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|
pub mod helper;
use anyhow::{Result, anyhow};
use helper::ReadExt;
use log::{debug, info};
use std::{
env::args,
fs::File,
io::{BufReader, Cursor, Read, Seek, SeekFrom, Write, copy},
};
fn main() -> anyhow::Result<()> {
env_logger::init_from_env("LOG");
let mut file = BufReader::new(File::open(args().nth(1).unwrap())?);
let signature = file.read_cstr()?;
let file_version = file.read_u32_be()?;
let player_version = file.read_cstr()?;
let unity_version = file.read_cstr()?;
let size = file.read_u64_be()?;
let blockindex_comp_size = file.read_u32_be()?;
let blockindex_decomp_size = file.read_u32_be()?;
let flags = file.read_u32_be()?;
let meta_comp_scheme = CompressionScheme::from_flag_num((flags & 0x3f) as u8)
.ok_or(anyhow!("unknown block compression"))?;
let blockindex_eof = flags & 0x80 != 0;
let blockindex_has_directory = flags & 0x40 != 0;
let blockindex_need_padding = flags & 0x200 != 0;
info!("signature={signature:?}");
info!("file_version={file_version:?}");
info!("player_version={player_version:?}");
info!("unity_version={unity_version:?}");
debug!("size={size:?}");
debug!("meta_comp_size={blockindex_comp_size:?}");
debug!("meta_decomp_size={blockindex_decomp_size:?}");
debug!("flags={flags:?}");
debug!("meta_comp_scheme={meta_comp_scheme:?}");
debug!("blockindex_eof={blockindex_eof:?}");
debug!("blockindex_has_directory={blockindex_has_directory:?}");
debug!("blockindex_need_padding={blockindex_need_padding:?}");
let mut blockindex = {
let restore_position = if blockindex_eof {
let pos = file.stream_position()?;
file.seek(SeekFrom::End(-(blockindex_comp_size as i64)))?;
Some(pos)
} else {
None
};
let mut blockindex = vec![0u8; blockindex_comp_size as usize];
file.read_exact(&mut blockindex)?;
if let Some(pos) = restore_position {
file.seek(SeekFrom::Start(pos))?;
}
let blockindex =
meta_comp_scheme.decompress(blockindex, blockindex_decomp_size as usize)?;
Cursor::new(blockindex)
};
{
// align stream
let off = file.stream_position()? % 16;
if off != 0 {
file.seek_relative(16 - off as i64)?;
}
}
blockindex.read_u128_be()?;
let num_blocks = blockindex.read_u32_be()?;
debug!("num_blocks={num_blocks:?}");
let mut blocks = Vec::new();
for _ in 0..num_blocks {
let block_decomp_size = blockindex.read_u32_be()?;
let block_comp_size = blockindex.read_u32_be()?;
let block_flags = blockindex.read_u16_be()?;
let block_comp_scheme = CompressionScheme::from_flag_num((block_flags & 0x3f) as u8)
.ok_or(anyhow!("unknown block compression"))?;
blocks.push((block_comp_size, block_decomp_size, block_comp_scheme))
}
let num_nodes = blockindex.read_u32_be()?;
debug!("num_nodes={num_nodes:?}");
let mut nodes = Vec::new();
for _ in 0..num_nodes {
let offset = blockindex.read_u64_be()?;
let size = blockindex.read_u64_be()?;
let status = blockindex.read_u32_be()?;
let name = blockindex.read_cstr()?;
info!("found node {name:?} (offset={offset}, size={size}, status={status})");
nodes.push((offset, size, status, name))
}
let mut storage = Vec::new();
for (comp_size, decomp_size, comp_scheme) in blocks {
let mut comp_buf = vec![0u8; comp_size as usize];
file.read_exact(&mut comp_buf)?;
let decomp_buf = comp_scheme.decompress(comp_buf, decomp_size as usize)?;
assert_eq!(decomp_size, decomp_buf.len() as u32);
storage.extend_from_slice(&decomp_buf);
}
let mut storage = Cursor::new(storage);
for (offset, size, _status, name) in nodes {
storage.seek(SeekFrom::Start(offset))?;
info!("extracting {name:?}");
let mut file = File::create(format!("/tmp/{}", name))?;
copy(&mut (&mut storage).take(size), &mut file)?;
}
Ok(())
}
#[derive(Debug, Clone, Copy, PartialEq)]
enum CompressionScheme {
None,
LZMA,
LZ4,
LZ4HC,
LZHAM,
}
impl CompressionScheme {
pub fn from_flag_num(n: u8) -> Option<CompressionScheme> {
Some(match n & 0x3f {
0 => CompressionScheme::None,
1 => CompressionScheme::LZMA,
2 => CompressionScheme::LZ4,
3 => CompressionScheme::LZ4HC,
4 => CompressionScheme::LZHAM,
_ => return None,
})
}
pub fn decompress(&self, block: Vec<u8>, decomp_size: usize) -> Result<Vec<u8>> {
match self {
CompressionScheme::None => Ok(block),
CompressionScheme::LZMA => {
let mut r = lzma::Reader::from(Cursor::new(block))?;
let mut buf = Vec::new();
r.read_to_end(&mut buf)?;
Ok(buf)
}
// CompressionScheme::LZ4HC | CompressionScheme::LZ4 => {
// Ok(lz4_flex::block::decompress(&block, decomp_size).context("lz4 decomp")?)
// }
CompressionScheme::LZ4HC | CompressionScheme::LZ4 => {
File::create("/tmp/a")?.write_all(&block)?;
Ok(lz4::block::decompress(&block, Some(decomp_size as i32))?)
// Ok(lz4::block::decompress(&block, None)?)
}
CompressionScheme::LZHAM => todo!(),
}
}
}
|
