Reports

Thanks to the suggestion from Jmb about using ndarray::ArrayView2, I was able to get create the attribute with the desired DATASPACE definition:

use anyhow::{Ok, Result};
use hdf5::types::FixedAscii;
use hdf5::{Dataspace, File};
use std::path::PathBuf;
use std::str::Bytes;

use ndarray::ArrayView2;

fn main() -> Result<()> {
  let hdf5_path = PathBuf::from(
      "SVM15_npp_d20181005_t2022358_e2024003_b35959_c20181008035331889474_cspp_bck.h5",
  );
  let file = File::open_rw(hdf5_path)?;

  let gmtco_name =
      "GMTCO_npp_d20181005_t2022358_e2024003_b35959_c20181008035331889474_cspp_bck.h5";

  let attr_name = "FixedAscii_2D_array";
  let ascii_array: hdf5::types::FixedAscii<79> =
      hdf5::types::FixedAscii::from_ascii(&gmtco_name)?;
  let ascii_array = [ascii_array];
  let data = ArrayView2::from_shape((1, 1), &ascii_array)?;
  file.new_attr::<hdf5::types::FixedAscii<79>>()
      .shape([1, 1])
      .create(attr_name)?
      .write(&data)?;

  Ok(())
}

which results in the attribute (as shown via h5dump):

$> h5dump -a FixedAscii_2D_array SVM15_npp_d20181005_t2022358_e2024003_b35959_c20181008035331889474_cspp_bck.h5

HDF5 "SVM15_npp_d20181005_t2022358_e2024003_b35959_c20181008035331889474_cspp_bck.h5" {
ATTRIBUTE "FixedAscii_2D_array" {
   DATATYPE  H5T_STRING {
      STRSIZE 79;
      STRPAD H5T_STR_NULLPAD;
      CSET H5T_CSET_ASCII;
      CTYPE H5T_C_S1;
   }
   DATASPACE  SIMPLE { ( 1, 1 ) / ( 1, 1 ) }
   DATA {
   (0,0): "GMTCO_npp_d20181005_t2022358_e2024003_b35959_c20181008035331889474_cspp_bck.h5\000"
   }
}
}

As far as I can tell, there is as yet no high-level interface to set STRPAD to H5T_STR_NULLTERM rather than H5T_STR_NULLPAD, however I believe this can be done using the hdf5-sys crate in an unsafe block.

I have created a git repo containing many examples of reading and writing HDF5 (and NetCDF4) attributes and datasets (including several variants of the above solution) at https://codeberg.org/gpcureton/hdf5_netcdf_test.rs , in the hope that it may be useful for people trying to use the Rust interface to HDF5 and NetCDF4.

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