VFD development (iRODS)

I'm currently looking at developing a VFD for iRODS. The iRODS module for HDF5 appears not to have been touched in 3 years, and is restricted to the 1.6 API, and doesn't support file writing, apparently, making it unusable in our environment.

Has anyone else done this already and kept it to themselves (and, more importantly, would be willing to share)? Google doesn't show anything other than the aforementioned iRODS module. I'd prefer not to reinvent the wheel.

Are there better resources for undertaking this task beyond reading the source code and http://www.hdfgroup.org/HDF5/doc/TechNotes/VFL.html

Hi,

Does anyone know how to retrieve the parent group from an open dataset or open child group? In other words, navigate 'backwards' from a child to the parent.
I'm using HDF5 1.6 with c++.

Thanks,
Mark

You can ask for the path to the node you have (H5Rget_name) and strip away the last part. Note that due to the complexities introduced by links and references, a node can have multiple names or even none at all, but in most practical situation this approach should work fine.

Konrad.

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On 29 Apr 2011, at 18:19, Mark Kelly wrote:

Does anyone know how to retrieve the parent group from an open dataset or open child group? In other words, navigate 'backwards' from a child to the parent.

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Konrad Hinsen
Centre de Biophysique Moléculaire, CNRS Orléans
Synchrotron Soleil - Division Expériences
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Tel. +33-1 69 35 97 15
E-Mail: research at khinsen dot fastmail dot net
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Yes, that may work (probably with H5Iget_name, though) in many cases. The limitation here is that since an HDF5 groups/datasets/etc may have multiple hard links to it (i.e. have multiple "parents"), we don't store any "parent" information on objects.

  Quincey

···

On Apr 29, 2011, at 2:23 PM, Konrad Hinsen wrote:

On 29 Apr 2011, at 18:19, Mark Kelly wrote:

Does anyone know how to retrieve the parent group from an open dataset or open child group? In other words, navigate 'backwards' from a child to the parent.

You can ask for the path to the node you have (H5Rget_name) and strip away the last part. Note that due to the complexities introduced by links and references, a node can have multiple names or even none at all, but in most practical situation this approach should work fine.

Hi,

Thanks for the reply. H5Iget_name worked perfectly. H5Rget_name was only introduced in 1.8.0 (I am using 1.6).
In my case, there will only be one hard link to the dataset, so practically it's ok.
Also noted from the docs: When possible,|H5Iget_name|returns the path with which the object was opened, so it may also work if ever multiple links to it but only one path was used to open it.

Thanks again!

···

On 29/04/2011 3:36 PM, Quincey Koziol wrote:

On Apr 29, 2011, at 2:23 PM, Konrad Hinsen wrote:

On 29 Apr 2011, at 18:19, Mark Kelly wrote:

Does anyone know how to retrieve the parent group from an open dataset or open child group? In other words, navigate 'backwards' from a child to the parent.

You can ask for the path to the node you have (H5Rget_name) and strip away the last part. Note that due to the complexities introduced by links and references, a node can have multiple names or even none at all, but in most practical situation this approach should work fine.

  Yes, that may work (probably with H5Iget_name, though) in many cases. The limitation here is that since an HDF5 groups/datasets/etc may have multiple hard links to it (i.e. have multiple "parents"), we don't store any "parent" information on objects.

  Quincey

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Mark Kelly
NexGen Ergonomics Inc.
(514) 685-8593
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