Memcpy of native array to managed array in C++ CLI
Am I doing this right?
I get a pointer to a native array and need to copy to a managed array. Use memcpy() with a pin_ptr.
unsigned char* pArray;
unsigned int arrayCount;
// get pArray & arrayCount (from a COM method)
ManagedClass->ByteArray = gcnew array<Byte,1>(arrayCount)
pin_ptr<System::Byte> pinPtrArray = &ManagedClass-&开发者_JAVA百科gt;ByteArray[0];
memcpy_s(pinPtrArray, arrayCount, pArray, arrayCount);
arrayCount is the actual length of pArray, so not really worried about that aspect. Looked at the code and the array is copied from a vector. So I can set the managed array size safely.
That works, but isn't safe. You'll blow the garbage collected heap to smithereens when you get arrayCount wrong. Very hard to diagnose.
Marshal::Copy() is safe and just as fast.
You are doing it almost right:
pin_ptr<Byte> pinPtrArray = &ManagedClass.ByteArray[ManagedClass.ByeArray->GetLowerBound(0)];
Marshal::Copy is not safe and not as fast. Always use pinned pointers in managed C++.
Edit: If you want to, you can check the length to make sure the memcpy won't exceed the bounds first, e.g.:
if (arrayCount > ManagedClass.ByteArray.Length)
(throw Out of bounds copy exception)
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