Moving and counting inventory items

        // Attempts to fill given target to the given amount of the given item by transferring it
        // from the list of sources
        private void LoadItem(
            List<IMyTerminalBlock> sources,
            IMyTerminalBlock target,
            string id,
            string subid,
            VRage.MyFixedPoint amount)
        {
            if (target == null)
                return;

            var todo = amount - CountItems(target, id, subid);
            if (todo <= 0)
                return;

            var targetInventory = target.GetInventory(0);
            foreach (IMyTerminalBlock source in sources)
            {
                for (int i = 0; i < source.GetInventoryCount(); i++)
                {
                    var inventory = source.GetInventory(i);
                    var items = inventory.GetItems();
                    for (int j = 0; j < items.Count; j++)
                    {
                        var item = items[j];

                        if (!item.Content.TypeId.ToString().Equals(id))
                            continue;

                        if (!item.Content.SubtypeName.Equals(subid))
                            continue;

                        var transfer = VRage.MyFixedPoint.Min(todo, item.Amount);
                        if (!inventory.IsConnectedTo(targetInventory))
                            continue;

                        inventory.TransferItemTo(targetInventory, j, null, true, transfer);
                        todo -= transfer;
                        if (todo <= 0)
                            return;
                    }
                }
            }
        }

        // Counts the number of items of a given type in the given block
        private VRage.MyFixedPoint CountItems(IMyTerminalBlock block, string id, string subid)
        {
            if (block == null)
                return 0;

            VRage.MyFixedPoint result = 0;
            for (int i = 0; i < block.GetInventoryCount(); i++)
            {
                var inventory = block.GetInventory(i);
                foreach (var item in inventory.GetItems())
                    if (item.Content.TypeId.ToString() == id && item.Content.SubtypeName == subid)
                        result += item.Amount;
            }
            return result;
        }