unserialize() with encoding conversion

utils.php

<?php


/**
 * Hacked unserialize: works when encoding changed after serialization
 * Problem: serialize cp1250, convert to utf8, unserialize. Length in bytes is bigger now!
 *
 * Also, it throws when something else is wrong
 *
 * @param  string $s
 * @return mixed
 *
 * @throws ErrorException
 */
function unserialize2($s) {
	$offsetError = FALSE;

	set_error_handler(function($severity, $message, $file, $line) use (&$offsetError) {
		if ($offsetError === FALSE && preg_match('~Error at offset \d+ of \d+ bytes~', $message)) $offsetError = TRUE;
		else {
			restore_error_handler();
			throw new \ErrorException($message, 0, $severity, $file, $line);
		}
	});

	// try normal
	$ret = unserialize($s);

	// recode
	if ($offsetError) {
		$s = preg_replace_callback(
			'!(?<=^|;)s:(\d+)(?=:"(.*?)";(?:}|a:|s:|b:|d:|i:|o:|N;))!s',
			'_serialize_fix_callback',
			$s
		);

		$ret = unserialize($s);
	}

	restore_error_handler();

	return $ret;
}
// used in previous function
function _serialize_fix_callback($match) {
	return 's:' . strlen($match[2]);
}