loxi_frontend: move classes only used by c to c_gen

 - flags
 - identifiers
 - match
 - translation
 - type_maps

were only used by the c backend. I'm moving them to c_gen to
unclutter the loxi_front_end space (and updating references
in the c backend)
diff --git a/c_gen/loci_utils.py b/c_gen/loci_utils.py
new file mode 100644
index 0000000..bc3092f
--- /dev/null
+++ b/c_gen/loci_utils.py
@@ -0,0 +1,267 @@
+import c_gen.of_g_legacy as of_g
+
+def class_signature(members):
+    """
+    Generate a signature string for a class in canonical form
+
+    @param cls The class whose signature is to be generated
+    """
+    return ";".join([",".join([x["m_type"], x["name"], str(x["offset"])])
+                     for x in members])
+
+def type_dec_to_count_base(m_type):
+    """
+    Resolve a type declaration like uint8_t[4] to a count (4) and base_type
+    (uint8_t)
+
+    @param m_type The string type declaration to process
+    """
+    count = 1
+    chk_ar = m_type.split('[')
+    if len(chk_ar) > 1:
+        count_str = chk_ar[1].split(']')[0]
+        if count_str in of_g.ofp_constants:
+            count = of_g.ofp_constants[count_str]
+        else:
+            count = int(count_str)
+        base_type = chk_ar[0]
+    else:
+        base_type = m_type
+    return count, base_type
+
+def list_to_entry_type(cls):
+    """
+    Return the entry type for a list
+    """
+    slen = len("of_list_")
+    return "of_" + cls[slen:]
+
+def type_to_short_name(m_type):
+    if m_type in of_g.of_base_types:
+        tname = of_g.of_base_types[m_type]["short_name"]
+    elif m_type in of_g.of_mixed_types:
+        tname = of_g.of_mixed_types[m_type]["short_name"]
+    else:
+        tname = "unknown"
+    return tname
+
+def type_to_name_type(cls, member_name):
+    """
+    Generate the root name of a member for accessor functions, etc
+    @param cls The class name
+    @param member_name The member name
+    """
+    members = of_g.unified[cls]["union"]
+    if not member_name in members:
+        debug("Error:  %s is not in class %s for acc_name defn" %
+              (member_name, cls))
+        os.exit()
+
+    mem = members[member_name]
+    m_type = mem["m_type"]
+    id = mem["memid"]
+    tname = type_to_short_name(m_type)
+
+    return "o%d_m%d_%s" % (of_g.unified[cls]["object_id"], id, tname)
+
+
+def member_to_index(m_name, members):
+    """
+    Given a member name, return the index in the members dict
+    @param m_name The name of the data member to search for
+    @param members The dict of members
+    @return Index if found, -1 not found
+
+    Note we could generate an index when processing the original input
+    """
+    count = 0
+    for d in members:
+        if d["name"] == m_name:
+            return count
+        count += 1
+    return -1
+
+def member_base_type(cls, m_name):
+    """
+    Map a member to its of_ type
+    @param cls The class name
+    @param m_name The name of the member being gotten
+    @return The of_ type of the member
+    """
+    rv = of_g.unified[cls]["union"][m_name]["m_type"]
+    if rv[-2:] == "_t":
+        return rv
+    return rv + "_t"
+
+def member_type_is_octets(cls, m_name):
+    return member_base_type(cls, m_name) == "of_octets_t"
+
+def member_returns_val(cls, m_name):
+    """
+    Should get accessor return a value rather than void
+    @param cls The class name
+    @param m_name The member name
+    @return True if of_g config and the specific member allow a
+    return value.  Otherwise False
+    """
+    m_type = of_g.unified[cls]["union"][m_name]["m_type"]
+    return (config_check("get_returns") =="value" and
+            m_type in of_g.of_scalar_types)
+
+def config_check(str, dictionary = of_g.code_gen_config):
+    """
+    Return config value if in dictionary; else return False.
