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authorpeterbell10 <peterbell10@live.co.uk>2018-01-21 19:45:13 +0100
committerGitHub <noreply@github.com>2018-01-21 19:45:13 +0100
commitab350d1e43edef1a39f48d2771a9f136b3c4ae5f (patch)
treed0c89fd7b5a4dfc58999835074576175c72cee54 /src
parentUpdate libevent to 2.1.8 (#4152) (diff)
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Diffstat (limited to '')
-rw-r--r--src/CMakeLists.txt1
-rw-r--r--src/ItemGrid.cpp188
-rw-r--r--src/ItemGrid.h21
-rw-r--r--src/LazyArray.h134
4 files changed, 257 insertions, 87 deletions
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b5daedfaa..f2732bf8f 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -118,6 +118,7 @@ SET (HDRS
Inventory.h
Item.h
ItemGrid.h
+ LazyArray.h
LightingThread.h
LineBlockTracer.h
LinearInterpolation.h
diff --git a/src/ItemGrid.cpp b/src/ItemGrid.cpp
index 69aa976c6..045f083c8 100644
--- a/src/ItemGrid.cpp
+++ b/src/ItemGrid.cpp
@@ -12,11 +12,10 @@
-cItemGrid::cItemGrid(int a_Width, int a_Height) :
+cItemGrid::cItemGrid(int a_Width, int a_Height):
m_Width(a_Width),
m_Height(a_Height),
- m_NumSlots(a_Width * a_Height),
- m_Slots(new cItem[a_Width * a_Height]),
+ m_Slots(a_Width * a_Height),
m_IsInTriggerListeners(false)
{
}
@@ -25,19 +24,9 @@ cItemGrid::cItemGrid(int a_Width, int a_Height) :
-cItemGrid::~cItemGrid()
-{
- delete[] m_Slots;
- m_Slots = nullptr;
-}
-
-
-
-
-
bool cItemGrid::IsValidSlotNum(int a_SlotNum) const
{
- return ((a_SlotNum >= 0) && (a_SlotNum < m_NumSlots));
+ return ((a_SlotNum >= 0) && (a_SlotNum < m_Slots.size()));
}
@@ -77,7 +66,7 @@ void cItemGrid::GetSlotCoords(int a_SlotNum, int & a_X, int & a_Y) const
if (!IsValidSlotNum(a_SlotNum))
{
LOGWARNING("%s: SlotNum out of range: %d in grid of range %d",
- __FUNCTION__, a_SlotNum, m_NumSlots
+ __FUNCTION__, a_SlotNum, m_Slots.size()
);
a_X = -1;
a_Y = -1;
@@ -93,12 +82,9 @@ void cItemGrid::GetSlotCoords(int a_SlotNum, int & a_X, int & a_Y) const
void cItemGrid::CopyFrom(const cItemGrid & a_Src)
{
- ASSERT(m_Width == a_Src.m_Width);
- ASSERT(m_Height == a_Src.m_Height);
- for (int i = m_NumSlots - 1; i >= 0; --i)
- {
- m_Slots[i] = a_Src.m_Slots[i];
- }
+ m_Width = a_Src.m_Width;
+ m_Height = a_Src.m_Height;
+ m_Slots = a_Src.m_Slots;
// The listeners are not copied
}
@@ -121,11 +107,11 @@ const cItem & cItemGrid::GetSlot(int a_SlotNum) const
if (!IsValidSlotNum(a_SlotNum))
{
LOGWARNING("%s: Invalid slot number, %d out of %d slots",
- __FUNCTION__, a_SlotNum, m_NumSlots
+ __FUNCTION__, a_SlotNum, m_Slots.size()
);
- return m_Slots[0];
+ a_SlotNum = 0;
}
- return m_Slots[a_SlotNum];
+ return m_Slots.GetAt(a_SlotNum);
}
@@ -155,11 +141,15 @@ void cItemGrid::SetSlot(int a_SlotNum, const cItem & a_Item)
if (!IsValidSlotNum(a_SlotNum))
{
LOGWARNING("%s: Invalid slot number %d out of %d slots",
- __FUNCTION__, a_SlotNum, m_NumSlots
+ __FUNCTION__, a_SlotNum, m_Slots.size()
);
return;
}
- m_Slots[a_SlotNum] = a_Item;
+
+ if (!a_Item.IsEmpty() || m_Slots.IsStorageAllocated())
+ {
+ m_Slots[a_SlotNum] = a_Item;
+ }
TriggerListeners(a_SlotNum);
}
@@ -190,13 +180,13 @@ void cItemGrid::EmptySlot(int a_SlotNum)
