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Diffstat (limited to 'yapf/fixedsizearray.hpp')
-rw-r--r-- | yapf/fixedsizearray.hpp | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/yapf/fixedsizearray.hpp b/yapf/fixedsizearray.hpp new file mode 100644 index 000000000..9d67c6877 --- /dev/null +++ b/yapf/fixedsizearray.hpp @@ -0,0 +1,90 @@ +/* $Id$ */ + +#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 + + ST_CONST(int, Tcapacity = Tcapacity_); // the array capacity (maximum size) + ST_CONST(int, TitemSize = sizeof(Titem_)); // size of item + ST_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 = const_cast<Titem*>(src.m_items); // here we break the 'const' modifier + 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 + + // walk through all allocated items backward and destroy them + for (Titem* pItem = &m_items[Size() - 1]; pItem >= m_items; pItem--) { + pItem->~Titem_(); + } + free(((int8*)m_items) - ThdrSize); + m_items = NULL; + } + +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 */ |