实用技巧：PHP截取中文字符串的问题_PHP

function FSubstr($title,$start,$len="",$magic=true) 

{

/**

  *  powered by Smartpig

  *  mailto:d.einstein@263.net

  */

  

$length = 0;

if($len == "") $len = strlen($title);



//判断起始为不正确位置

if($start > 0)

{

  $cnum = 0;

  for($i=0;$i<$start;$i  )

  {

   if(ord(substr($title,$i,1)) >= 128) $cnum   ;

  }

  if($cnum%2 != 0) $start--;

  

  unset($cnum);

}



if(strlen($title)<=$len) return substr($title,$start,$len);



$alen   = 0;

$blen = 0;



$realnum = 0;



for($i=$start;$i")

   {

    $cstep = 4;

    $length  = 4;

    $i  = 3;

    $realnum   ;

    if($magic)

    {

     $alen   ;

    }

   }

   else if(substr($title,$i,5) == "&")

   {

    $cstep = 5;

    $length  = 5;

    $i  = 4;

    $realnum   ;

    if($magic)

    {

     $alen   ;

    }

   }

   else if(substr($title,$i,6) == """)

   {

    $cstep = 6;

    $length  = 6;

    $i  = 5;

    $realnum   ;

    if($magic)

    {

     $alen   ;

    }

   }

   else if(substr($title,$i,6) == "'")

   {

    $cstep = 6;

    $length  = 6;

    $i  = 5;

    $realnum   ;

    if($magic)

    {

     $alen   ;

    }

   }

   else if(preg_match("/&#(\d );/i",substr($title,$i,8),$match))

   {

    $cstep = strlen($match[0]);

    $length  = strlen($match[0]);

    $i  = strlen($match[0])-1;

    $realnum   ;

    if($magic)

    {

     $blen   ;

     $ctype = 1;

    }

   }

  }else{

   if(ord($cur)>=128)

   {

    $cstep = 2;

    $length  = 2;

    $i  = 1;

    $realnum   ;

    if($magic)

    {

     $blen   ;

     $ctype = 1;

    }

   }else{

    $cstep = 1;

    $length  =1;

    $realnum   ;

    if($magic)

    {

     $alen  ;

    }

   }

  }

  

  if($magic)

  {

   if(($blen*2 $alen) == ($len*2)) break;

   if(($blen*2 $alen) == ($len*2 1))

   {

    if($ctype == 1)

    {

     $length -= $cstep;

     break;

    }else{

     break;

    }

   }

  }else{

   if($realnum == $len) break;

  }

}



unset($cur);

unset($alen);

unset($blen);

unset($realnum);

unset($ctype);

unset($cstep);



return substr($title,$start,$length);

}