if (!IsValidSlotNum(a_SlotNum))
{
LOGWARNING("%s: Invalid slot number %d out of %d slots",
- __FUNCTION__, a_SlotNum, m_NumSlots
+ __FUNCTION__, a_SlotNum, m_Slots.size()
);
return;
}
// Check if already empty:
- if (m_Slots[a_SlotNum].IsEmpty())
+ if (m_Slots.GetAt(a_SlotNum).IsEmpty())
{
return;
}
@@ -215,11 +205,11 @@ bool cItemGrid::IsSlotEmpty(int a_SlotNum) const
if (!IsValidSlotNum(a_SlotNum))
{
LOGWARNING("%s: Invalid slot number %d out of %d slots",
- __FUNCTION__, a_SlotNum, m_NumSlots
+ __FUNCTION__, a_SlotNum, m_Slots.size()
);
return true;
}
- return m_Slots[a_SlotNum].IsEmpty();
+ return m_Slots.GetAt(a_SlotNum).IsEmpty();
}
@@ -237,7 +227,12 @@ bool cItemGrid::IsSlotEmpty(int a_X, int a_Y) const
void cItemGrid::Clear(void)
{
- for (int i = 0; i < m_NumSlots; i++)
+ if (!m_Slots.IsStorageAllocated())
+ {
+ return; // Already clear
+ }
+
+ for (int i = 0; i < m_Slots.size(); i++)
{
m_Slots[i].Empty();
TriggerListeners(i);
@@ -250,27 +245,34 @@ void cItemGrid::Clear(void)
int cItemGrid::HowManyCanFit(const cItem & a_ItemStack, bool a_AllowNewStacks)
{
- char NumLeft = a_ItemStack.m_ItemCount;
+ int NumLeft = a_ItemStack.m_ItemCount;
int MaxStack = ItemHandler(a_ItemStack.m_ItemType)->GetMaxStackSize();
- for (int i = m_NumSlots - 1; i >= 0; i--)
+
+ if (!m_Slots.IsStorageAllocated())
{
- if (m_Slots[i].IsEmpty())
+ // Grid is empty, all slots are available
+ return a_AllowNewStacks ? std::min(NumLeft, m_Slots.size() * MaxStack) : 0;
+ }
+
+ for (const auto & Slot : m_Slots)
+ {
+ if (Slot.IsEmpty())
{
if (a_AllowNewStacks)
{
NumLeft -= MaxStack;
}
}
- else if (m_Slots[i].IsEqual(a_ItemStack))
+ else if (Slot.IsEqual(a_ItemStack))
{
- NumLeft -= MaxStack - m_Slots[i].m_ItemCount;
+ NumLeft -= MaxStack - Slot.m_ItemCount;
}
if (NumLeft <= 0)
{
// All items fit
return a_ItemStack.m_ItemCount;
}
- } // for i - m_Slots[]
+ } // for Slot - m_Slots[]
return a_ItemStack.m_ItemCount - NumLeft;
}
@@ -283,7 +285,7 @@ int cItemGrid::AddItemToSlot(const cItem & a_ItemStack, int a_Slot, int a_Num, i
if (!IsValidSlotNum(a_Slot))
{
LOGWARNING("%s: Invalid slot number %d out of %d slots",
- __FUNCTION__, a_Slot, m_NumSlots
+ __FUNCTION__, a_Slot, m_Slots.size()
);
return 0;
}
@@ -308,33 +310,38 @@ int cItemGrid::AddItemToSlot(const cItem & a_ItemStack, int a_Slot, int a_Num, i
-int cItemGrid::AddItem(cItem & a_ItemStack, bool a_AllowNewStacks, int a_PrioritarySlot)
+int cItemGrid::AddItem(cItem & a_ItemStack, bool a_AllowNewStacks, int a_PrioritySlot)
{
int NumLeft = a_ItemStack.m_ItemCount;
int MaxStack = a_ItemStack.GetMaxStackSize();
- if ((a_PrioritarySlot != -1) && !IsValidSlotNum(a_PrioritarySlot))
+ if ((a_PrioritySlot != -1) && !IsValidSlotNum(a_PrioritySlot))
{
LOGWARNING("%s: Invalid slot number %d out of %d slots",
- __FUNCTION__, a_PrioritarySlot, m_NumSlots
+ __FUNCTION__, a_PrioritySlot, m_Slots.size()
);
- a_PrioritarySlot = -1;
+ a_PrioritySlot = -1;
+ }
+
+ if (!a_AllowNewStacks && !m_Slots.IsStorageAllocated())
+ {
+ return 0; // No existing stacks to add to
}
- // Try prioritarySlot first:
+ // Try prioritySlot first:
if (
