Some knowledge about a phar path condensed into a class

PharPath.php

<?php

/**
 * Some knowledge about a phar path condensed
 * into a class
 */
class PharPath
{
    private $path;

    public function __construct($path) {

        $this->setPath($path);
    }

    /**
     * @param string $url
     * @throws \UnexpectedValueException
     */
    public function setPath($url) {

        $this->path = strtr($url, '\\', '/'); # UNIX Paths Normalization;
        $this->getPathToPharFile(); // trigger Exception to validate input.
    }

    public function hasScheme() {

        return substr($this->path, 0, 7) === 'phar://';
    }

    /**
     * @return string path to the .phar file on disk
     * @throws \UnexpectedValueException
     */
    public function getPathToPharFile() {

        if (!$this->hasScheme()) {
            // by php convention, phar files included via phar:// are announced
            // without that scheme prefix.
            return $this->path;
        }

        $path = $this->getSchemeFreePath();
        $offset = strrpos($path, '.phar'); // phar:// wrapper looks from the end
        if ($offset === false) {
            throw new \UnexpectedValueException('Phar does not have the .phar extension but it is needed.');
        }
        $path = substr($path, 0, $offset + 5);

        return $path;
    }

    /**
     * @return string path without the (optional) phar:// stream wrapper scheme prefix
     */
    public function getSchemeFreePath() {

        $buffer = $this->path;
        $this->hasScheme() && $buffer = substr($buffer, 7);

        return $buffer;
    }

    /**
     * @return string path inside the phar, normally a file or directory
     */
    public function getPharPath() {

        if (!$this->hasScheme()) {
            return '';
        }

        $path = $this->getSchemeFreePath();
        $base = $this->getPathToPharFile();

        if ($base === $path) {
            return '';
        }

        return substr($path, strlen($base));
    }
}