Remove member_offset_iterator

It is undocumented and its fields don't carry descriptive names, thus code using
it is hard to read and understand. With all the preceding work it only had a
single user left.

Author: tautschnig

src/util/pointer_offset_size.cpp

@@ -21,62 +21,38 @@ Author: Daniel Kroening, kroening@kroening.com
 #include "ssa_expr.h"
 #include "std_expr.h"
 
-member_offset_iterator::member_offset_iterator(
-  const struct_typet &_type,
-  const namespacet &_ns):
-  current({0, 0}),
-  type(_type),
-  ns(_ns),
-  bit_field_bits(0)
+mp_integer member_offset(
+  const struct_typet &type,
+  const irep_idt &member,
+  const namespacet &ns)
 {
-}
+  mp_integer result = 0;
+  std::size_t bit_field_bits = 0;
 
-member_offset_iterator &member_offset_iterator::operator++()
-{
-  if(current.second!=-1) // Already failed?
+  for(const auto &comp : type.components())
   {
-    const auto &comp=type.components()[current.first];
-    if(comp.type().id()==ID_c_bit_field)
+    if(comp.get_name() == member)
+      return result;
+
+    if(comp.type().id() == ID_c_bit_field)
     {
-      // take the extra bytes needed
-      std::size_t w=to_c_bit_field_type(comp.type()).get_width();
+      const std::size_t w = to_c_bit_field_type(comp.type()).get_width();
       bit_field_bits += w;
-      current.second += bit_field_bits / 8;
+      result += bit_field_bits / 8;
       bit_field_bits %= 8;
     }
     else
     {
       DATA_INVARIANT(
         bit_field_bits == 0, "padding ensures offset at byte boundaries");
-      const typet &subtype=comp.type();
-      mp_integer sub_size=pointer_offset_size(subtype, ns);
-      if(sub_size==-1)
-        current.second=-1; // give up
-      else current.second+=sub_size;
+      const mp_integer sub_size = pointer_offset_size(comp.type(), ns);
+      if(sub_size == -1)
+        return -1;
+      result += sub_size;
     }
   }
-  ++current.first;
-  return *this;
-}
 
-mp_integer member_offset(
-  const struct_typet &type,
-  const irep_idt &member,
-  const namespacet &ns)
-{
-  const struct_typet::componentst &components=type.components();
-  member_offset_iterator offsets(type, ns);
-
-  for(struct_typet::componentst::const_iterator
-      it=components.begin();
-      it!=components.end() && offsets->second!=-1;
-      ++it, ++offsets)
-  {
-    if(it->get_name()==member)
-      break;
-  }
-
-  return offsets->second;
+  return result;
 }
 
 mp_integer member_offset_bits(

src/util/pointer_offset_size.h

@@ -24,22 +24,6 @@ class constant_exprt;
 
 // these return -1 on failure
 
-// NOLINTNEXTLINE(readability/identifiers)
-class member_offset_iterator
-{
-  typedef std::pair<size_t, mp_integer> refst;
-  refst current;
-  const struct_typet &type;
-  const namespacet &ns;
-  size_t bit_field_bits;
-public:
-  member_offset_iterator(const struct_typet &_type,
-                         const namespacet &_ns);
-  member_offset_iterator &operator++();
-  const refst &operator*() const { return current; }
-  const refst* operator->() const { return &current; }
-};
-
 mp_integer member_offset(
   const struct_typet &type,
   const irep_idt &member,