Convert number in 64 bit integer about hdf5.node HOT 4 CLOSED

sorry i find the solution

from hdf5.node.

javascript does not have all 64 bits; the number is internally stored as a double which truncates the bits

I have a wrapper for Int64 for the id's but it doesn't really appear on the javascript side

What is the now object?

Is it a scalar you want to store or a table or dataset of many timestamps?

from hdf5.node.

a dataset, i finally found a solution like this
`const int64 = Date.now() // 1456909977176 (00 00 01 53 36 9a 06 58)
const b = new Buffer(8)
const MAX_UINT32 = 0xFFFFFFFF

// write
const big = ~~(int64 / MAX_UINT32)
const low = (int64 % MAX_UINT32) - big

b.writeUInt32BE(big, 0) // 00 00 01 53 00 00 00 00
b.writeUInt32BE(low, 4) // 00 00 01 53 36 9a 06 58
b.type=H5Type.H5T_STD_I64BE;`

My object is not a 64 bit integer in javascript but it's stored in 64bit integer in HDF5 file

I have another question : is it possible to add Attributes to a Dataset ?

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property value pairs get written as attributes. To write them after the dataset exists I'm forgetting and will look into it.

For getting them without opening the dataset there is the getDatasetAttributes on groups and file.

https://hdf-ni.github.io/hdf5.node/tut/attributes-tutorial.html

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