1 files changed, 99 insertions, 0 deletions
diff --git a/src/yapf/fixedsizearray.hpp b/src/yapf/fixedsizearray.hpp
new file mode 100644
index 000000000..48b177f3c
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+++ b/src/yapf/fixedsizearray.hpp
@@ -0,0 +1,99 @@
+/* $Id$ */
+
+#ifndef  FIXEDSIZEARRAY_HPP
+#define  FIXEDSIZEARRAY_HPP
+
+
+/** fixed size array
+ *  Upon construction it preallocates fixed size block of memory
+ *  for all items, but doesn't construct them. Item's construction
+ *  is delayed. */
+template <class Titem_, int Tcapacity_>
+struct CFixedSizeArrayT {
+	/** the only member of fixed size array is pointer to the block
+	 *  of C array of items. Header can be found on the offset -sizeof(CHdr). */
+	Titem_ *m_items;
+
+	/** header for fixed size array */
+	struct CHdr
+	{
+		int    m_num_items; ///< number of items in the array
+		int    m_ref_cnt;   ///< block reference counter (used by copy constructor and by destructor)
+	};
+
+	// make types and constants visible from outside
+	typedef Titem_ Titem; // type of array item
+
+	static const int Tcapacity = Tcapacity_;     // the array capacity (maximum size)
+	static const int TitemSize = sizeof(Titem_); // size of item
+	static const int ThdrSize  = sizeof(CHdr);   // size of header
+
+	/** Default constructor. Preallocate space for items and header, then initialize header. */
+	CFixedSizeArrayT()
+	{
+		// allocate block for header + items (don't construct items)
+		m_items = (Titem*)(((int8*)malloc(ThdrSize + Tcapacity * sizeof(Titem))) + ThdrSize);
+		SizeRef() = 0; // initial number of items
+		RefCnt() = 1; // initial reference counter
+	}
+
+	/** Copy constructor. Preallocate space for items and header, then initialize header. */
+	CFixedSizeArrayT(const CFixedSizeArrayT<Titem_, Tcapacity_>& src)
+	{
+		// share block (header + items) with the source array
+		m_items = src.m_items;
+		RefCnt()++; // now we share block with the source
+	}
+
+	/** destroy remaining items and free the memory block */
+	~CFixedSizeArrayT()
+	{
+		// release one reference to the shared block
+		if ((--RefCnt()) > 0) return; // and return if there is still some owner
+
+		Clear();
+		// free the memory block occupied by items
+		free(((int8*)m_items) - ThdrSize);
+		m_items = NULL;
+	}
+
+	/** Clear (destroy) all items */
+	FORCEINLINE void Clear()
+	{
+		// walk through all allocated items backward and destroy them
+		for (Titem* pItem = &m_items[Size() - 1]; pItem >= m_items; pItem--) {
+			pItem->~Titem_();
+		}
+		// number of items become zero
+		SizeRef() = 0;
+	}
+
+protected:
+	/** return reference to the array header (non-const) */
+	FORCEINLINE CHdr& Hdr() { return *(CHdr*)(((int8*)m_items) - ThdrSize); }
+	/** return reference to the array header (const) */
+	FORCEINLINE const CHdr& Hdr() const { return *(CHdr*)(((int8*)m_items) - ThdrSize); }
+	/** return reference to the block reference counter */
+	FORCEINLINE int& RefCnt() { return Hdr().m_ref_cnt; }
+	/** return reference to number of used items */
+	FORCEINLINE int& SizeRef() { return Hdr().m_num_items; }
+public:
+	/** return number of used items */
+	FORCEINLINE int Size() const { return Hdr().m_num_items; }
+	/** return true if array is full */
+	FORCEINLINE bool IsFull() const { return Size() >= Tcapacity; };
+	/** return true if array is empty */
+	FORCEINLINE bool IsEmpty() const { return Size() <= 0; };
+	/** index validation */
+	FORCEINLINE void CheckIdx(int idx) const { assert(idx >= 0); assert(idx < Size()); }
+	/** add (allocate), but don't construct item */
+	FORCEINLINE Titem& AddNC() { assert(!IsFull()); return m_items[SizeRef()++]; }
+	/** add and construct item using default constructor */
+	FORCEINLINE Titem& Add() { Titem& item = AddNC(); new(&item)Titem; return item; }
+	/** return item by index (non-const version) */
+	FORCEINLINE Titem& operator [] (int idx) { CheckIdx(idx); return m_items[idx]; }
+	/** return item by index (const version) */
+	FORCEINLINE const Titem& operator [] (int idx) const { CheckIdx(idx); return m_items[idx]; }
+};
+
+#endif /* FIXEDSIZEARRAY_HPP */