52 lines
1.2 KiB
Rust
52 lines
1.2 KiB
Rust
use std::io::Read;
|
|
|
|
use crate::FatFs;
|
|
use crate::subslice::SubSlice;
|
|
use crate::utils::replace;
|
|
|
|
pub struct ClusterChainReader<'a> {
|
|
sub_slice: SubSlice<'a>,
|
|
|
|
next_cluster: Option<u32>,
|
|
}
|
|
|
|
impl<'a> ClusterChainReader<'a> {
|
|
pub fn new(fat_fs: &'a FatFs, first_cluster: u32) -> ClusterChainReader<'a> {
|
|
let next_cluster = fat_fs.next_cluster(first_cluster).unwrap_or(None);
|
|
|
|
let sub_slice = fat_fs.cluster_as_subslice(first_cluster);
|
|
|
|
ClusterChainReader {
|
|
sub_slice,
|
|
next_cluster,
|
|
}
|
|
}
|
|
|
|
fn next_cluster(&mut self) -> bool {
|
|
let Some(next_cluster) = self.next_cluster else {
|
|
return false;
|
|
};
|
|
|
|
replace(&mut self.sub_slice, |sub_slice| {
|
|
let fat_fs = sub_slice.release();
|
|
|
|
self.next_cluster = fat_fs.next_cluster(next_cluster).unwrap_or(None);
|
|
|
|
fat_fs.cluster_as_subslice(next_cluster)
|
|
});
|
|
|
|
true
|
|
}
|
|
}
|
|
|
|
impl<'a> Read for ClusterChainReader<'a> {
|
|
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
|
|
if self.sub_slice.is_empty() {
|
|
if !self.next_cluster() {
|
|
return Ok(0);
|
|
}
|
|
}
|
|
|
|
self.sub_slice.read(buf)
|
|
}
|
|
}
|