use std::cmp::min;
use std::io::Result;
use super::{ReadAt, WriteAt, Size};
impl<'a> ReadAt for &'a [u8] {
fn read_at(&self, pos: u64, buf: &mut [u8]) -> Result<usize> {
if pos >= self.len() as u64 {
return Ok(0);
}
let pos = pos as usize;
let bytes = min(buf.len(), self.len() - pos);
buf[..bytes].copy_from_slice(&self[pos..(pos + bytes)]);
Ok(bytes)
}
}
impl<'a> ReadAt for &'a mut [u8] {
fn read_at(&self, pos: u64, buf: &mut [u8]) -> Result<usize> {
self.as_ref().read_at(pos, buf)
}
}
impl<'a> WriteAt for &'a mut [u8] {
fn write_at(&mut self, pos: u64, buf: &[u8]) -> Result<usize> {
if pos >= self.len() as u64 {
return Ok(0);
}
let pos = pos as usize;
let bytes = min(buf.len(), self.len() - pos);
self[pos..(pos + bytes)].copy_from_slice(&buf[..bytes]);
Ok(bytes)
}
fn flush(&mut self) -> Result<()> {
Ok(())
}
}
impl<'a> Size for &'a [u8] {
fn size(&self) -> Result<Option<u64>> {
Ok(Some(self.len() as u64))
}
}
impl<'a> Size for &'a mut [u8] {
fn size(&self) -> Result<Option<u64>> {
self.as_ref().size()
}
}