[−][src]Trait positioned_io_preview::ReadAt
Trait for reading bytes at an offset.
Implementations should be able to read bytes without changing any sort of
read position. Self should not change at all. Buffering reads is unlikely
to be useful, since each time read_at()
is called, the position may be
completely different.
Examples
Read the fifth 512-byte sector of a file:
use std::fs::File; use positioned_io::ReadAt; // note that file does not need to be mut let file = File::open("tests/pi.txt")?; // read up to 512 bytes let mut buf = [0; 512]; let bytes_read = file.read_at(2048, &mut buf)?;
Required methods
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.
This function may yield fewer bytes than the size of buf
, if it was
interrupted or hit the "end of file".
See Read::read()
for details.
Provided methods
fn read_exact_at(&self, pos: u64, buf: &mut [u8]) -> Result<()>
Reads the exact number of bytes required to fill buf
from an offset.
Errors if the "end of file" is encountered before filling the buffer.
See Read::read_exact()
for details.