signature_scanner

1. Overview

The signature_scanner.cpp file searches media for filesystem or file signatures independently of partition metadata.

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 signature_scanner.hpp.

Primary responsibilities:

  • Scan byte ranges in chunks
  • Match configured signatures
  • Generate candidate offsets
  • Avoid duplicate or implausible results

2. File Identity and Scope

  • Source path: src/signature_scanner.cpp
  • Language: C++
  • File role: implementation file
  • Physical lines: 72
  • Non-empty lines: 61
  • SHA-256: 180ca4a647b74f2a5c7d5ad6000cfd8a5a314d6b7847cfb4c34624a90ba26671

The declarations in this file use the global namespace.

3. Dependencies

3.1 Project Headers

  • signature_scanner.hpp
  • i18n.hpp

3.2 Standard and External Headers

  • array
  • string

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

  • constexpr uint64_t MiB=1024ull*1024ull
  • constexpr uint64_t GiB=1024ull*1024ull*1024ull

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:

  • NTFS
  • NTFS candidate
  • NTFS boot sector detected
  • ext4 candidate
  • ext4 superblock detected
  • Btrfs candidate
  • Btrfs superblock detected

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:

  • uint64_t adaptive_stride(uint64_t disk_size) – Implements the operation identified by this API and updates or returns the associated state.
  • bool is_ntfs(const std::array<unsigned char,512>&b) – Evaluates the stated condition and returns the corresponding Boolean result.
  • bool is_fat32(const std::array<unsigned char,512>&b) – Evaluates the stated condition and returns the corresponding Boolean result.
  • bool is_exfat(const std::array<unsigned char,512>&b) – Evaluates the stated condition and returns the corresponding Boolean result.
  • bool looks_ext4(DiskReader&reader,uint64_t offset) – Implements the operation identified by this API and updates or returns the associated state.
  • bool looks_btrfs(DiskReader&reader,uint64_t offset) – Implements the operation identified by this API and updates or returns the associated state.
  • std::vector<ScanResult> SignatureScanner::scan(DiskReader&reader,std::vector<std::string>&logs) – Inspects the source and reports matching candidates or detected metadata.

8. Operational Flow

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

  1. Scan byte ranges in chunks.
  2. Match configured signatures.
  3. Generate candidate offsets.
  4. Avoid duplicate or implausible results.
  5. Expose or execute the detected APIs: adaptive_stride, is_ntfs, is_fat32, is_exfat, looks_ext4, looks_btrfs, scan.
  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.
  • On-disk structures are accepted only after validating signatures, magic values and structural constraints.
  • 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.
  • Binary decoding uses low-level memory operations or casts; alignment, endianness and packed-structure assumptions require careful review.
  • 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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