sop / jwx

lib/JWX/Util/Base64.php

<?php

declare(strict_types = 1);

namespace Sop\JWX\Util;

/**
 * Class offering Base64 encoding and decoding.
 */
class Base64
{
    /**
     * Encode a string using base64url variant.
     *
     * @see https://en.wikipedia.org/wiki/Base64#URL_applications
     */
    public static function urlEncode(string $data): string
    {
        return strtr(rtrim(self::encode($data), '='), '+/', '-_');
    }

    /**
     * Decode a string using base64url variant.
     *
     * @see https://en.wikipedia.org/wiki/Base64#URL_applications
     *
     * @throws \UnexpectedValueException
     */
    public static function urlDecode(string $data): string
    {
        $data = strtr($data, '-_', '+/');
        switch (strlen($data) % 4) {
            case 0:
                break;
            case 2:
                $data .= '==';
                break;
            case 3:
                $data .= '=';
                break;
            default:
                throw new \UnexpectedValueException(
                    'Malformed base64url encoding.');
        }
        return self::decode($data);
    }

    /**
     * Check whether string is validly base64url encoded.
     *
     * @see https://en.wikipedia.org/wiki/Base64#URL_applications
     */
    public static function isValidURLEncoding(string $data): bool
    {
        return 1 === preg_match('#^[A-Za-z0-9\-_]*$#', $data);
    }

    /**
     * Encode a string in base64.
     *
     * @see https://tools.ietf.org/html/rfc4648#section-4
     */
    public static function encode(string $data): string
    {
        return base64_encode($data);
    }

    /**
     * Decode a string from base64 encoding.
     *
     * @see https://tools.ietf.org/html/rfc4648#section-4
     *
     * @throws \RuntimeException If decoding fails
     */
    public static function decode(string $data): string
    {
        $ret = base64_decode($data, true);
        if (!is_string($ret)) {

The condition is_string($ret) is always true.

            $err = error_get_last();
            $msg = isset($err) && __FILE__ === $err['file'] ? $err['message'] : null;
            throw new \RuntimeException($msg ?? 'base64_decode() failed.');
        }
        return $ret;
    }

    /**
     * Check whether string is validly base64 encoded.
     *
     * @see https://tools.ietf.org/html/rfc4648#section-4
     */
    public static function isValid(string $data): bool
    {
        return 1 === preg_match('#^[A-Za-z0-9+/]*={0,2}$#', $data);
    }
}