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//! SectorReader — trait for reading 2048-byte disc sectors.
//!
//! Implemented by Drive (SCSI) and IsoFile (file-backed).
//! Used by UDF parser, disc scanner, label parsers — anything that
//! reads sectors doesn't need to know where they come from.
use crate::error::Result;
/// Read 2048-byte sectors from a disc or disc image.
pub trait SectorReader: Send {
/// Read `count` sectors starting at `lba` into `buf`.
/// `buf` must be at least `count * 2048` bytes.
/// `recovery`: true = full retry/reset loop (ripping), false = single attempt (verify).
/// File-backed readers ignore the flag.
fn read_sectors(
&mut self,
lba: u32,
count: u16,
buf: &mut [u8],
recovery: bool,
) -> Result<usize>;
/// Total capacity in sectors, if known.
fn capacity(&self) -> u32 {
0
}
}
/// SectorReader backed by a file (ISO image).
/// Seeks to lba * 2048, reads count * 2048 bytes.
pub struct FileSectorReader {
file: std::io::BufReader<std::fs::File>,
capacity: u32,
}
impl FileSectorReader {
pub fn open(path: &str) -> std::io::Result<Self> {
let file = std::fs::File::open(path)?;
let len = file.metadata()?.len();
let sectors = len / 2048;
if sectors > u32::MAX as u64 {
// ~8 TB hard cap (u32::MAX × 2048 bytes). Path lives in the
// typed Error variant — no English in the message.
return Err(crate::error::Error::IsoTooLarge {
path: path.to_string(),
}
.into());
}
let capacity = sectors as u32;
Ok(Self {
file: std::io::BufReader::with_capacity(4 * 1024 * 1024, file),
capacity,
})
}
}
impl SectorReader for FileSectorReader {
fn read_sectors(
&mut self,
lba: u32,
count: u16,
buf: &mut [u8],
_recovery: bool,
) -> Result<usize> {
use std::io::{Read, Seek, SeekFrom};
let offset = lba as u64 * 2048;
let bytes = count as usize * 2048;
self.file
.seek(SeekFrom::Start(offset))
.map_err(|e| crate::error::Error::IoError { source: e })?;
self.file
.read_exact(&mut buf[..bytes])
.map_err(|e| crate::error::Error::IoError { source: e })?;
Ok(bytes)
}
fn capacity(&self) -> u32 {
self.capacity
}
}