写的几个函数，关键词描红，搜索关键词过滤，生成SQL查询关键词

1，生成SQL关键词，去除了特殊字符

2，关键词描红，

3，可选是否过滤。

/* 关键词描红 */
function SearchReplaceKw($string,$sokw='',$useSafe=false)
{
  if($useSafe) $sokw = SafeStrip($sokw);
  if(empty($sokw) || empty($string)) return $string;
  $sokw = preg_replace('/\s+/','|',$sokw);
  return preg_replace("/($sokw)/",'<font color="red">\\1</font>',$string);
}

/* 去除特殊字符,不包括空格 */
function SafeStrip($kw)
{
  if(strlen($kw) == 0) return '';
  $badString = '~!@#$%^&*()_+|-=\\{}[];\':",./<>?';
  $length = strlen($badString);
  $pos = 0;
  while($pos < $length)
  {
    $kw = str_replace($badString{$pos},'',$kw);
    $pos++;
  }
  return preg_replace('/([\r\n\t]+)/','',$kw);
}

function MkQueryString($string,$useSafe=true)
{
  if($useSafe) $string = SafeStrip($string);
  if(empty($string)) return '';
  return preg_replace("/([\s%]+)/",'%', '%'.trim($string).'%');
}