From e6b14bc67d491a3c2efffe1c728cfc0ef7f068b9 Mon Sep 17 00:00:00 2001
From: Dimitri Vlachos <dimitri.j.vlachos@gmail.com>
Date: Tue, 28 Jan 2025 18:02:49 +0000
Subject: [PATCH] Enhance HDF5 dataset reading function with improved error
 handling

---
 include/dx2/h5/h5read_processed.h | 95 +++++++++++++++++++++++--------
 1 file changed, 70 insertions(+), 25 deletions(-)

diff --git a/include/dx2/h5/h5read_processed.h b/include/dx2/h5/h5read_processed.h
index 1b636ca..5118641 100644
--- a/include/dx2/h5/h5read_processed.h
+++ b/include/dx2/h5/h5read_processed.h
@@ -7,34 +7,79 @@
 #include <string>
 #include <vector>
 
+/**
+ * @brief Reads a dataset from an HDF5 file into an std::vector.
+ *
+ * @tparam T The type of data to read (e.g., int, double).
+ * @param filename The path to the HDF5 file.
+ * @param dataset_name The name of the dataset to read.
+ * @return A std::vector containing the data from the dataset.
+ * @throws std::runtime_error If the file, dataset, or datatype cannot be opened
+ * or read.
+ */
 template <typename T>
-std::vector<T> read_array_from_h5_file(std::string filename,
-                                       std::string array_name) {
+std::vector<T> read_array_from_h5_file(const std::string &filename,
+                                       const std::string &dataset_name) {
+  // Start measuring time
   auto start_time = std::chrono::high_resolution_clock::now();
+
+  // Open the HDF5 file
   hid_t file = H5Fopen(filename.c_str(), H5F_ACC_RDONLY, H5P_DEFAULT);
   if (file < 0) {
-    std::cout << "Error: Unable to open " << filename.c_str()
-              << " as a hdf5 reflection table" << std::endl;
-    std::exit(1);
+    throw std::runtime_error("Error: Unable to open file: " + filename);
   }
 
-  hid_t dataset = H5Dopen(file, array_name.c_str(), H5P_DEFAULT);
-  hid_t datatype = H5Dget_type(dataset);
-  size_t datatype_size = H5Tget_size(datatype);
-  assert((datatype_size == sizeof(T)));
-  hid_t dataspace = H5Dget_space(dataset);
-  size_t num_elements = H5Sget_simple_extent_npoints(dataspace);
-  hid_t space = H5Dget_space(dataset);
-  std::vector<T> data_out(num_elements);
-
-  H5Dread(dataset, datatype, H5S_ALL, space, H5P_DEFAULT, &data_out[0]);
-  float total_time = std::chrono::duration_cast<std::chrono::duration<double>>(
-                         std::chrono::high_resolution_clock::now() - start_time)
-                         .count();
-  std::cout << "READ TIME for " << array_name << " : " << total_time << "s"
-            << std::endl;
-
-  H5Dclose(dataset);
-  H5Fclose(file);
-  return data_out;
-}
+  try {
+    // Open the dataset
+    hid_t dataset = H5Dopen(file, dataset_name.c_str(), H5P_DEFAULT);
+    if (dataset < 0) {
+      throw std::runtime_error("Error: Unable to open dataset: " +
+                               dataset_name);
+    }
+
+    try {
+      // Get the datatype and check size
+      hid_t datatype = H5Dget_type(dataset);
+      size_t datatype_size = H5Tget_size(datatype);
+      if (datatype_size != sizeof(T)) {
+        throw std::runtime_error(
+            "Error: Dataset type size does not match expected type size.");
+      }
+
+      // Get the dataspace and the number of elements
+      hid_t dataspace = H5Dget_space(dataset);
+      size_t num_elements = H5Sget_simple_extent_npoints(dataspace);
+
+      // Allocate a vector to hold the data
+      std::vector<T> data_out(num_elements);
+
+      // Read the data into the vector
+      herr_t status = H5Dread(dataset, datatype, H5S_ALL, H5S_ALL, H5P_DEFAULT,
+                              data_out.data());
+      if (status < 0) {
+        throw std::runtime_error("Error: Unable to read dataset: " +
+                                 dataset_name);
+      }
+
+      // Close the dataset and return the data
+      H5Dclose(dataset);
+      H5Fclose(file);
+
+      // Log timing
+      auto end_time = std::chrono::high_resolution_clock::now();
+      double elapsed_time =
+          std::chrono::duration<double>(end_time - start_time).count();
+      std::cout << "READ TIME for " << dataset_name << " : " << elapsed_time
+                << "s" << std::endl;
+
+      return data_out;
+
+    } catch (...) {
+      H5Dclose(dataset); // Ensure dataset is closed in case of failure
+      throw;
+    }
+  } catch (...) {
+    H5Fclose(file); // Ensure file is closed in case of failure
+    throw;
+  }
+}
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