- (a_PrioritarySlot != -1) &&
+ (a_PrioritySlot != -1) &&
(
- m_Slots[a_PrioritarySlot].IsEmpty() ||
- m_Slots[a_PrioritarySlot].IsEqual(a_ItemStack)
+ m_Slots[a_PrioritySlot].IsEmpty() ||
+ m_Slots[a_PrioritySlot].IsEqual(a_ItemStack)
)
)
{
- NumLeft -= AddItemToSlot(a_ItemStack, a_PrioritarySlot, NumLeft, MaxStack);
+ NumLeft -= AddItemToSlot(a_ItemStack, a_PrioritySlot, NumLeft, MaxStack);
}
// Scan existing stacks:
- for (int i = 0; i < m_NumSlots; i++)
+ for (int i = 0; i < m_Slots.size(); i++)
{
if (m_Slots[i].IsEqual(a_ItemStack))
{
@@ -352,7 +359,7 @@ int cItemGrid::AddItem(cItem & a_ItemStack, bool a_AllowNewStacks, int a_Priorit
return (a_ItemStack.m_ItemCount - NumLeft);
}
- for (int i = 0; i < m_NumSlots; i++)
+ for (int i = 0; i < m_Slots.size(); i++)
{
if (m_Slots[i].IsEmpty())
{
@@ -371,12 +378,12 @@ int cItemGrid::AddItem(cItem & a_ItemStack, bool a_AllowNewStacks, int a_Priorit
-int cItemGrid::AddItems(cItems & a_ItemStackList, bool a_AllowNewStacks, int a_PrioritarySlot)
+int cItemGrid::AddItems(cItems & a_ItemStackList, bool a_AllowNewStacks, int a_PrioritySlot)
{
int TotalAdded = 0;
for (cItems::iterator itr = a_ItemStackList.begin(); itr != a_ItemStackList.end();)
{
- int NumAdded = AddItem(*itr, a_AllowNewStacks, a_PrioritarySlot);
+ int NumAdded = AddItem(*itr, a_AllowNewStacks, a_PrioritySlot);
if (itr->m_ItemCount == NumAdded)
{
itr = a_ItemStackList.erase(itr);
@@ -399,7 +406,12 @@ int cItemGrid::RemoveItem(const cItem & a_ItemStack)
{
int NumLeft = a_ItemStack.m_ItemCount;
- for (int i = 0; i < m_NumSlots; i++)
+ if (!m_Slots.IsStorageAllocated())
+ {
+ return 0; // No items to remove
+ }
+
+ for (int i = 0; i < m_Slots.size(); i++)
{
if (NumLeft <= 0)
{
@@ -433,12 +445,12 @@ int cItemGrid::ChangeSlotCount(int a_SlotNum, int a_AddToCount)
if (!IsValidSlotNum(a_SlotNum))
{
LOGWARNING("%s: Invalid slot number %d out of %d slots, ignoring the call, returning -1",
- __FUNCTION__, a_SlotNum, m_NumSlots
+ __FUNCTION__, a_SlotNum, m_Slots.size()
);
return -1;
}
- if (m_Slots[a_SlotNum].IsEmpty())
+ if (m_Slots.GetAt(a_SlotNum).IsEmpty())
{
// The item is empty, it's not gonna change
return 0;
@@ -482,13 +494,13 @@ cItem cItemGrid::RemoveOneItem(int a_SlotNum)
if (!IsValidSlotNum(a_SlotNum))
{
LOGWARNING("%s: Invalid slot number %d out of %d slots, ignoring the call, returning empty item",
- __FUNCTION__, a_SlotNum, m_NumSlots
+ __FUNCTION__, a_SlotNum, m_Slots.size()
);
return cItem();
}
// If the slot is empty, return an empty item
- if (m_Slots[a_SlotNum].IsEmpty())
+ if (m_Slots.GetAt(a_SlotNum).IsEmpty())
{
return cItem();
}
@@ -526,12 +538,17 @@ cItem cItemGrid::RemoveOneItem(int a_X, int a_Y)
int cItemGrid::HowManyItems(const cItem & a_Item)
{
+ if (!m_Slots.IsStorageAllocated())
+ {
+ return 0;
+ }
+
int res = 0;
- for (int i = 0; i < m_NumSlots; i++)
+ for (auto & Slot : m_Slots)
{
- if (m_Slots[i].IsEqual(a_Item))
+ if (Slot.IsEqual(a_Item))
{
- res += m_Slots[i].m_ItemCount;
+ res += Slot.m_ItemCount;
}
}
return res;
@@ -571,9 +588,9 @@ int cItemGrid::GetFirstUsedSlot(void) const
int cItemGrid::GetLastEmptySlot(void) const
{
