diff --git a/c_gen/c_type_maps.py b/c_gen/c_type_maps.py
index 07f8dd5..a0fec7e 100644
--- a/c_gen/c_type_maps.py
+++ b/c_gen/c_type_maps.py
@@ -792,6 +792,7 @@
     gen_obj_to_type_map_functions(out)
 
     out.write("extern const int *const of_object_fixed_len[OF_VERSION_ARRAY_MAX];\n")
+    out.write("extern const int *const of_object_extra_len[OF_VERSION_ARRAY_MAX];\n")
 
     out.write("""
 /**
@@ -1064,6 +1065,47 @@
 """)
 
 
+def gen_extra_length_array(out):
+    """
+    Generate an array giving the extra lengths of all objects/versions
+    @param out The file handle to which to write
+    """
+    out.write("""
+/**
+ * An array with the number of bytes in the extra length part
+ * of each OF object
+ */
+""")
+
+    for version in of_g.of_version_range:
+        out.write("""
+static const int\nof_object_extra_len_v%d[OF_OBJECT_COUNT] = {
+    -1,   /* of_object is not instantiable */
+""" % version)
+        for i, cls in enumerate(of_g.all_class_order):
+            comma = ","
+            if i == len(of_g.all_class_order) - 1:
+                comma = ""
+            val = "-1" + comma
+            if (cls, version) in of_g.base_length:
+                val = str(of_g.extra_length.get((cls, version), 0)) + comma
+            out.write("    %-5s /* %d: %s */\n" % (val, i + 1, cls))
+        out.write("};\n")
+
+    out.write("""
+/**
+ * Unified map of extra length part of each object
+ */
+const int *const of_object_extra_len[OF_VERSION_ARRAY_MAX] = {
+    NULL,
+""")
+    for version in of_g.of_version_range:
+        out.write("    of_object_extra_len_v%d,\n" % version)
+    out.write("""
+};
+""")
+
+
 ################################################################
 ################################################################