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Implementation And Python Reference

C++ Implementation

The maintained Windows implementation is ../dspack_cpp.cpp, built as CLI and GUI by ../build_dspack_cpp.ps1.

  • MappedFile opens the source archive read-only and maps it into memory.
  • Pack::Parse() validates the common index fields, records, string table, and payload bounds.
  • Path helpers resolve names and reject traversal; C++ also rejects rooted/drive paths and output collisions within one archive.
  • LzdBlock()/LzdResource() decode LZD.
  • ZlibApi/ZlibResource() decode ZLib through a local zlib1.dll.
  • ExtractSingleArchive() is shared by the GUI and batch CLI; it dispatches files to a bounded worker pool.
  • The Win32 GUI uses background workers, cancellation, posted progress updates, and the Windows folder picker.

See C++ GUI And CLI for build, usage, runtime dependency, and validation.

Older Python Reference

../dspack.py is the older, slower reference implementation. It has a single-archive CLI, no GUI, and no native worker pool. It remains for readable algorithm study, comparison, and its experimental 7-Zip LZX bridge. The LZX bridge has not been checked against a real FEAR 3 LZX member. Do not assume Python-only behavior exists in C++.

Validation

  • One LZD call captured from the live game in x32dbg produced output with identical SHA-256 in Python and the game buffer.
  • C++ Boot.dsPack (2,464 entries) and Patch.dsPack (40 entries) matched previous extracted references byte-for-byte.
  • Selected large LZD resources from Resource.dsPack matched Python output byte-for-byte.
  • Synthetic raw and wrapped ZLib fixtures matched original bytes.
  • No installed archive contained internally compressed ZLib or LZX entries. ZLib has synthetic-fixture coverage only; LZX has no real-game end-to-end test.
  • A warm-cache Boot extraction measured 0.58 s C++ vs 19.0 s Python on the development machine, approximately 33x in that run. This is illustrative only.

Limits

  • Only .dsPack v107/v108.
  • Common indexes are parsed; auxiliary engine lookup structures are not fully reconstructed.
  • C++ supports LZD/ZLib, not LZX. Python's LZX bridge is experimental.
  • Audio conversion, archive writing/recompression, timestamp restoration, and exact duplicate-priority behavior are out of scope.
  • MiniPack is a filesystem/mount behavior, not compression.