WordPress Version: 6.4
/**
* Determines if a Unicode codepoint is valid.
*
* @since 2.7.0
*
* @param int $i Unicode codepoint.
* @return bool Whether or not the codepoint is a valid Unicode codepoint.
*/
function valid_unicode($i)
{
$i = (int) $i;
return 0x9 === $i || 0xa === $i || 0xd === $i || 0x20 <= $i && $i <= 0xd7ff || 0xe000 <= $i && $i <= 0xfffd || 0x10000 <= $i && $i <= 0x10ffff;
}