Distance Converting Class

Distance.php

<?php

namespace TYPO3\Units\UnitType;

use TYPO3\Units\Error\UnitConstantException;

/**
 * Class to convert distance unit values into others
 * For example it converts meter to inch and backwards
 * or Megameter in mile
 */
class Distance {

  const Mm = 1000000,
		km = 1000,
		hm = 100,
		dam = 10,
		m = 1,
		dm = 0.1,
		cm = 0.01,
		mm = 0.001,
		µm = 0.000001,
		nm = 0.000000001,
		Å = 0.0000000001,
		pm = 0.000000000001,
		fm = 0.000000000000001,
		inch = 0.0254,
		mile = 1609.344;

	/**
	 * @param float $value
	 * @param string $from
	 * @param string $to
	 * @return float
	 * @throws \TYPO3\Units\Error\UnitConstantException
	 */
	public static function convert($value, $from, $to) {

		try{
			$fromFactor = constant('self::'.$from);
		}catch(\Exception $e){
			$classReflection = new \TYPO3\Flow\Reflection\ClassReflection(__CLASS__);
			throw new UnitConstantException('You want to convert from an unknown unit ('.$from.'). Possible types are: '.implode(', ',array_keys($classReflection->getConstants())),1362041112,$e);
		}

		try{
			$toFactor = constant('self::'.$to);
		}catch(\Exception $e){
			$classReflection = new \TYPO3\Flow\Reflection\ClassReflection(__CLASS__);
			throw new UnitConstantException('You want to convert from an unknown unit ('.$from.'). Possible types are: '.implode(', ',array_keys($classReflection->getConstants())),1362041112,$e);
		}

		return $value * $fromFactor / $toFactor;

	}
}