How to detect whether a string is UTF8 encoded code under PHP

Give a string, how to determine what it is encoded?

PHP has a function: mb_detect_encoding.

But this thing needs to have a mb_string library, not everywhere can use.

function Is_utf8 ($string) {return Preg_match ('%^ (?: [\x09\x0a\x0d\x20-\x7e] # ascii| [\XC2-\XDF] [\X80-\XBF] # Non-overlong 2-byte| \XE0[\XA0-\XBF][\X80-\XBF] # excluding overlongs| [\xe1-\xec\xee\xef] [\X80-\XBF] {2} # straight 3-byte| \XED[\X80-\X9F][\X80-\XBF] # excluding surrogates| \XF0[\X90-\XBF][\X80-\XBF]{2} # Planes 1-3| [\xf1-\xf3] [\X80-\XBF] {3} # planes 4-15| \XF4[\X80-\X8F][\X80-\XBF]{2} # Plane) *$%xs ', $string); }

Accuracy is basically the same as mb_detect_encoding, to be right together, to be wrong together.
Code detection is not possible 100% accurate, this thing has been able to basically meet the requirements.

