This functions returns the input string padded on the left, the right, or both sides to the specified padding length. If the optional argument pad_string is not supplied, the input is padded with spaces, otherwise it is padded with characters from pad_string up to the limit.
Optional argument pad_type can be STR_PAD_RIGHT, STR_PAD_LEFT, or STR_PAD_BOTH. If pad_type is not specified it is assumed to be STR_PAD_RIGHT.
If the value of pad_length is negative or less than the length of the input string, no padding takes place.
Note: The pad_string may be truncated if the required number of padding characters can't be evenly divided by the pad_string's length.