Mohamad
herr_t H5Dtransfer (hid_t src_space_id, const void *src_buf, H5T_t type, hid_t dst_space_id, /*out*/void *dst_buf); I'm not certain that this will be any use on its own. If a selection is gigabytes and the VOL layer only has a small buffer available, then it needs to be able to make these transfers in pieces, performing puts/sends or whatever as appropriate. The function would be more useful if it was re-entrant and had a buffer size_type so that the selection could be copied by the first N, then next N, then next N until exhausted. herr_t H5Sselect_iterate (hid_t dataspace_id, H5S_select_iterator_t op, void *op_data); This function would be great and should be higher priority than the first because you can do the first using this second one - and don't have the problem of the limited buffer size. The user can iterate over the dataspace and copy as much or as little on each entry to the callback function as desired and maintain their own book keeping of where they left off. If the selection has huge contiguous chunks, the user callback can break these into pieces and perform the appropriate copies as substeps. If the selection is very sparse, then an internal buffer can be filled and acted upon as the iterations progress. the callback function herr_t (*H5S_select_iterate_t)(hsize_t *offset_coords, hsize_t length, void * op_data); could be improved by adding a user callback void *pointer so that when you call iterate - you pass a pointer to the function - and also a user pointer to a data structure of the user's choice, which is passed to the callback as a user parameter. This way we can track intermediate transfer objects (like if we only partially transferred data or are filling an internal buffer) and in the case of multiple threads acting on these iterations, we can make sure each thread has its own data pointer an avoid static/global objects which will not be safe. I just wrote this off the top of my head, so criticism welcome. JB -----Original Message----- From: h5vol-boun...@hdfgroup.org [mailto:h5vol-boun...@hdfgroup.org] On Behalf Of Mohamad Chaarawi Sent: 21 August 2012 23:45 To: HDF5 Virtual Object Layer (VOL) Discussions; hdf-forum@hdfgroup.org; hdf5...@hdfgroup.org Subject: [H5vol] RFC for new Dataspace routines Hi All, Please find attached an RFC that describes a couple of dataspace routines that we plan to add to the HDF5 API in the near future. If you have the time, please give it a read and feel free to send us comments. We would like to hear from you if you see that you could benefit from those routines but would like to change something or would like us to consider adding other routines. It would be great, in either case, if you could include your use case. Thank you, Mohamad
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