diff --git a/examples/mcpe/src/main.rs b/examples/mcpe/src/main.rs index 65360cd..830a38a 100644 --- a/examples/mcpe/src/main.rs +++ b/examples/mcpe/src/main.rs @@ -1,12 +1,16 @@ -use miniz_oxide::deflate::{compress_to_vec, compress_to_vec_zlib}; +use miniz_oxide::deflate::{compress_to_vec, compress_to_vec_zlib, CompressionLevel}; use miniz_oxide::inflate::{decompress_to_vec, decompress_to_vec_zlib}; +use rusty_leveldb::compressor::NoneCompressor; use rusty_leveldb::{Compressor, CompressorList, Options, DB}; use std::rc::Rc; +/// A zlib compressor that with zlib wrapper +/// +/// This is use for old world format struct ZlibCompressor(u8); impl ZlibCompressor { - /// level 0-10 + /// compression level 0-10 pub fn new(level: u8) -> Self { assert!(level <= 10); Self(level) @@ -26,10 +30,19 @@ impl Compressor for ZlibCompressor { } } +/// A zlib compressor that without zlib wrapper +/// +/// > windowBits can also be –8..–15 for raw deflate. In this case, -windowBits determines the window size. deflate() will then generate raw deflate data with no zlib header or trailer, and will not compute a check value. +/// > +/// > From [zlib manual](https://zlib.net/manual.html) +/// +/// It seems like Mojang use this for newer version +/// +/// A copy of Mojang's implementation can be find [here](https://github.com/reedacartwright/rbedrock/blob/fb32a899da4e15c1aaa0d6de2b459e914e183516/src/leveldb-mcpe/db/zlib_compressor.cc#L119). struct RawZlibCompressor(u8); impl RawZlibCompressor { - /// level 0-10 + /// compression level 0-10 pub fn new(level: u8) -> Self { assert!(level <= 10); Self(level) @@ -51,19 +64,40 @@ impl Compressor for RawZlibCompressor { pub fn mcpe_options(compression_level: u8) -> Options { let mut opt = Options::default(); - opt.compressor = 0; + + // Mojang create a custom [compressor list](https://github.com/reedacartwright/rbedrock/blob/fb32a899da4e15c1aaa0d6de2b459e914e183516/src/leveldb-mcpe/include/leveldb/options.h#L123) + // Sample config for compressor list can be find in [here](https://github.com/reedacartwright/rbedrock/blob/fb32a899da4e15c1aaa0d6de2b459e914e183516/src/leveldb-mcpe/mcpe_sample_setup.cpp#L24-L28) + // + // Their compression id can be find in [here](https://github.com/reedacartwright/rbedrock/blob/fb32a899da4e15c1aaa0d6de2b459e914e183516/src/leveldb-mcpe/include/leveldb/zlib_compressor.h#L38) + // and [here](https://github.com/reedacartwright/rbedrock/blob/fb32a899da4e15c1aaa0d6de2b459e914e183516/src/leveldb-mcpe/include/leveldb/zlib_compressor.h#L48) + // + // Compression id will be use in [here](https://github.com/reedacartwright/rbedrock/blob/fb32a899da4e15c1aaa0d6de2b459e914e183516/src/leveldb-mcpe/table/format.cc#L125-L150) let mut list = CompressorList::new(); - list.set_with_id(0, RawZlibCompressor::new(compression_level)); - list.set_with_id(1, ZlibCompressor::new(compression_level)); + list.set_with_id(0, NoneCompressor::default()); + list.set_with_id(2, ZlibCompressor::new(compression_level)); + list.set_with_id(4, RawZlibCompressor::new(compression_level)); opt.compressor_list = Rc::new(list); + + // Set compressor + // Minecraft bedrock may use other id than 4 however default is 4. [Mojang's implementation](https://github.com/reedacartwright/rbedrock/blob/fb32a899da4e15c1aaa0d6de2b459e914e183516/src/leveldb-mcpe/table/table_builder.cc#L152) + // + // There is a bug in this library that you have to open a database with the same compression type as it was written to. + // If raw data is smaller than compression, Mojang will use raw data. [Mojang's implementation](https://github.com/reedacartwright/rbedrock/blob/fb32a899da4e15c1aaa0d6de2b459e914e183516/src/leveldb-mcpe/table/table_builder.cc#L155-L165) + // There is a small chance that compression id 0 exists, you should use compression id 0 to write it. + opt.compressor = 4; + opt } +/// Path to world's db folder +const PATH: &str = "mcpe_db"; + +/// Mojang use `DefaultLevel` for world compression +const COMPRESSION_LEVEL: u8 = CompressionLevel::DefaultLevel as u8; + fn main() { - let path = "mcpe_db"; - let compression_level = 10; - let opt = mcpe_options(compression_level); - let mut db = DB::open(path, opt).unwrap(); + let opt = mcpe_options(COMPRESSION_LEVEL); + let mut db = DB::open(PATH, opt).unwrap(); db.put(b"~local_player", b"NBT data goes here").unwrap(); let value = db.get(b"~local_player").unwrap(); assert_eq!(&value, b"NBT data goes here")