Why htmlspecialchars_decode in PHP does not have the charset parameter as in its counterpart?

Question

There is a charset parameter in htmlspecialchars but the decode version does not have it. In comparison to the similar htmlentities, the encode and decode functions both have the charset parameter. So I can't choose what charset I am decoding back to?

Answer 1

htmlspecialchars() requires the charset parameter only when converting charsets who's special characters are not in the 'default' positions. Hence, charsets ISO-8859-1, ISO-8859-15, UTF-8, cp866, cp1251, cp1252, and KOI8-R do not require the charset parameter.

htmlspecialchars_decode() converts entities (& " ' < >) back to their character equivalent and therefore does not need to be passed a charset.

As htmlentities() converts 'all' characters to their equivalent entity, a charset can be passed in html_entity_decode() to ensure the entities are decoded to the relevant character in the charset.