From ac83eeff9bba12330595460fa47996e6c1ba9d46 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Erik=20Fr=C3=B6jdh?= <erik.frojdh@psi.ch>
Date: Mon, 27 Oct 2025 15:46:31 +0100
Subject: [PATCH] added tell and better error checking to cluster file (#239)

- Check feof and ferror when reading frames
- added tell member function to ClusterFile
---
 RELEASE.md                      |  1 +
 include/aare/ClusterFile.hpp    | 21 ++++++++++++++++++---
 python/src/bind_ClusterFile.hpp |  1 +
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/RELEASE.md b/RELEASE.md
index 02aa857..7f7fed8 100644
--- a/RELEASE.md
+++ b/RELEASE.md
@@ -5,6 +5,7 @@
 Bugfixes: 
 
 - File supports reading new master json file format (multiple ROI's not supported yet)
+- Added tell to ClusterFile. Returns position in bytes for debugging
 
 ### 2025.8.22
 
diff --git a/include/aare/ClusterFile.hpp b/include/aare/ClusterFile.hpp
index 1f6961a..ccdace3 100644
--- a/include/aare/ClusterFile.hpp
+++ b/include/aare/ClusterFile.hpp
@@ -189,6 +189,16 @@ class ClusterFile {
         }
     }
 
+    /**
+     * @brief Return the current position in the file (bytes)
+     */
+    int64_t tell() {
+        if (!fp) {
+            throw std::runtime_error(LOCATION + "File not opened");
+        }
+        return ftell(fp);
+    }
+
     /** @brief Open the file in specific mode
      *
      */
@@ -354,15 +364,20 @@ template <typename ClusterType, typename Enable>
 ClusterVector<ClusterType>
 ClusterFile<ClusterType, Enable>::read_frame_without_cut() {
     if (m_mode != "r") {
-        throw std::runtime_error("File not opened for reading");
+        throw std::runtime_error(LOCATION + "File not opened for reading");
     }
     if (m_num_left) {
         throw std::runtime_error(
-            "There are still photons left in the last frame");
+            LOCATION + "There are still photons left in the last frame");
     }
     int32_t frame_number;
     if (fread(&frame_number, sizeof(frame_number), 1, fp) != 1) {
-        throw std::runtime_error(LOCATION + "Could not read frame number");
+        if (feof(fp))
+            throw std::runtime_error(LOCATION + "Unexpected end of file");
+        else if (ferror(fp))
+            throw std::runtime_error(LOCATION + "Error reading from file");
+
+        throw std::runtime_error(LOCATION + "Unexpected error (not feof or ferror) when reading frame number");
     }
 
     int32_t n_clusters; // Saved as 32bit integer in the cluster file
diff --git a/python/src/bind_ClusterFile.hpp b/python/src/bind_ClusterFile.hpp
index 5a707a4..f4a692c 100644
--- a/python/src/bind_ClusterFile.hpp
+++ b/python/src/bind_ClusterFile.hpp
@@ -45,6 +45,7 @@ void define_ClusterFile(py::module &m, const std::string &typestr) {
                  return v;
              })
         .def("set_roi", &ClusterFile<ClusterType>::set_roi, py::arg("roi"))
+        .def("tell", &ClusterFile<ClusterType>::tell)
         .def(
             "set_noise_map",
             [](ClusterFile<ClusterType> &self, py::array_t<int32_t> noise_map) {