void __format_nan_or_inf(char * buf, double x,
ios_base::fmtflags flags) {
static const char* inf[2] = { "inf", "Inf" };
static const char* nan[2] = { "nan", "NaN" };
const char** inf_or_nan = 0;
if (_Stl_is_inf((double)x)) { // Infinity
inf_or_nan = inf;
if (_Stl_is_neg_inf((double)x))
*buf++ = '-';
else if (flags & ios_base::showpos)
*buf++ = '+';
}
else { // NaN
inf_or_nan = nan;
if (_Stl_is_neg_nan((double)x))
*buf++ = '-';
else if (flags & ios_base::showpos)
*buf++ = '+';
}
strcpy(buf, flags & ios_base::uppercase ? inf_or_nan[1] : inf_or_nan[0]);
}
void __format_float(char * buf, const char * bp,
int decpt, int sign, max_double_type x,
ios_base::fmtflags flags,
int precision, bool islong)
{
const char* inf[2] = { "inf", "INF" };
const char* nan[2] = { "nan", "NAN" };
// Output of infinities and NANs does not depend on the format flags
if (_Stl_is_nan_or_inf((double)x)) { // Infinity or NaN
const char** inf_or_nan = 0;
if (_Stl_is_inf((double)x)) { // Infinity
inf_or_nan = inf;
if (_Stl_is_neg_inf((double)x))
*buf++ = '-';
else if (flags & ios_base::showpos)
*buf++ = '+';
}
else { // NaN
inf_or_nan = nan;
if (_Stl_is_neg_nan((double)x))
*buf++ = '-';
else if (flags & ios_base::showpos)
*buf++ = '+';
}
strcpy(buf, flags & ios_base::uppercase ? inf_or_nan[1] : inf_or_nan[0]);
}
else { // representable number
switch (flags & ios_base::floatfield) {
case ios_base::scientific:
__format_float_scientific(buf, bp, decpt, sign, x, flags,
precision, islong);
break;
case ios_base::fixed:
__format_float_fixed(buf, bp, decpt, sign, x, flags,
precision, islong);
break;
default: // g format
// establish default precision
if (flags & ios_base::showpoint || precision > 0) {
if (precision == 0) precision = 1;
}
else
precision = 6;
// reset exponent if value is zero
if (x == 0)
decpt = 1;
int kk = precision;
if (!(flags & ios_base::showpoint)) {
int n = strlen(bp);
if (n < kk)
kk = n;
while (kk >= 1 && bp[kk-1] == '0')
--kk;
}
if (decpt < -3 || decpt > precision) {
precision = kk - 1;
__format_float_scientific(buf, bp, decpt, sign, x,
flags, precision, islong);
}
else {
precision = kk - decpt;
__format_float_fixed(buf, bp, decpt, sign, x,
flags, precision, islong);
}
break;
} /* switch */
} /* else */
}
