use std::alloc::{self, Layout, LayoutErr};
const DEFAULT_ALIGN_BYTES: usize = 4;
#[derive(PartialEq, Eq)]
pub struct Allocation {
layout: Layout,
ptr: *mut u8,
}
impl Allocation {
pub fn new(size: usize, align: Option<usize>) -> Result<Self, LayoutErr> {
let alignment = align.unwrap_or(DEFAULT_ALIGN_BYTES);
let layout = Layout::from_size_align(size, alignment)?;
let ptr = unsafe { alloc::alloc(layout) };
if ptr.is_null() {
alloc::handle_alloc_error(layout);
}
Ok(Self { ptr, layout })
}
pub fn as_mut_ptr(&self) -> *mut u8 {
self.ptr
}
pub fn size(&self) -> usize {
self.layout.size()
}
pub fn align(&self) -> usize {
self.layout.align()
}
pub fn as_slice(&self) -> &[u8] {
unsafe { std::slice::from_raw_parts(self.as_mut_ptr(), self.size()) }
}
pub fn as_mut_slice(&mut self) -> &mut [u8] {
unsafe { std::slice::from_raw_parts_mut(self.as_mut_ptr(), self.size()) }
}
}
impl Drop for Allocation {
fn drop(&mut self) {
unsafe {
alloc::dealloc(self.ptr, self.layout);
}
}
}