Services_JSON::utf162utf8( string $utf16 ): string

194    function utf162utf8($utf16)195    {196        _deprecated_function( __METHOD__, '5.3.0', 'The PHP native JSON extension' );197 198        // oh please oh please oh please oh please oh please199        if($this->_mb_convert_encoding) {200            return mb_convert_encoding($utf16, 'UTF-8', 'UTF-16');201        }202 203        $bytes = (ord($utf16[0]) << 8) | ord($utf16[1]);204 205        switch(true) {206            case ((0x7F & $bytes) == $bytes):207                // this case should never be reached, because we are in ASCII range208                // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8209                return chr(0x7F & $bytes);210 211            case (0x07FF & $bytes) == $bytes:212                // return a 2-byte UTF-8 character213                // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8214                return chr(0xC0 | (($bytes >> 6) & 0x1F))215                     . chr(0x80 | ($bytes & 0x3F));216 217            case (0xFFFF & $bytes) == $bytes:218                // return a 3-byte UTF-8 character219                // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8220                return chr(0xE0 | (($bytes >> 12) & 0x0F))221                     . chr(0x80 | (($bytes >> 6) & 0x3F))222                     . chr(0x80 | ($bytes & 0x3F));223        }224 225        // ignoring UTF-32 for now, sorry226        return '';227    }