#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
extern char *__dtoa(double, int, int, int *, int *, char **);
extern void __freedtoa(char *);
char *
gcvt(double value, int ndigit, char *buf)
{
char *digits, *dst, *src;
int i, decpt, sign;
struct lconv *lconv;
lconv = localeconv();
if (ndigit == 0) {
buf[0] = '\0';
return (buf);
}
digits = __dtoa(value, 2, ndigit, &decpt, &sign, NULL);
if (digits == NULL)
return (NULL);
if (decpt == 9999) {
snprintf(buf, ndigit + 1, "%s%s", sign ? "-" : "",
*digits == 'I' ? "inf" : "nan");
__freedtoa(digits);
return (buf);
}
dst = buf;
if (sign)
*dst++ = '-';
if (decpt < 0 || decpt > ndigit) {
if (--decpt < 0) {
sign = 1;
decpt = -decpt;
} else
sign = 0;
src = digits;
*dst++ = *src++;
dst = stpcpy(dst, lconv->decimal_point);
while (*src != '\0')
*dst++ = *src++;
*dst++ = 'e';
if (sign)
*dst++ = '-';
else
*dst++ = '+';
if (decpt < 10) {
*dst++ = '0';
*dst++ = '0' + decpt;
*dst = '\0';
} else {
for (sign = decpt, i = 0; (sign /= 10) != 0; i++)
continue;
dst[i + 1] = '\0';
while (decpt != 0) {
dst[i--] = '0' + decpt % 10;
decpt /= 10;
}
}
} else {
for (i = 0, src = digits; i < decpt; i++) {
if (*src != '\0')
*dst++ = *src++;
else
*dst++ = '0';
}
if (*src != '\0') {
if (src == digits)
*dst++ = '0';
dst = stpcpy(dst, lconv->decimal_point);
for (i = decpt; digits[i] != '\0'; i++) {
*dst++ = digits[i];
}
}
*dst = '\0';
}
__freedtoa(digits);
return (buf);
}