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//! The following is derived from Rust's
//! library/std/src/sys/unix/io.rs
//! dca3f1b786efd27be3b325ed1e01e247aa589c3b.
//!
//! All code in this file is licensed MIT or Apache 2.0 at your option.
#![allow(unsafe_code)]
use crate::backend::c;
#[cfg(not(linux_raw))]
use c::size_t as __kernel_size_t;
use core::marker::PhantomData;
use core::slice;
#[cfg(linux_raw)]
use linux_raw_sys::general::__kernel_size_t;
#[derive(Copy, Clone)]
#[repr(transparent)]
pub struct IoSlice<'a> {
vec: c::iovec,
_p: PhantomData<&'a [u8]>,
}
impl<'a> IoSlice<'a> {
#[inline]
pub fn new(buf: &'a [u8]) -> IoSlice<'a> {
IoSlice {
vec: c::iovec {
iov_base: buf.as_ptr() as *mut u8 as *mut c::c_void,
iov_len: buf.len() as _,
},
_p: PhantomData,
}
}
#[inline]
pub fn advance(&mut self, n: usize) {
if self.vec.iov_len < n as _ {
panic!("advancing IoSlice beyond its length");
}
unsafe {
// `__kernel_size_t` will always have the same size as `usize`, but it is a `u32` on
// 32-bit platforms and `u64` on 64-bit platforms when using `linux_raw` backend
self.vec.iov_len -= n as __kernel_size_t;
self.vec.iov_base = self.vec.iov_base.add(n);
}
}
#[inline]
pub fn as_slice(&self) -> &[u8] {
unsafe { slice::from_raw_parts(self.vec.iov_base as *mut u8, self.vec.iov_len as usize) }
}
}
#[repr(transparent)]
pub struct IoSliceMut<'a> {
vec: c::iovec,
_p: PhantomData<&'a mut [u8]>,
}
impl<'a> IoSliceMut<'a> {
#[inline]
pub fn new(buf: &'a mut [u8]) -> IoSliceMut<'a> {
IoSliceMut {
vec: c::iovec {
iov_base: buf.as_mut_ptr() as *mut c::c_void,
iov_len: buf.len() as _,
},
_p: PhantomData,
}
}
#[inline]
pub fn advance(&mut self, n: usize) {
if self.vec.iov_len < n as _ {
panic!("advancing IoSliceMut beyond its length");
}
unsafe {
// `__kernel_size_t` will always have the same size as `usize`, but it is a `u32` on
// 32-bit platforms and `u64` on 64-bit platforms when using `linux_raw` backend
self.vec.iov_len -= n as __kernel_size_t;
self.vec.iov_base = self.vec.iov_base.add(n);
}
}
#[inline]
pub fn as_slice(&self) -> &[u8] {
unsafe { slice::from_raw_parts(self.vec.iov_base as *mut u8, self.vec.iov_len as usize) }
}
#[inline]
pub fn as_mut_slice(&mut self) -> &mut [u8] {
unsafe {
slice::from_raw_parts_mut(self.vec.iov_base as *mut u8, self.vec.iov_len as usize)
}
}
}