Initial import

LoxiGen is the work of several developers, not just myself.
diff --git a/py_gen/util.py b/py_gen/util.py
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+# Copyright 2013, Big Switch Networks, Inc.
+#
+# LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
+# the following special exception:
+#
+# LOXI Exception
+#
+# As a special exception to the terms of the EPL, you may distribute libraries
+# generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
+# that copyright and licensing notices generated by LoxiGen are not altered or removed
+# from the LoxiGen Libraries and the notice provided below is (i) included in
+# the LoxiGen Libraries, if distributed in source code form and (ii) included in any
+# documentation for the LoxiGen Libraries, if distributed in binary form.
+#
+# Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
+#
+# You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
+# a copy of the EPL at:
+#
+# http://www.eclipse.org/legal/epl-v10.html
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# EPL for the specific language governing permissions and limitations
+# under the EPL.
+
+"""
+Utilities for generating the target Python code
+"""
+
+import os
+import of_g
+import loxi_front_end.type_maps as type_maps
+import loxi_utils.loxi_utils as utils
+
+templates_dir = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'templates')
+
+def render_template(out, name, **context):
+    utils.render_template(out, name, [templates_dir], context)
+
+def render_static(out, name):
+    utils.render_static(out, name, [templates_dir])
+
+def lookup_unified_class(cls, version):
+    unified_class = of_g.unified[cls][version]
+    if "use_version" in unified_class: # deref version ref
+        ref_version = unified_class["use_version"]
+        unified_class = of_g.unified[cls][ref_version]
+    return unified_class
+
+def primary_wire_type(cls, version):
+    if cls in type_maps.stats_reply_list:
+        return type_maps.type_val[("of_stats_reply", version)]
+    elif cls in type_maps.stats_request_list:
+        return type_maps.type_val[("of_stats_request", version)]
+    elif cls in type_maps.flow_mod_list:
+        return type_maps.type_val[("of_flow_mod", version)]
+    elif (cls, version) in type_maps.type_val:
+        return type_maps.type_val[(cls, version)]
+    elif type_maps.message_is_extension(cls, version):
+        return type_maps.type_val[("of_experimenter", version)]
+    elif type_maps.action_is_extension(cls, version):
+        return type_maps.type_val[("of_action_experimenter", version)]
+    elif type_maps.action_id_is_extension(cls, version):
+        return type_maps.type_val[("of_action_id_experimenter", version)]
+    elif type_maps.instruction_is_extension(cls, version):
+        return type_maps.type_val[("of_instruction_experimenter", version)]
+    elif type_maps.queue_prop_is_extension(cls, version):
+        return type_maps.type_val[("of_queue_prop_experimenter", version)]
+    elif type_maps.table_feature_prop_is_extension(cls, version):
+        return type_maps.type_val[("of_table_feature_prop_experimenter", version)]
+    else:
+        raise ValueError
+
+def constant_for_value(version, group, value):
+    return (["const." + v["ofp_name"] for k, v in of_g.identifiers.items()
+             if k in of_g.identifiers_by_group[group] and
+                eval(v["values_by_version"].get(version, "None")) == value] or [value])[0]