pyNgSpice/src/circuit/inpeval.c

/**********
Copyright 1990 Regents of the University of California.  All rights reserved.
Author: 1985 Thomas L. Quarles
**********/

#include "ngspice.h"
#include <stdio.h>
#include <ctype.h>
#include "inpdefs.h"
#include "inp.h"

double INPevaluate(char **line, int *error, int gobble)
		/* non-zero to gobble rest of token, zero to leave it alone */
{
    char *token;
    char *here;
    double mantis;
    int expo1;
    int expo2;
    int sign;
    int expsgn;
    char *tmpline;

    /* setup */
    tmpline = *line;
    if (gobble) {
	*error = INPgetUTok(line, &token, 1);
	if (*error)
	    return ((double) 0.0);
    } else {
	token = *line;
	*error = 0;
    }
    mantis = 0;
    expo1 = 0;
    expo2 = 0;
    sign = 1;
    expsgn = 1;
    /* loop through all of the input token */
    here = token;
    if (*here == '+')
	here++;			/* plus, so do nothing except skip it */
    if (*here == '-') {		/* minus, so skip it, and change sign */
	here++;
	sign = -1;
    }
    if ((*here == 0) || ((!(isdigit(*here))) && (*here != '.'))) {
	/* number looks like just a sign! */
	*error = 1;
	/* back out the 'gettok' operation */
	*line = tmpline;
	if (gobble) {
	    FREE(token);
	} else {
	    *line = here;
	}
	return (0);
    }
    while (isdigit(*here)) {
	/* digit, so accumulate it. */
	mantis = 10 * mantis + *here - '0';
	here++;
    }
    if (*here == 0) {
	/* reached the end of token - done. */
	if (gobble) {
	    FREE(token);
	} else {
	    *line = here;
	}
	return ((double) mantis * sign);
    }
    if (*here == ':') {
	/* hack for subcircuit node numbering */
	*error = 1;
	*line = tmpline;
	return 0.0;
    }
    /* after decimal point! */
    if (*here == '.') {
	/* found a decimal point! */
	here++;			/* skip to next character */
	if (*here == 0) {
	    /* number ends in the decimal point */
	    if (gobble) {
		FREE(token);
	    } else {
		*line = here;
	    }
	    return ((double) mantis * sign);
	}
	while (isdigit(*here)) {
	    /* digit, so accumulate it. */
	    mantis = 10 * mantis + *here - '0';
	    expo1 = expo1 - 1;
	    if (*here == 0) {
		/* reached the end of token - done. */
		if (gobble) {
		    FREE(token);
		} else {
		    *line = here;
		}
		return (mantis * sign * pow(10., (double) expo1));
	    }
	    here++;
	}
    }
    /* now look for "E","e",etc to indicate an exponent */
    if ((*here == 'E') || (*here == 'e') || (*here == 'D')
	|| (*here == 'd')) {
	/* have an exponent, so skip the e */
	here++;
	/* now look for exponent sign */
	if (*here == '+')
	    here++;		/* just skip + */
	if (*here == '-') {
	    here++;		/* skip over minus sign */
	    expsgn = -1;	/* and make a negative exponent */
	    /* now look for the digits of the exponent */
	}
	while (isdigit(*here)) {
	    expo2 = 10 * expo2 + *here - '0';
	    here++;
	}
    }
    /* now we have all of the numeric part of the number, time to
     * look for the scale factor (alphabetic)
     */
    switch (*here) {
    case 't':
    case 'T':
	expo1 = expo1 + 12;
	break;
    case 'g':
    case 'G':
	expo1 = expo1 + 9;
	break;
    case 'k':
    case 'K':
	expo1 = expo1 + 3;
	break;
    case 'u':
    case 'U':
	expo1 = expo1 - 6;
	break;
    case 'n':
    case 'N':
	expo1 = expo1 - 9;
	break;
    case 'p':
    case 'P':
	expo1 = expo1 - 12;
	break;
    case 'f':
    case 'F':
	expo1 = expo1 - 15;
	break;
    case 'm':
    case 'M':
	{
	    /* special case for m - may be m or mil or meg */
	    if (*(here + 1) != 0 && *(here + 2) != 0) {
		/* at least 2 characters, so check them. */
		if ((*(here + 1) == 'E') || (*(here + 1) == 'e')) {
		    if ((*(here + 2) == 'G') || (*(here + 2) == 'g')) {
			expo1 = expo1 + 6;
			if (gobble) {
			    FREE(token);
			} else {
			    *line = here;
			}
			return (sign * mantis *
				pow((double) 10,
				    (double) (expo1 + expsgn * expo2)));
		    }
		} else if ((*(here + 1) == 'I') || (*(here + 1) == 'i')) {
		    if ((*(here + 2) == 'L') || (*(here + 2) == 'l')) {
			expo1 = expo1 - 6;
			mantis = mantis * 25.4;
			if (gobble) {
			    FREE(token);
			} else {
			    *line = here;
			}
			return (sign * mantis *
				pow((double) 10,
				    (double) (expo1 + expsgn * expo2)));
		    }
		}
	    }
	    /* not either special case, so just m => 1e-3 */
	    expo1 = expo1 - 3;
	}
	break;
    default:
	break;
    }
    if (gobble) {
	FREE(token);
    } else {
	*line = here;
    }
    return (sign * mantis *
	    pow((double) 10, (double) (expo1 + expsgn * expo2)));
}