一个好用的UBB类！

<?php
/*
如有转载，请注明作者

原作者: 何志强
改进:   SonyMusic[sonymusic@163.net]
文件:   ubb.php
备注:   说是改进，其实核心函数parse()已经完全重写了，而且思路也是不一样的。
        不过仍是受何志强的例子的启发，而且测试的例子还有URLCHECK等几个函数也是沿用的何志强的程序，谢谢何志强。
        目前还没有颜色的功能，但我会加入的。
        如果在程序上有什么BUG或不便的地方，请给我MAIL。
        谢谢！
改进功能:
    对字符串进行UBB编码,该类目前只支持下列几个简单且实用的编码:
    1. URL裢接
       
       http://头可以不需要
       如也是可以的。
    2. Email裢接
       
    3. 图片裢接
       
       同URL链接一样，前面的http也可以不要。
    4. 文字方面
       粗体字
       斜体字
       加下划线
       

1号标题字

...

6号标题字

       
       
       [tt][/tt]
       [s][/s]
       
       [em][/em]
       [strong][/strong]
       [code][/code]
       [samp][/samp]
       [kbd][/kbd]
       [var][/var]
       [dfn][/dfn]
       [cite][/cite]
       
       
       
    注意以下几点:
    1. url,email,img等标签是不分大小写的.
    2. 在标签中不允许有TAB键出现，但空格允许。
    3. 该类要调用htmlencode,htmlencode4textarea,emailcheck函数和urlcheck类.
    4. 修改后支持嵌套，但url,email,img这三个标签不是允许嵌套的。
技术资料:
    Ultimate Bulletin Board
        http://www.ultimatebb.com/
    What is UBB Code
        http://www.scriptkeeper.com/ubb/ubbcode.html
*/

include("urlcheck.php");
include("otherfunc.php"); //这两个文件的内容，附在最后。

//ubbcode类
class ubbcode{
    var $call_time=0;
   //可处理标签及处理函数对应表
   var $tags = array(  //小写的标签 => 对应的处理函数
                       @#url@# => @#$this->url@#,
                       @#email@# => @#$this->email@#,
                       @#img@# => @#$this->img@#,
                       @#b@# => @#$this->simple@#,
                       @#i@# => @#$this->simple@#,
                       @#u@# => @#$this->simple@#,
                       @#tt@# => @#$this->simple@#,
                       @#s@# => @#$this->simple@#,
                       @#strike@# => @#$this->simple@#,
                       @#h1@# => @#$this->simple@#,
                       @#h2@# => @#$this->simple@#,
                       @#h3@# => @#$this->simple@#,
                       @#h4@# => @#$this->simple@#,
                       @#h5@# => @#$this->simple@#,
                       @#h6@# => @#$this->simple@#,
                       @#sup@# => @#$this->simple@#,
                       @#sub@# => @#$this->simple@#,
                       @#em@# => @#$this->simple@#,
                       @#strong@# => @#$this->simple@#,
                       @#code@# => @#$this->simple@#,
                       @#samp@# => @#$this->simple@#,
                       @#kbd@# => @#$this->simple@#,
                       @#var@# => @#$this->simple@#,
                       @#dfn@# => @#$this->simple@#,
                       @#cite@# => @#$this->simple@#,
                       @#small@# => @#$this->simple@#,
                       @#big@# => @#$this->simple@#,
                       @#blink@# => @#$this->simple@#
                    );
   //url裢接属性
   var $attr_url;
   //url合法性检查对象
   var $urlcheck;

   function ubbcode($attr_url){
      $this->attr_url = @#@#.$attr_url;
      $this->urlcheck = new urlcheck();
   }

   //对$str进行UBB编码解析
   function parse($str){
           $this->call_time++;
      $parse = @#@#.htmlencode($str);

      $ret = @#@#;
      while(true){
          $eregi_ret=eregi("\[[#]{0,1}[[:alnum:]]{1,7}\]",$parse,$eregi_arr); //查找[xx]
        if(!$eregi_ret){
            $ret .= $parse;
            break;  //如果没有，返回
         }
         $pos = @strpos($parse,$eregi_arr[0]);
         $tag_len=strlen($eregi_arr[0])-2;//标记长度
        $tag_start=substr($eregi_arr[0],1,$tag_len);
        $tag=strtolower($tag_start);
        
         if((($tag=="url") or ($tag=="email") or ($tag=="img")) and ($this->call_time>1)){
             echo $this->call_time."<br>";
             return $parse;//如果不能是不能嵌套的标记，直接返回
        }
        
