Viewing file:  DecToRoman.php (2.94 KB) -rw-r--r--
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<?php
namespace Mpdf\Conversion;
/**
* @link https://github.com/JeroenDeDauw/RomanNumbers
* @license GNU GPL v2+
*/
class DecToRoman
{
private $symbolMap;
public function __construct(array $symbolMap = [])
{
if ($symbolMap !== []) {
$this->symbolMap = $symbolMap;
} else {
$this->symbolMap = [['I', 'V'], ['X', 'L'], ['C', 'D'], ['M']];
}
}
public function convert($number, $toUpper = true)
{
$this->ensureNumberIsAnInteger($number);
$this->ensureNumberIsWithinBounds($number);
return $this->constructRomanString($number, $toUpper);
}
private function ensureNumberIsAnInteger($number)
{
if (!is_int($number)) {
throw new \InvalidArgumentException('Can only translate integers to roman');
}
}
private function ensureNumberIsWithinBounds($number)
{
if ($number < 1) {
throw new \OutOfRangeException('Numbers under one cannot be translated to roman');
}
if ($number > $this->getUpperBound()) {
throw new \OutOfBoundsException('The provided number is to big to be fully translated to roman');
}
}
public function getUpperBound()
{
$symbolGroupCount = count($this->symbolMap);
$valueOfOne = 10 ** ($symbolGroupCount - 1);
$hasFiveSymbol = array_key_exists(1, $this->symbolMap[$symbolGroupCount - 1]);
return $valueOfOne * ($hasFiveSymbol ? 9 : 4) - 1;
}
private function constructRomanString($number, $toUpper)
{
$romanNumber = '';
$symbolMapCount = count($this->symbolMap);
for ($i = 0; $i < $symbolMapCount; $i++) {
$divisor = 10 ** ($i + 1);
$remainder = $number % $divisor;
$digit = $remainder / (10 ** $i);
$number -= $remainder;
$romanNumber = $this->formatDigit($digit, $i) . $romanNumber;
if ($number === 0) {
break;
}
}
if (!$toUpper) {
$romanNumber = strtolower($romanNumber);
}
return $romanNumber;
}
private function formatDigit($digit, $orderOfMagnitude)
{
if ($digit === 0) {
return '';
}
if ($digit === 4 || $digit === 9) {
return $this->formatFourOrNine($digit, $orderOfMagnitude);
}
$romanNumber = '';
if ($digit >= 5) {
$digit -= 5;
$romanNumber .= $this->getFiveSymbol($orderOfMagnitude);
}
$romanNumber .= $this->formatOneToThree($orderOfMagnitude, $digit);
return $romanNumber;
}
private function formatFourOrNine($digit, $orderOfMagnitude)
{
$firstSymbol = $this->getOneSymbol($orderOfMagnitude);
$secondSymbol = $digit === 4
? $this->getFiveSymbol($orderOfMagnitude)
: $this->getTenSymbol($orderOfMagnitude);
return $firstSymbol . $secondSymbol;
}
private function formatOneToThree($orderOfMagnitude, $digit)
{
return str_repeat($this->getOneSymbol($orderOfMagnitude), $digit);
}
private function getOneSymbol($orderOfMagnitude)
{
return $this->symbolMap[$orderOfMagnitude][0];
}
private function getFiveSymbol($orderOfMagnitude)
{
return $this->symbolMap[$orderOfMagnitude][1];
}
private function getTenSymbol($orderOfMagnitude)
{
return $this->symbolMap[$orderOfMagnitude + 1][0];
}
}
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