Add special memory allocator for Lua that should take some memory stress away from heavy scripting.

BBGE/MemoryAllocatorSmallBlock.h

@@ -0,0 +1,100 @@
+#ifndef MEMORY_ALLOCATOR_SMALL_BLOCK_H
+#define MEMORY_ALLOCATOR_SMALL_BLOCK_H
+
+/* Optimized memory allocator for small & frequent (de-)allocations.
+ * Low memory overhead. Used for Lua.
+ * Inspired by http://dns.achurch.org/cgi-bin/hg/aquaria-psp/file/tip/PSP/src/lalloc.c
+*/
+
+// Originally made for LV3proj_ng (https://github.com/fgenesis/lv3proj_ng)
+// Hacked in shape for use in Aquaria
+// Public domain
+
+
+#include <vector>
+
+class SmallBlockAllocator
+{
+public:
+
+    SmallBlockAllocator(unsigned int blockSizeMin, unsigned int blockSizeMax, unsigned int blockSizeIncr = 8,
+                        unsigned int elemsPerBlockMin = 64, unsigned int elemsPerBlockMax = 2048);
+
+    ~SmallBlockAllocator();
+
+    void *Alloc(void *ptr, size_t newsize, size_t oldsize);
+
+
+private:
+
+    void *_Alloc(unsigned int size);
+    void *_Realloc(void *ptr, unsigned int newsize, unsigned int oldsize);
+    void _Free(void* ptr, unsigned int size);
+
+    void *_FallbackAlloc(unsigned int size);
+    void _FallbackFree(void *ptr);
+
+    struct Block
+    {
+        // block header start
+        Block *next;
+        Block *prev;
+        unsigned short maxElems;
+        unsigned short freeElems;
+        unsigned short elemSize;
+        unsigned short bitmapInts;
+        // block header end
+
+        unsigned int bitmap[1]; // variable sized
+        // actual storage memory starts after bitmap[bitmapInts]
+
+        inline unsigned char *getPtr()
+        {
+            return (unsigned char*)&bitmap[bitmapInts];
+        }
+        inline const unsigned char *getPtr() const
+        {
+            return (unsigned char*)&bitmap[bitmapInts];
+        }
+        inline unsigned char *getEndPtr()
+        {
+            return getPtr() + (maxElems * elemSize);
+        }
+        inline const unsigned char *getEndPtr() const
+        {
+            return getPtr() + (maxElems * elemSize);
+        }
+
+        void *allocElem();
+        void freeElem(unsigned char *ptr);
+        bool contains(unsigned char *ptr) const;
+    };
+
+    Block *_AllocBlock(unsigned int elemCount, unsigned int elemSize);
+    void _FreeBlock(Block *blk);
+    Block *_AppendBlock(unsigned int elemSize);
+    Block *_GetFreeBlock(unsigned int elemSize); // NULL if none free
+
+    Block *_FindBlockContainingPtr(void *ptr);
+
+    inline unsigned int GetIndexForElemSize(unsigned int elemSize)
+    {
+        //ASSERT(elemSize);
+        //ASSERT(elemSize <= _blockSizeMax);
+        return ((elemSize + (_blockSizeIncr - 1)) / _blockSizeIncr) - 1;
+    }
+
+    static bool Block_ptr_cmp(const Block *blk,  const void *ptr);
+
+    Block **_blocks;
+    std::vector<Block*> _allblocks; // always sorted by pointer address
+
+    unsigned int _blockSizeMin;
+    unsigned int _blockSizeMax;
+    unsigned int _blockSizeIncr;
+
+    unsigned int _elemsPerBlockMin;
+    unsigned int _elemsPerBlockMax;
+};
+
+#endif