         $parse2 = substr($parse,0,$pos);//标记之前
         $parse = substr($parse,$pos+$tag_len+2);//标记之后
         if(!isset($this->tags[$tag])){
             echo "$tag_start<br>";
            $ret .= $parse2.@#[@#.$tag_start.@#]@#;
            continue;//如果是不支持的标记
         }
        
         //查找对对应的结束标记
         $eregi_ret=eregi("\[\/".$tag."\]",$parse,$eregi_arr);
         if(!$eregi_ret){
            $ret .= $parse2.@#[@#.$tag_start.@#]@#;
            continue;//如果没有对应该的结束标记
         }
         $pos=strpos($parse,$eregi_arr[0]);
         $value=substr($parse,0,$pos);//这是起止标记之间的内容
         $tag_end=substr($parse,$pos+2,$tag_len);
         $parse=substr($parse,$pos+$tag_len+3);//结束标记之后的内容
         
         if(($tag!="url") and ($tag!="email") and ($tag!="img")){
             $value=$this->parse($value);
        }

         $ret .= $parse2;
         eval(@#$ret .= @#.$this->tags[$tag].@#("@#.$tag_start.@#","@#.$tag_end.@#","@#.$value.@#");@#);
      }
        $this->call_time--;
      return $ret;
   }

   function simple($start,$end,$value){
      return @#<@#.$start.@#>@#.$value.@#</@#.$end.@#>@#;
   }

   function url($start,$end,$value){
           $trim_value=trim($value);
        if (strtolower(substr($trim_value,0,7))!="http://")
            $trim_value="http://".$trim_value;
      if($this->urlcheck->check($trim_value)) return @#<a href="@#.$trim_value.@#" @#.$this->attr_url.@#>@#.$value.@#</a>@#;
      else return @#[@#.$start.@#]@#.$value.@#[/@#.$end.@#]@#;
   }

   function email($start,$end,$value){
      if(emailcheck($value)) return @#<a href="mailto:@#.$value.@#">@#.$value.@#</a>@#;
      else return @#[@#.$start.@#]@#.$value.@#[/@#.$end.@#]@#;
   }

   function img($start,$end,$value){
           $trim_value=trim($value);
        if ((strtolower(substr($trim_value,0,7))!="http://") or ($this->urlcheck->check($trim_value)))
               return @#<img src="@#.$trim_value.@#"></img>@#;
      else return @#[@#.$start.@#]@#.$value.@#[/@#.$end.@#]@#;
   }
}

//测试
echo @#<html>@#;
echo @#<head><title>测试</title></head>@#;
echo @#<body>@#;
echo @#<form action="@#.str2url($PATH_INFO).@#" method="post">@#;
echo @#<textarea cols="100" rows="10" name="ubb">@#.htmlencode4textarea($ubb).@#</textarea><br>@#;
echo @#<input type="submit" value="转换">@#;
echo @#</form>@#;

if(isset($ubb)){
   $ubbcode = new ubbcode(@#target="_blank"@#);
   echo @#<hr>@#.$ubbcode->parse($ubb);
}

echo @#</body>@#;
echo @#</html>@#;

?>

文件urlcheck.php的内容
<?php
//urlcheck.php
class urlcheck{
   var $regex = array(//协议名(注意在这里必须写成小写) => 对应的正则表达式
                      @#ftp@# => @#$this->ftpurl@#,
                      @#file@# => @#$this->fileurl@#,
                      @#http@# => @#$this->httpurl@#,
                      @#https@# => @#$this->httpurl@#,
                      @#gopher@# => @#$this->gopherurl@#,
                      @#news@# => @#$this->newsurl@#,
                      @#nntp@# => @#$this->nntpurl@#,
                      @#telnet@# => @#$this->telneturl@#,
                      @#wais@# => @#$this->waisurl@#
                     );

   var $lowalpha;
   var $hialpha;
   var $alpha;
   var $digit;
   var $safe;
   var $extra;
   var $national;
   var $punctuation;
   var $reserved;
   var $hex;
   var $escape;
   var $unreserved;
   var $uchar;
   var $xchar;
   var $digits;

   var $urlpath;
   var $password;
   var $user;
   var $port;
   var $hostnumber;
   var $alphadigit;
   var $toplabel;
   var $domainlabel;
   var $hostname;
   var $host;
   var $hostport;
   var $login;

   //ftp
   var $ftptype;
   var $fsegment;
   var $fpath;
   var $ftpurl;

   //file
   var $fileurl;

   //http,https
   var $search;
   var $hsegment;
   var $hpath;
   var $httpurl;

