Juliet/include/Core/Container/Vector.h

@@ -6,7 +6,7 @@
 
 namespace Juliet
 {
-    template <typename Type>
+    template <typename Type, size_t ReserveSize = 16, bool AllowRealloc = false>
     struct VectorArena
     {
         void Create()
@@ -16,8 +16,27 @@ namespace Juliet
             DataFirst = DataLast = nullptr;
             Count                = 0;
             Stride               = sizeof(Type);
-            Arena                = ArenaAllocate(JULIET_DEBUG_ONLY({ .CanReserveMore = false }));
+            ArenaParams params{ .AllowRealloc = AllowRealloc JULIET_DEBUG_ONLY(, .CanReserveMore = false) };
+            Arena         = ArenaAllocate(params);
+            InternalArena = true;
+
+            Reserve(ReserveSize);
         }
+
+        void Create(NonNullPtr<Arena> arena)
+        {
+            Assert(!Arena);
+            static_assert(AllowRealloc == false);
+
+            DataFirst = DataLast = nullptr;
+            Count                = 0;
+            Stride               = sizeof(Type);
+            Arena                = arena.Get();
+            InternalArena        = false;
+
+            Reserve(ReserveSize);
+        }
+
         void Destroy()
         {
             ArenaRelease(Arena);
@@ -27,6 +46,22 @@ namespace Juliet
             Arena                = nullptr;
         }
 
+        void Reserve(size_t newCapacity)
+        {
+            if (newCapacity > Capacity)
+            {
+                if (Data == nullptr)
+                {
+                    Data = ArenaPushArray<Type>(Arena, newCapacity);
+                }
+                else if (AllowRealloc && InternalArena)
+                {
+                    Data = static_cast<Type*>(ArenaReallocate(Arena, Data, Capacity, newCapacity, AlignOf(Type), true));
+                }
+                Capacity = newCapacity;
+            }
+        }
+
         void Resize(size_t newCount)
         {
             Type* entry = ArenaPushArray<Type>(Arena, newCount);
@@ -39,7 +74,7 @@ namespace Juliet
         {
             Assert(Arena);
 
-            Type* entry = ArenaPushStruct<Type>(Arena);
+            Type* entry = Data + (Count * Stride);
             *entry      = value;
 
             if (Count == 0)
@@ -54,7 +89,7 @@ namespace Juliet
         {
             Assert(Arena);
 
-            Type* entry = ArenaPushStruct<Type>(Arena);
+            Type* entry = Data + (Count * Stride);
             *entry      = std::move(value);
 
             if (Count == 0)
@@ -86,8 +121,6 @@ namespace Juliet
             {
                 DataFirst = DataLast = nullptr;
             }
-
-            ArenaPop(Arena, Stride);
         }
 
         void Clear()
@@ -117,8 +150,11 @@ namespace Juliet
         Arena* Arena;
         Type*  DataFirst;
         Type*  DataLast;
+        Type*  Data;
         size_t Count;
+        size_t Capacity;
         size_t Stride;
+        bool   InternalArena : 1;
     };
     static_assert(std::is_standard_layout_v<VectorArena<int>>,
                   "VectorArena must have a standard layout to remain POD-like.");

Juliet/include/Juliet.h

@@ -21,7 +21,7 @@
 
 #ifdef DEBUG
 #define JULIET_DEBUG 1
-#define JULIET_DEBUG_ONLY(expr) expr
+#define JULIET_DEBUG_ONLY(...) __VA_ARGS__
 #else
 #define JULIET_DEBUG 0
 #define JULIET_DEBUG_ONLY(expr)

Juliet/src/Core/Memory/MemoryArena.cpp

@@ -213,7 +213,9 @@ namespace Juliet
 
     void* ArenaReallocate(NonNullPtr<Arena> arena, void* oldPtr, size_t oldSize, size_t newSize, size_t align, bool shouldBeZeroed)
     {
-        // Find the correct block
+        void* result = ArenaPush(arena, newSize, align, shouldBeZeroed);
+
+        // Find the correct block to release
         Arena* block = nullptr;
         for (block = arena->Current; block != nullptr; block = block->Previous)
         {
@@ -224,6 +226,10 @@ namespace Juliet
         }
         Assert(block != nullptr);
 
+        // Copy old to new
+        MemCopy(result, oldPtr, oldSize);
+
+        // Zero the old memory
         MemoryZero(oldPtr, oldSize);
         ArenaFreeNode* freeNode = static_cast<ArenaFreeNode*>(oldPtr);
         ptrdiff_t      posPtr   = static_cast<Byte*>(oldPtr) - reinterpret_cast<Byte*>(block);
@@ -244,7 +250,7 @@ namespace Juliet
             }
             block->FreeNodes = freeNode;
         }
-        return ArenaPush(arena, newSize, align, shouldBeZeroed);
+        return result;
     }
 
     void ArenaPopTo(NonNullPtr<Arena> arena, size_t position)

Juliet/src/Core/Memory/MemoryArenaTests.cpp

@@ -117,28 +117,6 @@ namespace Juliet::UnitTest
 
         ArenaRelease(testArena);
 
-        // Setup Pool and Arena for Pop Tests
-        size_t     testPoolSize = Megabytes(1);
-        void*      testBacking  = Calloc(1, testPoolSize);
-        MemoryPool pool;
-        pool.BaseAddress = testBacking;
-        pool.TotalSize   = testPoolSize;
-        pool.FreeList    = nullptr;
-
-        // Initialize FreeList (Simulate pool)
-        size_t blockSize = Kilobytes(128);
-        size_t numBlocks = testPoolSize / blockSize;
-        uint8* ptr       = static_cast<uint8*>(testBacking);
-        for (size_t i = 0; i < numBlocks; ++i)
-        {
-            MemoryBlock* blk = reinterpret_cast<MemoryBlock*>(ptr + i * blockSize);
-            blk->Magic       = MemoryBlock::kMagic;
-            blk->TotalSize   = blockSize;
-            blk->Used        = 0;
-            blk->Next        = pool.FreeList;
-            pool.FreeList    = blk;
-        }
-
         {
             // Test reallocate
             Arena* arena           = ArenaAllocate({ .AllowRealloc = true });
@@ -154,6 +132,8 @@ namespace Juliet::UnitTest
             Assert(secondCharArray);
             Assert(thirdCharArray);
             Assert(fourthCharArray);
+
+            ArenaRelease(arena);
         }
 
         printf("All Paged MemoryArena tests passed.\n");