Reference to the post before the current in a plugin

[Rankun]

Hello!

I'm currently writing a number of plugins for a game we plan on our forums. One part of this game is that a game master can drop items in form of posts and a participant can pick these items up. However, I'm stuck at the point where I have to check whether the post before the own post contains such an item.

Look at this sample code:

PHP Code:

if (is_member_of($post, 161)) {
  if (strstr($post['message'], 'GET') != False) {
    $post['title'] = '<i>-- ITEM OBTAINED --</i> ('.$itemname.')';
  }
} 


Group 161 is the participants of the game, and here, if one of them posts GET, he can pick up said item. However, I don't see any way how to check if there's an item hidden in the post above his. I'm looking for a variable like $prevpost['message']. If anyone has a clever idea ...