   //gopher
   var $gopher_string;
   var $selector;
   var $gtype;
   var $gopherurl;

   //news
   var $article;
   var $group;
   var $grouppart;
   var $newsurl;

   //nntp
   var $nntpurl;

   //telnet
   var $telneturl;

   //wais
   var $wpath;
   var $wtype;
   var $database;
   var $waisdoc;
   var $waisindex;
   var $waisdatabase;
   var $waisurl;

   function check($url){
      $pos = @strpos($url,@#:@#,1);
      if($pos<1) return false;
      $prot = substr($url,0,$pos);
      if(!isset($this->regex[$prot])) return false;
      eval(@#$regex = @#.$this->regex[$prot].@#;@#);
      return ereg(@#^@#.$regex.@#$@#,$url);
   }

   function urlcheck(){
      $this->lowalpha = @#[a-z]@#;
      $this->hialpha = @#[A-Z]@#;
      $this->alpha = @#(@#.$this->lowalpha.@#|@#.$this->hialpha.@#)@#;
      $this->digit = @#[0-9]@#;
      $this->safe = @#[$.+_-]@#;
      $this->extra = @#[*()\@#!,]@#;
      $this->national = @#([{}|\^~`]|\\[|\\])@#;
      $this->punctuation = @#[<>#%"]@#;
      $this->reserved = @#[?;/:@&=]@#;
      $this->hex = @#(@#.$this->digit.@#|[a-fA-F])@#;
      $this->escape = @#(%@#.$this->hex.@#{2})@#;
      $this->unreserved = @#(@#.$this->alpha.@#|@#.$this->digit.@#|@#.$this->safe.@#|@#.$this->extra.@#)@#;
      $this->uchar = @#(@#.$this->unreserved.@#|@#.$this->escape.@#)@#;
      $this->xchar = @#(@#.$this->unreserved.@#|@#.$this->reserved.@#|@#.$this->escape.@#)@#;
      $this->digits = @#(@#.$this->digit.@#+)@#;

      $this->urlpath = @#(@#.$this->xchar.@#*)@#;
      $this->password = @#((@#.$this->uchar.@#|[?;&=]@#.@#)*)@#;
      $this->user = @#((@#.$this->uchar.@#|[?;&=]@#.@#)*)@#;
      $this->port = $this->digits;
      $this->hostnumber = @#(@#.$this->digits.@#.@#.$this->digits.@#.@#.$this->digits.@#.@#.$this->digits.@#)@#;
      $this->alphadigit = @#(@#.$this->alpha.@#|@#.$this->digit.@#)@#;
      $this->toplabel = @#(@#.$this->alpha.@#|(@#.$this->alpha.@#(@#.$this->alphadigit.@#|-)*@#.$this->alphadigit.@#))@#;
      $this->domainlabel = @#(@#.$this->alphadigit.@#|(@#.$this->alphadigit.@#(@#.$this->alphadigit.@#|-)*@#.$this->alphadigit.@#))@#;
      $this->hostname = @#((@#.$this->domainlabel.@#\\.)*@#.$this->toplabel.@#)@#;
      $this->host = @#(@#.$this->hostname.@#|@#.$this->hostnumber.@#)@#;
      $this->hostport = @#(@#.$this->host.@#(:@#.$this->port.@#)?)@#;
      $this->login = @#((@#.$this->user.@#(:@#.$this->password.@#)?@)?@#.$this->hostport.@#)@#;

      $this->ftptype = @#[aidAID]@#;
      $this->fsegment = @#((@#.$this->uchar.@#|[?:@&=])*)@#;
      $this->fpath = @#(@#.$this->fsegment.@#(/@#.$this->fsegment.@#)*)@#;
      $this->ftpurl = @#([fF][tT][pP]://@#.$this->login.@#(/@#.$this->fpath.@#(;[tT][yY][pP][eE]=@#.$this->ftptype.@#)?)?)@#;

      $this->fileurl = @#([fF][iI][lL][eE]://(@#.$this->host.@#|[lL][oO][cC][aA][lL][hH][oO][sS][tT])?/@#.$this->fpath.@#)@#;

      $this->search = @#((@#.$this->uchar.@#|[;:@&=])*)@#;
      $this->hsegment = @#((@#.$this->uchar.@#|[;:@&=])*)@#;
      $this->hpath = @#(@#.$this->hsegment.@#(/@#.$this->hsegment.@#)*)@#;
      $this->httpurl = @#([hH][tT][tT][pP][sS]?://@#.$this->hostport.@#(/@#.$this->hpath.@#([?]@#.$this->search.@#)?)?)@#;

