From 03043e0bc34353ec5d2e9056082419ee6dbe1ff9 Mon Sep 17 00:00:00 2001
From: froejdh_e <erik.frojdh@psi.ch>
Date: Fri, 27 Oct 2023 11:32:21 +0200
Subject: [PATCH] cleaned up read_clusters

---
 src/cluster_reader.c    | 19 ++++++++-----------
 tests/test_functions.py |  2 +-
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/src/cluster_reader.c b/src/cluster_reader.c
index 69a8be0..f4aeba7 100644
--- a/src/cluster_reader.c
+++ b/src/cluster_reader.c
@@ -2,30 +2,28 @@
 #include <assert.h>
 
 size_t read_clusters(FILE *fp, size_t n_clusters, Cluster *buf, uint32_t *n_left) {
-    int iframe = 0;
-    uint32_t nph = *n_left;
+    int32_t iframe = 0;     // frame number needs to be 4 bytes!
+    uint32_t nph = *n_left; // number of clusters in frame needs to be 4 bytes!
 
     size_t nph_read = 0;
     uint32_t nn = *n_left;
-    size_t nr = 0;
 
-    // read photons left from previous frame
+
+    // if there are photons left from previous frame read them first
     if (nph) {
         if (nph > n_clusters) {
             // if we have more photons left in the frame then photons to read we
-            // read directly
+            // read directly the requested number
             nn = n_clusters;
         } else {
             nn = nph;
         }
-        nr += fread((void *)(buf + nph_read), sizeof(Cluster), nn, fp);
-        nph_read += nn;
-        *n_left = nph - nn;
+        nph_read += fread((void *)(buf + nph_read), sizeof(Cluster), nn, fp);
+        *n_left = nph - nn; //write back the number of photons left
     }
     if (nph_read < n_clusters) {
         // keep on reading frames and photons until reaching n_clusters
         while (fread(&iframe, sizeof(iframe), 1, fp)) {
-
             // read number of clusters in frame
             if (fread(&nph, sizeof(nph), 1, fp)) {
                 if (nph > (n_clusters - nph_read))
@@ -33,8 +31,7 @@ size_t read_clusters(FILE *fp, size_t n_clusters, Cluster *buf, uint32_t *n_left
                 else
                     nn = nph;
 
-                nr += fread((void *)(buf + nph_read), sizeof(Cluster), nn, fp);
-                nph_read += nn;
+                nph_read += fread((void *)(buf + nph_read), sizeof(Cluster), nn, fp);
                 *n_left = nph - nn;
             }
             if (nph_read >= n_clusters)
diff --git a/tests/test_functions.py b/tests/test_functions.py
index 0a44db9..953fac3 100644
--- a/tests/test_functions.py
+++ b/tests/test_functions.py
@@ -7,6 +7,6 @@ import sys
 #     fname= (data_path/'beam_En700eV_-40deg_300V_10us_d0_f0_100.clust').as_posix()
 #     r = ClusterFileReader(fname)
 #     clusters = r.read(10)
-#     result = clusterize(clusters)
+#     result = clusterize(3, clusters)
 #     assert sys.getrefcount(clusters) == 2 #Over counts by one due to call by reference
 #     assert sys.getrefcount(result) == 2 
\ No newline at end of file