feat(bgcode): MeatPack G-code decoder (DD-011 phase 2) (#188) - #234
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Adds the MeatPack encoding (both variants) to the .bgcode decoder: a GCode block encoded with
MeatPack now decodes end-to-end (optionally after DEFLATE) to plain G-code.
The decoder is a faithful TS port of the MIT jamesgopsill/meatpack unpacker (© 2025 James Gopsill;
derived from the published Prusa spec), attribution preserved — NO AGPL libbgcode/OctoPrint-MeatPack
code (RR-003 §8). MeatPack packs the 15 most common g-code chars into 4-bit nibbles (first char =
low nibble); nibble 0xF escapes a full literal byte; FF FF <cmd> toggles packing/no-spaces; the
stream starts disabled (FF FF FB enables it).
Validated by HAND-COMPUTED vectors (the nibble table applied by hand as an oracle independent of the
decoder's own table): packable line, left/right/double full-width escapes, the (\n,\n)→single-newline
special case, no-spaces + disable-packing commands, invalid-command rejection — plus block-level
integration through openBgcode (None + DEFLATE × MeatPack/MeatPack-comments). Output is bounded
(bomb defense). Real PrusaSlicer meatpack files = phase-4 golden-equivalence.
Also fixes a docs-build regression: bgcode.ts's `{@link ContainerError}` (an unresolvable
cross-package typedoc link that landed in dev via #233's squash) → a code span, restoring the
API-docs warning budget to 3/3.
heatshrink compression remains phase 3.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
sobechestnut-dev
enabled auto-merge (squash)
July 27, 2026 20:12
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Phase 2 of the #188 bgcode epic (DD-011 §14). Does not close #188 — heatshrink (phase 3), container-adapter integration + golden-equivalence (phase 4), and the §7.3 review (phase 5) remain.
What
The MeatPack G-code encoding (both variants —
MeatPackandMeatPack (comments preserved)). A.bgcodeGCode block encoded with MeatPack now decodes end-to-end (optionally after DEFLATE) to plain G-code.Licensing — clean, and attributed
The decoder is a faithful TypeScript port of the MIT
jamesgopsill/meatpackunpacker (© 2025 James Gopsill), which is itself derived from the published Prusa spec — attribution preserved in the source header. No AGPLlibbgcode/OctoPrint-MeatPack code (RR-003 §8: port only from MIT/BSD/ISC with attribution).Validation — independent oracle, not just round-trip
RR-003 flagged that the MeatPack table "must be reconstructed and validated, not lifted." Rather than a self-consistent round-trip (which shares the table's blind spot), the tests use hand-computed vectors — each expected byte stream is assembled by applying the published nibble table by hand, so a wrong table/order/escape is caught:
G1 X2.5\n, left/right/double full-width escapes, the(\n,\n)→single-newline special case, the no-spaces and disable-packing commands, and invalid-command rejection;openBgcode(None + DEFLATE × MeatPack/MeatPack-comments).Output is bounded (decompression-bomb defense). Real PrusaSlicer meatpack files land in phase 4 for golden-equivalence.
Also: fixes a docs-build regression
bgcode.ts's{@link ContainerError}— an unresolvable cross-package typedoc link — landed indevwhen #233's phase-1 fix was dropped in the squash-merge, pushing the API-docs warning budget to 4 > 3. This PR downgrades it to a code span, restoring 3/3.Verification
typeCheck✓,lint✓ (0 errors),docs:build✓ (3/3), CI-liketest:packages✓ (22 bgcode tests),pack:check✓ (additivemeatpack.*snapshot).🤖 Generated with Claude Code