Initial project state: .NET reference, design, Rust port (M0+M1), evidence

Layout:
- src/                    .NET 10 x64 reference: MxNativeCodec, MxNativeClient,
                          MxAsbClient, probes, tests, harnesses. Executable spec.
- design/                 Architectural plan for the Rust port (M0–M6), error
                          model, protocol invariants, risks (R1–R16), adversarial
                          review log (review.md).
- rust/                   Rust workspace. M0 skeleton + M1 codec parity.
                          mxaccess-codec: 215 unit tests + 2 cross-implementation
                          parity tests (byte-identical against .NET reference).
                          Other crates are M0 stubs awaiting M2+.
- captures/               Frida + netsh + pcap evidence per CLAUDE.md
                          ("captures are evidence, not throwaway logs").
- analysis/               Decompiled C# (frida/proxy/decompiled-*),
                          Ghidra exports for native DLLs (`exports/` only —
                          working state at `projects/` and AVEVA's input
                          binaries at `input/` are gitignored).
- docs/                   Reverse-engineering reference docs.
- tools/                  Setup-LiveProbeEnv.ps1 (Infisical credential fetcher),
                          Compute-Crc.ps1 (.NET parity helper).
- .github/workflows/      Rust CI: fmt + build + test + clippy on Windows.
- LICENSE                 MIT (Joseph Doherty, 2026).

Verified:
- cargo test --workspace → 217 passed (215 unit + 2 .NET parity), 0 failed
- cargo clippy --workspace -- -D warnings → clean
- cargo fmt --all -- --check → clean
- cargo publish --dry-run -p mxaccess-codec → packages cleanly

Excluded from history (see .gitignore):
- **/bin, **/obj, **/target — build artifacts
- analysis/ghidra/projects/ — Ghidra working state (regenerable)
- analysis/ghidra/input/ — AVEVA proprietary DLLs (vendor IP)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

analysis/decompiled/aaServicesContractIAuthenticateASB/Invensys.Compression/AAFastEncoderWindow.cs

