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pub mod block_reader;
pub mod header;
pub mod multi_reader;
use anyhow::Result;
use block_reader::BlockReader;
use header::{BlockInfo, NodeInfo, UnityFSHeader};
use log::debug;
use multi_reader::MultiReader;
use std::{
io::{Error, ErrorKind, Read, Seek, SeekFrom},
sync::Arc,
};
pub struct UnityFS<T> {
reader: MultiReader<T>,
blocks: Arc<Vec<BlockInfo>>,
inner_seek_offset: u64,
pub header: UnityFSHeader,
}
pub struct NodeReader<T> {
inner: T,
position: u64,
offset: u64,
size: u64,
}
impl<T: Read + Seek> UnityFS<T> {
pub fn open(mut file: T) -> Result<Self> {
let (header, blocks) = UnityFSHeader::read(&mut file)?;
let inner_seek_offset = file.stream_position()?;
Ok(Self {
blocks: Arc::new(blocks),
header,
inner_seek_offset,
reader: MultiReader::new(file)?,
})
}
pub fn find_main_file(&self) -> Option<&NodeInfo> {
self.header
.nodes()
.iter()
.find(|n| n.name.split_once(".").is_none())
}
pub fn read<'a>(&'a self, node: &NodeInfo) -> Result<NodeReader<BlockReader<MultiReader<T>>>> {
let mut inner = self.reader.clone();
inner.seek(SeekFrom::Start(self.inner_seek_offset))?;
let mut br = BlockReader::new(self.blocks.clone(), inner, self.inner_seek_offset);
br.seek(SeekFrom::Start(node.offset))?;
Ok(NodeReader {
size: node.size,
offset: node.offset,
position: 0,
inner: br,
})
}
}
impl<T: Read> Read for NodeReader<T> {
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
let bytes_left = self.size - self.position;
let end = buf.len().min(bytes_left as usize);
let size = self.inner.read(&mut buf[..end])?;
self.position += size as u64;
Ok(size)
}
}
impl<T: Seek + Read> Seek for NodeReader<T> {
fn seek(&mut self, pos: SeekFrom) -> std::io::Result<u64> {
match pos {
SeekFrom::Current(n) if n >= 0 => {
for _ in 0..n {
self.read_exact(&mut [0u8])?;
}
Ok(self.stream_position()?)
}
SeekFrom::Start(n) => {
debug!("seek node to {n} (off={})", self.offset);
if n > self.size {
return Err(Error::new(ErrorKind::NotSeekable, "seek out of bounds"));
}
self.position = n;
self.inner.seek(SeekFrom::Start(self.offset + n))
}
_ => unimplemented!(),
}
}
fn stream_position(&mut self) -> std::io::Result<u64> {
Ok(self.position)
}
}
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