Keep a spare memory block in fixed size allocator to avoid large allocation overhead on the chunk boundary

nel/include/nel/misc/fixed_size_allocator.h

@@ -107,6 +107,7 @@ private:
 	uint	_NumBlockPerChunk;
 	//
 	uint	_NumAlloc;
+	uint8	*_SpareMem;
 };
 
 } // NLMISC

nel/src/misc/fixed_size_allocator.cpp

@@ -41,6 +41,7 @@ CFixedSizeAllocator::CFixedSizeAllocator(uint numBytesPerBlock, uint numBlockPer
 	nlassert(_NumBytesPerBlock >= numBytesPerBlock);
 	_NumBlockPerChunk = std::max(numBlockPerChunk, (uint) 3);
 	_NumAlloc = 0;
+	_SpareMem = NULL;
 }
 
 // *****************************************************************************************************************
@@ -49,10 +50,11 @@ CFixedSizeAllocator::~CFixedSizeAllocator()
 	if (_NumAlloc != 0)
 	{
 #ifdef NL_DEBUG
-			nlwarning("%d blocks were not freed", (int) _NumAlloc);
+		nlwarning("%d blocks were not freed, leaking memory", (int) _NumAlloc);
 #endif
-		return;
 	}
+	else
+	{
 		if (_NumChunks > 0)
 		{
 			nlassert(_NumChunks == 1);
@@ -60,6 +62,11 @@ CFixedSizeAllocator::~CFixedSizeAllocator()
 			delete _FreeSpace->Chunk;
 		}
 	}
+	if (_SpareMem)
+	{
+		aligned_free(_SpareMem);
+	}
+}
 
 // *****************************************************************************************************************
 void *CFixedSizeAllocator::alloc()
@@ -115,7 +122,10 @@ CFixedSizeAllocator::CChunk::~CChunk()
 	nlassert(NumFreeObjs == 0);
 	nlassert(Allocator->_NumChunks > 0);
 	-- (Allocator->_NumChunks);
+	if (Allocator->_SpareMem)
 		aligned_free(Mem); //delete[] Mem;
+	else
+		Allocator->_SpareMem = Mem;
 }
 
 // *****************************************************************************************************************
@@ -125,7 +135,15 @@ void CFixedSizeAllocator::CChunk::init(CFixedSizeAllocator *alloc)
 	nlassert(alloc != NULL);
 	Allocator = alloc;
 	//
+	if (Allocator->_SpareMem)
+	{
+		Mem = Allocator->_SpareMem;
+		Allocator->_SpareMem = NULL;
+	}
+	else
+	{
 		Mem = (uint8 *)aligned_malloc(getBlockSizeWithOverhead() * alloc->getNumBlockPerChunk(), NL_DEFAULT_MEMORY_ALIGNMENT); // new uint8[getBlockSizeWithOverhead() * alloc->getNumBlockPerChunk()];
+	}
 	//
 	getNode(0).Chunk = this;
 	getNode(0).Next = &getNode(1);