@Override
	public ItemStack transferStackInSlot(EntityPlayer playerIn, int fromSlot) {
	    ItemStack previous = null;
	    Slot slot = (Slot) this.inventorySlots.get(fromSlot);

	    if (slot != null && slot.getHasStack()) {
	        ItemStack current = slot.getStack();
	        previous = current.copy();

	        if (fromSlot < 9) {
	            if (!this.mergeItemStack(current, 9, 45, true))
	                return null;
	        } else {
	            if (!this.mergeItemStack(current, 0, 9, false))
	                return null;
	        }

	        if (current.getCount() == 0)
	            slot.putStack((ItemStack) null);
	        else
	            slot.onSlotChanged();

	        if (current.getCount() == previous.getCount())
	            return null;
	        
	      
	    }
	    return previous;
	}
	
	@Override
	protected boolean mergeItemStack(ItemStack stack, int startIndex, int endIndex, boolean useEndIndex) {
	    boolean success = false;
	    int index = startIndex;

	    if (useEndIndex)
	        index = endIndex - 1;

	    Slot slot;
	    ItemStack stackinslot;

	    if (stack.isStackable()) {
	        while (stack.getCount() > 0 && (!useEndIndex && index < endIndex || useEndIndex && index >= startIndex)) {
	            slot = (Slot) this.inventorySlots.get(index);
	            stackinslot = slot.getStack();

	            if (stackinslot != null && stackinslot.getItem() == stack.getItem() && (!stack.getHasSubtypes() || stack.getMetadata() == stackinslot.getMetadata()) && ItemStack.areItemStackTagsEqual(stack, stackinslot)) {
	                int l = stackinslot.getCount() + stack.getCount();
	                int maxsize = Math.min(stack.getMaxStackSize(), slot.getItemStackLimit(stack));

	                if (l <= maxsize) {
	                    stack.setCount(0);
	                    stackinslot.setCount(1);
	                    slot.onSlotChanged();
	                    success = true;
	                } else if (stackinslot.getCount() < maxsize) {
	                    stack.setCount(stack.getCount() - stack.getMaxStackSize() - stackinslot.getCount());
	                    stackinslot.setCount(stack.getMaxStackSize());
	                    slot.onSlotChanged();
	                    success = true;
	                }
	            }

	            if (useEndIndex) {
	                --index;
	            } else {
	                ++index;
	            }
	        }
	    }

	    if (stack.getCount() > 0) {
	        if (useEndIndex) {
	            index = endIndex - 1;
	        } else {
	            index = startIndex;
	        }

	        while (!useEndIndex && index < endIndex || useEndIndex && index >= startIndex && stack.getCount() > 0) {
	            slot = (Slot) this.inventorySlots.get(index);
	            stackinslot = slot.getStack();

	            if (stackinslot == null && slot.isItemValid(stack)) {
	                if (stack.getCount() < slot.getItemStackLimit(stack)) {
	                    slot.putStack(stack.copy());
	                    stack.setCount(0);
	                    success = true;
	                    break;
	                } else {
	                    ItemStack newstack = stack.copy();
	                    newstack.setCount(slot.getItemStackLimit(stack));
	                    slot.putStack(newstack);
	                    stack.setCount(stack.getCount() - slot.getItemStackLimit(stack));
	                    success = true;
	                }
	            }

	            if (useEndIndex) {
	                --index;
	            } else {
	                ++index;
	            }
	        }
	    }

	    return success;
	}