Detailed explanation of how to use PHP custom function to implement two-dimensional array sorting function

/**作用: 二维数组排序函数,支持多键名排序
 * 返回: 排序好的数组
 * 使用: array_msort(数组,需要排序的键名,排序方式);
 * 例子: array_msort($cflist,"chapter_orderid","SORT_ASC");
 *    array_msort($arr,"name","SORT_ASC","type","SORT_DESC","size","SORT_ASC","SORT_STRING");
 */
function array_msort($ArrayData,$KeyName1,$SortOrder1 = "SORT_ASC",$SortType1 = "SORT_REGULAR") {
  if(!is_array($ArrayData)) {
    return $ArrayData;
  }
  // 获取参数数量.
  $ArgCount = func_num_args();
  // 排序,并放置到SortRule数组
  for($i = 1;$i < $ArgCount;$i ++) {
    $Arg = func_get_arg($i);
    if(!eregi("SORT",$Arg)) {
      $KeyNameList[] = $Arg;
      $SortRule[] = &#39;$&#39;.$Arg;
    }
    else {
      $SortRule[] = $Arg;
    }
  }
  // Get the values according to the keys and put them to array.
  foreach($ArrayData AS $Key => $Info) {
    foreach($KeyNameList AS $KeyName) {
      ${$KeyName}[$Key] = $Info[$KeyName];
    }
  }
  // Create the eval string and eval it.
  $EvalString = &#39;array_multisort(&#39;.join(",",$SortRule).&#39;,$ArrayData);&#39;;
  eval($EvalString);
  return $ArrayData;
}