examples/Stdlib/ConsoleApp/UNITS.C

// UNITS.C
//
/*
Copyright (c) 1997-2010 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
* Neither the name of Nokia Corporation nor the names of its contributors
  may be used to endorse or promote products derived from this software
  without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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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