Detect CJK characters in PHP

Question

I've got an input box that allows UTF8 characters -- can I detect whether the characters are in Chinese, Japanese, or Korean programmatically (part of some Unicode range, perhaps)? I would change search methods depending on if MySQL's fulltext searching would work (it won't work for CJK characters).

Thanks!

Answer 1

// is chinese, japanese or korean language
function isCjk($string) {
    return isChinese($string) || isJapanese($string) || isKorean($string);
}

function isChinese($string) {
    return preg_match("/\p{Han}+/u", $string);
}

function isJapanese($string) {
    return preg_match('/[\x{4E00}-\x{9FBF}\x{3040}-\x{309F}\x{30A0}-\x{30FF}]/u', $string);
}

function isKorean($string) {
    return preg_match('/[\x{3130}-\x{318F}\x{AC00}-\x{D7AF}]/u', $string);
}

Answer 2

CJK characters are restricted to certain Unicode Blocks. You need to check the characters if they are inside these blocks, and should consider surrogates (32bit characters) too.