date and time created 90/05/03 17:47:31 by bostic

[unix-history] / usr / src / lib / libcompat / 4.3 / ecvt.c

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)ecvt.c      5.1 (Berkeley) %G%";
#endif LIBC_SCCS and not lint

/*
*      ecvt converts to decimal
*      the number of digits is specified by ndigit
*      decpt is set to the position of the decimal point
*      sign is set to 0 for positive, 1 for negative
*/

char    *cvt();

#define NDIG    80
char*
ecvt(arg, ndigits, decpt, sign)
double arg;
int ndigits, *decpt, *sign;
{
       return(cvt(arg, ndigits, decpt, sign, 1));
}

char*
fcvt(arg, ndigits, decpt, sign)
double arg;
int ndigits, *decpt, *sign;
{
       return(cvt(arg, ndigits, decpt, sign, 0));
}

static char*
cvt(arg, ndigits, decpt, sign, eflag)
double arg;
int ndigits, *decpt, *sign;
{
       register int r2;
       double fi, fj;
       register char *p, *p1;
       static char buf[NDIG];
       double modf();

       if (ndigits<0)
               ndigits = 0;
       if (ndigits>=NDIG-1)
               ndigits = NDIG-2;
       r2 = 0;
       *sign = 0;
       p = &buf[0];
       if (arg<0) {
               *sign = 1;
               arg = -arg;
       }
       arg = modf(arg, &fi);
       p1 = &buf[NDIG];
       /*
        * Do integer part
        */
       if (fi != 0) {
               p1 = &buf[NDIG];
               while (fi != 0) {
                       fj = modf(fi/10, &fi);
                       *--p1 = (int)((fj+.03)*10) + '0';
                       r2++;
               }
               while (p1 < &buf[NDIG])
                       *p++ = *p1++;
       } else if (arg > 0) {
               while ((fj = arg*10) < 1) {
                       arg = fj;
                       r2--;
               }
       }
       p1 = &buf[ndigits];
       if (eflag==0)
               p1 += r2;
       *decpt = r2;
       if (p1 < &buf[0]) {
               buf[0] = '\0';
               return(buf);
       }
       while (p<=p1 && p<&buf[NDIG]) {
               arg *= 10;
               arg = modf(arg, &fj);
               *p++ = (int)fj + '0';
       }
       if (p1 >= &buf[NDIG]) {
               buf[NDIG-1] = '\0';
               return(buf);
       }
       p = p1;
       *p1 += 5;
       while (*p1 > '9') {
               *p1 = '0';
               if (p1>buf)
                       ++*--p1;
               else {
                       *p1 = '1';
                       (*decpt)++;
                       if (eflag==0) {
                               if (p>buf)
                                       *p = '0';
                               p++;
                       }
               }
       }
       *p = '\0';
       return(buf);
}