PHP Functions

A PHP function is a piece of code that performs a specific task. It is declared using the function keyword, followed by the name of the function and a set of parentheses. Within the parentheses, you can define the parameters that the function will accept. Functions can also return a value if they are called with the return keyword.

bzread() reads from the given bzip2 file pointer. Reading stops when length (uncompressed) bytes have been read or EOF is reached, whichever comes first. By default, a maximum of 1024 uncompressed bytes are read at a time.

The hex2bin() function converts a hexadecimal encoded string into its binary form. It's useful for working with data that has been encoded in hexadecimal, since this allows you to view the original data without the hexadecimal characters.

This PHP string function is used to add a backslash before certain characters in a string to make it safe for use in a database or for display on a web page. The function takes the string that needs to be escaped and adds the backslash before any non-alphanumeric character in it.

The rtrim() function removes white spaces and other predefined characters from the right side of a string. It can be useful when preparing data for transmission over text-only channels.