Added function tng_data_get_stride_length()

Retrieves the stride length of a data block.

2 files changed, 110 insertions, 0 deletions

diff --git a/include/tng_io.h b/include/tng_io.h
index e39797f..1e7f187 100644
--- a/include/tng_io.h
+++ b/include/tng_io.h
@@ -2736,6 +2736,25 @@ tng_function_status DECLSPECDLLEXPORT tng_particle_data_vector_interval_get
                  char *type);
 
 /**
+ * @brief Get the stride length of a specific data (particle dependency does not matter)
+ * block, either in the current frame set or of a specific frame.
+ * @param tng_data is the trajectory data container.
+ * @param block_id is the block ID of the data block, of which to retrieve the
+ * stride length of the data.
+ * @param frame is the frame from which to get the stride length. If frame is set to -1
+ * no specific frame will be used, but instead the first frame, starting from the last read
+ * frame set, containing the data block will be used.
+ * @param stride_length is set to the value of the stride length of the data block.
+ * @return  TNG_SUCCESS (0) if successful, TNG_FAILURE (1) if a minor error
+ * has occurred or TNG_CRITICAL (2) if a major error has occured.
+ */
+tng_function_status DECLSPECDLLEXPORT tng_data_get_stride_length
+                (tng_trajectory_t tng_data,
+                 const int64_t block_id,
+                 int64_t frame,
+                 int64_t *stride_length);
+
+/**
  * @brief Get the date and time of initial file creation in ISO format (string).
  * @param tng_data is a trajectory data container.
  * @param time is a pointer to the string in which the date will be stored. Memory
diff --git a/src/lib/tng_io.c b/src/lib/tng_io.c
index b91db67..7586e92 100644
--- a/src/lib/tng_io.c
+++ b/src/lib/tng_io.c
@@ -14729,6 +14729,92 @@ tng_function_status DECLSPECDLLEXPORT tng_particle_data_vector_interval_get
     return(TNG_SUCCESS);
 }
 
+tng_function_status DECLSPECDLLEXPORT tng_data_get_stride_length
+                (tng_trajectory_t tng_data,
+                 const int64_t block_id,
+                 int64_t frame,
+                 int64_t *stride_length)
+{
+    tng_trajectory_frame_set_t frame_set;
+    tng_function_status stat;
+    tng_non_particle_data_t np_data;
+    tng_particle_data_t p_data;
+    long file_pos;
+    int is_particle_data;
+    int64_t data_first_frame;
+    
+    frame_set = &tng_data->current_trajectory_frame_set;
+    
+    if(tng_data->current_trajectory_frame_set_input_file_pos <= 0)
+    {
+        frame = 0;
+    }
+    
+    if(frame >= 0)
+    {
+        stat = tng_frame_set_of_frame_find(tng_data, frame);
+        if(stat != TNG_SUCCESS)
+        {
+            return(stat);
+        }
+    }
+    stat = tng_data_find(tng_data, block_id, &np_data);
+    if(stat != TNG_SUCCESS)
+    {
+        stat = tng_particle_data_find(tng_data, block_id, &p_data);
+        if(stat != TNG_SUCCESS)
+        {
+            stat = tng_frame_set_read_current_only_data_from_block_id(tng_data, TNG_USE_HASH, block_id);
+            /* If no specific frame was required read until this data block is found */
+            if(frame < 0)
+            {
+                file_pos = ftell(tng_data->input_file);
+                while(stat != TNG_SUCCESS && file_pos < tng_data->input_file_len)
+                {
+                    stat = tng_frame_set_read_next_only_data_from_block_id(tng_data, TNG_USE_HASH, block_id);
+                    file_pos = ftell(tng_data->input_file);
+                }
+            }
+            if(stat != TNG_SUCCESS)
+            {
+                return(stat);
+            }
+            stat = tng_data_find(tng_data, block_id, &np_data);
+            if(stat != TNG_SUCCESS)
+            {
+                stat = tng_particle_data_find(tng_data, block_id, &p_data);
+                if(stat != TNG_SUCCESS)
+                {
+                    return(stat);
+                }
+                else
+                {
+                    is_particle_data = 1;
+                }
+            }
+            else
+            {
+                is_particle_data = 0;
+            }
+        }
+        else
+        {
+            is_particle_data = 1;
+        }
+    }
+    else
+    {
+        is_particle_data = 0;
+    }
+    if(is_particle_data)
+    {
+        *stride_length = p_data->stride_length;
+    }
+    else
+    {
+        *stride_length = np_data->stride_length;
+    }
+}
 
 tng_function_status DECLSPECDLLEXPORT tng_time_get_str
                 (const tng_trajectory_t tng_data,
@@ -15287,6 +15373,11 @@ tng_function_status DECLSPECDLLEXPORT tng_util_non_particle_data_next_frame_read
         {
             return(stat);
         }
+        stat = tng_data_find(tng_data, block_id, &data);
+        if(stat != TNG_SUCCESS)
+        {
+            return(stat);
+        }
     }
     if(data->last_retrieved_frame < 0)
     {