- for (int i = m_NumSlots - 1; i >= 0; i--)
+ for (int i = m_Slots.size() - 1; i >= 0; i--)
{
- if (m_Slots[i].IsEmpty())
+ if (m_Slots.GetAt(i).IsEmpty())
{
return i;
}
@@ -587,9 +604,14 @@ int cItemGrid::GetLastEmptySlot(void) const
int cItemGrid::GetLastUsedSlot(void) const
{
- for (int i = m_NumSlots - 1; i >= 0; i--)
+ if (!m_Slots.IsStorageAllocated())
+ {
+ return -1; // No slots are used
+ }
+
+ for (int i = m_Slots.size() - 1; i >= 0; i--)
{
- if (!m_Slots[i].IsEmpty())
+ if (!m_Slots.GetAt(i).IsEmpty())
{
return i;
}
@@ -606,14 +628,14 @@ int cItemGrid::GetNextEmptySlot(int a_StartFrom) const
if ((a_StartFrom != -1) && !IsValidSlotNum(a_StartFrom))
{
LOGWARNING("%s: Invalid slot number %d out of %d slots",
- __FUNCTION__, a_StartFrom, m_NumSlots
+ __FUNCTION__, a_StartFrom, m_Slots.size()
);
a_StartFrom = -1;
}
- for (int i = a_StartFrom + 1; i < m_NumSlots; i++)
+ for (int i = a_StartFrom + 1; i < m_Slots.size(); i++)
{
- if (m_Slots[i].IsEmpty())
+ if (m_Slots.GetAt(i).IsEmpty())
{
return i;
}
@@ -630,14 +652,19 @@ int cItemGrid::GetNextUsedSlot(int a_StartFrom) const
if ((a_StartFrom != -1) && !IsValidSlotNum(a_StartFrom))
{
LOGWARNING("%s: Invalid slot number %d out of %d slots",
- __FUNCTION__, a_StartFrom, m_NumSlots
+ __FUNCTION__, a_StartFrom, m_Slots.size()
);
a_StartFrom = -1;
}
- for (int i = a_StartFrom + 1; i < m_NumSlots; i++)
+ if (!m_Slots.IsStorageAllocated())
+ {
+ return -1; // No slots are used
+ }
+
+ for (int i = a_StartFrom + 1; i < m_Slots.size(); i++)
{
- if (!m_Slots[i].IsEmpty())
+ if (!m_Slots.GetAt(i).IsEmpty())
{
return i;
}
@@ -651,13 +678,18 @@ int cItemGrid::GetNextUsedSlot(int a_StartFrom) const
void cItemGrid::CopyToItems(cItems & a_Items) const
{
- for (int i = 0; i < m_NumSlots; i++)
+ if (!m_Slots.IsStorageAllocated())
+ {
+ return; // Nothing to copy
+ }
+
+ for (const auto & Slot : m_Slots)
{
- if (!m_Slots[i].IsEmpty())
+ if (!Slot.IsEmpty())
{
- a_Items.push_back(m_Slots[i]);
+ a_Items.push_back(Slot);
}
- } // for i - m_Slots[]
+ } // for Slot - m_Slots[]
}
@@ -668,9 +700,15 @@ bool cItemGrid::DamageItem(int a_SlotNum, short a_Amount)
{
if (!IsValidSlotNum(a_SlotNum))
{
- LOGWARNING("%s: invalid slot number %d out of %d slots, ignoring.", __FUNCTION__, a_SlotNum, m_NumSlots);
+ LOGWARNING("%s: invalid slot number %d out of %d slots, ignoring.", __FUNCTION__, a_SlotNum, m_Slots.size());
return false;
}
+
+ if (!m_Slots.IsStorageAllocated())
+ {
+ return false; // Nothing to damage
+ }
+
return m_Slots[a_SlotNum].DamageItem(a_Amount);
}
@@ -736,7 +774,7 @@ void cItemGrid::GenerateRandomLootWithBooks(const cLootProbab * a_LootProbabs, s
break;
}
} // for j - a_LootProbabs[]
- SetSlot(Rnd % m_NumSlots, CurrentLoot);
+ SetSlot(Rnd % m_Slots.size(), CurrentLoot);
} // for i - NumSlots
}
diff --git a/src/ItemGrid.h b/src/ItemGrid.h
index e744afd87..ee2dc79f3 100644
--- a/src/ItemGrid.h
+++ b/src/ItemGrid.h
@@ -9,6 +9,7 @@
#pragma once
#include "Item.h"
+#include "LazyArray.h"
@@ -33,12 +34,10 @@ public:
cItemGrid(int a_Width, int a_Height);
- ~cItemGrid();
-
// tolua_begin
int GetWidth (void) const { return m_Width; }
