Method of reading CSV file function implemented in PHP

function read_csv($cvs) {
  $shuang = false;
  $str = file_get_contents($cvs);
  for ($i=0;$i<strlen($str);$i++) {
    if($str{$i}==&#39;"&#39;) {
      if($shuang) {
        if($str{$i+1}==&#39;"&#39;) {
          $str{$i} = &#39;*&#39;;
          $str{$i+1} = &#39;*&#39;;
        } else {
          $shuang = false;
        }
      } else {
        $shuang = true;
      }
    }
    if($str{$i}==&#39;,&#39;) {
      if($shuang) {
      } else {
        $str{$i} = &#39;|&#39;;
      }
    }
    if($str{$i}=="\n") {
      if($shuang) {
        $str{$i} = &#39;^&#39;;
      } else {
      }
    }
  }
  $str = str_replace(array(&#39;"&#39;,&#39;*&#39;),array(&#39;&#39;,&#39;"&#39;),$str);
  $a1 = explode("\n",$str);
  $array = array();
  foreach($a1 as $k=>$value) {
    if($value) {
      $value = str_replace("^","\n",$value);
      $array[$k] = explode("|",$value);
    }
  }
  return $array;
}