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 common functions, the compatibility functions are always available, as long as their dependencies are met.
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 forcrypt()
Constants
PASSWORD_BCRYPT
PASSWORD_DEFAULT
Function reference
- password_get_info($hash)
- Parameters:
$hash (
string
) – Password hash
- Returns:
Information about the hashed password
- Return type:
array
For more information, please refer to the PHP manual for password_get_info().
- password_hash($password, $algo[, $options = array()])
- Parameters:
$password (
string
) – Plain-text password$algo (
int
) – Hashing algorithm$options (
array
) – Hashing options
- Returns:
Hashed password or FALSE on failure
- Return type:
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()
withMCRYPT_DEV_URANDOM
-openssl_random_pseudo_bytes()
- /dev/arandom - /dev/urandom
- password_needs_rehash()
- Parameters:
$hash (
string
) – Password hash$algo (
int
) – Hashing algorithm$options (
array
) – Hashing options
- Returns:
TRUE if the hash should be rehashed to match the given algorithm and options, FALSE otherwise
- Return type:
bool
For more information, please refer to the PHP manual for password_needs_rehash().
- password_verify($password, $hash)
- Parameters:
$password (
string
) – Plain-text password$hash (
string
) – Password hash
- Returns:
TRUE if the password matches the hash, FALSE if not
- Return type:
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
- hash_equals($known_string, $user_string)
- Parameters:
$known_string (
string
) – Known string$user_string (
string
) – User-supplied string
- Returns:
TRUE if the strings match, FALSE otherwise
- Return type:
string
For more information, please refer to the PHP manual for hash_equals().
- hash_pbkdf2($algo, $password, $salt, $iterations[, $length = 0[, $raw_output = FALSE]])
- Parameters:
$algo (
string
) – Hashing algorithm$password (
string
) – Password$salt (
string
) – Hash salt$iterations (
int
) – Number of iterations to perform during derivation$length (
int
) – Output string length$raw_output (
bool
) – Whether to return raw binary data
- Returns:
Password-derived key or FALSE on failure
- Return type:
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,
$config['charset']
will be used.
Dependencies
iconv extension
Important
This dependency is optional and these functions will always be declared. If iconv is not available, they WILL fall-back to their non-mbstring versions.
Important
Where a character set is supplied, it must be supported by iconv and in a format that it recognizes.
Note
For you own dependency check on the actual mbstring
extension, use the MB_ENABLED
constant.
Function reference
- mb_strlen($str[, $encoding = NULL])
- Parameters:
$str (
string
) – Input string$encoding (
string
) – Character set
- Returns:
Number of characters in the input string or FALSE on failure
- Return type:
string
For more information, please refer to the PHP manual for mb_strlen().
- mb_strpos($haystack, $needle[, $offset = 0[, $encoding = NULL]])
- Parameters:
$haystack (
string
) – String to search in$needle (
string
) – Part of string to search for$offset (
int
) – Search offset$encoding (
string
) – Character set
- Returns:
Numeric character position of where $needle was found or FALSE if not found
- Return type:
mixed
For more information, please refer to the PHP manual for mb_strpos().
- mb_substr($str, $start[, $length = NULL[, $encoding = NULL]])
- Parameters:
$str (
string
) – Input string$start (
int
) – Position of first character$length (
int
) – Maximum number of characters$encoding (
string
) – Character set
- Returns:
Portion of $str specified by $start and $length or FALSE on failure
- Return type:
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
- array_column(array $array, $column_key[, $index_key = NULL])
- Parameters:
$array (
array
) – Array to fetch results from$column_key (
mixed
) – Key of the column to return values from$index_key (
mixed
) – Key to use for the returned values
- Returns:
An array of values representing a single column from the input array
- Return type:
array
For more information, please refer to the PHP manual for array_column().
- hex2bin($data)
- Parameters:
$data (
array
) – Hexadecimal representation of data
- Returns:
Binary representation of the given data
- Return type:
string
For more information, please refer to the PHP manual for hex2bin().