Add multi-extent file support (ECMA-119 9.1.6) by oceanplexian · Pull Request #55 · kdomanski/iso9660

oceanplexian · 2026-02-17T20:04:44Z

Add multi-extent file support

This implements multi-extent directory record support as described in ECMA-119 section 9.1.6, following the guidance @kdomanski gave in Unpackerr/unpackerr#264.

When bit 7 of the FileFlags field is set on a directory record, it means that record is not the final one for the file. Consecutive records with the flag set should have their extents collected and concatenated. This is how ISO9660 handles files larger than 4GB (since ExtentLength is a 32-bit field).

The implementation follows the same approach as the Linux kernel isofs (https://github.com/torvalds/linux/blob/v5.6/fs/isofs/inode.c#LL1279C4):

When parsing directory entries in GetAllChildren(), if the multi-extent flag (dirFlagMultiExtent, 0x80) is set, the entry extent info is accumulated in a pending list
When we hit a record without the flag (the final record), all accumulated extents plus the final one are attached to the resulting File
Reader() returns an io.MultiReader that spans all extents seamlessly
Size() returns the sum of all extent lengths

The dirFlagMultiExtent constant was already defined in the codebase but was not being used - this PR puts it to work.

Changes

image_reader.go: Added extent struct, extents field on File, updated GetAllChildren() to detect and merge multi-extent records, updated Reader() and Size() to handle multiple extents
multi_extent_test.go: Tests for multi-extent files (3 extents merged into 1 file), mixed multi-extent and regular files, and verification that single-extent files remain unchanged

Test plan

All existing tests pass (the TestReadWriteRecordingTimestamp failure is pre-existing and timezone-related)
New multi-extent tests pass
Single-extent file behavior is unchanged (verified by test)
Tested with a real 5GB multi-extent ISO created by mkisofs -iso-level 3 — file was correctly extracted with byte-perfect SHA-256 verification

Per ECMA-119 section 9.1.6, when bit 7 of the FileFlags field is set on a directory record, it indicates the record is not the final one for that file. Consecutive records with this flag should have their extents collected and concatenated to form the complete file. This is needed for files larger than 4GB (2^32 bytes), which must be split across multiple extents due to the 32-bit ExtentLength field. Changes: - Added extent struct to represent a single contiguous region - File now carries an optional extents slice for multi-extent files - GetAllChildren() detects the multi-extent flag and merges consecutive directory records into a single File with multiple extents - Reader() returns an io.MultiReader spanning all extents - Size() returns the sum of all extent lengths - Added tests for multi-extent files, mixed with regular files, and verified single-extent behavior is unchanged

Parse Joliet SVDs (identified by escape sequences %/@, %/C, %/E) and prefer them over the primary VD in RootDir(). Directory entry identifiers are decoded from UTF-16BE to UTF-8, giving callers full-length filenames instead of 8.3 DOS-truncated names. - Store escape sequences from supplementary VDs (bytes 88-120) - Add isJoliet() helper to detect Joliet SVDs - RootDir() prefers Joliet VD when available, falls back to primary - GetAllChildren() decodes UTF-16BE identifiers for Joliet entries - Name() returns decoded Joliet names directly (no 8.3 processing) - Propagate joliet flag to child File structs - Add test with real Joliet ISO fixture

