Crate mca

mca

A simple but effective & fast writer / reader for Minecrafts Region Files (mca).

Reading a chunk and decompressing it’s data

use std::{fs::File, io::Read};
use mca::RegionReader;

let mut data = Vec::new();
File::open("r.0.0.mca")?.read_to_end(&mut data)?;

// Initialize the region
// This mostly just validates the header
let region = RegionReader::new(&data)?;

// Get a specific chunk based of it's chunk coordinates
let chunk = region.get_chunk(0, 0)?.unwrap();

// Decompress the chunk data
// This will most commonly be either ZLib or LZ4 compressed
let decompressed = chunk.decompress()?;

// You can now bring your own NBT parser to parse the actual chunk data here
// I recommend either `simdnbt` or `fastnbt` for this.

And you can very easily write back the data

use std::{fs::File};
use mca::RegionWriter;

let data = vec![]; // some chunk data to write

// Initialize the region writer
let mut writer = RegionWriter::new();

// Push a chunk to the writer
writer.push_chunk(&data, (0, 0))?;

// Write the writer to a buffer
let mut buf = vec![];
writer.write(&mut buf)?;

// Write the buffer to a file
File::create("r.0.0.mca")?.write_all(&buf)?;

Theres also a RegionIter that you can use to easily iterate over all possible chunks in a region.

use mca::RegionReader;

// Here you will actually get the region data
let data = vec![];
let region = RegionReader::new(&data)?;

// Then just call `.iter()` on the region
for chunk in region.iter() {
    // Iterator item is a Result<Option<RawChunk>>
    // So after the first unwrap we check if
    // there's actually a chunk or not
    if let Some(chunk) = chunk.unwrap() {
        // found chunk
    } else {
        // no chunk
    }    
}

Structs

PendingChunk

A pending chunk, holds all metadata used in region chunk payloads.

RawChunk

A raw compressed chunk, holds the compression type used.
And the specific chunk byte slice from the region data

RegionIter

An iterator over all chunks inside a region

RegionReader

A Minecraft region

RegionWriter

A writer used to write chunks to a region (mca) file.

Enums

CompressionType

Compression types used in chunks

McaError

Constants

REGION_SIZE

How wide / tall a region is.