hfs_fork_io

1. Overview

The hfs_fork_io.cpp file reads logical file forks through HFS+ extents and allocation blocks.

This is an implementation file. It contains executable logic for the subsystem, including parsing, I/O, validation, recovery flow, or graphical behavior declared by the corresponding interface.

Its paired source or interface file is hfs_fork_io.hpp.

Primary responsibilities:

  • Resolve data and resource fork extents
  • Read fragmented fork ranges
  • Integrate overflow extents
  • Expose bounded logical reads

2. File Identity and Scope

  • Source path: src/hfs_fork_io.cpp
  • Language: C++
  • File role: implementation file
  • Physical lines: 313
  • Non-empty lines: 282
  • SHA-256: e0c94377ba59b6e97916878488630cf7bae616d3bf4f18c2592dfb018c25ff32

Declared namespaces:

  • hfs

3. Dependencies

3.1 Project Headers

  • hfs_fork_io.hpp
  • hfs_btree.hpp

3.2 Standard and External Headers

  • algorithm
  • cstring
  • sstream

These dependencies define the file’s compile-time integration with the recovery engine, GTK interface, on-disk format decoders, operating-system services, or C++ standard library.

4. Declared Types

No class, structure, or enumeration definition is declared directly in this file.

5. Constants and Configuration Values

No preprocessor or compile-time constants were detected as top-level declarations in this file.

5.1 Operational Strings, Paths, Formats, or Commands

The following code literals are operationally relevant and may identify filesystem paths, helper commands, formats, signatures, or subsystem labels:

  • hfs_fork_io.hpp
  • hfs_btree.hpp
  • HFS+ fork: requested
  • HFS+ fork: read failed at disk offset
  • HFS+ extents-overflow walk:
  • HFS+: cannot load Extents Overflow file content
  • HFS+: Extents Overflow file too small for B-tree
  • HFS+: Extents Overflow node 0 not a header node
  • HFS+: Extents Overflow B-tree header parse failed
  • HFS+: read failure on overflow extent (start_block=
  • HFS+: requested

6. Data Members and Persistent State

No class data members are declared directly in this file, or the file primarily implements methods declared elsewhere.

7. API and Function Inventory

The following callable interfaces or definitions were detected:

  • bool read_fork_inline(DiskReader&reader,uint64_t volume_offset,uint32_t block_size,const ForkData&fork,uint64_t max_bytes,std::vector<unsigned char>&out,std::vector<std::string>&logs) – Reads or derives the requested information and returns or stores the decoded result.
  • bool read_fork_block_inline(DiskReader&reader,uint64_t volume_offset,uint32_t block_size,const ForkData&fork,uint64_t fork_logical_offset,unsigned char*block_buf) – Reads or derives the requested information and returns or stores the decoded result.
  • bool read_one_extent(DiskReader&reader,uint64_t volume_offset,uint32_t block_size,const ForkExtent&e,uint64_t want_bytes,std::vector<unsigned char>&out) – Reads or derives the requested information and returns or stores the decoded result.
  • size_t collect_overflow_extents(const std::vector<unsigned char>&btree_buf,const HeaderRec&hdr,uint8_t forkType,uint32_t fileID,std::vector<ForkExtent>&out,std::vector<std::string>&logs) – Implements the operation identified by this API and updates or returns the associated state.
  • bool read_fork_full(DiskReader&reader,uint64_t volume_offset,uint32_t block_size,const ForkData&fork,const ForkData&extents_file,uint8_t forkType,uint32_t fileID,uint64_t max_bytes,std::vector<unsigned char>&extents_btree_buffer,std::vector<unsigned char>&out,std::vector<std::string>&logs) – Reads or derives the requested information and returns or stores the decoded result.

8. Operational Flow

The subsystem represented by this file normally participates in the following flow:

  1. Resolve data and resource fork extents.
  2. Read fragmented fork ranges.
  3. Integrate overflow extents.
  4. Expose bounded logical reads.
  5. Expose or execute the detected APIs: read_fork_inline, read_fork_block_inline, read_one_extent, collect_overflow_extents, read_fork_full.
  6. Return explicit results, progress data, recovered records, or diagnostics to the calling layer.

9. Validation and Error Handling

  • Byte offsets, sizes and lengths must be validated before arithmetic and before every read to avoid overflow and out-of-bounds access.
  • Input and output paths require existence checks, permission handling and safe destination construction.

10. Runtime, Concurrency, and Resource Management

  • Deterministic behavior: callers depend on explicit return values and stable data structures to distinguish successful recovery from partial or invalid results.

11. Security and Data-Recovery Considerations

  • Recovery code should prefer read-only source access and avoid writing to the original damaged medium.
  • Raw devices and image files are treated as untrusted binary input; every offset and length must remain bounded by the source size.

12. Implementation Considerations

  • The implementation should remain aligned with declarations in the paired header and preserve documented return-value semantics.
  • Large-device arithmetic uses 64-bit values; additions and multiplications should be checked before use as offsets or allocation sizes.

13. Integration with the Recovery Pipeline

  • The file belongs to the source-discovery, parsing or support layer.
  • Its results feed scanner, recovery or reporting modules through shared models.
  • The API should remain deterministic so higher layers can combine results safely.

14. Licensing and Provenance

No explicit copyright or software-license statement was detected in the opening section of this individual file. Distribution terms should therefore be verified against the project-level license and repository metadata.

The SHA-256 value in this document can be used to associate the generated documentation with the exact source version analyzed.

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