Add checks for empty HDF5 datasets in readArrayNdOfValues

Enhanced the readArrayNdOfValues method to check if the target HDF5 dataset is empty before attempting to read, throwing exceptions for empty or inaccessible datasets. Also improved error handling for dataspace and dataset closing operations.

Author: philippeVerney

src/eml2/HdfProxy.cpp

@@ -254,7 +254,7 @@ void HdfProxy::close()
 	}
 }
 
-void HdfProxy::readArrayNdOfValues(const std::string & datasetName, void* values, hid_t datatype)
+void HdfProxy::readArrayNdOfValues(const std::string& datasetName, void* values, hid_t datatype)
 {
 	if (!isOpened()) {
 		open();
@@ -264,9 +264,33 @@ void HdfProxy::readArrayNdOfValues(const std::string & datasetName, void* values
 	if (dataset < 0) {
 		throw invalid_argument("The HDF5 dataset " + datasetName + " could not be opened.");
 	}
+
+	// check if the dataset is empty
+	hid_t dataspace = H5Dget_space(dataset);
+	if (dataspace < 0) {
+		H5Dclose(dataset);
+		throw invalid_argument("The dataspace for the dataset " + datasetName + " could not be opened.");
+	}
+	hssize_t hdf5ValueCount = H5Sget_simple_extent_npoints(dataspace);
+	if (hdf5ValueCount < 0) {
+		H5Sclose(dataspace);
+		H5Dclose(dataset);
+		throw invalid_argument("The number of values of the dataset " + datasetName + " could not be read.");
+	}
+	else if (hdf5ValueCount == 0) {
+		H5Sclose(dataspace);
+		H5Dclose(dataset);
+		throw invalid_argument("The dataset " + datasetName + " is empty and consequently cannot be read.");
+	}
+	if (H5Sclose(dataspace) < 0) {
+		throw invalid_argument("Cannot close the HDF5 dataspace of the HDF5 dataset " + datasetName);
+	}
+
 	hid_t readingError = H5Dread (dataset, datatype, H5S_ALL, H5S_ALL, H5P_DEFAULT, values);
 
-	H5Dclose(dataset);
+	if (H5Dclose(dataset) < 0) {
+		throw invalid_argument("Cannot close the HDF5 dataset " + datasetName);
+	}
 	if (readingError < 0) {
 		throw invalid_argument("The HDF5 dataset " + datasetName + " could not be read.");
 	}