1 unstable release

Uses old Rust 2015

0.1.0 Oct 16, 2017

#1139 in Filesystem

Used in scoundrel



JavaScript 1K SLoC // 0.1% comments Rust 856 SLoC // 0.0% comments


Linux Status Build status


filearco_rs is a Rust crate for creating and reading a simple archive format. It was designed for game development, but can be used for other purposes.

It also includes a command-line utility, filearco, that writes all the files in a directory hierarchy into an archive.


This example demonstrates creating a FileArco version 1 archive file and retrieving a text file from that same archive.

extern crate filearco;

use std::path::Path

fn main() {
    let path = Path::new("archive.fac");
    let archive = filearco::v1::FileArco::new(path).ok().unwrap();
    let license = archive.get("LICENSE-MIT").unwrap()
    let license_text = license.as_str().ok().unwrap();
    println!("{}", license_text);

File Format

Version 1

NOTE: All data is stored in LSB (i.e. "little endian") byte order.

// Ofset 0x00: Start of file
struct Header {
    id: [u8; 8],           // b"FILEARCO"
    version_number: u64    // 1
    file_offset: u64,      // Offset to first file
    page_size: u64,        // Memory Page Size of system that created file
    entries_length: u64,   // Length of Entries table (in bytes)
    entries_checksum: u64, // CRC64-ISO checksum of Entries table

// Offset 0x30:
header_checksum: u64 // CRC64-ISO checksum of Header

// Offset 0x38:
// Start of serialized HashMap<String, Entry>
number_of_entries: u64

// Offset 0x40: Start of first file's metadata
file_name_length: u64,             // Length of file path (in bytes)
file_name: [u8; file_name_length]  // File path as raw UTF-8 string

struct Entry {
    offset: u64, 
    length: u64,
    aligned_length: u64,
    checksum: u64
// Metadata for the second file (and so on) follow directly after

// NOTE: the last Entry is followed by enough zeros to make the next section
// start at a multiple of header.page_size

// Offset M * header.page_size: Start of file contents section

// Offset header.file_offset + entry.offset: Start of a file's contents
contents: [u8; entry.length] // Contents of file as byte array

// NOTE: Each contents array is followed by enough zeros to make the next file
// contents array start at a multiple of header.page_size


filearco_rs should Work on Windows and any POSIX compatible system (Linux, Mac OSX, etc.).

filearco_rs is continuously tested on:

  • x86_64-unknown-linux-gnu (Linux)
  • i686-unknown-linux-gnu
  • x86_64-unknown-linux-musl (Linux w/ MUSL)
  • i686-unknown-linux-musl
  • x86_64-apple-darwin (Mac OSX)
  • i686-apple-darwin
  • x86_64-pc-windows-msvc (Windows)
  • i686-pc-windows-msvc
  • x86_64-pc-windows-gnu
  • i686-pc-windows-gnu

filearco_rs is continuously cross-compiled for:

  • arm-unknown-linux-gnueabihf
  • aarch64-unknown-linux-gnu
  • mips-unknown-linux-gnu
  • aarch64-unknown-linux-musl
  • i686-linux-android
  • x86_64-linux-android
  • arm-linux-androideabi
  • aarch64-linux-android
  • i386-apple-ios
  • x86_64-apple-ios
  • i686-unknown-freebsd
  • x86_64-unknown-freebsd
  • x86_64-unknown-netbsd
  • asmjs-unknown-emscripten


~44K SLoC