1 files changed, 113 insertions, 0 deletions
diff --git a/src/tests/tng_io_read_pos_util.c b/src/tests/tng_io_read_pos_util.c
new file mode 100644
index 0000000..12bf2ed
--- /dev/null
+++ b/src/tests/tng_io_read_pos_util.c
@@ -0,0 +1,113 @@
+/* This code is part of the tng binary trajectory format.
+ *
+ *  The high-level API of the TNG API is used where appropriate.
+ *
+ *                      VERSION 1.0
+ *
+ * Written by Magnus Lundborg
+ * Copyright (c) 2012, The GROMACS development team.
+ * check out http://www.gromacs.org for more information.
+ *
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the License, or (at your option) any later version.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <tng_io.h>
+
+int main(int argc, char **argv)
+{
+    tng_trajectory_t traj;
+    float *positions = 0; // A 1-dimensional array
+                                      // to be populated
+    int64_t n_particles, n_frames, tot_n_frames, stride_length, i, j;
+    // Set a default frame range
+    int64_t first_frame = 0, last_frame = 5000;
+    int k;
+
+    if(argc <= 1)
+    {
+        printf("No file specified\n");
+        printf("Usage:\n");
+        printf("tng_io_read_pos <tng_file> "
+               "[first_frame = %"PRId64"] [last_frame = %"PRId64"]\n",
+               first_frame, last_frame);
+        exit(1);
+    }
+
+    // A reference must be passed to allocate memory
+    tng_util_trajectory_open(argv[1], 'r', &traj);
+    
+    if(argc >= 3)
+    {
+        first_frame = strtoll(argv[2], 0, 10);
+        if(argc >= 4)
+        {
+            last_frame = strtoll(argv[3], 0, 10);
+        }
+    }
+
+    if(tng_num_frames_get(traj, &tot_n_frames) != TNG_SUCCESS)
+    {
+        printf("Cannot determine the number of frames in the file\n");
+        tng_util_trajectory_close(&traj);
+        exit(1);
+    }
+
+    if(tng_num_particles_get(traj, &n_particles) != TNG_SUCCESS)
+    {
+        printf("Cannot determine the number of particles in the file\n");
+        tng_util_trajectory_close(&traj);
+        exit(1);
+    }
+    
+    printf("%"PRId64" frames in file\n", tot_n_frames);
+
+    if(last_frame > tot_n_frames - 1)
+    {
+        last_frame = tot_n_frames - 1;
+    }
+
+    n_frames = last_frame - first_frame + 1;
+
+
+    // Get the positions of all particles in the requested frame range.
+    // The positions are stored in the positions array.
+    // N.B. No proper error checks.
+    if(tng_util_pos_read_range(traj, 0, last_frame, &positions, &stride_length)
+       == TNG_SUCCESS)
+    {
+        // Print the positions of the wanted particle (zero based)
+        for(i=0; i < n_frames; i += stride_length)
+        {
+            printf("\nFrame %"PRId64":\n", first_frame + i);
+            for(j=0; j < n_particles; j++)
+            {
+                printf("Atom nr: %"PRId64"", j);
+                for(k=0; k < 3; k++)
+                {
+                    printf("\t%f", positions[i/stride_length*n_particles*
+                                             3+j*3+k]);
+                }
+                printf("\n");
+            }
+        }
+    }
+    else
+    {
+        printf("Cannot read positions\n");
+    }
+
+    // Free memory
+    if(positions)
+    {
+        free(positions);
+    }
+    tng_util_trajectory_close(&traj);
+
+    return(0);
+}