@@ -0,0 +1,285 @@
+using System;
+using System.Diagnostics;
+
+namespace Invensys.Compression;
+
+internal class AAFastEncoderWindow
+{
+	private byte[] window;
+
+	private int bufPos;
+
+	private int bufEnd;
+
+	private const int FastEncoderHashShift = 4;
+
+	private const int FastEncoderHashtableSize = 2048;
+
+	private const int FastEncoderHashMask = 2047;
+
+	private const int FastEncoderWindowSize = 8192;
+
+	private const int FastEncoderWindowMask = 8191;
+
+	private const int FastEncoderMatch3DistThreshold = 16384;
+
+	internal const int MaxMatch = 258;
+
+	internal const int MinMatch = 3;
+
+	private const int SearchDepth = 32;
+
+	private const int GoodLength = 4;
+
+	private const int NiceLength = 32;
+
+	private const int LazyMatchThreshold = 6;
+
+	private ushort[] prev;
+
+	private ushort[] lookup;
+
+	public int BytesAvailable => bufEnd - bufPos;
+
+	public AADeflateInput UnprocessedInput => new AADeflateInput
+	{
+		Buffer = window,
+		StartIndex = bufPos,
+		Count = bufEnd - bufPos
+	};
+
+	public int FreeWindowSpace => 16384 - bufEnd;
+
+	public AAFastEncoderWindow()
+	{
+		ResetWindow();
+	}
+
+	public void FlushWindow()
+	{
+		ResetWindow();
+	}
+
+	private void ResetWindow()
+	{
+		window = new byte[16646];
+		prev = new ushort[8450];
+		lookup = new ushort[2048];
+		bufPos = 8192;
+		bufEnd = bufPos;
+	}
+
+	public void CopyBytes(byte[] inputBuffer, int startIndex, int count)
+	{
+		Array.Copy(inputBuffer, startIndex, window, bufEnd, count);
+		bufEnd += count;
+	}
+
+	public void MoveWindows()
+	{
+		Array.Copy(window, bufPos - 8192, window, 0, 8192);
+		for (int i = 0; i < 2048; i++)
+		{
+			int num = lookup[i] - 8192;
+			if (num <= 0)
+			{
+				lookup[i] = 0;
+			}
+			else
+			{
+				lookup[i] = (ushort)num;
+			}
+		}
+		for (int i = 0; i < 8192; i++)
+		{
+			long num2 = (long)prev[i] - 8192L;
+			if (num2 <= 0)
+			{
+				prev[i] = 0;
+			}
+			else
+			{
+				prev[i] = (ushort)num2;
+			}
+		}
+		bufPos = 8192;
+		bufEnd = bufPos;
+	}
+
+	private uint HashValue(uint hash, byte b)
+	{
+		return (hash << 4) ^ b;
+	}
+
+	private uint InsertString(ref uint hash)
+	{
+		hash = HashValue(hash, window[bufPos + 2]);
+		uint num = lookup[hash & 0x7FF];
+		lookup[hash & 0x7FF] = (ushort)bufPos;
+		prev[bufPos & 0x1FFF] = (ushort)num;
+		return num;
+	}
+
+	private void InsertStrings(ref uint hash, int matchLen)
+	{
+		if (bufEnd - bufPos <= matchLen)
+		{
+			bufPos += matchLen - 1;
+			return;
+		}
+		while (--matchLen > 0)
+		{
+			InsertString(ref hash);
+			bufPos++;
+		}
+	}
+
+	internal bool GetNextSymbolOrMatch(AAMatch match)
+	{
+		uint hash = HashValue(0u, window[bufPos]);
+		hash = HashValue(hash, window[bufPos + 1]);
+		int matchPos = 0;
+		int num;
+		if (bufEnd - bufPos <= 3)
+		{
+			num = 0;
+		}
+		else
+		{
+			int num2 = (int)InsertString(ref hash);
+			if (num2 != 0)
+			{
+				num = FindMatch(num2, out matchPos, 32, 32);
+				if (bufPos + num > bufEnd)
+				{
+					num = bufEnd - bufPos;
+				}
+			}
+			else
+			{
+				num = 0;
+			}
+		}
+		if (num < 3)
+		{
+			match.State = AAMatchState.HasSymbol;
+			match.Symbol = window[bufPos];
+			bufPos++;
+		}
+		else
+		{
+			bufPos++;
+			if (num <= 6)
+			{
+				int matchPos2 = 0;
+				int num3 = (int)InsertString(ref hash);
+				int num4;
+				if (num3 != 0)
+				{
+					num4 = FindMatch(num3, out matchPos2, (num < 4) ? 32 : 8, 32);
+					if (bufPos + num4 > bufEnd)
+					{
+						num4 = bufEnd - bufPos;
+					}
+				}
+				else
+				{
+					num4 = 0;
+				}
+				if (num4 > num)
+				{
+					match.State = AAMatchState.HasSymbolAndMatch;
+					match.Symbol = window[bufPos - 1];
+					match.Position = matchPos2;
+					match.Length = num4;
+					bufPos++;
+					num = num4;
+					InsertStrings(ref hash, num);
+				}
+				else
+				{
+					match.State = AAMatchState.HasMatch;
+					match.Position = matchPos;
+					match.Length = num;
+					num--;
+					bufPos++;
+					InsertStrings(ref hash, num);
+				}
+			}
+			else
+			{
+				match.State = AAMatchState.HasMatch;
+				match.Position = matchPos;
+				match.Length = num;
+				InsertStrings(ref hash, num);
+			}
+		}
+		if (bufPos == 16384)
+		{
+			MoveWindows();
+		}
+		return true;
+	}
+
+	private int FindMatch(int search, out int matchPos, int searchDepth, int niceLength)
+	{
+		int num = 0;
+		int num2 = 0;
+		int num3 = bufPos - 8192;
+		byte b = window[bufPos];
+		while (search > num3)
+		{
+			if (window[search + num] == b)
+			{
+				int i;
+				for (i = 0; i < 258 && window[bufPos + i] == window[search + i]; i++)
+				{
+				}
+				if (i > num)
+				{
+					num = i;
+					num2 = search;
+					if (i > 32)
+					{
+						break;
+					}
+					b = window[bufPos + i];
+				}
+			}
+			if (--searchDepth == 0)
+			{
+				break;
+			}
+			search = prev[search & 0x1FFF];
+		}
+		matchPos = bufPos - num2 - 1;
+		if (num == 3 && matchPos >= 16384)
+		{
+			return 0;
+		}
+		return num;
+	}
+
+	[Conditional("DEBUG")]
+	private void VerifyHashes()
+	{
+		for (int i = 0; i < 2048; i++)
+		{
+			ushort num = lookup[i];
+			while (num != 0 && bufPos - num < 8192)
+			{
+				ushort num2 = prev[num & 0x1FFF];
+				if (bufPos - num2 >= 8192)
+				{
+					break;
+				}
+				num = num2;
+			}
+		}
+	}
+
+	private uint RecalculateHash(int position)
+	{
+		return (uint)(((window[position] << 8) ^ (window[position + 1] << 4) ^ window[position + 2]) & 0x7FF);
+	}
+}