diff --git a/src/python/of12/class_maps.py b/src/python/of12/class_maps.py
new file mode 100644
index 0000000..cd60deb
--- /dev/null
+++ b/src/python/of12/class_maps.py
@@ -0,0 +1,346 @@
+
+# Class to array member map
+class_to_members_map = {
+    'ofp_aggregate_stats_reply'     : [
+                                       'packet_count',
+                                       'byte_count',
+                                       'flow_count'
+                                      ],
+    'ofp_role_request'              : [
+                                       'role',
+                                       'generation_id'
+                                      ],
+    'ofp_table_stats'               : [
+                                       'table_id',
+                                       'name',
+                                       'match',
+                                       'wildcards',
+                                       'write_actions',
+                                       'apply_actions',
+                                       'write_setfields',
+                                       'apply_setfields',
+                                       'metadata_match',
+                                       'metadata_write',
+                                       'instructions',
+                                       'config',
+                                       'max_entries',
+                                       'active_count',
+                                       'lookup_count',
+                                       'matched_count'
+                                      ],
+    'ofp_table_mod'                 : [
+                                       'table_id',
+                                       'config'
+                                      ],
+    'ofp_group_stats'               : [
+                                       'length',
+                                       'group_id',
+                                       'ref_count',
+                                       'packet_count',
+                                       'byte_count'
+                                      ],
+    'ofp_instruction_actions'       : [
+                                       'type',
+                                       'len'
+                                      ],
+    'ofp_queue_stats'               : [
+                                       'port_no',
+                                       'queue_id',
+                                       'tx_bytes',
+                                       'tx_packets',
+                                       'tx_errors'
+                                      ],
+    'ofp_packet_in'                 : [
+                                       'buffer_id',
+                                       'total_len',
+                                       'reason',
+                                       'table_id',
+                                       'match'
+                                      ],
+    'ofp_error_experimenter_msg'    : [
+                                       'type',
+                                       'exp_type',
+                                       'experimenter'
+                                      ],
+    'ofp_bucket_counter'            : [
+                                       'packet_count',
+                                       'byte_count'
+                                      ],
+    'ofp_port_stats_request'        : [
+                                       'port_no'
+                                      ],
+    'ofp_stats_request'             : [
+                                       'type',
+                                       'flags'
+                                      ],
+    'ofp_instruction'               : [
+                                       'type',
+                                       'len'
+                                      ],
+    'ofp_group_stats_request'       : [
+                                       'group_id'
+                                      ],
+    'ofp_experimenter_header'       : [
+                                       'experimenter',
+                                       'exp_type'
+                                      ],
+    'ofp_aggregate_stats_request'   : [
+                                       'table_id',
+                                       'out_port',
+                                       'out_group',
+                                       'cookie',
+                                       'cookie_mask',
+                                       'match'
+                                      ],
+    'ofp_queue_get_config_request'  : [
+                                       'port'
+                                      ],
+    'ofp_action_nw_ttl'             : [
+                                       'type',
+                                       'len',
+                                       'nw_ttl'
+                                      ],
+    'ofp_port_status'               : [
+                                       'reason',
+                                       'desc'
+                                      ],
+    'ofp_action_header'             : [
+                                       'type',
+                                       'len'
+                                      ],
+    'ofp_port_mod'                  : [
+                                       'port_no',
+                                       'hw_addr',
+                                       'config',
+                                       'mask',
+                                       'advertise'
+                                      ],
+    'ofp_action_output'             : [
+                                       'type',
+                                       'len',
+                                       'port',
+                                       'max_len'
+                                      ],
+    'ofp_switch_config'             : [
+                                       'flags',
+                                       'miss_send_len'
+                                      ],
+    'ofp_queue_prop_experimenter'   : [
+                                       'prop_header',
+                                       'experimenter'
+                                      ],
+    'ofp_instruction_write_metadata' : [
+                                       'type',
+                                       'len',
+                                       'metadata',
+                                       'metadata_mask'
+                                      ],
+    'ofp_action_experimenter_header' : [
+                                       'type',
+                                       'len',
+                                       'experimenter'
+                                      ],
+    'ofp_queue_get_config_reply'    : [
+                                       'port'
+                                      ],
+    'ofp_oxm_experimenter_header'   : [
+                                       'oxm_header',
+                                       'experimenter'
+                                      ],
+    'ofp_action_set_queue'          : [
+                                       'type',
+                                       'len',
+                                       'queue_id'
+                                      ],
+    'ofp_action_set_field'          : [
+                                       'type',
+                                       'len',
+                                       'field'
+                                      ],
+    'ofp_flow_stats'                : [
+                                       'length',
+                                       'table_id',
+                                       'duration_sec',
+                                       'duration_nsec',
+                                       'priority',
+                                       'idle_timeout',
+                                       'hard_timeout',
+                                       'cookie',
+                                       'packet_count',
+                                       'byte_count',
+                                       'match'
+                                      ],
