Implement reading files beyond cluster (untested).

src/dir.rs

@@ -1,6 +1,5 @@
 use std::io::prelude::*;
 use std::io;
-use std::io::Cursor;
 use std::str;
 use byteorder::{LittleEndian, ReadBytesExt};
 use chrono::{DateTime, Date, TimeZone, Local};
@@ -96,17 +95,8 @@ impl FatDir {
     
     pub fn list(&mut self) -> io::Result<Vec<FatDirEntry>> {
         let mut entries = Vec::new();
-        let cluster_size = self.state.borrow().get_cluster_size() as usize;
-        let mut buf = vec![0; cluster_size];
         loop {
-            let size = self.rdr.read(&mut buf)?;
+            let entry = self.read_dir_entry()?;
-            if size == 0 {
-                break;
-            }
-            
-            let mut cur = Cursor::new(&buf[..size]);
-            loop {
-                let entry = self.read_dir_entry(&mut cur)?;
             if entry.name[0] == 0 {
                 break; // end of dir
             }
@@ -115,27 +105,27 @@ impl FatDir {
             }
             entries.push(entry);
         }
-        }
         
         Ok(entries)
     }
     
-    fn read_dir_entry(&self, rdr: &mut Read) -> io::Result<FatDirEntry> {
+    fn read_dir_entry(&mut self) -> io::Result<FatDirEntry> {
         let mut name = [0; 11];
-        rdr.read(&mut name)?;
+        self.rdr.read(&mut name)?;
+        let attrs = FatFileAttributes::from_bits(self.rdr.read_u8()?).expect("invalid attributes");
         Ok(FatDirEntry {
-            name:             name,
+            name,
-            attrs:            FatFileAttributes::from_bits(rdr.read_u8()?).unwrap(),
+            attrs,
-            reserved_0:       rdr.read_u8()?,
+            reserved_0:       self.rdr.read_u8()?,
-            create_time_0:    rdr.read_u8()?,
+            create_time_0:    self.rdr.read_u8()?,
-            create_time_1:    rdr.read_u16::<LittleEndian>()?,
+            create_time_1:    self.rdr.read_u16::<LittleEndian>()?,
-            create_date:      rdr.read_u16::<LittleEndian>()?,
+            create_date:      self.rdr.read_u16::<LittleEndian>()?,
-            access_date:      rdr.read_u16::<LittleEndian>()?,
+            access_date:      self.rdr.read_u16::<LittleEndian>()?,
-            first_cluster_hi: rdr.read_u16::<LittleEndian>()?,
+            first_cluster_hi: self.rdr.read_u16::<LittleEndian>()?,
-            modify_time:      rdr.read_u16::<LittleEndian>()?,
+            modify_time:      self.rdr.read_u16::<LittleEndian>()?,
-            modify_date:      rdr.read_u16::<LittleEndian>()?,
+            modify_date:      self.rdr.read_u16::<LittleEndian>()?,
-            first_cluster_lo: rdr.read_u16::<LittleEndian>()?,
+            first_cluster_lo: self.rdr.read_u16::<LittleEndian>()?,
-            size:             rdr.read_u32::<LittleEndian>()?,
+            size:             self.rdr.read_u32::<LittleEndian>()?,
             state:            self.state.clone(),
         })
     }

src/file.rs

@@ -7,35 +7,50 @@ use fs::FatSharedStateRef;
 
 #[allow(dead_code)]
 pub struct FatFile {
-    first_sector: u32,
+    first_cluster: u32,
     size: u32,
     offset: u32,
+    current_cluster: Option<u32>,
     state: FatSharedStateRef,
 }
 
 impl FatFile {
     pub(crate) fn new(first_cluster: u32, size: u32, state: FatSharedStateRef) -> FatFile {
-        let first_sector = state.borrow().sector_from_cluster(first_cluster);
         FatFile {
-            first_sector, size, state, offset: 0,
+            first_cluster, size, state,
+            current_cluster: Some(first_cluster),
+            offset: 0,
         }
     }
 }
 
 impl Read for FatFile {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let (offset, read_size) = {
+        let mut buf_offset: usize = 0;
-            let state = self.state.borrow();
+        let cluster_size = self.state.borrow().get_cluster_size();
-            let offset = state.offset_from_sector(self.first_sector) + self.offset as u64;
-            let mut read_size = cmp::min((self.size - self.offset) as usize, buf.len());
-            // FIXME: allow only one cluster for now
-            read_size = cmp::min(read_size, (state.get_cluster_size() - self.offset) as usize);
-            (offset, read_size)
-        };
         let mut state = self.state.borrow_mut();
-        state.rdr.seek(SeekFrom::Start(offset))?;
+        loop {
-        let size = state.rdr.read(&mut buf[..read_size])?;
+            let offset_in_cluster = self.offset % cluster_size;
-        self.offset += size as u32;
+            let bytes_left_in_cluster = (cluster_size - offset_in_cluster) as usize;
-        Ok(size)
+            let bytes_left_in_file = (self.size - self.offset) as usize;
+            let bytes_left_in_buf = buf.len() - buf_offset;
+            let read_size = cmp::min(cmp::min(bytes_left_in_file, bytes_left_in_cluster), bytes_left_in_buf);
+            if read_size == 0 {
+                break;
+            }
+            let current_cluster = self.current_cluster.unwrap();
+            let offset_in_fs = state.offset_from_cluster(current_cluster) + (offset_in_cluster as u64);
+            state.rdr.seek(SeekFrom::Start(offset_in_fs))?;
+            let read_bytes = state.rdr.read(&mut buf[buf_offset..buf_offset+read_size])?;
+            if read_bytes == 0 {
+                break;
+            }
+            self.offset += read_bytes as u32;
+            buf_offset += read_bytes;
+            if self.offset % cluster_size == 0 {
+                self.current_cluster = state.table.get_next_cluster(current_cluster);
+            }
+        }
+        Ok(buf_offset)
     }
 }

src/fs.rs

@@ -48,11 +48,8 @@ impl FatSharedState {
         self.boot.bpb.sectors_per_cluster as u32 * self.boot.bpb.bytes_per_sector as u32
     }
     
-    pub(crate) fn get_root_dir_sector(&self) -> u32 {
+    pub(crate) fn offset_from_cluster(&self, cluser: u32) -> u64 {
-        match self.fat_type {
+        self.offset_from_sector(self.sector_from_cluster(cluser))
-            FatType::Fat12 | FatType::Fat16 => self.first_data_sector - self.root_dir_sectors,
-            _ => self.sector_from_cluster(self.boot.bpb.root_cluster)
-        }
     }
 }
 
@@ -242,10 +239,6 @@ impl FatFileSystem {
         Ok(boot)
     }
     
-    // pub(crate) fn offset_from_cluster(&self, cluser: u32) -> u64 {
-    //     self.offset_from_sector(self.sector_from_cluster(cluser))
-    // }
-    
     pub fn root_dir(&mut self) -> FatDir {
         let state = self.state.borrow();
         let root_rdr: Box<Read> = match state.fat_type {
@@ -277,12 +270,8 @@ impl FatSlice {
 
 impl Read for FatSlice {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let (offset, read_size) = {
-            let state = self.state.borrow();
         let offset = self.begin + self.offset;
-            let mut read_size = cmp::min((self.size - self.offset) as usize, buf.len());
+        let read_size = cmp::min((self.size - self.offset) as usize, buf.len());
-            (offset, read_size)
-        };
         let mut state = self.state.borrow_mut();
         state.rdr.seek(SeekFrom::Start(offset))?;
         let size = state.rdr.read(&mut buf[..read_size])?;