# VDATA.HPP — reconstruction notes (2026-07-19)

**The first ENGINE-side backfill** (the header `plug.hpp` includes; lost from both 1995 trees —
`VDATA.CPP` survives in `CODE/RP/MUNGA`, only the `.HPP` was missing).

Basis: back-dated from `C:\VWE\BT412\engine\MUNGA\VDATA.h` (the drifted WinTesla-era copy).
Transformations: `#pragma once` → the `VDATA_HPP` guard PLUG.HPP expects (PLUG.HPP:30 names it);
`#include "memstrm.h"` → guarded `<memstrm.hpp>` (survives in CODE/RP/MUNGA); banner cloned from
the surviving VDATA.CPP banner ("vdata.cc / Connection Library"); body/indentation restyled to
the 1995 house pattern. Content otherwise byte-for-byte the WinTesla enum + class.

Validation [T1]:
- Method set matches the surviving `VDATA.CPP` exactly (2 ctors, dtor, TestInstance,
  BuildFromPage, static GetClassID(CString&)).
- ClassID numbering matches every decomp-known constant: `TrivialSubsystemClassID`=0xF,
  `CameraShipClassID`=0x45, `MechClassID`=0xBB9, `MechSubsystemClassID`=0xBBC region,
  `L4ApplicationClassID`=1003 — i.e. the WinTesla file preserved 1995 numbering.
- `MemoryStream_Read/Write` inline pair is a verified period idiom (used across 1995 headers).
- **Compile-proven**: with this one backfill, the ORIGINAL `BTL4MODE.CPP` and `BTMSSN.CPP`
  compile CLEAN under BC++ 4.52 with the authentic OPT.MAK flags (btl4mode.obj 3,751 bytes).

Uncertainty [T4]: whether the ND (4000) / Tools (60000) / W4 (70000) enum sections and any
tail entries postdate 4.10 — appended IDs don't shift earlier values, so all decomp-verified
constants are unaffected either way.