Moved out a function for generating C code for a struct type

The code for generating the C-like code for a struct type moved into a
sperate function. This allows for the caller to turn off generating the
body of the struct (useful for when declaring a variable of the type of
the struct).

Author: thk123

src/ansi-c/expr2c.cpp

@@ -359,29 +359,7 @@ std::string expr2ct::convert_rec(
   }
   else if(src.id()==ID_struct)
   {
-    const struct_typet &struct_type=to_struct_type(src);
-
-    std::string dest=q+"struct";
-
-    const irep_idt &tag=struct_type.get_tag();
-    if(tag!="") dest+=" "+id2string(tag);
-    dest+=" {";
-
-    for(struct_typet::componentst::const_iterator
-        it=struct_type.components().begin();
-        it!=struct_type.components().end();
-        it++)
-    {
-      dest+=' ';
-      dest+=convert_rec(it->type(), c_qualifierst(), id2string(it->get_name()));
-      dest+=';';
-    }
-
-    dest+=" }";
-
-    dest+=d;
-
-    return dest;
+    return convert_struct_type(src, q, d);
   }
   else if(src.id()==ID_incomplete_struct)
   {
@@ -708,6 +686,97 @@ std::string expr2ct::convert_rec(
 
 /*******************************************************************\
 
+Function: expr2ct::convert_struct_type
+
+  Inputs:
+          src - the struct type being converted
+          qualifiers - any qualifiers on the type
+          declarator - the declarator on the type
+
+ Outputs: Returns a type declaration for a struct, containing the
+          body of the struct and in that body the padding parameters.
+
+ Purpose: To generate C-like string for defining the given struct
+
+\*******************************************************************/
+std::string expr2ct::convert_struct_type(
+  const typet &src,
+  const std::string &qualifiers_str,
+  const std::string &declarator_str)
+{
+  return convert_struct_type(src, qualifiers_str, declarator_str, true, true);
+}
+
+/*******************************************************************\
+
+Function: expr2ct::convert_struct_type
+
+  Inputs:
+          src - the struct type being converted
+          qualifiers - any qualifiers on the type
+          declarator - the declarator on the type
+          inc_struct_body - when generating the code, should we include
+                            a complete definition of the struct
+          inc_padding_parameters - should the padding parameters be included
+                                   Note this only makes sense if inc_struct_body
+
+ Outputs: Returns a type declaration for a struct, optionally containing the
+          body of the struct (and in that body, optionally the padding
+          parameters).
+
+ Purpose: To generate C-like string for declaring (or defining) the given struct
+
+\*******************************************************************/
+std::string expr2ct::convert_struct_type(
+  const typet &src,
+  const std::string &qualifiers,
+  const std::string &declarator,
+  bool inc_struct_body,
+  bool inc_padding_parameters)
+{
+  // Either we are including the body (in which case it makes sense to include
+  // or exclude the parameters) or there is no body so therefore we definitely
+  // shouldn't be including the parameters
+  assert(inc_struct_body || !inc_padding_parameters);
+
+  const struct_typet &struct_type=to_struct_type(src);
+
+  std::string dest=qualifiers+"struct";
+
+  const irep_idt &tag=struct_type.get_tag();
+  if(tag!="")
+    dest+=" "+id2string(tag);
+
+  if(inc_struct_body)
+  {
+    dest+=" {";
+
+    for(struct_typet::componentst::const_iterator
+        it=struct_type.components().begin();
+        it!=struct_type.components().end();
+        it++)
+    {
+      // Skip padding parameters unless we including them
+      if(it->get_is_padding() && !inc_padding_parameters)
+      {
+        continue;
+      }
+
+      dest+= ' ';
+      dest+=convert_rec(it->type(), c_qualifierst(), id2string(it->get_name()));
+      dest+= ';';
+    }
+
+    dest+=" }";
+  }
+
+  dest+=declarator;
+
+  return dest;
+}
+
+/*******************************************************************\
+
 Function: expr2ct::convert_typecast
 
   Inputs:

src/ansi-c/expr2c_class.h

@@ -38,6 +38,18 @@ class expr2ct
     const c_qualifierst &qualifiers,
     const std::string &declarator);
 
+  virtual std::string convert_struct_type(
+    const typet &src,
+    const std::string &qualifiers_str,
+    const std::string &declarator_str);
+
+  std::string convert_struct_type(
+    const typet &src,
+    const std::string &qualifer_str,
+    const std::string &declarator_str,
+    bool inc_struct_body,
+    bool inc_padding_parameters);
+
   static std::string indent_str(unsigned indent);
 
   std::unordered_map<irep_idt,