Class BufferAPI

src/python/PyImath/PyImathBufferProtocol.cpp:24–74

//
template <class ArrayT>
class BufferAPI
{
  using T = typename ArrayT::BaseType;
  static_assert (std::is_same<ArrayT, FixedArray<T> >::value,
                 "BufferAPI is only valid for FixedArray classes");

  public:

    virtual ~BufferAPI()
      { delete[] shape; delete[] stride; }

    //  The size, in bytes, of the smallest individual element of a buffer
    // element.  For example, a V3fArray is a 2D array of 4-byte floats.
    Py_ssize_t atomicSize() const
      { return FixedArrayAtomicSize<T>::value; }

    //  NonCopyable
    BufferAPI (const BufferAPI &rhs)            = delete;
    BufferAPI &operator= (const BufferAPI &rhs) = delete;

    //  API
    virtual bool        sharedBuffer() const = 0;
    virtual Py_ssize_t  numBytes() const     = 0;
    virtual bool        readOnly() const     = 0;
    virtual void *      buffer()             = 0;

  protected:

    BufferAPI (const unsigned int length, const unsigned int interleave)
     : dimensions (FixedArrayDimension<T>::value),
            shape (new Py_ssize_t[dimensions]),
           stride (new Py_ssize_t[dimensions])
    {
        shape[0]  = Py_ssize_t (length);
        stride[0] = atomicSize() * FixedArrayWidth<T>::value * interleave;
        for (int d=1; d<dimensions; d++)
        {
            shape[d]  = FixedArrayWidth<T>::value * interleave;
            stride[d] = atomicSize();
        }
    }

  public:

    //  The number of dimensions in the data buffer (e.g. a one dimensional
    // FixedArray of V3fs would have a data buffer dimension of 2).
    int dimensions;

    Py_ssize_t *shape;
    Py_ssize_t *stride;
};


//  The SharedBuffer class is used for buffers that will be shared between