php中GB2312转UTF8

（转）http://jyqx.spaces.live.com/blog/cns!F9F71C7D6CB19944!203.entry

按照性能从高到低依次是iconv,mbstring和自制字库，下面的代码简单演示了一下！其他代码互转也差不多

PHP CODE

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<?function encode_conver($subject,$function){   switch ($function){    case 1:     $subject=iconv("GB2312","UTF-8",$subject);     break;    case 2:     $subject=mb_convert_encoding($subject, "UTF-8", "GB2312");     break;    case 3:     $subject=gb2utf8($subject);     break;   }   return $subject;}function gb2utf8($string) {  $ut="";  $gb=file("./gbk.txt");  $gb=explode("|",$gb[0]);  $utf=file("./utf8.txt");  $utf=explode("|",$utf[0]);  $gb=array_flip($gb);  while ($string){   $st=substr($string,0,1);   $string=substr($string,1);   if (ord($st)<128){      $ut.=$st;   } else {    $st.=substr($string,0,1);    $string=substr($string,1);   $ut.=$utf[$gb[$st]];   }  }  return $ut; }?>