delharc

A Rust library for parsing and extracting content of LHA/LZH archives.

What it does

This library provides ways to parse the content of LHA headers and allows to read files, compressed with the methods used by the archive format.

Files using this format usually have .lzh or .lha extensions, or .pma in case of the CP/M archiver. Some formats, such as the retro chip-tune YM format, use LHA as its default packaging method. The entire content of the Aminet has also been packaged using this format.

What it doesn't do

This library does not provide high level methods for creating files or directories from the extracted archives.

Usage

Add to Cargo.toml:

[dependencies]
delharc = "0.8"

For more information, please see the Documentation.

No std

Since version 0.6, delharc can be used without the std library. In this instance the alloc external crate will be required instead.

[dependencies.delharc]
version = "0.8"
default-features = false
features = ["lh1", "lz", "pm"] # select desired features

delharc API was originally built around the std::io types such as io::Error and io::Read.

This design choice made it impossible to adapt delharc to be used in the absence of the std::io library without some significant implementation changes.

To work around this problem the stub_io module and error module was added. stub_io contains an I/O proxy trait Read and a Take type which are now used as interfaces for generic types throughout the library. Instead of relying on io::Error for fallible results delharc defines its own error::LhaError which encapsulates an I/O error type.

With std library enabled, error::LhaError converts to io::Error via the From trait and stub_io::Read is implemented for all io::Read implementations.

For std users the difference from previous versions is that methods previously returning io::Result now return Result<_, LhaError<io::Error>>. This might break cases when result Err(error) from calls to delharc methods is returned as is without the ? or From conversion.

Now, when using default-features = false the std feature needs to be added back.

Upgrading

A lot has happened in version 0.8, including some breaking changes. Please consult the CHANGELOG for the full list of updates.

Rust Version

delharc requires Rustc version 1.95 or greater.

Acknowledgements

The decompression functions in this library, with minor modifications, were implemented in Rust by the author of this project, based on LHASA - Free Software LHA implementation written in C.

Many thanks to Simon Howard for collecting and reverse engineering all these algorithms into one very good and understandable source code.

License

This project is licensed under either of

• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)
• Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)

at your option.