Struct positioned_io_preview::RandomAccessFile

pub struct RandomAccessFile { /* fields omitted */ }

A wrapper for File that provides optimized random access through ReadAt and WriteAt.

• On Unix the operating system is advised that reads will be in random order (FADV_RANDOM).
• On Windows the implementation is orders of magnitude faster than ReadAt directly on File.

Examples

Read the fifth 512-byte sector of a file:

use positioned_io::{RandomAccessFile, ReadAt};

// open a file (note: binding does not need to be mut)
let raf = RandomAccessFile::open("tests/pi.txt")?;

// read up to 512 bytes
let mut buf = [0; 512];
let bytes_read = raf.read_at(2048, &mut buf)?;

Methods

impl RandomAccessFile

pub fn open<P: AsRef<Path>>(path: P) -> Result<RandomAccessFile>

Opens a file for random access.

pub fn try_new(file: File) -> Result<RandomAccessFile>

Creates a RandomAccessFile wrapper around a File.

pub fn try_into_inner(self) -> Result<File, (RandomAccessFile, Error)>

Tries to unwrap the inner File.

Trait Implementations

impl ReadAt for RandomAccessFile

fn read_at(&self, pos: u64, buf: &mut [u8]) -> Result<usize>

Reads bytes from an offset in this source into a buffer, returning how many bytes were read.

fn read_exact_at(&self, pos: u64, buf: &mut [u8]) -> Result<()>

Reads the exact number of bytes required to fill buf from an offset.

impl WriteAt for RandomAccessFile

fn write_at(&mut self, pos: u64, buf: &[u8]) -> Result<usize>

Writes bytes from a buffer to an offset, returning the number of bytes written.

fn flush(&mut self) -> Result<()>

Flush this writer, ensuring that any intermediately buffered data reaches its destination.

fn write_all_at(&mut self, pos: u64, buf: &[u8]) -> Result<()>

Writes a complete buffer at an offset.

impl Debug for RandomAccessFile

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.