<?php
function bbcode_format ($str) {
    $str = htmlentities($str);

    $simple_search = array(
                '/\[b\](.*?)\[\/b\]/is',                                
                '/\[i\](.*?)\[\/i\]/is',                                
                '/\[u\](.*?)\[\/u\]/is',                                
                '/\[url\=(.*?)\](.*?)\[\/url\]/is',                         
                '/\[url\](.*?)\[\/url\]/is',                             
                '/\[align\=(left|center|right)\](.*?)\[\/align\]/is',    
                '/\[img\](.*?)\[\/img\]/is',                            
                '/\[mail\=(.*?)\](.*?)\[\/mail\]/is',                    
                '/\[mail\](.*?)\[\/mail\]/is',                            
                '/\[font\=(.*?)\](.*?)\[\/font\]/is',                    
                '/\[size\=(.*?)\](.*?)\[\/size\]/is',                    
                '/\[color\=(.*?)\](.*?)\[\/color\]/is',        
                );

    $simple_replace = array(
                '<strong>$1</strong>',
                '<em>$1</em>',
                '<u>$1</u>',
                '<a href="$1">$2</a>',
                '<a href="$1">$1</a>',
                '<div style="text-align: $1;">$2</div>',
                '<img src="$1" />',
                '<a href="mailto:$1">$2</a>',
                '<a href="mailto:$1">$1</a>',
                '<span style="font-family: $1;">$2</span>',
                '<span style="font-size: $1;">$2</span>',
                '<span style="color: $1;">$2</span>',
                );

    // Do simple BBCode's
    $str = preg_replace ($simple_search, $simple_replace, $str);

    // Do <blockquote> BBCode
    $str = bbcode_quote ($str);

    return $str;
}



function bbcode_quote ($str) {
    $open = '<blockquote>';
    $close = '</blockquote>';

    // How often is the open tag?
    preg_match_all ('/\[quote\]/i', $str, $matches);
    $opentags = count($matches['0']);

    // How often is the close tag?
    preg_match_all ('/\[\/quote\]/i', $str, $matches);
    $closetags = count($matches['0']);

    // Check how many tags have been unclosed
    // And add the unclosing tag at the end of the message
    $unclosed = $opentags - $closetags;
    for ($i = 0; $i < $unclosed; $i++) {
        $str .= '</blockquote>';
    }

    // Do replacement
    $str = str_replace ('[' . 'quote]', $open, $str);
    $str = str_replace ('[/' . 'quote]', $close, $str);

    return $str;
}
?>