libCCI

A small, dependency-light C library that reads and writes the CCI ("CCIM") compressed container used for original-Xbox disc images. It is the reference implementation of the format specified in FORMAT.md; ports to other languages (C#, Rust, …) should follow that document.

CCI stores a disc as fixed 2048-byte sectors, each either raw or a single LZ4 block, with a random-access index so any sector decodes independently. Large images may be split across multiple parts (name.1.cci, name.2.cci, …), which libCCI discovers and stitches transparently.

Features

• Decode single-part and split (multi-part) images.
• Encode raw images to CCI (LZ4-HC), with optional splitting at a size target.
• I/O-agnostic core driven by read/write callbacks — usable over stdio, a QEMU block child, memory, etc. — plus a stdio convenience layer.
• No dependencies beyond LZ4 (bundled as a submodule, or use the system copy).

Building

git clone --recursive https://github.com/Team-Resurgent/libCCI
cd libCCI
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
ctest --test-dir build --output-on-failure

If you cloned without --recursive: git submodule update --init --recursive. To link the system LZ4 instead of the bundled one: -DCCI_SYSTEM_LZ4=ON.

CLI examples

build/cci_info    game.cci                 # show sector count / size
build/cci_extract game.cci  game.iso       # decode back to a raw image
build/cci_encode  game.iso  game           # -> game.cci
build/cci_encode  game.iso  game 4294967296 # split into game.1.cci, game.2.cci, ...

Using the library

#include <cci/cci.h>

cci_volume *v;
if (cci_open_file(&v, "game.cci") == CCI_OK) {          /* split-aware */
    uint8_t sector[CCI_SECTOR_SIZE];
    cci_volume_read_sector(v, lba, sector);
    /* or an arbitrary byte range: cci_volume_read(v, off, buf, len); */
    cci_volume_free(v);
}

For non-file backings (e.g. an emulator's block layer), open a cci_reader directly with your own cci_read_fn and wrap parts in a cci_volume.

License

GPL-2.0-or-later. See LICENSE. Bundled LZ4 (third_party/lz4) is BSD-2-Clause.

Format derived from Team-Resurgent's XboxToolkit.