/**
* Performs a rounded division.
*
* Rounding is performed when the remainder of the division is not zero.
*
* @param string $a The dividend.
* @param string $b The divisor.
* @param int $roundingMode The rounding mode.
*
* @return string
*
* @throws \InvalidArgumentException If the rounding mode is invalid.
* @throws RoundingNecessaryException If RoundingMode::UNNECESSARY is provided but rounding is necessary.
*/
public function divRound($a, $b, $roundingMode)
{
list($quotient, $remainder) = $this->divQR($a, $b);
$hasDiscardedFraction = $remainder !== '0';
$isPositiveOrZero = ($a[0] === '-') === ($b[0] === '-');
$discardedFractionSign = function () use($remainder, $b) {
$r = $this->abs($this->mul($remainder, '2'));
$b = $this->abs($b);
return $this->cmp($r, $b);
};
$increment = false;
switch ($roundingMode) {
case RoundingMode::UNNECESSARY:
if ($hasDiscardedFraction) {
throw RoundingNecessaryException::roundingNecessary();
}
break;
case RoundingMode::UP:
$increment = $hasDiscardedFraction;
break;
case RoundingMode::DOWN:
break;
case RoundingMode::CEILING:
$increment = $hasDiscardedFraction && $isPositiveOrZero;
break;
case RoundingMode::FLOOR:
$increment = $hasDiscardedFraction && !$isPositiveOrZero;
break;
case RoundingMode::HALF_UP:
$increment = $discardedFractionSign() >= 0;
break;
case RoundingMode::HALF_DOWN:
$increment = $discardedFractionSign() > 0;
break;
case RoundingMode::HALF_CEILING:
$increment = $isPositiveOrZero ? $discardedFractionSign() >= 0 : $discardedFractionSign() > 0;
break;
case RoundingMode::HALF_FLOOR:
$increment = $isPositiveOrZero ? $discardedFractionSign() > 0 : $discardedFractionSign() >= 0;
break;
case RoundingMode::HALF_EVEN:
$lastDigit = (int) substr($quotient, -1);
$lastDigitIsEven = $lastDigit % 2 === 0;
$increment = $lastDigitIsEven ? $discardedFractionSign() > 0 : $discardedFractionSign() >= 0;
break;
default:
throw new \InvalidArgumentException('Invalid rounding mode.');
}
if ($increment) {
return $this->add($quotient, $isPositiveOrZero ? '1' : '-1');
}
return $quotient;
}
/**
* @param int $roundingMode The rounding mode.
* @param BigDecimal $number The number to round.
* @param string $divisor The divisor.
* @param string|null $two The expected rounding to a scale of two, or null if an exception is expected.
* @param string|null $one The expected rounding to a scale of one, or null if an exception is expected.
* @param string|null $zero The expected rounding to a scale of zero, or null if an exception is expected.
*/
private function doTestRoundingMode($roundingMode, BigDecimal $number, $divisor, $two, $one, $zero)
{
foreach ([$zero, $one, $two] as $scale => $expected) {
if ($expected === null) {
$this->setExpectedException(RoundingNecessaryException::getNamespace());
}
$actual = $number->dividedBy($divisor, $scale, $roundingMode);
if ($expected !== null) {
$this->assertBigDecimalInternalValues($expected, $scale, $actual);
}
}
}
/**
* @param integer $roundingMode The rounding mode.
* @param BigInteger $number The number to round.
* @param string $divisor The divisor.
* @param string|null $ten The expected rounding to a scale of two, or null if an exception is expected.
* @param string|null $hundred The expected rounding to a scale of one, or null if an exception is expected.
* @param string|null $thousand The expected rounding to a scale of zero, or null if an exception is expected.
*/
private function doTestDividedByWithRoundingMode($roundingMode, BigInteger $number, $divisor, $ten, $hundred, $thousand)
{
foreach ([$ten, $hundred, $thousand] as $expected) {
$divisor .= '0';
if ($expected === null) {
$this->setExpectedException(RoundingNecessaryException::getNamespace());
}
$actual = $number->dividedBy($divisor, $roundingMode);
if ($expected !== null) {
$this->assertBigIntegerEquals($expected, $actual);
}
}
}
/**
* @return array
*/
public function providerToScale()
{
return [['1/8', 3, RoundingMode::UNNECESSARY, '0.125'], ['1/16', 3, RoundingMode::UNNECESSARY, RoundingNecessaryException::getNamespace()], ['1/16', 3, RoundingMode::HALF_DOWN, '0.062'], ['1/16', 3, RoundingMode::HALF_UP, '0.063'], ['1/9', 30, RoundingMode::DOWN, '0.111111111111111111111111111111'], ['1/9', 30, RoundingMode::UP, '0.111111111111111111111111111112'], ['1/9', 100, RoundingMode::UNNECESSARY, RoundingNecessaryException::getNamespace()]];
}
