auto_ptr for arrays
Solution 1
Use
std::vector<BYTE> buffer(cbType);
pType = (WM_MEDIA_TYPE*)&buffer[0];
or since C++11
std::vector<BYTE> buffer(cbType);
pType = (WM_MEDIA_TYPE*)buffer.data();
instead.
Additional: If someone is asking if the Vectors are guaranteed to be contiguous the answer is Yes since C++ 03 standard. There is another thread that already discussed it.
If C++11 is supported by your compiler, unique_ptr can be used for arrays.
unique_ptr<BYTE[]> buffer(new BYTE[cbType]);
pType = (WM_MEDIA_TYPE*)buffer.get();
Solution 2
boost scoped_array
or you can use boost scoped_ptr
with a custom deleter
Solution 3
There is nothing for this in the current std library. However, the future standard C++0x has an unique_ptr, which comes in replacement of auto_ptr, and which works with arrays.
A first implementation can be found here: unique_ptr
Solution 4
Not in STL. Boost has some smart pointers with a similar idea. Check out scoped_array and shared_array
Comments
-
heavyd almost 2 years
In short, I am wondering if there is an auto_ptr like type for arrays. I know I could roll my own, I'm just making sure that there isn't already something out there.
I know about vectors as well. however I don't think I can use them. I am using several of the Windows APIs/SDKs such as the Windows Media SDK, Direct Show API which in order to get back some structures to call a function which takes a pointer and a size twice. The first time passing NULL as the pointer to get back the size of the structure that I have to allocated in order to receive the data I am looking for. For example:
CComQIPtr<IWMMediaProps> pProps(m_pStreamConfig); DWORD cbType = 0; WM_MEDIA_TYPE *pType = NULL; hr = pProps->GetMediaType(NULL, &cbType); CHECK_HR(hr); pType = (WM_MEDIA_TYPE*)new BYTE[cbType]; // Would like to use auto_ptr instread hr = pProps->GetMediaType(pType, &cbType); CHECK_HR(hr); // ... do some stuff delete[] pType;
Since cbType typically comes back bigger than sizeof(WM_MEDIA_TYPE) due to the fact is has a pointer to another structure in it, I can't just allocate WM_MEDIA_TYPE objects. Is there anything like this out there?