getAnyPtr.h

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#ifndef FWCore_Utilities_getAnyPtr_h
#define FWCore_Utilities_getAnyPtr_h
 
#include <cassert>
#include <memory>
 
namespace edm {
  template <typename T>
  inline std::unique_ptr<T> getAnyPtr(void* p, int offset) {
    // A union is used to avoid possible copies during the triple cast that would otherwise be needed.
    // std::unique_ptr<T> edp(static_cast<T*>(static_cast<void *>(static_cast<unsigned char *>(p) + offset)));
    union {
      void* vp;
      unsigned char* ucp;
      T* tp;
    } pointerUnion;
    assert(p != nullptr);
    pointerUnion.vp = p;
    pointerUnion.ucp += offset;
    return std::unique_ptr<T>(pointerUnion.tp);
  }
}  // namespace edm
 
#endif