一個阿拉伯數字轉中文數字的函數

最近因需要，寫了個“阿拉伯數字轉中文數字的函數”。搜索了精華區只見到一個類似的。
感覺到我的算法不錯，所以貼出來共享一下如果要用於金額的轉換，對小數部分的處理要做一下修改
<?php
function ch_num($num,$mode=true) {
  $char = array("零","壹","貳","三","肆","伍","陸","柒","捌","玖");
  $dw = array("","拾","佰","仟","","萬","億","兆");
  $dec = "點";
  $retval = "";

  if($mode)
    preg_match_all("/^0*(\d*)\.?(\d*)/",$num, $ar);
  else
    preg_match_all("/(\d*)\.?(\d*)/",$num, $ar);

  if($ar[2][0] != "")
    $retval = $dec . ch_num($ar[2][0],false); //如果有小數，先遞歸處理小數
  if($ar[1][0] != "") {
    $str = strrev($ar[1][0]);
    for($i=0;$i<strlen($str);$i++) {
      $out[$i] = $char[$str[$i]];
      if($mode) {
        $out[$i] .= $str[$i] != "0"? $dw[$i%4] : "";
        if($str[$i]+$str[$i-1] == 0)
          $out[$i] = "";
        if($i%4 == 0)
          $out[$i] .= $dw[4+floor($i/4)];
      }
    }
    $retval = join("",array_reverse($out)) . $retval;
  }
  return $retval;
}

//echo ch_num("12345006789001.123");
//echo ch_num("880079.1234");
echo ch_num("300045.0123");

?>