截取中文字符串PHP代碼

/*


中文字符串截取
@param string $string
@param int $sublen
@param int $start
@param string $code
*/
function substr_zh ( $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 = $start * 2;
  $sublen = $sublen * 2;
  $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;

}
}</pre>