--- a/wutils.py	Tue Mar 08 14:57:45 2011 -0800
+++ b/wutils.py	Tue Mar 08 16:03:45 2011 -0800
@@ -233,3 +233,66 @@
     return run_argv([env['PYTHON']] + execvec, env, cwd=cwd)
 
 
+def get_list_from_file(file_path, list_name):
+    '''Looks for a Python list called list_name in the file specified
+    by file_path and returns it.
+
+    If the file or list name aren't found, this function will return
+    an empty list.
+
+    '''
+
+    list = []
+
+    # Read in the file if it exists.
+    if os.path.exists(file_path):
+        file_in = open(file_path, "r")
+
+        # Look for the list.
+        list_string = ""
+        parsing_multiline_list = False
+        for line in file_in:
+            if list_name in line or parsing_multiline_list:
+                list_string += line
+
+                # Handle multiline lists.
+                if ']' not in list_string:
+                    parsing_multiline_list = True
+                else:
+                    # Evaluate the list once its end is reached.
+                    # Make the split function only split it once.
+                    list = eval(list_string.split('=', 1)[1].strip())
+                    break
+
+        # Close the file
+        file_in.close()
+
+    return list
+
+
+def read_config_file():
+    '''Reads the NS-3 configuration file and returns a list of enabled modules.
+
+    This function first looks for the ns3 configuration file (.ns3rc)
+    in the current working directory and then looks in the ~
+    directory.
+
+    '''
+
+    # See if the ns3 configuration file exists in the current working
+    # directory and then look for it in the ~ directory.
+    dot_ns3rc_name = '.ns3rc'
+    dot_ns3rc_path = dot_ns3rc_name
+    if not os.path.exists(dot_ns3rc_path):
+        dot_ns3rc_path = os.path.expanduser('~/') + dot_ns3rc_name
+        if not os.path.exists(dot_ns3rc_path):
+            # Enable all modules if the .ns3rc file can't be found.
+            return ['all_modules']
+
+    # Read in the ns3 configuration file.
+    modules_enabled = get_list_from_file(dot_ns3rc_path, 'modules_enabled')
+    if not modules_enabled:
+        # Enable all modules if the modules_enabled line can't be found.
+        return ['all_modules']
+
+    return modules_enabled