M-Labs/rust-fatfs
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Support FAT mirroring.

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This commit is contained in:
Rafał Harabień 2017-10-10 23:18:32 +02:00
parent 0c6e9aec5b
commit d52b0918ca
1 changed files with 22 additions and 14 deletions
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36
src/fs.rs
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@ -128,7 +128,7 @@ impl <'a> FileSystem<'a> {
let root_rdr = { let root_rdr = {
match self.fat_type { match self.fat_type {
FatType::Fat12 | FatType::Fat16 => DirRawStream::Root(DiskSlice::from_sectors( FatType::Fat12 | FatType::Fat16 => DirRawStream::Root(DiskSlice::from_sectors(
self.first_data_sector - self.root_dir_sectors, self.root_dir_sectors, self)), self.first_data_sector - self.root_dir_sectors, self.root_dir_sectors, 1, self)),
_ => DirRawStream::File(File::new(Some(self.boot.bpb.root_dir_first_cluster), None, self)), _ => DirRawStream::File(File::new(Some(self.boot.bpb.root_dir_first_cluster), None, self)),
} }
}; };
@ -217,13 +217,18 @@ impl <'a> FileSystem<'a> {
} }
fn fat_slice<'b>(&'b self) -> DiskSlice<'b, 'a> { fn fat_slice<'b>(&'b self) -> DiskSlice<'b, 'a> {
let bytes_per_sector = self.boot.bpb.bytes_per_sector as u64;
let fat_offset = self.boot.bpb.reserved_sectors as u64 * bytes_per_sector;
let sectors_per_fat = let sectors_per_fat =
if self.boot.bpb.sectors_per_fat_16 == 0 { self.boot.bpb.sectors_per_fat_32 } if self.boot.bpb.sectors_per_fat_16 == 0 { self.boot.bpb.sectors_per_fat_32 }
else { self.boot.bpb.sectors_per_fat_16 as u32 }; else { self.boot.bpb.sectors_per_fat_16 as u32 };
let fat_size = sectors_per_fat as u64 * bytes_per_sector; let mirroring_enabled = self.boot.bpb.extended_flags & 0x80 == 0;
DiskSlice::new(fat_offset, fat_size, self) let (fat_first_sector, mirrors) = if mirroring_enabled {
(self.boot.bpb.reserved_sectors as u32, self.boot.bpb.fats)
} else {
let active_fat = (self.boot.bpb.extended_flags & 0x0F) as u32;
let fat_first_sector = (self.boot.bpb.reserved_sectors as u32) + active_fat * sectors_per_fat;
(fat_first_sector, 1)
};
DiskSlice::from_sectors(fat_first_sector, sectors_per_fat, mirrors, self)
} }
pub(crate) fn cluster_iter<'b>(&'b self, cluster: u32) -> ClusterIterator<'b, 'a> { pub(crate) fn cluster_iter<'b>(&'b self, cluster: u32) -> ClusterIterator<'b, 'a> {
@ -242,17 +247,18 @@ pub(crate) struct DiskSlice<'a, 'b: 'a> {
begin: u64, begin: u64,
size: u64, size: u64,
offset: u64, offset: u64,
mirrors: u8,
fs: &'a FileSystem<'b>, fs: &'a FileSystem<'b>,
} }
impl <'a, 'b> DiskSlice<'a, 'b> { impl <'a, 'b> DiskSlice<'a, 'b> {
pub(crate) fn new(begin: u64, size: u64, fs: FileSystemRef<'a, 'b>) -> Self { pub(crate) fn new(begin: u64, size: u64, mirrors: u8, fs: FileSystemRef<'a, 'b>) -> Self {
DiskSlice { begin, size, fs, offset: 0 } DiskSlice { begin, size, mirrors, fs, offset: 0 }
} }
pub(crate) fn from_sectors(first_sector: u32, sectors_count: u32, fs: FileSystemRef<'a, 'b>) -> Self { pub(crate) fn from_sectors(first_sector: u32, sector_count: u32, mirrors: u8, fs: FileSystemRef<'a, 'b>) -> Self {
let bytes_per_sector = fs.boot.bpb.bytes_per_sector as u64; let bytes_per_sector = fs.boot.bpb.bytes_per_sector as u64;
Self::new(first_sector as u64 * bytes_per_sector, sectors_count as u64 * bytes_per_sector, fs) Self::new(first_sector as u64 * bytes_per_sector, sector_count as u64 * bytes_per_sector, mirrors, fs)
} }
pub(crate) fn global_pos(&self) -> u64 { pub(crate) fn global_pos(&self) -> u64 {
@ -276,11 +282,13 @@ impl <'a, 'b> Write for DiskSlice<'a, 'b> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> { fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
let offset = self.begin + self.offset; let offset = self.begin + self.offset;
let write_size = cmp::min((self.size - self.offset) as usize, buf.len()); let write_size = cmp::min((self.size - self.offset) as usize, buf.len());
let mut disk = self.fs.disk.borrow_mut(); for i in 0..self.mirrors {
disk.seek(SeekFrom::Start(offset))?; let mut disk = self.fs.disk.borrow_mut();
let size = disk.write(&buf[..write_size])?; disk.seek(SeekFrom::Start(offset + i as u64 * self.size))?;
self.offset += size as u64; disk.write_all(&buf[..write_size])?;
Ok(size) }
self.offset += write_size as u64;
Ok(write_size)
} }
fn flush(&mut self) -> io::Result<()> { fn flush(&mut self) -> io::Result<()> {