examples/Stdlib/ConsoleApp/UNITS.C

// UNITS.C
//
// Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
//

#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "PATHNAME.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[225]; // was [MAXSUBUNITS]
        char *denominator[225]; // was [MAXSUBUNITS]
        double factor;
};

struct {
        char *prefixname;
        char *prefixval;
}      prefixtable[MAXPREFIXES];


char *NULLUNIT = "";

int unitcount;
int prefixcount;


char *
dupstr(char *str)
{
        char *ret;

        ret = (char *)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);
}

extern int getopt(int, char **, const char *);

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);
                }
        }

        return(0);
}
                                                                                                        

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