php公用函数：获取字符串中英文混合长度

//获取字符串中英文混合长度
function get_strlen($str, $charset = 'utf-8')
{
  if ($charset == 'utf-8') $str = iconv('utf-8', 'gb2312', $str);
  $num   = strlen($str);
  $cnNum = 0;
  for ($i = 0; $i < $num; $i++) {
    if (ord(substr($str, $i + 1, 1)) > 127) {
      $cnNum++;
      $i++;
    }
  }
  $enNum = $num - ($cnNum * 2);
  return $cnNum * 2 + $enNum;
}