unarc-rs

A Rust library for reading and extracting various archive formats, with a focus on legacy/retro formats from the BBS era, plus modern formats like 7z.

Supported Formats

Installation

Add to your Cargo.toml:

[dependencies]
unarc-rs = "0.5"

Quick Start

Using the Unified API (Recommended)

use unarc_rs::unified::ArchiveFormat;

// Open archive directly from path
let mut archive = ArchiveFormat::open_path("archive.arj")?;

// Iterate over entries
for entry in archive.entries_iter() {
    let entry = entry?;
    println!("{}: {} bytes", entry.name(), entry.original_size());
}

Extracting Files

use std::fs::File;
use unarc_rs::unified::ArchiveFormat;

let mut archive = ArchiveFormat::open_path("archive.zip")?;

while let Some(entry) = archive.next_entry()? {
    // Extract to a file
    let mut output = File::create(entry.file_name())?;
    archive.read_to(&entry, &mut output)?;
}

Using a Specific Format

use std::fs::File;
use unarc_rs::unified::ArchiveFormat;

let file = File::open("data.arj")?;
let mut archive = ArchiveFormat::Arj.open(file)?;

for entry in archive.entries_iter() {
    let entry = entry?;
    let data = archive.read(&entry)?;
    // ... process data
}

Format Detection

use std::path::Path;
use unarc_rs::unified::{ArchiveFormat, is_supported_archive};

// Check if a file is a supported archive
if is_supported_archive(Path::new("file.arj")) {
    println!("Supported!");
}

// Get format from path
if let Some(format) = ArchiveFormat::from_path(Path::new("archive.zoo")) {
    println!("Format: {}", format.name()); // "ZOO"
}

API Overview

ArchiveFormat

• open_path(path) - Open archive from file path (auto-detects format)
• open(reader) - Open archive from any Read + Seek
• from_path(path) / from_extension(ext) - Detect format
• name() / extension() / extensions() - Format metadata

UnifiedArchive

• next_entry() - Get next entry (returns Option<ArchiveEntry>)
• entries_iter() - Iterator over all entries
• read(&entry) - Read entry data into Vec<u8>
• read_to(&entry, &mut writer) - Stream entry data to writer
• skip(&entry) - Skip entry without reading

ArchiveEntry

• name() / file_name() - Entry name (with/without path)
• original_size() / compressed_size() - Sizes
• compression_method() - Compression algorithm used
• compression_ratio() - Compression efficiency
• modified_time() - Modification timestamp
• crc() - Checksum

Format-Specific Notes

7z

Full support via the sevenz-rust2 crate. Supports LZMA, LZMA2, and other 7z compression methods.

ZIP

Full support via the zip crate with legacy compression methods enabled.

RAR

Full support for RAR4 and RAR5 via the unrar crate (uses native unrar library).

LHA/LZH

Full support via the excellent delharc crate.

ARC

Classic DOS archiver. Crushed & Distilled methods are not supported.

ARJ

Popular in the BBS scene in the 90s. Multi-volume and encrypted archives are not supported.

UC2

UltraCompressor II archive format. Supports decompression with SuperMaster dictionary and custom master entries.

Out of Scope

Not on the todo list:

• TAR - Use tar

Background

This library was written for my icy_board BBS project. It focuses on extraction (not creation) of legacy archive formats.

Contributions welcome! Contact me on the icy_board repo or via email if I miss issues/PRs here.

License

MIT OR Apache-2.0