+    'ofp_flow_removed'              : [
+                                       'cookie',
+                                       'priority',
+                                       'reason',
+                                       'table_id',
+                                       'duration_sec',
+                                       'duration_nsec',
+                                       'idle_timeout',
+                                       'hard_timeout',
+                                       'packet_count',
+                                       'byte_count',
+                                       'match'
+                                      ],
+    'ofp_queue_prop_min_rate'       : [
+                                       'prop_header',
+                                       'rate'
+                                      ],
+    'ofp_header'                    : [
+                                       'version',
+                                       'type',
+                                       'length',
+                                       'xid'
+                                      ],
+    'ofp_stats_reply'               : [
+                                       'type',
+                                       'flags'
+                                      ],
+    'ofp_queue_stats_request'       : [
+                                       'port_no',
+                                       'queue_id'
+                                      ],
+    'ofp_group_features_stats'      : [
+                                       'types',
+                                       'capabilities',
+                                       'max_groups',
+                                       'actions'
+                                      ],
+    'ofp_group_mod'                 : [
+                                       'command',
+                                       'type',
+                                       'group_id'
+                                      ],
+    'ofp_port_stats'                : [
+                                       'port_no',
+                                       'rx_packets',
+                                       'tx_packets',
+                                       'rx_bytes',
+                                       'tx_bytes',
+                                       'rx_dropped',
+                                       'tx_dropped',
+                                       'rx_errors',
+                                       'tx_errors',
+                                       'rx_frame_err',
+                                       'rx_over_err',
+                                       'rx_crc_err',
+                                       'collisions'
+                                      ],
+    'ofp_packet_queue'              : [
+                                       'queue_id',
+                                       'port',
+                                       'len'
+                                      ],
+    'ofp_port'                      : [
+                                       'port_no',
+                                       'hw_addr',
+                                       'name',
+                                       'config',
+                                       'state',
+                                       'curr',
+                                       'advertised',
+                                       'supported',
+                                       'peer',
+                                       'curr_speed',
+                                       'max_speed'
+                                      ],
+    'ofp_switch_features'           : [
+                                       'datapath_id',
+                                       'n_buffers',
+                                       'n_tables',
+                                       'capabilities',
+                                       'reserved'
+                                      ],
+    'ofp_queue_prop_header'         : [
+                                       'property',
+                                       'len'
+                                      ],
+    'ofp_flow_stats_request'        : [
+                                       'table_id',
+                                       'out_port',
+                                       'out_group',
+                                       'cookie',
+                                       'cookie_mask',
+                                       'match'
+                                      ],
+    'ofp_bucket'                    : [
+                                       'len',
+                                       'weight',
+                                       'watch_port',
+                                       'watch_group'
+                                      ],
+    'ofp_action_pop_mpls'           : [
+                                       'type',
+                                       'len',
+                                       'ethertype'
+                                      ],
+    'ofp_match'                     : [
+                                       'type',
+                                       'length'
+                                      ],
+    'ofp_flow_mod'                  : [
+                                       'cookie',
+                                       'cookie_mask',
+                                       'table_id',
+                                       'command',
+                                       'idle_timeout',
+                                       'hard_timeout',
+                                       'priority',
+                                       'buffer_id',
+                                       'out_port',
+                                       'out_group',
+                                       'flags',
+                                       'match'
+                                      ],
+    'ofp_packet_out'                : [
+                                       'buffer_id',
+                                       'in_port',
+                                       'actions_len'
+                                      ],
+    'ofp_instruction_goto_table'    : [
+                                       'type',
+                                       'len',
+                                       'table_id'
+                                      ],
+    'ofp_queue_prop_max_rate'       : [
+                                       'prop_header',
+                                       'rate'
+                                      ],
+    'ofp_experimenter_stats_header' : [
+                                       'experimenter',
+                                       'exp_type'
+                                      ],
+    'ofp_action_group'              : [
+                                       'type',
+                                       'len',
+                                       'group_id'
+                                      ],
+    'ofp_desc_stats'                : [
+                                       'mfr_desc',
+                                       'hw_desc',
+                                       'sw_desc',
+                                       'serial_num',
+                                       'dp_desc'
+                                      ],
+    'ofp_action_push'               : [
+                                       'type',
+                                       'len',
+                                       'ethertype'
+                                      ],
+    'ofp_group_desc_stats'          : [
+                                       'length',
+                                       'type',
+                                       'group_id'
+                                      ],
+    'ofp_error_msg'                 : [
+                                       'type',
+                                       'code'
+                                      ],
+    'ofp_action_mpls_ttl'           : [
+                                       'type',
+                                       'len',
+                                       'mpls_ttl'
+                                      ],
+    '_ignore' : []
+}