Fix UDF trimming for BD-R dumps

[whatever-industries]

Summary

• detect UDF from the validated primary Anchor Volume Descriptor Pointer at LBA 256 even when the volume-recognition sequence is absent or not recognized
• preserve the reserve Volume Descriptor Sequence extent and include it when calculating the trimmed filesystem size
• include the trailing AVDP after the larger of the partition end and reserve-VDS end
• add overflow checks and focused UDF size regression tests

Root cause

The existing trimming path used the partition end plus one sector. On affected BD-R media, the reserve VDS starts at the partition end and extends for another 16 sectors, followed by the trailing AVDP. Trimming at the partition boundary therefore produced a structurally incomplete image.

UDF parsing was also gated on recognizing NSR02 or NSR03 in the volume-recognition sequence. A valid primary AVDP is sufficient to identify and process the UDF layout, so this change restores that fallback.

Impact

Profile-mismatched BD-R media can now be trimmed to the complete recorded UDF filesystem instead of either stopping at the partition boundary or reading the remaining recordable-media capacity.

Validation

• release build completed successfully on macOS arm64
• all 362 tests passed, including the new UDF regression cases
• physical BD-R test with an HL-DT-ST BU40N:
  • READ CAPACITY: 23,729,248 sectors
  • detected UDF size: 23,728,976 sectors
  • SCSI errors: 0
  • EDC errors: 0
  • output size: 48,596,942,848 bytes
  • CRC32: 03fd2843
  • MD5: 5283760b72c644cb56cb21a3df5c6acd
  • SHA-1: 3225512d4f07a14cc08bd3b31aaaee4f42a8ec9a

The physical-disc output matches Redump #93203.

Fixes #398

Summary by CodeRabbit

• Bug Fixes

  • Improved UDF volume-size detection for discs with reserve and main volume descriptor sequences.
  • Added validation for invalid sector sizes, partition boundaries, and overflowing volume calculations.
  • Improved handling of primary volume descriptor locations and trailing volume descriptors.

• Tests

  • Added coverage for reserve metadata, partition-end fallback, metadata endpoint selection, and invalid inputs.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 859f0d84-c613-4f62-98f6-694968daaf68

📥 Commits

Reviewing files that changed from the base of the PR and between 1874b39 and 9960777.

📒 Files selected for processing (5)

• CMakeLists.txt
• dvd/dvd_dump.ixx
• filesystem/udf/udf_size.ixx
• tests/gtest/CMakeLists.txt
• tests/gtest/test_udf.cc

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📝 Walkthrough

Walkthrough

UDF volume-size detection now validates primary AVDPs, tracks reserve VDS metadata, and calculates the final sector count through a new tested module. CMake includes the module and its GoogleTest target.

Changes

UDF volume sizing

Layer / File(s)	Summary
UDF size calculation helper filesystem/udf/udf_size.ixx, tests/gtest/test_udf.cc, CMakeLists.txt, tests/gtest/CMakeLists.txt	Adds udf::get_volume_sectors_count, validates overflow and zero values, calculates metadata endpoints, and adds GoogleTest coverage.
DVD UDF detection integration dvd/dvd_dump.ixx	Validates primary AVDP locations, queues VDS extents, retains reserve VDS metadata, and uses the calculated sector count.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 99607

The change completes UDF filesystem trimming for affected BD-R images, including required reserve metadata and trailing descriptors; no actionable merge-blocking risk remains after normal checks and review.

Sequence Diagram(s)

sequenceDiagram
  participant DVDDump
  participant FilesystemContext
  participant UDFSize
  DVDDump->>FilesystemContext: validate primary AVDP at current LBA
  DVDDump->>FilesystemContext: retain and queue VDS extents
  DVDDump->>UDFSize: pass partition end and reserve VDS metadata
  UDFSize-->>DVDDump: return optional volume sector count
  DVDDump->>FilesystemContext: record size and clear UDF mode

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Possibly related PRs

• superg/redumper#309: Introduced related UDF size-detection logic in dvd/dvd_dump.ixx.
• superg/redumper#318: Extended the related UDF size-detection implementation.
• superg/redumper#376: Introduced the GoogleTest infrastructure used by the new UDF tests.

Suggested reviewers: superg

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: fixing UDF trimming for BD-R dumps.
Linked Issues check	✅ Passed	The changes address issue #398 by improving UDF detection and size calculation for complete BD-R filesystem trimming.
Out of Scope Changes check	✅ Passed	All code, build, and test changes support the stated UDF trimming fix and related regression coverage.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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