// We need the <pre> tag to make code-in-backticks work
function bporg_forums_allowed_tags( $component_allowedtags ) {
    $component_allowedtags['pre'] = array();
    return $component_allowedtags;

}
add_filter( 'bp_forums_allowed_tags', 'bporg_forums_allowed_tags' );
add_filter( 'bp_activity_allowed_tags', 'bporg_forums_allowed_tags' );

// Borrowed from bbPress
function bporg_encodeit( $matches ) {
    $text = trim($matches[2]);
    $text = htmlspecialchars($text, ENT_QUOTES);
    $text = str_replace(array("\r\n", "\r"), "\n", $text);
    $text = preg_replace("|\n\n\n+|", "\n\n", $text);
    $text = str_replace('&amp;amp;', '&amp;', $text);
    $text = str_replace('&amp;lt;', '&lt;', $text);
    $text = str_replace('&amp;gt;', '&gt;', $text);
    $text = "<code>$text</code>";
    if ( "`" != $matches[1] )
        $text = "<pre>$text</pre>";
    return $text;
}

// Borrowed from bbPress
function bporg_decodeit( $matches ) {
    $text = $matches[2];
    $trans_table = array_flip(get_html_translation_table(HTML_ENTITIES));
    $text = strtr($text, $trans_table);
    $text = str_replace('<br />', '<coded_br />', $text);
    $text = str_replace('<p>', '<coded_p>', $text);
    $text = str_replace('</p>', '</coded_p>', $text);
    $text = str_replace(array('&#38;','&amp;'), '&', $text);
    $text = str_replace('&#39;', "'", $text);
    if ( '<pre><code>' == $matches[1] )
        $text = "\n$text\n";
    return "`$text`";
}

// Borrowed from bbPress. Makes code in backticks work, both in forum posts and in activity updates.
function bporg_code_trick( $text ) {
    $text = str_replace(array("\r\n", "\r"), "\n", $text);
    $text = preg_replace_callback("|(`)(.*?)`|", 'bporg_encodeit', $text);
    $text = preg_replace_callback("!(^|\n)`(.*?)`!s", 'bporg_encodeit', $text);
    return $text;
}
add_filter( 'bp_get_the_topic_post_content', 'bporg_code_trick', 1 );
add_filter( 'bp_get_activity_content_body', 'bporg_code_trick', 1 );