator;
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num = theunit->numerator;
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while (*num && *den) {
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comp = strcmp(*den, *num);
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if (!comp) {
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/* if (*den!=NULLUNIT) free(*den);
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if (*num!=NULLUNIT) free(*num);*/
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*den++ = NULLUNIT;
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*num++ = NULLUNIT;
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}
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else if (comp < 0)
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den++;
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else
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num++;
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}
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}
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/*
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Looks up the definition for the specified unit.
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Returns a pointer to the definition or a null pointer
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if the specified unit does not appear in the units table.
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*/
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static char buffer[100]; /* buffer for lookupunit answers with
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prefixes */
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char *
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lookupunit(char *unit)
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{
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int i;
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char *copy;
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for (i = 0; i < unitcount; i++) {
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if (!strcmp(unittable[i].uname, unit))
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return unittable[i].uval;
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}
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if (unit[strlen(unit) - 1] == '^') {
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copy = dupstr(unit);
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copy[strlen(copy) - 1] = 0;
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for (i = 0; i < unitcount; i++) {
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if (!strcmp(unittable[i].uname, copy)) {
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strcpy(buffer, copy);
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free(copy);
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return buffer;
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}
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}
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free(copy);
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}
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if (unit[strlen(unit) - 1] == 's') {
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copy = dupstr(unit);
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copy[strlen(copy) - 1] = 0;
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for (i = 0; i < unitcount; i++) {
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if (!strcmp(unittable[i].uname, copy)) {
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strcpy(buffer, copy);
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free(copy);
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return buffer;
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}
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}
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if (copy[strlen(copy) - 1] == 'e') {
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copy[strlen(copy) - 1] = 0;
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for (i = 0; i < unitcount; i++) {
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if (!strcmp(unittable[i].uname, copy)) {
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strcpy(buffer, copy);
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free(copy);
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return buffer;
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}
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}
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}
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free(copy);
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}
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for (i = 0; i < prefixcount; i++) {
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if (!strncmp(prefixtable[i].prefixname, unit,
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strlen(prefixtable[i].prefixname))) {
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unit += strlen(prefixtable[i].prefixname);
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if (!strlen(unit) || lookupunit(unit)) {
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strcpy(buffer, prefixtable[i].prefixval);
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strcat(buffer, " ");
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strcat(buffer, unit);
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return buffer;
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}
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}
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}
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return 0;
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}
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/*
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reduces a product of symbolic units to primitive units.
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The three low bits are used to return flags:
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bit 0 (1) set on if reductions were performed without error.
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bit 1 (2) set on if no reductions are performed.
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bit 2 (4) set on if an unknown unit is discovered.
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*/
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#define ERROR 4
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int
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reduceproduct(struct unittype * theunit, int flip)
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{
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char *toadd;
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char **product;
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int didsomething = 2;
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if (flip)
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product = theunit->denominator;
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else
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product = theunit->numerator;
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for (; *product; product++) {
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for (;;) {
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if (!strlen(*product))
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break;
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toadd = lookupunit(*product);
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if (!toadd) {
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printf("unknown unit '%s'\n", *product);
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return ERROR;
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}
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if (strchr(toadd, PRIMITIVECHAR))
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break;
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didsomething = 1;
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if (*product != NULLUNIT) {
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free(*product);
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*product = NULLUNIT;
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}
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if (addunit(theunit, toadd, flip))
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return ERROR;
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}
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}
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return didsomething;
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}
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/*
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Reduces numerator and denominator of the specified unit.
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Returns 0 on success, or 1 on unknown unit error.
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*/
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int
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reduceunit(struct unittype * theunit)
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{
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int ret;
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ret = 1;
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while (ret & 1) {
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ret = reduceproduct(theunit, 0) | reduceproduct(theunit, 1);
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if (ret & 4)
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return 1;
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}
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return 0;
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}
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int
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compareproducts(char **one, char **two)
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{
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while (*one || *two) {
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if (!*one && *two != NULLUNIT)
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return 1;
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if (!*two && *one != NULLUNIT)
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return 1;
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if (*one == NULLUNIT)
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one++;
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else if (*two == NULLUNIT)
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two++;
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else if (strcmp(*one, *two))
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return 1;
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else
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one++, two++;
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}
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return 0;
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}
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/* Return zero if units are compatible, nonzero otherwise */
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int
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compareunits(struct unittype * first, struct unittype * second)
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{
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return
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compareproducts(first->numerator, second->numerator) ||
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compareproducts(first->denominator, second->denominator);
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}
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int
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completereduce(struct unittype * unit)
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{
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if (reduceunit(unit))
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return 1;
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sortunit(unit);
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cancelunit(unit);
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return 0;
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}
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void
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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);
|
|
}
|
|
|
|
|
|
void
|
|
main(int argc, char **argv)
|
|
{
|
|
|
|
struct unittype have, want;
|
|
char havestr[81], wantstr[81];
|
|
char optchar;
|
|
char *userfile = 0;
|
|
int quiet = 0;
|
|
|
|
extern char *optarg;
|
|
extern int optind;
|
|
|
|
while (EOF != (optchar = getopt(argc, argv, "vqf:"))) {
|
|
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);
|
|
}
|
|
}
|
|
}
|