Look, if forum post have $hide_smilies is set to 1, I dont want the :p, :o to be replacen with images.

This is how I output forum post bbcode($message);

And Function:

function bbcode($str)
{
    $str = htmlentities($str);

    $find = array(
    "/:p/",
    "/:o/",
    '/\[b](.*?)\[\/b]/is',
    '/\[u](.*?)\[\/u]/is',
    '/\[i](.*?)\[\/i]/is'
    );

    $replace = array(
    '<img src="/images/forum/icon_tongue.gif" alt=":p" border="0" height="15" width="15">',
    '<img src="/images/forum/icon_embarrassed.gif" alt=":o" border="0" height="15" width="15">'
    '<strong>$1</strong>',
    '<u>$1</u>',
    '&开发者_高级运维lt;i>$1</i>',

    $str = preg_replace($find, $replace, $str);



    return nl2br($str);

Thanks

Edit

function bbcode($str, $hide_smilies = 0)
{

$str = htmlentities($str);

$find = array(
    '/\[b](.*?)\[\/b]/is',
    '/\[u](.*?)\[\/u]/is',
    '/\[i](.*?)\[\/i]/is',
);


$replace = array(
    '<strong>$1</strong>',
    '<u>$1</u>',
    '<i>$1</i>'
);

if ($hide_smilies == 0) 
{
    $find[] = "/:p/";
    $find[] = "/:o/";

    $replace[] = '<img src="/images/forum/icon_tongue.gif" alt=":p" border="0" height="15" width="15">';
    $replace[] = '<img src="/images/forum/icon_embarrassed.gif" alt=":o" border="0" height="15" width="15">';
}

$str = preg_replace($find, $replace, $str);


return nl2br($str);
}

This works but now (if hide_smilies=0) some characters like " gets replaced with " and so on

if hide smilies is set to 1 then just echo out $message instead of echo'ing out bbcode($message). here is a simple ternary statement that should work:

echo ($hide_smilies==1) ? $message : bbcode($message);

Just use array_slice() to chop off the unwanted bits. I'm assuming you can pass the $hide_smilies variable to the bbcode() function.

<?php
function bbcode($str, $hide_smilies=0) {
    $str = htmlentities($str);

    $find = array(
    "/:p/",
    "/:o/",
    '/\[b](.*?)\[\/b]/is',
    '/\[u](.*?)\[\/u]/is',
    '/\[i](.*?)\[\/i]/is',
    );

    $replace = array(
    '<img src="/images/forum/icon_tongue.gif" alt=":p" border="0" height="15" width="15">',
    '<img src="/images/forum/icon_embarrassed.gif" alt=":o" border="0" height="15" width="15">',
    '<strong>$1</strong>',
    '<u>$1</u>',
    '<i>$1</i>',
    );

    if ($hide_smilies) {
        $find = array_slice($find, 2);
        $replace = array_slice($replace, 2);
    }

    $str = preg_replace($find, $replace, $str);

    return nl2br($str);
}
?>

If I'm understanding correctly, you still want to replace [b]'s and [i]'s with their HTML equivalents even if $hide_smilies is 1, right? In that case, initialize each array with only the non-smiley pattenrs and then add the extra elements if $hide_smilies = 1. For example:

// either pass in $hide_smilies, declare it global inside bbcode(),
// or use $_GLOBALS['hide_smilies']
function bbcode($str, $hide_smilies)
{
    $str = htmlentities($str);

    $find = array(
    '/\[b](.*?)\[\/b]/is',
    '/\[u](.*?)\[\/u]/is',
    '/\[i](.*?)\[\/i]/is'
    );

    $replace = array(
    '<strong>$1</strong>',
    '<u>$1</u>',
    '<i>$1</i>');


    if ($hide_smilies == 1)
    {
        $find[] = "/:p/";
        $find[] = "/:o/";

        $replace[] = '<img src="/images/forum/icon_tongue.gif" alt=":p" border="0" height="15" width="15">';
        $replace[] = '<img src="/images/forum/icon_embarrassed.gif" alt=":o" border="0" height="15" width="15">';
    }

    $str = preg_replace($find, $replace, $str);

    return nl2br($str);
}

function bbcode($str)
{
    $str = htmlentities($str);

    $find = array(
        '/\[b](.*?)\[\/b]/is',
        '/\[u](.*?)\[\/u]/is',
        '/\[i](.*?)\[\/i]/is'
    );

    $replace = array(
        '<strong>$1</strong>',
        '<u>$1</u>',
        '<i>$1</i>',
     );

    $str = preg_replace($find, $replace, $str);

    return nl2br($str);
}

Just add a parameter to the function and change the way you build the $find array, accordingly.

function bbcode($str, $hideSmilies = false)
{

$find = array(
'/\[b](.*?)\[\/b]/is',
'/\[u](.*?)\[\/u]/is',
'/\[i](.*?)\[\/i]/is'
);

if (!$hideSmilies)
{
    $find[] = "/:p/";
    $find[] = "/:o/";
}