Script to give random objects from the content of a prim, with emphasis on the objects being no-copy

Z&A Give Random Object.lsl

//////////////////////////////////////////////////////////////////////
// Z&A Give Random Object
// By Antony Fairport
//
// Simple example of how you could create a script that will give a
// random object from inventory, on touch, and also allow for the
// fact that some or all of the objects might be no-copy.
//
// Note that this approach probably won't scale so well if the object
// is filled with many items. In that case, rather that reloading
// the list each time, it'd probably make sense to do some in-script
// management of a once-loaded list.
//
// Also note that this script does "one copy only" tracking and this
// too places an upper-limit on how well the script scales. I would
// suggest compiling as Mono.
//
// Use in a live situation at your own risk.

//////////////////////////////////////////////////////////////////////
// Globals.
list g_lObjects = [];
list g_lGivenTo = [];

//////////////////////////////////////////////////////////////////////
// Default state.
default
{
    //////////////////////////////////////////////////////////////////
    // Jump to the load state on startup.
    state_entry()
    {
        state LoadAvailable;
    }
}

//////////////////////////////////////////////////////////////////////
// State that loads the available objects.
state LoadAvailable
{
    //////////////////////////////////////////////////////////////////
    // Load the list on state entry.
    state_entry()
    {
        // Get how many objects are available.
        integer iMax = llGetInventoryNumber( INVENTORY_OBJECT );
        integer i;

        // Make sure the list is empty.
        g_lObjects = [];
        
        // For each object in inventory...
        for ( i = 0; i < iMax; i++ )
        {
            // Get the name of the item.
            string sObject = llGetInventoryName( INVENTORY_OBJECT, i );
            
            // If the current owner has transfer rights...
            if ( ( llGetInventoryPermMask( sObject, MASK_OWNER ) & PERM_TRANSFER ) == PERM_TRANSFER )
            {
                // ...add the item to the applicable list.
                g_lObjects += [ sObject ];
            }
        }

        // If there's something to give...
        if ( llGetListLength( g_lObjects ) > 0 )
        {        
            // ...go the the giver state...
            state GiveRandomObject;
        }
        else
        {
            // ...go to the empty state.
            state RunningOnEmpty;
        }
    }
}

//////////////////////////////////////////////////////////////////////
// State where we wait to give a random object.
state GiveRandomObject
{
    //////////////////////////////////////////////////////////////////
    // Handle the end of a touch.
    touch_end( integer num_detected )
    {
        // Note that we only give to the first toucher in this touch
        // event. If more than one avatar touched at the same time the one
        // that SL has decided was first "wins" this time around. The others
        // will get their chance in a moment.
        
        // Get who's after the object.
        key kToucher = llDetectedKey( 0 );
        
        // Have they already had something from us?
        if ( ~llListFindList( g_lGivenTo, [ kToucher ] ) )
        {
            llSay( 0, "Sorry " + llDetectedName( 0 ) + ", you've already had an item from me." );
        }
        else
        {
            // Randomise the list...
            list l = llListRandomize( g_lObjects, 1 );
        
            // Give the object at the head of the list to the person who touched us.
            llGiveInventory( kToucher, llList2String( l, 0 ) );        

            // Add that person to the list of people who've had something.
            g_lGivenTo += [ kToucher ];
            
            // If the object was no-copy/trans we'll have one less item in
            // inventory. Refresh our list of what's available.
            state LoadAvailable;
        }
    }
    
    //////////////////////////////////////////////////////////////////
    // Handle changes.
    changed( integer change )
    {
        // If the content, or the owner, has changed...
        if ( ( change & CHANGED_INVENTORY ) || ( change & CHANGED_OWNER ) )
        {
            // ...reset the script.
            llResetScript();
        }
    }
}

//////////////////////////////////////////////////////////////////////
// State we go to when inventory is empty.
state RunningOnEmpty
{
    //////////////////////////////////////////////////////////////////
    // Handle the end of a touch.
    touch_start( integer num_detected )
    {
        llSay( 0, "Sorry, I'm now empty." );
    }
    
    //////////////////////////////////////////////////////////////////
    // Handle changes.
    changed( integer change )
    {
        // If the content, or the owner, has changed...
        if ( ( change & CHANGED_INVENTORY ) || ( change & CHANGED_OWNER ) )
        {
            // ...reset the script.
            llResetScript();
        }
    }
}