This PR contains the following updates: | Package | Update | Change | |---|---|---| | [Unpackerr/unpackerr](https://github.com/Unpackerr/unpackerr) | minor | `0.14.5` → `0.15.0` | --- ### Release Notes <details> <summary>Unpackerr/unpackerr (Unpackerr/unpackerr)</summary> ### [`v0.15.0`](https://github.com/Unpackerr/unpackerr/releases/tag/v0.15.0): Version 15 in 8 years [Compare Source](Unpackerr/unpackerr@v0.14.5...v0.15.0) #### New Features - Folder setting `delete_after` has a default setting of 10 minutes. - Log file mode can now be set. - Will now unpack multi-file 7zip archives. - Log file is now automatically created. - FreeBSD rc.d improvements to allow overriding username. - Progress updates are now logged. Every 15 seconds (configurable), the app logs the current extraction percentage. - Adds `exclude_path` to the folder watcher so you can ignore specific paths. - Folder setting `disable_recursion` works correctly now. - Empty download folders are removed when archives are removed. - Golift docker image now uses alpine instead of scratch. ##### These features are thanks to [@oceanplexian](https://github.com/oceanplexian) - Supports non-UTF8 file encoding (Japanese, Chinese, etc). - Improved ISO9660 ([Joilet](kdomanski/iso9660#55)) support. - [UDF](https://github.com/golift/udf) support (like ISO, but bigger). - Splits FLAC/CUE files for Lidarr. **This is still experimental and feedback is requested.** - Archives with an incorrect extension may still be extracted. We now detect the file type using the first few bytes. #### Bug Fixes It's a pretty big list, but at the end of the day all of the bugs pretty much lead to the same problem: extraction failed. A lot of these problems have been fixed and extractions are considerably more reliable. #### Merged Contributions - update arch pkgbuild by [@davidnewhall](https://github.com/davidnewhall) in [#479](Unpackerr/unpackerr#479) - update install.sh script by [@davidnewhall](https://github.com/davidnewhall) in [#480](Unpackerr/unpackerr#480) - add overrides for examples and docker by [@davidnewhall](https://github.com/davidnewhall) in [#481](Unpackerr/unpackerr#481) - Remove expanding of URL previews by [@BoKKeR](https://github.com/BoKKeR) in [#500](Unpackerr/unpackerr#500) - docs: add clarify delete\_after needing to be greater than 0 by [@bakerboy448](https://github.com/bakerboy448) in [#485](Unpackerr/unpackerr#485) - fix docs by [@davidnewhall](https://github.com/davidnewhall) in [#501](Unpackerr/unpackerr#501) - Update linter, fix some bugs by [@davidnewhall](https://github.com/davidnewhall) in [#503](Unpackerr/unpackerr#503) - set default for folder delete after to 10m by [@davidnewhall](https://github.com/davidnewhall) in [#530](Unpackerr/unpackerr#530) - Allows changing the log file mode. by [@davidnewhall](https://github.com/davidnewhall) in [#531](Unpackerr/unpackerr#531) - add multi-file 7z support to starr apps by [@davidnewhall](https://github.com/davidnewhall) in [#533](Unpackerr/unpackerr#533) - make log file on linux auto. allow dir instead of file for log file by [@davidnewhall](https://github.com/davidnewhall) in [#536](Unpackerr/unpackerr#536) - Update FreeBSD rc file. by [@davidnewhall](https://github.com/davidnewhall) in [#538](Unpackerr/unpackerr#538) - Provide progress updates. by [@davidnewhall](https://github.com/davidnewhall) in [#535](Unpackerr/unpackerr#535) - feat(folder): add exclude\_paths for watched folders by [@nicholaskurjo](https://github.com/nicholaskurjo) in [#572](Unpackerr/unpackerr#572) - fix(folder): honor disable\_recursion for watched archive files by [@nicholaskurjo](https://github.com/nicholaskurjo) in [#573](Unpackerr/unpackerr#573) - Silence logs when nothing configured by [@davidnewhall](https://github.com/davidnewhall) in [#574](Unpackerr/unpackerr#574) - fix lint by [@davidnewhall](https://github.com/davidnewhall) in [#577](Unpackerr/unpackerr#577) - Logs fallback to stdout by [@davidnewhall](https://github.com/davidnewhall) in [#579](Unpackerr/unpackerr#579) - Purge empty parent folder by [@davidnewhall](https://github.com/davidnewhall) in [#578](Unpackerr/unpackerr#578) - Dockerfile changes + build fix by [@davidnewhall](https://github.com/davidnewhall) in [#580](Unpackerr/unpackerr#580) - Polish ISO9660 support: Starr app extraction, UDF, multi-extent by [@oceanplexian](https://github.com/oceanplexian) in [#581](Unpackerr/unpackerr#581) - Add split\_flac toggle for Lidarr CUE+FLAC splitting by [@oceanplexian](https://github.com/oceanplexian) in [#583](Unpackerr/unpackerr#583) - fixes by [@davidnewhall](https://github.com/davidnewhall) in [#584](Unpackerr/unpackerr#584) - Manually import FLAC tracks into Lidarr after they're split. by [@davidnewhall](https://github.com/davidnewhall) in [#586](Unpackerr/unpackerr#586) #### Auto Updates - Update module github.com/prometheus/client\_golang to v1.20.5 by [@renovate](https://github.com/renovate)\[bot] in [#483](Unpackerr/unpackerr#483) - Update module golang.org/x/mod to v0.20.0 by [@renovate](https://github.com/renovate)\[bot] in [#482](Unpackerr/unpackerr#482) - Update module golang.org/x/mod to v0.22.0 - autoclosed by [@renovate](https://github.com/renovate)\[bot] in [#490](Unpackerr/unpackerr#490) - Update module github.com/fsnotify/fsnotify to v1.8.0 by [@renovate](https://github.com/renovate)\[bot] in [#498](Unpackerr/unpackerr#498) - chore(deps): update dependency go to v1.23.4 by [@renovate](https://github.com/renovate)\[bot] in [#506](Unpackerr/unpackerr#506) - Update GitHub Artifact Actions (major) by [@renovate](https://github.com/renovate)\[bot] in [#551](Unpackerr/unpackerr#551) - fix(deps): update golift.io/rotatorr digest to [`f6ac6fc`](Unpackerr/unpackerr@f6ac6fc) by [@renovate](https://github.com/renovate)\[bot] in [#575](Unpackerr/unpackerr#575) - fix(deps): update module golift.io/cnfg to v0.2.4 by [@renovate](https://github.com/renovate)\[bot] in [#576](Unpackerr/unpackerr#576) - Update module golift.io/cnfg to v0.2.5 by [@renovate](https://github.com/renovate)\[bot] in [#585](Unpackerr/unpackerr#585) - Update GitHub Artifact Actions (major) by [@renovate](https://github.com/renovate)\[bot] in [#588](Unpackerr/unpackerr#588) #### New Contributors - [@BoKKeR](https://github.com/BoKKeR) made their first contribution in [#500](Unpackerr/unpackerr#500) - [@nicholaskurjo](https://github.com/nicholaskurjo) made their first contribution in [#572](Unpackerr/unpackerr#572) - [@oceanplexian](https://github.com/oceanplexian) made their first contribution in [#581](Unpackerr/unpackerr#581) **Full Changelog**: <Unpackerr/unpackerr@v0.14.5...v0.15.0> </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://gitea.alexlebens.dev/alexlebens/infrastructure/pulls/4348 Co-authored-by: Renovate Bot <[email protected]> Co-committed-by: Renovate Bot <[email protected]>

