php 截取一定长度的字符串（该函数对GB2312使用有效

function ssubstr($string, $length, $dot = ' ...') {
 global $charset;

  if(strlen($string) <= $length) {
   return $string;
  }
  $string = str_replace(array('&', '"', '<', '>'), array('&', '"', '<', '>'), $string);
  $strcut = '';
  if(strtolower($charset) == 'utf-8') {
   $n = $tn = $noc = 0;
   while($n < strlen($string)) {
     $t = ord($string[$n]);
     if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
   $tn = 1; $n++; $noc++;
     } elseif (194 <= $t && $t <= 223) {
   $tn = 2; $n += 2; $noc += 2;
     } elseif (224 <= $t && $t < 239) {
   $tn = 3; $n += 3; $noc += 2;
     } elseif (240 <= $t && $t <= 247) {
   $tn = 4; $n += 4; $noc += 2;
     } elseif (248 <= $t && $t <= 251) {
   $tn = 5; $n += 5; $noc += 2;
     } elseif ($t == 252 || $t == 253) {
   $tn = 6; $n += 6; $noc += 2;
     } else {
   $n++;
     }
     if($noc >= $length)
     {
   break;
     }
   }
    if($noc > $length)
    {
    $n -= $tn;
    }
   $strcut = substr($string, 0, $n);
  } else {
    for($i = 0; $i < $length; $i++)
    {
     $strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];
    }
  }
 $strcut = str_replace(array('&', '"', '<', '>'), array('&', '"', '<', '>'), $strcut);
 return $strcut.$dot;
}

 
截取一定长度的字符串（该函数对gb2312使用有效）
function wordscut($string, $length ,$sss=0) {

if(strlen($string) > $length) {
               if($sss){
$length=$length - 3;
$addstr=@# ...@#;

}
  for($i = 0; $i < $length; $i++) {
   if(ord($string[$i]) > 127) {
$wordscut .= $string[$i].$string[$i + 1]; //
$i++;
   } else {
$wordscut .= $string[$i];
   }
  }
  return $wordscut.$addstr;
}
return $string;
}
?>