The following does the trick:
$str = "some മനുഷ്യന്റെ";
echo preg_replace('/[\x{00ff}-\x{ffff}]/u', '*', $str);
// some **********
echo preg_replace('/[^\x{00ff}-\x{ffff}]/u', '*', $str);
// *****മനുഷ്യന്റെ
The important thing is the u
-modifier (see here):
This modifier turns on additional
functionality of PCRE that is
incompatible with Perl. Pattern
strings are treated as UTF-8. This
modifier is available from PHP 4.1.0
or greater on Unix and from PHP 4.2.3
on win32. UTF-8 validity of the
pattern is checked since PHP 4.3.5.
And here a short description why \uFFFF
is not working in PHP:
Perl and PCRE do not support the
\uFFFF syntax. They use \x{FFFF}
instead. You can omit leading zeros in
the hexadecimal number between the
curly braces. Since \x by itself is
not a valid regex token, \x{1234} can
never be confused to match \x 1234
times. It always matches the Unicode
code point U+1234. \x{1234}{5678} will
try to match code point U+1234 exactly
5678 times.