The functions are roughly equivalent to their php counterparts
Although some php function parameters may not be available
abs addslashes base64 decode base64 encode bin2hex br2nl ceil chr crc32 dechex floor hex2bin hexdec htmlspecialchars lcfirst ltrim md5 mt rand nl2br ord pi pow rawurldecode rawurlencode round rtrim sha1 str ireplace str pad str repeat str replace str shuffle strip tags stripos stripslashes stristr strlen strpos strrchr strrev strripos strrpos strstr strtolower strtoupper substr trim ucfirst ucwords urldecode urlencode