LhAILa

LhA Integration Layer for AmigaOS 3.2.3

LhAILa is a native, system-oriented integration layer for classic LhA/LZH archives on AmigaOS 3.2.3.

The project does not try to invent a new archive format.

It accepts LhA as the de-facto Amiga archive standard and focuses on making it a better citizen of the operating system.

Project goals

LhAILa aims to provide a small, clear and reusable native archive core for:

• archive inspection
• archive testing
• archive extraction
• CLI integration
• ARexx integration
• later optional Workbench and DOS-facing integration

The guiding idea is:

System integration before reinvention.

Baseline

• Target OS: AmigaOS 3.2.3
• Reference SDK: NDK 3.2R4
• Toolchain target: vbcc, C89
• Style: native, explicit, deterministic, small-footprint

Scope of the first implementation

The initial implementation is intentionally narrow.

In scope

• read-only archive access
• list archive contents
• test archive integrity
• extract archive contents
• extract individual entries
• native library-first design
• CLI frontend
• ARexx frontend

Out of scope

• writing archives
• updating archives
• deleting from archives
• multi-format abstraction
• XPK-like plugin architecture
• handler/filesystem integration in the MVP
• GUI-heavy tooling in the MVP

Classic Profile 0.1

LhAILa uses a deliberately narrow Classic Profile.

Accepted archive family

• classic .lha / .lzh archives

Accepted header levels

• level 0
• level 1

Accepted methods

• -lh0-
• -lh1-
• -lh4-
• -lh5-

Recognized but not supported in 0.1

Examples include:

• header level 2
• -lh2-
• -lh3-
• -lh6-
• -lh7-
• LArc / .lzs
• PMarc / .pma

Anything outside the active profile is rejected cleanly and explicitly.

Architecture

LhAILa is built around a strict internal separation of responsibilities:

• Parser Layer
  Reads archive headers, entry boundaries and metadata.

• Profile Gate
  Decides whether an entry belongs to the supported Classic Profile.

• Method Registry
  Maps method IDs to internal decoder units.

• Decoder Units
  Perform decompression only.

• Sinks
  Consume decoded output for testing or extraction.

In short:

Parser finds. Profile permits. Registry selects. Decoder transforms. Sink consumes.

Design principles

• AmigaOS-first
• C89
• explicit ownership
• deterministic cleanup
• small modules
• clear contracts
• no hidden magic
• no shell tricks as infrastructure

Project status

This repository is currently in an early skeleton / architecture-first phase.

The current focus is:

1. internal type and contract definitions
2. archive open / iterate core
3. Classic Profile enforcement
4. first end-to-end decode path with -lh0-
5. test and extract pipeline
6. CLI
7. ARexx

Planned components

• lhaarchive.library
• lhaila CLI tool
• LHAILA ARexx port

Repository structure

src/
  core/
  internal/
  library/
  methods/
  orchestration/
  rexx/
  sinks/
  tools/

Non-goals

LhAILa is not intended to become:

• a universal archive framework

• a replacement for every archive tool

• a new compression ecosystem

• a clone of XPK, datatypes, or Unix archive tooling

Why this project exists

On classic Amiga systems, LhA is already the social and practical archive standard.
The interesting problem today is no longer “which archive format should win?” but:

How can LhA be integrated more cleanly and more natively into AmigaOS?

LhAILa is one answer to that question.

License

See LICENSE.