Check if number of written frames should be updated.

When reading a frame set the number of written frames in the
frame set should only be updated if the output file and the
input files are the same. This fixes a bug in one of the tests
in tng_testing.

Change-Id: Ia21d501b9723f756dfccf75e5d5bbac606cdc582

1 files changed, 8 insertions, 1 deletions

diff --git a/src/lib/tng_io.c b/src/lib/tng_io.c
index 658f9e4..180d339 100644
--- a/src/lib/tng_io.c
+++ b/src/lib/tng_io.c
@@ -3611,7 +3611,14 @@ static tng_function_status tng_frame_set_block_read
         tng_data->time_per_frame = -1;
     }
 
-    frame_set->n_written_frames = frame_set->n_frames;
+    /* If the output file and the input files are the same the number of
+     * frames in the file are the same number as has just been read.
+     * This is updated here to later on see if there have been new frames
+     * added and thereby the frame set needs to be rewritten. */
+    if(tng_data->output_file == tng_data->input_file)
+    {
+        frame_set->n_written_frames = frame_set->n_frames;
+    }
 
     return(TNG_SUCCESS);
 }