void
DigitList::roundFixedPoint(int32_t maximumFractionDigits) {
reduce(); // Remove trailing zeros.
if (fDecNumber->exponent >= -maximumFractionDigits) {
return;
}
decNumber scale; // Dummy decimal number, but with the desired number of
uprv_decNumberZero(&scale); // fraction digits.
scale.exponent = -maximumFractionDigits;
scale.lsu[0] = 1;
uprv_decNumberQuantize(fDecNumber, fDecNumber, &scale, &fContext);
reduce();
internalClear();
}
/**
* convert this number to an int32_t. Round if there is a fractional part.
* Return zero if the number cannot be represented.
*/
int32_t DigitList::getLong() /*const*/
{
int32_t result = 0;
if (getUpperExponent() > 10) {
// Overflow, absolute value too big.
return result;
}
if (fDecNumber->exponent != 0) {
// Force to an integer, with zero exponent, rounding if necessary.
// (decNumberToInt32 will only work if the exponent is exactly zero.)
DigitList copy(*this);
DigitList zero;
uprv_decNumberQuantize(copy.fDecNumber, copy.fDecNumber, zero.fDecNumber, &fContext);
result = uprv_decNumberToInt32(copy.fDecNumber, &fContext);
} else {
result = uprv_decNumberToInt32(fDecNumber, &fContext);
}
return result;
}
int64_t DigitList::getInt64() /*const*/ {
// Round if non-integer. (Truncate or round?)
// Return 0 if out of range.
// Range of in64_t is -9223372036854775808 to 9223372036854775807 (19 digits)
//
if (fDecNumber->digits + fDecNumber->exponent > 19) {
// Overflow, absolute value too big.
return 0;
}
decNumber *workingNum = fDecNumber;
if (fDecNumber->exponent != 0) {
// Force to an integer, with zero exponent, rounding if necessary.
DigitList copy(*this);
DigitList zero;
uprv_decNumberQuantize(copy.fDecNumber, copy.fDecNumber, zero.fDecNumber, &fContext);
workingNum = copy.fDecNumber;
}
uint64_t value = 0;
int32_t numDigits = workingNum->digits;
for (int i = numDigits-1; i>=0 ; --i) {
int v = workingNum->lsu[i];
value = value * (uint64_t)10 + (uint64_t)v;
}
if (decNumberIsNegative(workingNum)) {
value = ~value;
value += 1;
}
int64_t svalue = (int64_t)value;
// Check overflow. It's convenient that the MSD is 9 only on overflow, the amount of
// overflow can't wrap too far. The test will also fail -0, but
// that does no harm; the right answer is 0.
if (numDigits == 19) {
if (( decNumberIsNegative(fDecNumber) && svalue>0) ||
(!decNumberIsNegative(fDecNumber) && svalue<0)) {
svalue = 0;
}
}
return svalue;
}