Mb_check_encoding Check if the string is valid in the specified encoding

Ming: Bool Mb_check_encoding ([String $var = NULL [, String $encoding = Mb_internal_encoding ()]])
Checks whether the specified byte stream is valid in the specified encoding. It can effectively avoid the so-called "Invalid code attack (Invalid Encoding Attack)".

Parameters
Var
The byte stream to check. If this argument is omitted, this function checks all input from the original request.

Encoding

the desired encoding.

return value
Returns TRUE on success or FALSE on failure.

To check whether a string encoding is correct in utf-8, I recommend that the following function implement Mb_check_encoding ():

The code is as follows

Copy Code

<?php function Check_utf8 ($STR) { $len = strlen ($STR); for ($i = 0; $i < $len; $i + +) { $c = Ord ($str [$i]); if ($c > 128) { if ($c > 247) return false; ElseIf ($c > 239) $bytes = 4; ElseIf ($c > 223) $bytes = 3; ElseIf ($c > 191) $bytes = 2; else return false; if (($i + $bytes) > $len) return false; while ($bytes > 1) { $i + +; $b = Ord ($str [$i]); if ($b < 128 | | | $b > 191) return false; $bytes--; } } } return true; }//End of Check_utf8 ?>