unicode与utf8相互转换

function unicode_encode($name)
{
    $name = iconv('UTF-8', 'UCS-2', $name);
    $len = strlen($name);
    $str = '';
    for ($i = 0; $i < $len - 1; $i = $i + 2) {
        $c = $name[$i];
        $c2 = $name[$i + 1];
        if (ord($c) > 0) {    // 两个字节的文字
            $str .= '\u' . base_convert(ord($c), 10, 16) . base_convert(ord($c2), 10, 16);
        } else {
            $str .= $c2;
        }
    }
    return $str;
}

function unicode_decode($name)
{
    // 转换编码，将Unicode编码转换成可以浏览的utf-8编码
    $pattern = '/([\w]+)|(\\\u([\w]{4}))/i';
    preg_match_all($pattern, $name, $matches);
    if (!empty($matches)) {
        $name = '';
        for ($j = 0; $j < count($matches[0]); $j++) {
            $str = $matches[0][$j];
            if (strpos($str, '\\u') === 0) {
                $code = base_convert(substr($str, 2, 2), 16, 10);
                $code2 = base_convert(substr($str, 4), 16, 10);
                $c = chr($code) . chr($code2);
                $c = iconv('UCS-2', 'UTF-8', $c);
                $name .= $c;
            } else {
                $name .= $str;
            }
        }
    }
    return $name;
}