      $this->gopher_string = @#(@#.$this->xchar.@#*)@#;
      $this->selector = @#(@#.$this->xchar.@#*)@#;
      $this->gtype = $this->xchar;
      $this->gopherurl = @#([gG][oO][pP][hH][eE][rR]://@#.$this->hostport.@#(/(@#.$this->gtype.@#(@#.$this->selector.@#(%09@#.$this->search.@#(%09@#.$this->gopher_string.@#)?)?)?)?)?)@#;

      $this->article = @#((@#.$this->uchar.@#|[;/?:&=])+@@#.$this->host.@#)@#;
      $this->group = @#(@#.$this->alpha.@#(@#.$this->alpha.@#|@#.$this->digit.@#|[-.+_])*)@#;
      $this->grouppart = @#([*]|@#.$this->group.@#|@#.$this->article.@#)@#;
      $this->newsurl = @#([nN][eE][wW][sS]:@#.$this->grouppart.@#)@#;

      $this->nntpurl = @#([nN][nN][tT][pP]://@#.$this->hostport.@#/@#.$this->group.@#(/@#.$this->digits.@#)?)@#;

      $this->telneturl = @#([tT][eE][lL][nN][eE][tT]://@#.$this->login.@#/?)@#;

      $this->wpath = @#(@#.$this->uchar.@#*)@#;
      $this->wtype = @#(@#.$this->uchar.@#*)@#;
      $this->database = @#(@#.$this->uchar.@#*)@#;
      $this->waisdoc = @#([wW][aA][iI][sS]://@#.$this->hostport.@#/@#.$this->database.@#/@#.$this->wtype.@#/@#.$this->wpath.@#)@#;
      $this->waisindex = @#([wW][aA][iI][sS]://@#.$this->hostport.@#/@#.$this->database.@#[?]@#.$this->search.@#)@#;
      $this->waisdatabase = @#([wW][aA][iI][sS]://@#.$this->hostport.@#/@#.$this->database.@#)@#;
      $this->waisurl = @#(@#.$this->waisdatabase.@#|@#.$this->waisindex.@#|@#.$this->waisdoc.@#)@#;
   }
}

?>


文件otherfunc.php的内容
<?php
//otherfunc.php
function htmlencode($str){
   $str = (string)$str;

   $ret = @#@#;
   $len = strlen($str);
   $nl = false;
   for($i=0;$i<$len;$i++){
      $chr = $str[$i];
      switch($chr){
         case @#<@#:
            $ret .= @#<@#;
            $nl = false;
            break;
         case @#>@#:
            $ret .= @#>@#;
            $nl = false;
            break;
         case @#"@#:
            $ret .= @#"@#;
            $nl = false;
            break;
         case @#&@#:
            $ret .= @#&@#;
            $nl = false;
            break;
/*
         case @# @#:
            $ret .= @# @#;
            $nl = false;
            break;
*/        
         case chr(9):
            $ret .= @#    @#;
            $nl = false;
            break;
         case chr(10):
            if($nl) $nl = false;
            else{
               $ret .= @#<br>@#;
               $nl = true;
            }
            break;
         case chr(13):
            if($nl) $nl = false;
            else{
               $ret .= @#<br>@#;
               $nl = true;
            }
            break;
         default:
            $ret .= $chr;
            $nl = false;
            break;
      }
   }

   return $ret;
}


function htmlencode4textarea($str){
   $str = (string)$str;

   $ret = @#@#;
   $len = strlen($str);
   for($i=0;$i<$len;$i++){
      $chr = $str[$i];
      switch($chr){
         case @#<@#:
            $ret .= @#<@#;
            break;
         case @#>@#:
            $ret .= @#>@#;
            break;
         case @#"@#:
            $ret .= @#"@#;
            break;
         case @#&@#:
            $ret .= @#&@#;
            break;
         case @# @#:
            $ret .= @# @#;
            break;
         case chr(9):
            $ret .= @#    @#;
            break;
         default:
            $ret .= $chr;
            break;
      }
   }

   return $ret;
}

function emailcheck($email){
   $ret=false;
   if(strstr($email, @#@@#) && strstr($email, @#.@#)){
      if(eregi("^([_a-z0-9]+([\\._a-z0-9-]+)*)@([a-z0-9]{2,}(\\.[a-z0-9-]{2,})*\\.[a-z]{2,3})$", $email)){
         $ret=true;
      }
   }
   return $ret;
}

function str2url($path){
   return eregi_replace("%2f","/",urlencode($path));
}
?>

原文转自：http://www.ltesting.net