/* $Id: units.c,v 1.1.1.1 1996/06/08 03:43:43 alex 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 #include #include #include #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); } } return(0); }