PHP string encoding conversion

<?php
function phpcharset($data, $to)
{
    if (is_array($data)) {
        foreach ($data as $key => $val) {
            $data[$key] = phpcharset($val, $to);
        }
    } else {
        $encode_array = array(
            &#39;ASCII&#39;,
            &#39;UTF-8&#39;,
            &#39;GBK&#39;,
            &#39;GB2312&#39;,
            &#39;BIG5&#39;
        );
        $encoded      = mb_detect_encoding($data, $encode_array);
        $to           = strtoupper($to);
        if ($encoded != $to) {
            $data = mb_convert_encoding($data, $to, $encoded);
        }
    }
    return $data;
}
function toUTF8($data)
{
    return phpcharset($data, &#39;UTF-8&#39;);
}
function toGBK($data)
{
    return phpcharset($data, &#39;GBK&#39;);
}
function toASCII($data)
{
    return phpcharset($data, &#39;ASCII&#39;);
}
function toGB2312($data)
{
    return phpcharset($data, &#39;GB2312&#39;);
}
function toBIG5($data)
{
    return phpcharset($data, &#39;BIG5&#39;);
}
?>