Reread frame set after getting stride length.

After determining the stride length reread the current frame
set so that no data is skipped when reading a file.

Change-Id: I99c36b0cefe918ea39f22a559553d65b9a72a48f

1 files changed, 46 insertions, 41 deletions

diff --git a/src/lib/tng_io.c b/src/lib/tng_io.c
index 92d728a..73431df 100644
--- a/src/lib/tng_io.c
+++ b/src/lib/tng_io.c
@@ -1028,6 +1028,40 @@ static tng_function_status tng_block_header_read
 // }
 */
 
+static tng_function_status tng_reread_frame_set_at_file_pos
+                (tng_trajectory_t tng_data,
+                 const int64_t pos)
+{
+    tng_gen_block_t block;
+    tng_function_status stat;
+
+    tng_block_init(&block);
+
+    fseek(tng_data->input_file, pos, SEEK_SET);
+    if(pos > 0)
+    {
+        stat = tng_block_header_read(tng_data, block);
+        if(stat == TNG_CRITICAL || block->id != TNG_TRAJECTORY_FRAME_SET)
+        {
+            fprintf(stderr, "TNG library: Cannot read block header at pos %"PRId64". %s: %d\n", pos,
+                    __FILE__, __LINE__);
+            tng_block_destroy(&block);
+            return(TNG_FAILURE);
+        }
+
+        if(tng_block_read_next(tng_data, block,
+                               TNG_SKIP_HASH) != TNG_SUCCESS)
+        {
+            tng_block_destroy(&block);
+            return(TNG_CRITICAL);
+        }
+    }
+
+    tng_block_destroy(&block);
+
+    return(TNG_SUCCESS);
+}
+
 static tng_function_status tng_file_pos_of_subsequent_trajectory_block_get
                 (tng_trajectory_t tng_data,
                  int64_t *pos)
@@ -1100,30 +1134,12 @@ static tng_function_status tng_file_pos_of_subsequent_trajectory_block_get
     }
 
     /* Re-read the frame set that used to be the current one */
-    fseek(tng_data->input_file, curr_frame_set_pos, SEEK_SET);
-    if(curr_frame_set_pos > 0)
-    {
-        stat = tng_block_header_read(tng_data, block);
-        if(stat == TNG_CRITICAL || block->id != TNG_TRAJECTORY_FRAME_SET)
-        {
-            fprintf(stderr, "TNG library: Cannot read block header at pos %"PRId64". %s: %d\n", *pos,
-                    __FILE__, __LINE__);
-            tng_block_destroy(&block);
-            return(TNG_FAILURE);
-        }
+    tng_reread_frame_set_at_file_pos(tng_data, curr_frame_set_pos);
 
-        if(tng_block_read_next(tng_data, block,
-                               TNG_SKIP_HASH) != TNG_SUCCESS)
-        {
-            tng_block_destroy(&block);
-            return(TNG_CRITICAL);
-        }
-    }
+    fseek(tng_data->input_file, orig_pos, SEEK_SET);
 
     tng_block_destroy(&block);
 
-    fseek(tng_data->input_file, orig_pos, SEEK_SET);
-
     return(TNG_SUCCESS);
 }
 
@@ -1223,30 +1239,12 @@ static tng_function_status tng_length_of_current_frame_set_contents_get
     }
 
     /* Re-read the frame set that used to be the current one */
-    fseek(tng_data->input_file, curr_frame_set_pos, SEEK_SET);
-    if(curr_frame_set_pos > 0)
-    {
-        stat = tng_block_header_read(tng_data, block);
-        if(stat == TNG_CRITICAL || block->id != TNG_TRAJECTORY_FRAME_SET)
-        {
-            fprintf(stderr, "TNG library: Cannot read block header at pos %"PRId64". %s: %d\n",
-                    curr_frame_set_pos, __FILE__, __LINE__);
-            tng_block_destroy(&block);
-            return(TNG_FAILURE);
-        }
+    tng_reread_frame_set_at_file_pos(tng_data, curr_frame_set_pos);
 
-        if(tng_block_read_next(tng_data, block,
-                               TNG_SKIP_HASH) != TNG_SUCCESS)
-        {
-            tng_block_destroy(&block);
-            return(TNG_CRITICAL);
-        }
-    }
+    fseek(tng_data->input_file, orig_pos, SEEK_SET);
 
     tng_block_destroy(&block);
 
-    fseek(tng_data->input_file, orig_pos, SEEK_SET);
-
     return(TNG_SUCCESS);
 }
 
@@ -16492,7 +16490,7 @@ tng_function_status DECLSPECDLLEXPORT tng_data_get_stride_length
     tng_function_status stat;
     tng_non_particle_data_t np_data;
     tng_particle_data_t p_data;
-    long file_pos;
+    long orig_file_pos, file_pos;
     int is_particle_data;
 
     if(tng_data->current_trajectory_frame_set_input_file_pos <= 0)
@@ -16508,6 +16506,7 @@ tng_function_status DECLSPECDLLEXPORT tng_data_get_stride_length
             return(stat);
         }
     }
+    orig_file_pos = tng_data->current_trajectory_frame_set_input_file_pos;
     stat = tng_data_find(tng_data, block_id, &np_data);
     if(stat != TNG_SUCCESS)
     {
@@ -16527,6 +16526,8 @@ tng_function_status DECLSPECDLLEXPORT tng_data_get_stride_length
             }
             if(stat != TNG_SUCCESS)
             {
+                tng_reread_frame_set_at_file_pos(tng_data, orig_file_pos);
+
                 return(stat);
             }
             stat = tng_data_find(tng_data, block_id, &np_data);
@@ -16535,6 +16536,8 @@ tng_function_status DECLSPECDLLEXPORT tng_data_get_stride_length
                 stat = tng_particle_data_find(tng_data, block_id, &p_data);
                 if(stat != TNG_SUCCESS)
                 {
+                    tng_reread_frame_set_at_file_pos(tng_data, orig_file_pos);
+
                     return(stat);
                 }
                 else
@@ -16564,6 +16567,8 @@ tng_function_status DECLSPECDLLEXPORT tng_data_get_stride_length
     {
         *stride_length = np_data->stride_length;
     }
+    tng_reread_frame_set_at_file_pos(tng_data, orig_file_pos);
+
     return(TNG_SUCCESS);
 }