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.

• Password Hashing
  • Dependencies
  • Constants
  • Function reference
• Hash (Message Digest)
  • Dependencies
  • Function reference
• Multibyte String
  • Dependencies
  • Function reference
• Standard Functions
  • Dependencies
  • Function reference

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

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() with MCRYPT_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.

Dependencies

• iconv extension

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().