diff --git a/src/frontend/hud.cpp b/src/frontend/hud.cpp
index bcf623ce..b60d8535 100644
--- a/src/frontend/hud.cpp
+++ b/src/frontend/hud.cpp
@@ -108,21 +108,21 @@ std::shared_ptr<UINode> HudElement::getNode() const {
 
 std::shared_ptr<InventoryView> Hud::createContentAccess() {
     auto& content = frontend.getLevel().content;
-    auto indices = content.getIndices();
+    auto& indices = *content.getIndices();
     auto inventory = player.getInventory();
     
-    size_t itemsCount = indices->items.count();
+    size_t itemsCount = indices.items.count();
     auto accessInventory = std::make_shared<Inventory>(0, itemsCount);
     for (size_t id = 1; id < itemsCount; id++) {
         accessInventory->getSlot(id-1).set(ItemStack(id, 1));
     }
 
     SlotLayout slotLayout(-1, glm::vec2(), false, true, nullptr,
-    [=](uint, ItemStack& item) {
+    [inventory, &indices](uint, ItemStack& item) {
         auto copy = ItemStack(item);
         inventory->move(copy, indices);
     }, 
-    [=](uint, ItemStack& item) {
+    [this, inventory](uint, ItemStack& item) {
         inventory->getSlot(player.getChosenSlot()).set(item);
     });
 
@@ -494,12 +494,12 @@ void Hud::dropExchangeSlot() {
     
     auto indices = frontend.getLevel().content.getIndices();
     if (auto invView = std::dynamic_pointer_cast<InventoryView>(blockUI)) {
-        invView->getInventory()->move(stack, indices);
+        invView->getInventory()->move(stack, *indices);
     }
     if (stack.isEmpty()) {
         return;
     }
-    player.getInventory()->move(stack, indices);
+    player.getInventory()->move(stack, *indices);
     if (!stack.isEmpty()) {
         logger.warning() << "discard item [" << stack.getItemId() << ":"
                          << stack.getCount();
diff --git a/src/graphics/ui/elements/InventoryView.cpp b/src/graphics/ui/elements/InventoryView.cpp
index 22e1b82a..78e56e78 100644
--- a/src/graphics/ui/elements/InventoryView.cpp
+++ b/src/graphics/ui/elements/InventoryView.cpp
@@ -219,7 +219,7 @@ void SlotView::performLeftClick(ItemStack& stack, ItemStack& grabbed) {
         return;
     }
     if (!layout.itemSource && stack.accepts(grabbed) && layout.placing) {
-        stack.move(grabbed, content->getIndices());
+        stack.move(grabbed, *content->getIndices());
     } else {
         if (layout.itemSource) {
             if (grabbed.isEmpty()) {
diff --git a/src/items/Inventory.cpp b/src/items/Inventory.cpp
index 9797a15e..1d27e261 100644
--- a/src/items/Inventory.cpp
+++ b/src/items/Inventory.cpp
@@ -37,7 +37,7 @@ size_t Inventory::findSlotByItem(
 }
 
 void Inventory::move(
-    ItemStack& item, const ContentIndices* indices, size_t begin, size_t end
+    ItemStack& item, const ContentIndices& indices, size_t begin, size_t end
 ) {
     end = std::min(slots.size(), end);
     for (size_t i = begin; i < end && !item.isEmpty(); i++) {
diff --git a/src/items/Inventory.hpp b/src/items/Inventory.hpp
index 49560523..f0efdfe1 100644
--- a/src/items/Inventory.hpp
+++ b/src/items/Inventory.hpp
@@ -32,7 +32,7 @@ public:
 
     void move(
         ItemStack& item,
-        const ContentIndices* indices,
+        const ContentIndices& indices,
         size_t begin = 0,
         size_t end = -1
     );
diff --git a/src/items/ItemStack.cpp b/src/items/ItemStack.cpp
index 99cb0a0e..fdf1ff80 100644
--- a/src/items/ItemStack.cpp
+++ b/src/items/ItemStack.cpp
@@ -3,9 +3,6 @@
 #include "content/Content.hpp"
 #include "ItemDef.hpp"
 
-ItemStack::ItemStack() : item(ITEM_EMPTY), count(0) {
-}
-
 ItemStack::ItemStack(itemid_t item, itemcount_t count)
     : item(item), count(count) {
 }
@@ -28,9 +25,9 @@ bool ItemStack::accepts(const ItemStack& other) const {
     return item == other.getItemId();
 }
 
-void ItemStack::move(ItemStack& item, const ContentIndices* indices) {
-    auto& def = indices->items.require(item.getItemId());
-    int count = std::min(item.count, def.stackSize - this->count);
+void ItemStack::move(ItemStack& item, const ContentIndices& indices) {
+    auto& def = indices.items.require(item.getItemId());
+    itemcount_t count = std::min(item.count, def.stackSize - this->count);
     if (isEmpty()) {
         set(ItemStack(item.getItemId(), count));
     } else {
diff --git a/src/items/ItemStack.hpp b/src/items/ItemStack.hpp
index 1a8e191d..e2892bf3 100644
--- a/src/items/ItemStack.hpp
+++ b/src/items/ItemStack.hpp
@@ -6,10 +6,10 @@
 class ContentIndices;
 
 class ItemStack {
-    itemid_t item;
-    itemcount_t count;
+    itemid_t item = ITEM_EMPTY;
+    itemcount_t count = 0;
 public:
-    ItemStack();
+    ItemStack() = default;
 
     ItemStack(itemid_t item, itemcount_t count);
 
@@ -17,7 +17,12 @@ public:
     void setCount(itemcount_t count);
 
     bool accepts(const ItemStack& item) const;
-    void move(ItemStack& item, const ContentIndices* indices);
+
+    /// @brief Move items from one stack to another. 
+    /// If the target stack is completely filled, the source stack will be reduced.
+    /// @param item source stack
+    /// @param indices content indices
+    void move(ItemStack& item, const ContentIndices& indices);
 
     inline void clear() {
         set(ItemStack(0, 0));
diff --git a/src/logic/scripting/lua/libs/libinventory.cpp b/src/logic/scripting/lua/libs/libinventory.cpp
index 65f0dd7c..09be85d6 100644
--- a/src/logic/scripting/lua/libs/libinventory.cpp
+++ b/src/logic/scripting/lua/libs/libinventory.cpp
@@ -80,7 +80,7 @@ static int l_add(lua::State* L) {
 
     auto& inv = get_inventory(invid);
     ItemStack item(itemid, count);
-    inv.move(item, indices);
+    inv.move(item, *indices);
     return lua::pushinteger(L, item.getCount());
 }
 
@@ -144,9 +144,9 @@ static int l_move(lua::State* L) {
     auto& invB = get_inventory(invBid, 3);
     auto& slot = invA.getSlot(slotAid);
     if (slotBid == -1) {
-        invB.move(slot, content->getIndices());
+        invB.move(slot, *content->getIndices());
     } else {
-        invB.move(slot, content->getIndices(), slotBid, slotBid + 1);
+        invB.move(slot, *content->getIndices(), slotBid, slotBid + 1);
     }
     return 0;
 }
@@ -163,9 +163,9 @@ static int l_move_range(lua::State* L) {
     auto invB = get_inventory(invBid, 3);
     auto& slot = invA.getSlot(slotAid);
     if (slotBegin == -1) {
-        invB.move(slot, content->getIndices());
+        invB.move(slot, *content->getIndices());
     } else {
-        invB.move(slot, content->getIndices(), slotBegin, slotEnd);
+        invB.move(slot, *content->getIndices(), slotBegin, slotEnd);
     }
     return 0;
 }