How to write enum data type into a dataset?

[neroarth94]

I am trying to write a enum type into the dataset but is unable to. It always converts it to an int type. May I know how to insert into the dataset as an enum type?

example:

what i got instead:

what i have tried:

public enum AnEnum
{
    START,
    PAUSE,
    STOP
}
        
Hdf5.WriteDataset(groupId, "AnEnumDataset", new List<AnEnum>() { AnEnum.START}.ToArray());
Hdf5.WriteObject(groupId, new List<AnEnum>() { AnEnum.START}.ToArray(), "AnEnumDataset");
Hdf5.WriteOneValue(groupId, "AnEnumDataset", AnEnum.START, new Dictionary<string, List<string>>());

[flappah]

That's not possible right now but I ran into a similar issue and circumvented the issue by going to the underlying P/Invoke library. I've included one of the enumerations I'm using to write the data type to HDF5.

public class CommonPointRuleEnum : CustomEnumBase
    {
        private Dictionary<byte, string> _values = new Dictionary<byte, string>()
        {
            { 1, "average" },
            { 2, "low" },
            { 3, "high" },
            { 4, "all" }
        };

        private byte _current;

        public CommonPointRuleEnum()
        {

        }

        public CommonPointRuleEnum(byte current)
        {
            if (_values.ContainsKey(current))
            {
                this._current = current;
            }
            else
            {
                throw new InvalidDataException($"{current} is an invalid value!");
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="groupId"></param>
        /// <param name="current"></param>
        public override void WriteToHdf5(long groupId, byte current)
        {
            if (_values.ContainsKey(current))
            {
                _current = current;
                WriteToHdf5(groupId);
            }
            else
            {
                throw new InvalidDataException($"{current} is an invalid value!");
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="groupId"></param>
        public override void WriteToHdf5(long groupId)
        {
            long enum_id = H5T.enum_create(H5T.NATIVE_UINT8);

            var currentHandle = GCHandle.Alloc(_current, GCHandleType.Pinned);
            var handles = new List<GCHandle>();
            foreach (KeyValuePair<byte, string> item in _values)
            {
                var handle = GCHandle.Alloc(item.Key, GCHandleType.Pinned);
                H5T.enum_insert(enum_id, item.Value, handle.AddrOfPinnedObject());
                handles.Add(handle);
            }

            try
            {
                var space_id = H5S.create(H5S.class_t.SCALAR);
                var acpl = H5P.create(H5P.ATTRIBUTE_CREATE);
                H5P.set_char_encoding(acpl, H5T.cset_t.UTF8);

                var attr_id = H5A.create(groupId, "commonPointRule", enum_id, space_id, acpl, H5P.DEFAULT);
                H5A.write(attr_id, enum_id, currentHandle.AddrOfPinnedObject());
                H5A.close(attr_id);
            }
            finally
            {
                foreach (GCHandle handle in handles)
                {
                    handle.Free();
                }
                currentHandle.Free();
            }
        }
    }

Call it with:

var cprEnum = new CommonPointRuleEnum(1);
cprEnum.WriteToHdf5(hdf5GroupId);

[LiorBanai]

@flappah can't we wrap your implementation at my library so the user will have simplified Api to work with?

[flappah]

Sure! I think we need to generalize my approach a bit but yeah. We could definitely add it to your library!

[flappah]

Do you want me to generalize the code or do you want to do it yourself? I'm quite short in time this week since I've got a deadline coming up at the end of the week and next week I'm a week off but I could take a look at it in say a week or two.

[LiorBanai]

@flappah no pressure. If you would like to take a shoot on it it would be great. if not also ok :)
whatever you prefer

[flappah]

Good morning @LiorBanai. I still haven't gotten around adding my approach. It's been quite busy lately. But I'm planning on doing this as soon as I can get my hands free. Hope this'll be somewhere at the end of September now.

[LiorBanai]

Take your time. We are all busy those days 🙂

Thanks for the update.