php中截取字符串支持utf-8

截取字符串
<?php
$string="2006年4月我又长大了一岁！";
echo substr($string,1)."...";
//截取字符串
function SubstrGB($in,$num)
{
$pos=0;
$out="";
while($pos<strlen($in))
{
$c=substr($in,$pos,1);
if($c=="\n") break;
if(ord($c)>128)
{
$out.=$c;
$pos++;
$c=substr($in,$pos,1);
$out.=$c;
}
else
{
$out.=$c;
}
$pos++;
if($pos>=$num) break;
}
return $out;
}
echo SubstrGB($string,8) ;
?>
<?php
/***

•        cut_string.php   

• ------------------------------
• Date : Jul 16, 2005
• Copyright : none
• Mail :
• 作用:截取中文字符.

• ***/
  function cut_str($string, $sublen, $start = 0, $code = 'UTF-8')
  {
  if($code == 'UTF-8')
  {
  $pa = "/[x01-x7f]|[xc2-xdf][x80-xbf]|xe0[xa0-xbf][x80-xbf]|[xe1-xef][x80-xbf][x80-xbf]|xf0[x90-xbf][x80-xbf][x80-xbf]|[xf1-xf7][x80-xbf][x80-xbf][x80-xbf]/";
  preg_match_all($pa, $string, $t_string);
  if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."...";
  return join('', array_slice($t_string[0], $start, $sublen));
  }
  else
  {
  $start = $start2;
  $sublen = $sublen2;
  $strlen = strlen($string);
  $tmpstr = '';
  for($i=0; $i<$strlen; $i++)
  {
  if($i>=$start && $i<($start+$sublen))
  {
  if(ord(substr($string, $i, 1))>129) $tmpstr.= substr($string, $i, 2);
  else $tmpstr.= substr($string, $i, 1);
  }
  if(ord(substr($string, $i, 1))>129) $i++;
  }
  if(strlen($tmpstr)<$strlen ) $tmpstr.= "...";
  return $tmpstr;
  }
  }
  echo "
  ".cut_str($string,8,$start=0,$code='sdf') ;
  ?>