/**
* Returns a QuantityValue representing the given amount, automatically assuming
* a level of uncertainty based on the digits given.
*
* The upper and lower bounds are determined automatically from the given
* digits by increasing resp. decreasing the least significant digit.
* E.g. "+0.01" would have upperBound "+0.02" and lowerBound "+0.01",
* while "-100" would have upperBound "-99" and lowerBound "-101".
*
* @param DecimalValue $amount The quantity
* @param string $unit The quantity's unit (use "1" for unit-less quantities)
* @param int $exponent Decimal exponent to apply
*
* @return QuantityValue
*/
private function newUncertainQuantityFromDigits(DecimalValue $amount, $unit = '1', $exponent = 0)
{
$math = new DecimalMath();
if ($amount->getSign() === '+') {
$upperBound = $math->bump($amount);
$lowerBound = $math->slump($amount);
} else {
$upperBound = $math->slump($amount);
$lowerBound = $math->bump($amount);
}
$amount = $this->decimalParser->applyDecimalExponent($amount, $exponent);
$lowerBound = $this->decimalParser->applyDecimalExponent($lowerBound, $exponent);
$upperBound = $this->decimalParser->applyDecimalExponent($upperBound, $exponent);
return new QuantityValue($amount, $unit, $upperBound, $lowerBound);
}
/**
* Shift the decimal point according to the given exponent.
*
* @param DecimalValue $decimal
* @param int $exponent The exponent to apply (digits to shift by). A Positive exponent
* shifts the decimal point to the right, a negative exponent shifts to the left.
*
* @throws InvalidArgumentException
* @return DecimalValue
*/
public function shift(DecimalValue $decimal, $exponent)
{
if (!is_int($exponent)) {
throw new InvalidArgumentException('$exponent must be an integer');
}
if ($exponent == 0) {
return $decimal;
}
$sign = $decimal->getSign();
$intPart = $decimal->getIntegerPart();
$fractPart = $decimal->getFractionalPart();
if ($exponent < 0) {
$intPart = $this->shiftLeft($intPart, $exponent);
} else {
$fractPart = $this->shiftRight($fractPart, $exponent);
}
$digits = $sign . $intPart . $fractPart;
$digits = $this->stripLeadingZeros($digits);
return new DecimalValue($digits);
}
/**
* @dataProvider getSignProvider
*/
public function testGetSign(DecimalValue $value, $expected)
{
$actual = $value->getSign();
$this->assertSame($expected, $actual);
}