This PR contains the following updates: | Package | Update | Change | |---|---|---| | [golift/unpackerr](https://github.com/Unpackerr/unpackerr) | minor | `0.14.5` → `0.15.0` | --- ### Release Notes <details> <summary>Unpackerr/unpackerr (golift/unpackerr)</summary> ### [`v0.15.0`](https://github.com/Unpackerr/unpackerr/releases/tag/v0.15.0): Version 15 in 8 years [Compare Source](Unpackerr/unpackerr@v0.14.5...v0.15.0) ##### New Features - Folder setting `delete_after` has a default setting of 10 minutes. - Log file mode can now be set. - Will now unpack multi-file 7zip archives. - Log file is now automatically created. - FreeBSD rc.d improvements to allow overriding username. - Progress updates are now logged. Every 15 seconds (configurable), the app logs the current extraction percentage. - Adds `exclude_path` to the folder watcher so you can ignore specific paths. - Folder setting `disable_recursion` works correctly now. - Empty download folders are removed when archives are removed. - Golift docker image now uses alpine instead of scratch. ##### These features are thanks to [@oceanplexian](https://github.com/oceanplexian) - Supports non-UTF8 file encoding (Japanese, Chinese, etc). - Improved ISO9660 ([Joilet](kdomanski/iso9660#55)) support. - [UDF](https://github.com/golift/udf) support (like ISO, but bigger). - Splits FLAC/CUE files for Lidarr. **This is still experimental and feedback is requested.** - Archives with an incorrect extension may still be extracted. We now detect the file type using the first few bytes. ##### Bug Fixes It's a pretty big list, but at the end of the day all of the bugs pretty much lead to the same problem: extraction failed. A lot of these problems have been fixed and extractions are considerably more reliable. ##### Merged Contributions - update arch pkgbuild by [@davidnewhall](https://github.com/davidnewhall) in [#479](Unpackerr/unpackerr#479) - update install.sh script by [@davidnewhall](https://github.com/davidnewhall) in [#480](Unpackerr/unpackerr#480) - add overrides for examples and docker by [@davidnewhall](https://github.com/davidnewhall) in [#481](Unpackerr/unpackerr#481) - Remove expanding of URL previews by [@BoKKeR](https://github.com/BoKKeR) in [#500](Unpackerr/unpackerr#500) - docs: add clarify delete\_after needing to be greater than 0 by [@bakerboy448](https://github.com/bakerboy448) in [#485](Unpackerr/unpackerr#485) - fix docs by [@davidnewhall](https://github.com/davidnewhall) in [#501](Unpackerr/unpackerr#501) - Update linter, fix some bugs by [@davidnewhall](https://github.com/davidnewhall) in [#503](Unpackerr/unpackerr#503) - set default for folder delete after to 10m by [@davidnewhall](https://github.com/davidnewhall) in [#530](Unpackerr/unpackerr#530) - Allows changing the log file mode. by [@davidnewhall](https://github.com/davidnewhall) in [#531](Unpackerr/unpackerr#531) - add multi-file 7z support to starr apps by [@davidnewhall](https://github.com/davidnewhall) in [#533](Unpackerr/unpackerr#533) - make log file on linux auto. allow dir instead of file for log file by [@davidnewhall](https://github.com/davidnewhall) in [#536](Unpackerr/unpackerr#536) - Update FreeBSD rc file. by [@davidnewhall](https://github.com/davidnewhall) in [#538](Unpackerr/unpackerr#538) - Provide progress updates. by [@davidnewhall](https://github.com/davidnewhall) in [#535](Unpackerr/unpackerr#535) - feat(folder): add exclude\_paths for watched folders by [@nicholaskurjo](https://github.com/nicholaskurjo) in [#572](Unpackerr/unpackerr#572) - fix(folder): honor disable\_recursion for watched archive files by [@nicholaskurjo](https://github.com/nicholaskurjo) in [#573](Unpackerr/unpackerr#573) - Silence logs when nothing configured by [@davidnewhall](https://github.com/davidnewhall) in [#574](Unpackerr/unpackerr#574) - fix lint by [@davidnewhall](https://github.com/davidnewhall) in [#577](Unpackerr/unpackerr#577) - Logs fallback to stdout by [@davidnewhall](https://github.com/davidnewhall) in [#579](Unpackerr/unpackerr#579) - Purge empty parent folder by [@davidnewhall](https://github.com/davidnewhall) in [#578](Unpackerr/unpackerr#578) - Dockerfile changes + build fix by [@davidnewhall](https://github.com/davidnewhall) in [#580](Unpackerr/unpackerr#580) - Polish ISO9660 support: Starr app extraction, UDF, multi-extent by [@oceanplexian](https://github.com/oceanplexian) in [#581](Unpackerr/unpackerr#581) - Add split\_flac toggle for Lidarr CUE+FLAC splitting by [@oceanplexian](https://github.com/oceanplexian) in [#583](Unpackerr/unpackerr#583) - fixes by [@davidnewhall](https://github.com/davidnewhall) in [#584](Unpackerr/unpackerr#584) - Manually import FLAC tracks into Lidarr after they're split. by [@davidnewhall](https://github.com/davidnewhall) in [#586](Unpackerr/unpackerr#586) ##### Auto Updates - Update module github.com/prometheus/client\_golang to v1.20.5 by [@renovate](https://github.com/renovate)\[bot] in [#483](Unpackerr/unpackerr#483) - Update module golang.org/x/mod to v0.20.0 by [@renovate](https://github.com/renovate)\[bot] in [#482](Unpackerr/unpackerr#482) - Update module golang.org/x/mod to v0.22.0 - autoclosed by [@renovate](https://github.com/renovate)\[bot] in [#490](Unpackerr/unpackerr#490) - Update module github.com/fsnotify/fsnotify to v1.8.0 by [@renovate](https://github.com/renovate)\[bot] in [#498](Unpackerr/unpackerr#498) - chore(deps): update dependency go to v1.23.4 by [@renovate](https://github.com/renovate)\[bot] in [#506](Unpackerr/unpackerr#506) - Update GitHub Artifact Actions (major) by [@renovate](https://github.com/renovate)\[bot] in [#551](Unpackerr/unpackerr#551) - fix(deps): update golift.io/rotatorr digest to [`f6ac6fc`](Unpackerr/unpackerr@f6ac6fc) by [@renovate](https://github.com/renovate)\[bot] in [#575](Unpackerr/unpackerr#575) - fix(deps): update module golift.io/cnfg to v0.2.4 by [@renovate](https://github.com/renovate)\[bot] in [#576](Unpackerr/unpackerr#576) - Update module golift.io/cnfg to v0.2.5 by [@renovate](https://github.com/renovate)\[bot] in [#585](Unpackerr/unpackerr#585) - Update GitHub Artifact Actions (major) by [@renovate](https://github.com/renovate)\[bot] in [#588](Unpackerr/unpackerr#588) ##### New Contributors - [@BoKKeR](https://github.com/BoKKeR) made their first contribution in [#500](Unpackerr/unpackerr#500) - [@nicholaskurjo](https://github.com/nicholaskurjo) made their first contribution in [#572](Unpackerr/unpackerr#572) - [@oceanplexian](https://github.com/oceanplexian) made their first contribution in [#581](Unpackerr/unpackerr#581) **Full Changelog**: <Unpackerr/unpackerr@v0.14.5...v0.15.0> </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://gitea.alexlebens.dev/alexlebens/infrastructure/pulls/4349 Co-authored-by: Renovate Bot <[email protected]> Co-committed-by: Renovate Bot <[email protected]>

This was referenced Feb 17, 2026

Add UDF fallback and extract ISOs to root output directory golift/xtractr#114

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Polish ISO9660 support: Starr app extraction, UDF, multi-extent Unpackerr/unpackerr#581

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davidnewhall mentioned this pull request Feb 18, 2026

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Add multi-extent file support (ECMA-119 9.1.6)#55

Add multi-extent file support (ECMA-119 9.1.6)#55
oceanplexian wants to merge 2 commits intokdomanski:masterfrom
oceanplexian:fix/multi-extent-udf

oceanplexian commented Feb 17, 2026 •

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