PHP validator that checks if a given string is a valid/allowed filesystem path across operating systems

isValidPath.php

function isValidPath($value) {
  return (preg_match('/^(\/(?:(?:(?:(?:[a-zA-Z0-9\\-_.!~*\'():\@&=+\$,]+|(?:%[a-fA-F0-9][a-fA-F0-9]))*)(?:;(?:(?:[a-zA-Z0-9\\-_.!~*\'():\@&=+\$,]+|(?:%[a-fA-F0-9][a-fA-F0-9]))*))*)(?:\/(?:(?:(?:[a-zA-Z0-9\\-_.!~*\'():\@&=+\$,]+|(?:%[a-fA-F0-9][a-fA-F0-9]))*)(?:;(?:(?:[a-zA-Z0-9\\-_.!~*\'():\@&=+\$,]+|(?:%[a-fA-F0-9][a-fA-F0-9]))*))*))*))$/', (string) $value) > 0);
}