php 改进array_unique($array)函数

function unique($array) {
    sort ( $array );
    $arraylength = count ( $array );
    $endarray = array ();
    for($i = 0; $i < $arraylength; $i ++) {
        if ($i != "0") {
            $nextvalue = $array [$i - 1];
        } else {
            $nextvalue = "";
        }
        if ($i != $arraylength) {
            $prevalue = $array [$i + 1];
        } else {
            $prevalue = "";
        }
        $currentvalue = $array [$i];
        if ($currentvalue == $nextvalue || $currentvalue == $prevalue) {
            unset ( $array [$i] );
        } else {
            $endarray [] = $array [$i];
            continue;
        }
    }
    $array = $endarray;
    return $array;
}
//该片段来自于http://outofmemory.cn