+    @param str The lookup index
+    @param dictionary The dict to check; use code_gen_config if None
+    """
+
+    if str in dictionary:
+        return dictionary[str]
+
+    return False
+
+def h_file_to_define(name):
+    """
+    Convert a .h file name to the define used for the header
+    """
+    h_name = name[:-2].upper()
+    h_name = "_" + h_name + "_H_"
+    return h_name
+
+def type_to_cof_type(m_type):
+    if m_type in of_g.of_base_types:
+        if "cof_type" in of_g.of_base_types[m_type]:
+            return of_g.of_base_types[m_type]["cof_type"]
+    return m_type
+
+
+def member_is_scalar(cls, m_name):
+    return of_g.unified[cls]["union"][m_name]["m_type"] in of_g.of_scalar_types
+
+def type_is_scalar(m_type):
+    return m_type in of_g.of_scalar_types
+
+def skip_member_name(name):
+    return name.find("pad") == 0 or name in of_g.skip_members
+
+def enum_name(cls):
+    """
+    Return the name used for an enum identifier for the given class
+    @param cls The class name
+    """
+    return cls.upper()
+
+def class_in_version(cls, ver):
+    """
+    Return boolean indicating if cls is defined for wire version ver
+    """
+
+    return (cls, ver) in of_g.base_length
+
+def instance_to_class(instance, parent):
+    """
+    Return the name of the class for an instance of inheritance type parent
+    """
+    return parent + "_" + instance
+
+def sub_class_to_var_name(cls):
+    """
+    Given a subclass name like of_action_output, generate the
+    name of a variable like 'output'
+    @param cls The class name
+    """
+    pass
+
+def class_is_var_len(cls, version):
+    # Match is special case.  Only version 1.2 (wire version 3) is var
+    if cls == "of_match":
+        return version == 3
+
+    return not (cls, version) in of_g.is_fixed_length
+
+def base_type_to_length(base_type, version):
+    if base_type + "_t" in of_g.of_base_types:
+        inst_len = of_g.of_base_types[base_type + "_t"]["bytes"]
+    else:
+        inst_len = of_g.base_length[(base_type, version)]
+
+def version_to_name(version):
+    """
+    Convert an integer version to the C macro name
+    """
+    return "OF_" + of_g.version_names[version]
+
+##
+# Is class a flow modify of some sort?
+
+def cls_is_flow_mod(cls):
+    return cls in ["of_flow_mod", "of_flow_modify", "of_flow_add", "of_flow_delete",
+                   "of_flow_modify_strict", "of_flow_delete_strict"]
+
+def all_member_types_get(cls, version):
+    """
+    Get the members and list of types for members of a given class
+    @param cls The class name to process
+    @param version The version for the class
+    """
+    member_types = []
+
+    if not version in of_g.unified[cls]:
+        return ([], [])
+
+    if "use_version" in of_g.unified[cls][version]:
+        v = of_g.unified[cls][version]["use_version"]
+        members = of_g.unified[cls][v]["members"]
+    else:
+        members = of_g.unified[cls][version]["members"]
+    # Accumulate variables that are supported
+    for member in members:
+        m_type = member["m_type"]
+        m_name = member["name"]
+        if skip_member_name(m_name):
+            continue
+        if not m_type in member_types:
+            member_types.append(m_type)
+
+    return (members, member_types)
+
+def list_name_extract(list_type):
+    """
+    Return the base name for a list object of the given type
+    @param list_type The type of the list as appears in the input,
+    for example list(of_port_desc_t).
+    @return A pair, (list-name, base-type) where list-name is the
+    base name for the list, for example of_list_port_desc, and base-type
+    is the type of list elements like of_port_desc_t
+    """
+    base_type = list_type[5:-1]
+    list_name = base_type
+    if list_name.find("of_") == 0:
+        list_name = list_name[3:]
+    if list_name[-2:] == "_t":
+        list_name = list_name[:-2]
+    list_name = "of_list_" + list_name
+    return (list_name, base_type)
+
+def version_to_name(version):
+    """
+    Convert an integer version to the C macro name
+    """
+    return "OF_" + of_g.version_names[version]
+
+def gen_c_copy_license(out):
+    """
+    Generate the top comments for copyright and license
+    """
+    import c_gen.util
+    c_gen.util.render_template(out, '_copyright.c')
+
+def accessor_returns_error(a_type, m_type):
+    is_var_len = (not type_is_scalar(m_type)) and \
+        [x for x in of_g.of_version_range if class_is_var_len(m_type[:-2], x)] != []
+    if a_type == "set" and is_var_len:
+        return True
+    elif m_type == "of_match_t":
+        return True
+    else:
+        return False