PHP编码转换

class Phpclass {
   
    function __construct() {
        
    }
    
     /**
     * 转换字符编码
     * @param string $fContents 需要转换编码格式的内容
     * @param string $from 原编码格式
     * @param string $to   新编码格式
     * @return string
     */
    public function auto_charset($fContents, $from='gbk', $to='utf-8') 
    {
        $from = strtoupper($from)   == 'UTF8' ? 'utf-8' : $from;
        $to   = strtoupper($to)     == 'UTF8' ? 'utf-8' : $to;
        if (strtoupper($from) === strtoupper($to) || empty($fContents) || (is_scalar($fContents) && !is_string($fContents))) {
                //如果编码相同或者非字符串标量则不转换
                return $fContents;
        }
        if (is_string($fContents)) {
                if (function_exists('mb_convert_encoding')) {
                        return mb_convert_encoding($fContents, $to, $from);
                } elseif (function_exists('iconv')) {
                        return iconv($from, $to, $fContents);
                } else {
                        return $fContents;
                }
        }else {
                return $fContents;
        }
    }//auto_charset 
}