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use std::{
fs::File,
io::{ Read, Seek, SeekFrom, BufReader },
cell::RefCell,
};
use crate::{
arc::Archive,
sec::Sector,
error::ParseError,
};
use super::*;
pub struct FileStore {
handle: RefCell<BufReader<File>>
}
impl Store for FileStore {
#[inline]
fn new(main_file: File) -> crate::Result<Self> {
Ok(Self { handle: RefCell::new(BufReader::new(main_file)) })
}
#[inline]
fn read(&self, archive: &Archive) -> crate::Result<Vec<u8>> {
let expanded_header = archive.id > std::u16::MAX.into();
let mut current_sector = archive.sector;
let mut data = vec![0; archive.length];
let mut remaining = archive.length;
let mut data_block = vec![0; SECTOR_SIZE];
let mut current = 0;
let mut chunk = 0;
let header_len = if expanded_header { SECTOR_EXPANDED_HEADER_SIZE } else { SECTOR_HEADER_SIZE };
let data_len = if expanded_header { SECTOR_EXPANDED_DATA_SIZE } else { SECTOR_DATA_SIZE };
loop {
let offset = current_sector as usize * SECTOR_SIZE;
if remaining >= data_len {
self.handle.borrow_mut().seek(SeekFrom::Start(offset as u64))?;
self.handle.borrow_mut().read_exact(&mut data_block)?;
let sector = match Sector::new(&data_block, expanded_header) {
Ok(sector) => sector,
Err(_) => return Err(ParseError::Sector(archive.sector).into())
};
sector.header.validate(archive.id, chunk, archive.index_id)?;
current_sector = sector.header.next;
remaining -= data_len;
data[current..current + data_len].copy_from_slice(sector.data_block);
current += data_len;
} else {
if remaining == 0 { break; }
let mut data_block = vec![0; remaining + header_len];
self.handle.borrow_mut().seek(SeekFrom::Start(offset as u64))?;
self.handle.borrow_mut().read_exact(&mut data_block)?;
let sector = match Sector::new(&data_block, expanded_header) {
Ok(sector) => sector,
Err(_) => return Err(ParseError::Sector(archive.sector).into())
};
sector.header.validate(archive.id, chunk, archive.index_id)?;
data[current..current + remaining].copy_from_slice(sector.data_block);
break;
}
chunk += 1;
}
Ok(data)
}
}