####################### Compatibility Functions ####################### CodeIgniter provides a set of compatibility functions that enable you to use functions what are otherwise natively available in PHP, but only in higher versions or depending on a certain extension. Being custom implementations, these functions will also have some set of dependencies on their own, but are still useful if your PHP setup doesn't offer them natively. .. note:: Much like the :doc:`common functions `, the compatibility functions are always available, as long as their dependencies are met. .. contents:: :local: .. raw:: html
**************** Password Hashing **************** This set of compatibility functions offers a "backport" of PHP's standard `Password Hashing extension `_ that is otherwise available only since PHP 5.5. Dependencies ============ - PHP 5.3.7 - ``CRYPT_BLOWFISH`` support for ``crypt()`` Constants ========= - ``PASSWORD_BCRYPT`` - ``PASSWORD_DEFAULT`` Function reference ================== .. php:function:: password_get_info($hash) :param string $hash: Password hash :returns: Information about the hashed password :rtype: array For more information, please refer to the `PHP manual for password_get_info() `_. .. php:function:: password_hash($password, $algo[, $options = array()]) :param string $password: Plain-text password :param int $algo: Hashing algorithm :param array $options: Hashing options :returns: Hashed password or FALSE on failure :rtype: string For more information, please refer to the `PHP manual for password_hash() `_. .. note:: Unless you provide your own (and valid) salt, this function has a further dependency on an available CSPRNG source. Each of the following would satisfy that: - ``mcrypt_create_iv()`` with ``MCRYPT_DEV_URANDOM`` - ``openssl_random_pseudo_bytes()`` - /dev/arandom - /dev/urandom .. php:function:: password_needs_rehash() :param string $hash: Password hash :param int $algo: Hashing algorithm :param array $options: Hashing options :returns: TRUE if the hash should be rehashed to match the given algorithm and options, FALSE otherwise :rtype: bool For more information, please refer to the `PHP manual for password_needs_rehash() `_. .. php:function:: password_verify($password, $hash) :param string $password: Plain-text password :param string $hash: Password hash :returns: TRUE if the password matches the hash, FALSE if not :rtype: bool For more information, please refer to the `PHP manual for password_verify() `_. ********************* Hash (Message Digest) ********************* This compatibility layer contains backports for the ``hash_equals()`` and ``hash_pbkdf2()`` functions, which otherwise require PHP 5.6 and/or PHP 5.5 respectively. Dependencies ============ - None Function reference ================== .. php:function:: hash_equals($known_string, $user_string) :param string $known_string: Known string :param string $user_string: User-supplied string :returns: TRUE if the strings match, FALSE otherwise :rtype: string For more information, please refer to the `PHP manual for hash_equals() `_. .. php:function:: hash_pbkdf2($algo, $password, $salt, $iterations[, $length = 0[, $raw_output = FALSE]]) :param string $algo: Hashing algorithm :param string $password: Password :param string $salt: Hash salt :param int $iterations: Number of iterations to perform during derivation :param int $length: Output string length :param bool $raw_output: Whether to return raw binary data :returns: Password-derived key or FALSE on failure :rtype: string For more information, please refer to the `PHP manual for hash_pbkdf2() `_. **************** Multibyte String **************** This set of compatibility functions offers limited support for PHP's `Multibyte String extension `_. Because of the limited alternative solutions, only a few functions are available. .. note:: When a character set parameter is ommited, ``$config['charset']`` will be used. Dependencies ============ - `iconv `_ extension .. important:: This dependency is optional and these functions will always be declared. If iconv is not available, they WILL fall-back to their non-mbstring versions. .. important:: Where a character set is supplied, it must be supported by iconv and in a format that it recognizes. .. note:: For you own dependency check on the actual mbstring extension, use the ``MB_ENABLED`` constant. Function reference ================== .. php:function:: mb_strlen($str[, $encoding = NULL]) :param string $str: Input string :param string $encoding: Character set :returns: Number of characters in the input string or FALSE on failure :rtype: string For more information, please refer to the `PHP manual for mb_strlen() `_. .. php:function:: mb_strpos($haystack, $needle[, $offset = 0[, $encoding = NULL]]) :param string $haystack: String to search in :param string $needle: Part of string to search for :param int $offset: Search offset :param string $encoding: Character set :returns: Numeric character position of where $needle was found or FALSE if not found :rtype: mixed For more information, please refer to the `PHP manual for mb_strpos() `_. .. php:function:: mb_substr($str, $start[, $length = NULL[, $encoding = NULL]]) :param string $str: Input string :param int $start: Position of first character :param int $length: Maximum number of characters :param string $encoding: Character set :returns: Portion of $str specified by $start and $length or FALSE on failure :rtype: string For more information, please refer to the `PHP manual for mb_substr() `_. ****************** Standard Functions ****************** This set of compatibility functions offers support for a few standard functions in PHP that otherwise require a newer PHP version. Dependencies ============ - None Function reference ================== .. php:function:: array_column(array $array, $column_key[, $index_key = NULL]) :param array $array: Array to fetch results from :param mixed $column_key: Key of the column to return values from :param mixed $index_key: Key to use for the returned values :returns: An array of values representing a single column from the input array :rtype: array For more information, please refer to the `PHP manual for array_column() `_. .. php:function:: hex2bin($data) :param array $data: Hexadecimal representation of data :returns: Binary representation of the given data :rtype: string For more information, please refer to the `PHP manual for hex2bin() `_.