int GetHeight (void) const { return m_Height; }
- int GetNumSlots(void) const { return m_NumSlots; }
+ int GetNumSlots(void) const { return m_Slots.size(); }
/** Converts XY coords into slot number; returns -1 on invalid coords */
int GetSlotNum(int a_X, int a_Y) const;
@@ -49,7 +48,6 @@ public:
void GetSlotCoords(int a_SlotNum, int & a_X, int & a_Y) const;
/** Copies all items from a_Src to this grid.
- Both grids must be the same size (asserts).
Doesn't copy the listeners. */
void CopyFrom(const cItemGrid & a_Src);
@@ -84,21 +82,21 @@ public:
/** Adds as many items out of a_ItemStack as can fit.
If a_AllowNewStacks is set to false, only existing stacks can be topped up;
If a_AllowNewStacks is set to true, empty slots can be used for the rest.
- If a_PrioritarySlot is set to a positive value, then the corresponding slot will be used first (if empty or compatible with added items).
- If a_PrioritarySlot is set to -1, regular order applies.
+ If a_PrioritySlot is set to a positive value, then the corresponding slot will be used first (if empty or compatible with added items).
+ If a_PrioritySlot is set to -1, regular order applies.
Returns the number of items that fit.
*/
- int AddItem(cItem & a_ItemStack, bool a_AllowNewStacks = true, int a_PrioritarySlot = -1);
+ int AddItem(cItem & a_ItemStack, bool a_AllowNewStacks = true, int a_PrioritySlot = -1);
/** Same as AddItem, but works on an entire list of item stacks.
The a_ItemStackList is modified to reflect the leftover items.
If a_AllowNewStacks is set to false, only existing stacks can be topped up;
If a_AllowNewStacks is set to true, empty slots can be used for the rest.
- If a_PrioritarySlot is set to a positive value, then the corresponding slot will be used first (if empty or compatible with added items).
- If a_PrioritarySlot is set to -1, regular order applies.
+ If a_PrioritySlot is set to a positive value, then the corresponding slot will be used first (if empty or compatible with added items).
+ If a_PrioritySlot is set to -1, regular order applies.
Returns the total number of items that fit.
*/
- int AddItems(cItems & a_ItemStackList, bool a_AllowNewStacks = true, int a_PrioritarySlot = -1);
+ int AddItems(cItems & a_ItemStackList, bool a_AllowNewStacks = true, int a_PrioritySlot = -1);
/** Removes the specified item from the grid, as many as possible, up to a_ItemStack.m_ItemCount.
Returns the number of items that were removed. */
@@ -185,8 +183,7 @@ public:
protected:
int m_Width;
int m_Height;
- int m_NumSlots; // m_Width * m_Height, for easier validity checking in the access functions
- cItem * m_Slots; // x + m_Width * y
+ cLazyArray<cItem> m_Slots;
cListeners m_Listeners; ///< Listeners which should be notified on slot changes; the pointers are not owned by this object
cCriticalSection m_CSListeners; ///< CS that guards the m_Listeners against multi-thread access
diff --git a/src/LazyArray.h b/src/LazyArray.h
new file mode 100644
index 000000000..7015d6c47
--- /dev/null
+++ b/src/LazyArray.h
@@ -0,0 +1,134 @@
+
+#pragma once
+
+/** A dynamic array that defers allocation to the first modifying access.
