StackHelper.java

public static boolean addToInv(IInventory inv, ItemStack par1ItemStack)
    {
        ArrayList<ItemStack> inventorySlots = JavaHelp.newArrayList();
        boolean flag1 = false;
        int k = 0;
        ItemStack itemstack1 = null;
        for (int i = 0; i < inv.getSizeInventory(); i++)
        {
            inventorySlots.add(inv.getStackInSlot(i));
        }
        if (par1ItemStack == null) return false;
        if (par1ItemStack.isStackable())
        {
            while (par1ItemStack.stackSize > 0 && k < inv.getSizeInventory())
            {
                itemstack1 = inventorySlots.get(k);
                if (itemstack1 != null && itemstack1.getItem() == par1ItemStack.getItem() && (!par1ItemStack.getHasSubtypes() || par1ItemStack.getItemDamage() == itemstack1.getItemDamage()) && ItemStack.areItemStackTagsEqual(par1ItemStack, itemstack1))
                {
                    int l = itemstack1.stackSize + par1ItemStack.stackSize;
                    if (l <= par1ItemStack.getMaxStackSize())
                    {
                        par1ItemStack.stackSize = 0;
                        itemstack1.stackSize = l;
                        inv.markDirty();
                        flag1 = true;
                    }
                    else if (itemstack1.stackSize < par1ItemStack.getMaxStackSize())
                    {
                        par1ItemStack.stackSize -= par1ItemStack.getMaxStackSize() - itemstack1.stackSize;
                        itemstack1.stackSize = par1ItemStack.getMaxStackSize();
                        inv.markDirty();
                        flag1 = true;
                    }
                }
                ++k;
            }
        }
        if (par1ItemStack.stackSize > 0)
        {
            k = 0;
            while (k < inv.getSizeInventory())
            {
                itemstack1 = inventorySlots.get(k);
                if (itemstack1 == null)
                {
                    inv.setInventorySlotContents(k, par1ItemStack.copy());
                    inv.markDirty();
                    par1ItemStack.stackSize = 0;
                    flag1 = true;
                    break;
                }
                ++k;
            }
        }
        if (itemstack1 != null && itemstack1.stackSize == 0)
        {
            itemstack1 = null;
        }
        if (par1ItemStack != null && par1ItemStack.stackSize == 0)
        {
            par1ItemStack = null;
        }
        return flag1;
    }