(PHP 4 >= 4.0.1, PHP 5, PHP 7) Pad a string to a certain length with another string

(PHP 4, PHP 5) Case insensitive regular expression match

(PHP 4, PHP 5, PHP 7) Uppercase the first character of each word in a string

(PHP 4, PHP 5, PHP 7) Find the first occurrence of a string

(PHP 4 >= 4.3.0, PHP 5, PHP 7) Calculate the sha1 hash of a string

(PHP 7) Perform a regular expression search and replace using callbacks

(PHP 5 >= 5.2.0, PHP 7) Returns the error code of the last PCRE regex execution

(PHP 4, PHP 5, PHP 7) Perform a global regular expression match

(PECL ssdeep >= 1.0.0) Create a fuzzy hash from a string

(PHP 4, PHP 5, PHP 7) Binary safe case-insensitive string comparison