flatty_base/utils/
mem.rs

1use crate::{
2    error::{Error, ErrorKind},
3    traits::FlatBase,
4};
5use core::{ptr, ptr::NonNull};
6
7/// Check that memory size and alignment are suitable for `Self`.
8pub fn check_align_and_min_size<T: FlatBase + ?Sized>(bytes: &[u8]) -> Result<(), Error> {
9    if bytes.as_ptr().align_offset(T::ALIGN) != 0 {
10        Err(Error {
11            kind: ErrorKind::BadAlign,
12            pos: 0,
13        })
14    } else if bytes.len() < T::MIN_SIZE {
15        Err(Error {
16            kind: ErrorKind::InsufficientSize,
17            pos: 0,
18        })
19    } else {
20        Ok(())
21    }
22}
23
24pub unsafe fn slice_ptr_len<T>(slice: *mut [T]) -> usize {
25    unsafe { NonNull::new_unchecked(slice) }.len()
26}
27
28pub unsafe fn set_slice_ptr_len<T>(bytes: *mut [T], len: usize) -> *mut [T] {
29    ptr::slice_from_raw_parts_mut(bytes as *mut T, len)
30}
31
32pub unsafe fn offset_slice_ptr_start<T>(slice: *mut [T], count: isize) -> *mut [T] {
33    let (ptr, len) = (slice as *mut T, slice_ptr_len(slice));
34    ptr::slice_from_raw_parts_mut(ptr.offset(count), (len as isize - count) as usize)
35}
36
37#[doc(hidden)]
38#[macro_export]
39macro_rules! cast_wide_ptr_with_offset {
40    ($Type:ty, $ptr:expr, $count:expr $(,)?) => {{
41        let wptr = $ptr as *mut [u8];
42        let (ptr, len) = (wptr as *mut u8, ::core::ptr::NonNull::new_unchecked(wptr as *mut [u8]).len());
43        ::core::ptr::slice_from_raw_parts_mut(ptr.offset($count as isize), len) as *mut $Type
44    }};
45}
46pub use cast_wide_ptr_with_offset;
flatty_base/utils/mem.rs

flatty_base/utils/
mem.rs
