Struct FileReader 

pub struct FileReader<'a, D: BlockDevice> { /* private fields */ }

Streaming file reader.

Reads file data sequentially with zero heap allocation. Supports both OFS and FFS filesystems.

Example

let mut reader = FileReader::new(&device, FsType::Ffs, file_header_block)?;
let mut buf = [0u8; 1024];
loop {
    let n = reader.read(&mut buf)?;
    if n == 0 {
        break; // EOF
    }
    // Process buf[..n]
}

Implementations

impl<'a, D: BlockDevice> FileReader<'a, D>

pub fn new( device: &'a D, fs_type: FsType, header_block: u32, ) -> Result<Self, AffsError>

Create a new file reader from a file header block.

Arguments

• device - Block device to read from
• fs_type - Filesystem type (OFS or FFS)
• header_block - Block number of the file header

pub fn from_entry( device: &'a D, fs_type: FsType, header_block: u32, entry: &EntryBlock, ) -> Result<Self, AffsError>

Create a file reader from an already-parsed entry block.

This avoids re-reading the header block if you already have it.

Arguments

• device - Block device to read from
• fs_type - Filesystem type (OFS or FFS)
• header_block - Block number of the file header
• entry - Already-parsed entry block

pub const fn size(&self) -> u32

Get the total file size in bytes.

pub const fn header_block(&self) -> u32

Get the block number of the file header.

pub const fn remaining(&self) -> u32

Get the number of bytes remaining to read.

pub const fn is_eof(&self) -> bool

Check if we’ve reached end of file.

pub const fn position(&self) -> u32

Get current position in the file.

pub fn reset(&mut self)

Reset the reader to the beginning of the file.

This restores all internal state to allow reading from the start.

pub fn read(&mut self, out: &mut [u8]) -> Result<usize, AffsError>

Read data into a buffer.

Returns the number of bytes read. Returns 0 at end of file.

pub fn read_all(&mut self, out: &mut [u8]) -> Result<usize, AffsError>

Read the entire file into a buffer.

The buffer must be at least as large as the file size. Returns the number of bytes read.

pub fn seek(&mut self, position: u32) -> Result<(), AffsError>

Seek to a specific position in the file.

Note: Seeking backwards resets to the beginning and seeks forward, which may need to re-read extension blocks for large files.