PHP has a large collection of multibyte functions in the standard library for handling multibyte strings such as Japanese. Two useful multibyte functions that PHP provides are for detecting the encoding of a multibyte string, and converting from one multibyte encoding to another.

• mb_check_encoding()
• mb_convert_encoding()

To check if $string is in UTF-8 encoding, we call mb_check_encoding() like this:

if (mb_check_encoding($string, "UTF-8")) { // do_something(); }

To convert $string, which is currently Shift-JIS, to UTF-8, we call mb_convert_encoding() like this:

$convertedString = mb_convert_encoding($string, "UTF-8", "Shift-JIS);

A convenient feature of mb_convert_encoding() is that you can generalize the function by adding a list of character encodings to convert from. This can come in very handy if you want to convert all Japanese multibyte string encodings to UTF-8, or something else. There are actually 18 Japanese-specific multibyte encodings (that I know of), not including all the Unicode variants like UTF-8, UTF-16, etc. A lot of them come from the Japanese mobile phone carriers.

Let’s put all of this together and check if a string is UTF-8, and if it’s not, meaning it is one of the other 18 Japanese encoding types, let’s convert it to UTF-8.

if (!mb_check_encoding($string, "UTF-8")) {

   $string = mb_convert_encoding($string, "UTF-8",
      "Shift-JIS, EUC-JP, JIS, SJIS, JIS-ms, eucJP-win, SJIS-win, ISO-2022-JP,
       ISO-2022-JP-MS, SJIS-mac, SJIS-Mobile#DOCOMO, SJIS-Mobile#KDDI,
       SJIS-Mobile#SOFTBANK, UTF-8-Mobile#DOCOMO, UTF-8-Mobile#KDDI-A,
       UTF-8-Mobile#KDDI-B, UTF-8-Mobile#SOFTBANK, ISO-2022-JP-MOBILE#KDDI");
}

Posted in Japanese, Programming | 4 Comments »
leave a response | trackback