+Const references from the array before allocation will all be to the same default constructed value.
+It is therefore important that default constructed values are indistinguishable from each other. */
+template <typename T>
+class cLazyArray
+{
+ static_assert((!std::is_reference<T>::value && !std::is_array<T>::value),
+ "cLazyArray<T>: T must be a value type");
+ static_assert(std::is_default_constructible<T>::value,
+ "cLazyArray<T>: T must be default constructible");
+public:
+ using value_type = T;
+ using pointer = T *;
+ using const_pointer = const T *;
+ using reference = T &;
+ using const_reference = const T &;
+ using size_type = int;
+ using iterator = pointer;
+ using const_iterator = const_pointer;
+
+ cLazyArray(size_type a_Size) NOEXCEPT:
+ m_Size{ a_Size }
+ {
+ ASSERT(a_Size > 0);
+ }
+
+ cLazyArray(const cLazyArray & a_Other):
+ m_Size{ a_Other.m_Size }
+ {
+ if (a_Other.IsStorageAllocated())
+ {
+ // Note that begin() will allocate the array to copy into
+ std::copy(a_Other.begin(), a_Other.end(), begin());
+ }
+ }
+
+ cLazyArray(cLazyArray && a_Other) NOEXCEPT:
+ m_Array{ std::move(a_Other.m_Array) },
+ m_Size{ a_Other.m_Size }
+ {
+ }
+
+ cLazyArray & operator = (const cLazyArray & a_Other)
+ {
+ cLazyArray(a_Other).swap(*this);
+ return *this;
+ }
+
+ cLazyArray & operator = (cLazyArray && a_Other) NOEXCEPT
+ {
+ m_Array = std::move(a_Other.m_Array);
+ m_Size = a_Other.m_Size;
+ return *this;
+ }
+
+ T & operator [] (size_type a_Idx)
+ {
+ ASSERT((0 <= a_Idx) && (a_Idx < m_Size));
+ return data()[a_Idx];
+ }
+
+ const T & operator [] (size_type a_Idx) const
+ {
+ return GetAt(a_Idx);
+ }
+
+ // STL style interface
+
+ const_iterator cbegin() const { return data(); }
+ iterator begin() { return data(); }
+ const_iterator begin() const { return cbegin(); }
+
+ const_iterator cend() const { return data() + m_Size; }
+ iterator end() { return data() + m_Size; }
+ const_iterator end() const { return cend(); }
+
+ size_type size() const NOEXCEPT { return m_Size; }
+
+ const T * data() const
+ {
+ if (m_Array == nullptr)
+ {
+ m_Array.reset(new T[m_Size]);
+ }
+ return m_Array.get();
+ }
+
+ T * data()
+ {
+ static_assert(!std::is_const<typename decltype(m_Array)::element_type>::value, "");
+ const cLazyArray * const_this = this;
+ return const_cast<T *>(const_this->data());
+ }
+
+ void swap(cLazyArray & a_Other) NOEXCEPT
+ {
+ std::swap(m_Array, a_Other.m_Array);
+ std::swap(m_Size, a_Other.m_Size);
+ }
+
+ friend void swap(cLazyArray & a_Lhs, cLazyArray & a_Rhs) NOEXCEPT
+ {
+ a_Lhs.swap(a_Rhs);
+ }
+
+ // Extra functions to help avoid allocation
+
+ /** A const view of an element of the array. Never causes the array to allocate. */
+ const T & GetAt(size_type a_Idx) const
+ {
+ ASSERT((0 <= a_Idx) && (a_Idx < m_Size));
+ if (IsStorageAllocated())
+ {
+ return data()[a_Idx];
+ }
+ else
+ {
+ static const T DefaultValue;
+ return DefaultValue;
+ }
+ }
+
+ /** Returns true if the array has already been allocated. */
+ bool IsStorageAllocated() const NOEXCEPT { return (m_Array != nullptr); }
+
+private:
+ // Mutable so const data() can allocate the array
+ mutable std::unique_ptr<T[]> m_Array;
+ size_type m_Size;
+};
+