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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4680 | right-hear | 1 | #ifndef __refcount_h__ |
| 2 | #define __refcount_h__ |
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| 3 | |||
| 4 | #include "lispassert.h" |
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| 5 | #include "yacasbase.h" |
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| 6 | |||
| 7 | //------------------------------------------------------------------------------ |
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| 8 | // RefPtr - Smart pointer for (intrusive) reference counting. |
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| 9 | // Simply, an object's reference count is the number of RefPtrs refering to it. |
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| 10 | // The RefPtr will delete the referenced object when the count reaches zero. |
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| 11 | |||
| 12 | /*TODO: this might be improved a little by having RefPtr wrap the object being |
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| 13 | pointed to so the user of RefPtr does not need to add ReferenceCount explicitly. |
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| 14 | One can use RefPtr on any arbitrary object from that moment on. |
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| 15 | */ |
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| 16 | |||
| 17 | typedef ReferenceType ReferenceCount; |
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| 18 | |||
| 19 | template |
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| 20 | class RefPtr : public YacasBase // derived, so we can 'NEW LispPtr[nnn]' |
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| 21 | { |
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| 22 | public: |
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| 23 | // Default constructor (not explicit, so it auto-initializes) |
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| 24 | inline RefPtr() : iPtr(NULL) {} |
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| 25 | // Construct from pointer to T |
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| 26 | explicit RefPtr(T *ptr) : iPtr(ptr) { if (ptr) { ptr->iReferenceCount++; } } |
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| 27 | // Copy constructor |
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| 28 | RefPtr(const RefPtr &refPtr) : iPtr(refPtr.ptr()) { if (iPtr) { iPtr->iReferenceCount++; } } |
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| 29 | // Destructor |
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| 30 | ~RefPtr() |
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| 31 | { |
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| 32 | if (iPtr) |
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| 33 | { |
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| 34 | iPtr->iReferenceCount--; |
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| 35 | if (iPtr->iReferenceCount == 0) |
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| 36 | { |
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| 37 | delete iPtr; |
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| 38 | } |
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| 39 | } |
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| 40 | } |
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| 41 | // Assignment from pointer |
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| 42 | RefPtr &operator=(T *ptr) |
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| 43 | { |
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| 44 | if (ptr) |
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| 45 | { |
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| 46 | ptr->iReferenceCount++; |
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| 47 | } |
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| 48 | if (iPtr) |
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| 49 | { |
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| 50 | iPtr->iReferenceCount--; |
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| 51 | if (iPtr->iReferenceCount == 0) |
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| 52 | { |
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| 53 | delete iPtr; |
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| 54 | } |
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| 55 | } |
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| 56 | iPtr = ptr; |
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| 57 | return *this; |
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| 58 | } |
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| 59 | // Assignment from another |
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| 60 | RefPtr &operator=(const RefPtr &refPtr) { return this->operator=(refPtr.ptr()); } |
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| 61 | |||
| 62 | operator T*() const { return iPtr; } // implicit conversion to pointer to T |
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| 63 | T &operator*() const { return *iPtr; } // so (*refPtr) is a reference to T |
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| 64 | T *operator->() const { return iPtr; } // so (refPtr->member) accesses T's member |
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| 65 | T *ptr() const { return iPtr; } // so (refPtr.ptr()) returns the pointer to T (boost calls this method 'get') |
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| 66 | bool operator!() const { return !iPtr; } // is null pointer |
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| 67 | |||
| 68 | private: |
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| 69 | T *iPtr; |
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| 70 | }; |
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| 71 | |||
| 72 | |||
| 73 | #endif |
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| 74 |