lib9p: idl.gen: Clean up the bitfield code

1 files changed, 32 insertions, 22 deletions

diff --git a/lib9p/idl.gen b/lib9p/idl.gen
index 66161e2..047ea96 100755
--- a/lib9p/idl.gen
+++ b/lib9p/idl.gen
@@ -29,6 +29,12 @@ def tab_ljust(s: str, width: int) -> str:
     return s + " " * (width - cur)
 
 
+def add_prefix(p: str, s: str) -> str:
+    if s.startswith("_"):
+        return "_" + p + s[1:]
+    return p + s
+
+
 def join_lines(*args: str) -> str:
     return "\n".join([a.rstrip() for a in args]).rstrip() + "\n"
 
@@ -206,34 +212,38 @@ enum {idprefix}version {{
                     "",
                     *[k for k in typ.names if k not in typ.bits],
                 ]
-                namewidth = max(len(name) for name in names)
+                prefix = f"{idprefix.upper()}{typ.name.upper()}_"
+                namewidth = max(len(add_prefix(prefix, name)) for name in names)
 
                 ret += "\n"
                 for name in names:
                     if name == "":
                         ret += "\n"
-                    elif name.startswith(" "):
-                        ret += ifdef_push(2, c_ver_ifdef(typ.in_versions))
-                        sp = " " * (
-                            len("#  define ")
-                            + len(idprefix)
-                            + len(typ.name)
-                            + 1
-                            + namewidth
-                            + 2
-                            - len("/* unused")
-                        )
-                        ret += f"/* unused{sp}(({c_typename(typ)})(1<<{name[1:]})) */\n"
+                        continue
+
+                    if name.startswith(" "):
+                        vers = typ.in_versions
+                        c_name = ""
+                        c_val = f"1<<{name[1:]}"
                     else:
-                        ret += ifdef_push(2, c_ver_ifdef(typ.names[name].in_versions))
-                        if name.startswith("_"):
-                            c_name = f"_{idprefix.upper()}{typ.name.upper()}_{name[1:]}"
-                        else:
-                            c_name = f"{idprefix.upper()}{typ.name.upper()}_{name}"
-                        sp1 = "  " if _ifdef_stack[-1] else ""
-                        sp2 = " " if _ifdef_stack[-1] else "   "
-                        sp3 = " " * (2 + namewidth - len(name))
-                        ret += f"#{sp1}define{sp2}{c_name}{sp3}(({c_typename(typ)})({typ.names[name].val}))\n"
+                        vers = typ.names[name].in_versions
+                        c_name = add_prefix(prefix, name)
+                        c_val = f"{typ.names[name].val}"
+
+                    ret += ifdef_push(2, c_ver_ifdef(vers))
+
+                    # It is important all of the `beg` strings have
+                    # the same length.
+                    end = ""
+                    if name.startswith(" "):
+                        beg = "/* unused"
+                        end = " */"
+                    elif _ifdef_stack[-1]:
+                        beg = "#  define"
+                    else:
+                        beg = "#define  "
+
+                    ret += f"{beg} {c_name.ljust(namewidth)}  (({c_typename(typ)})({c_val})){end}\n"
                 ret += ifdef_pop(1)
             case idl.Struct():  # and idl.Message():
                 ret += c_typename(typ) + " {"