/rust/registry/src/index.crates.io-1949cf8c6b5b557f/rustix-1.0.7/src/utils.rs

Source
//! Miscellaneous minor utilities.

#![allow(dead_code)]
#![allow(unused_macros)]

use core::ffi::c_void;
use core::mem::{align_of, size_of};
use core::ptr::{null, null_mut, NonNull};

/// Convert a `&T` into a `*const T` without using an `as`.
#[inline]
pub(crate) const fn as_ptr<T>(t: &T) -> *const T {
    t
}

/// Convert a `&mut T` into a `*mut T` without using an `as`.
#[inline]
pub(crate) fn as_mut_ptr<T>(t: &mut T) -> *mut T {
    t
}

/// Convert an `Option<&T>` into a possibly-null `*const T`.
#[inline]
pub(crate) const fn option_as_ptr<T>(t: Option<&T>) -> *const T {
    match t {
        Some(t) => t,
        None => null(),
    }
}

/// Convert an `Option<&mut T>` into a possibly-null `*mut T`.
#[inline]
pub(crate) fn option_as_mut_ptr<T>(t: Option<&mut T>) -> *mut T {
    match t {
        Some(t) => t,
        None => null_mut(),
    }
}

/// Convert a `*mut c_void` to a `*mut T`, checking that it is not null,
/// misaligned, or pointing to a region of memory that wraps around the address
/// space.
pub(crate) fn check_raw_pointer<T>(value: *mut c_void) -> Option<NonNull<T>> {
    if (value as usize).checked_add(size_of::<T>()).is_none()
        || (value as usize) % align_of::<T>() != 0
    {
        return None;
    }

    NonNull::new(value.cast())
}

/// Create a union value containing a default value in one of its arms.
///
/// The field names a union field which must have the same size as the union
/// itself.
macro_rules! default_union {
    ($union:ident, $field:ident) => {{
        let u = $union {
            $field: Default::default(),
        };

        // Assert that the given field initializes the whole union.
        #[cfg(test)]
        unsafe {
            let field_value = u.$field;
            assert_eq!(
                core::mem::size_of_val(&u),
                core::mem::size_of_val(&field_value)
            );
            const_assert_eq!(memoffset::offset_of_union!($union, $field), 0);
        }

        u
    }};
}

Line	Count	Source
1		//! Miscellaneous minor utilities.
2
3		#![allow(dead_code)]
4		#![allow(unused_macros)]
5
6		use core::ffi::c_void;
7		use core::mem::{align_of, size_of};
8		use core::ptr::{null, null_mut, NonNull};
9
10		/// Convert a `&T` into a `*const T` without using an `as`.
11		#[inline]
12	0	pub(crate) const fn as_ptr<T>(t: &T) -> *const T {
13	0	t
14	0	} Unexecuted instantiation: rustix::utils::as_ptr::<rustix::event::epoll::Event> Unexecuted instantiation: rustix::utils::as_ptr::<[i8; 108]> Unexecuted instantiation: rustix::utils::as_ptr::<core::mem::maybe_uninit::MaybeUninit<libc::unix::linux_like::sockaddr_storage>> Unexecuted instantiation: rustix::utils::as_ptr::<rustix::timespec::Timespec> Unexecuted instantiation: rustix::utils::as_ptr::<rustix::fs::fd::Timestamps> Unexecuted instantiation: rustix::utils::as_ptr::<libc::unix::linux_like::sockaddr_un> Unexecuted instantiation: rustix::utils::as_ptr::<libc::unix::linux_like::sockaddr_storage>
15
16		/// Convert a `&mut T` into a `*mut T` without using an `as`.
17		#[inline]
18	0	pub(crate) fn as_mut_ptr<T>(t: &mut T) -> *mut T {
19	0	t
20	0	} Unexecuted instantiation: rustix::utils::as_mut_ptr::<libc::unix::linux_like::sockaddr_storage> Unexecuted instantiation: rustix::utils::as_mut_ptr::<u64>
21
22		/// Convert an `Option<&T>` into a possibly-null `*const T`.
23		#[inline]
24	0	pub(crate) const fn option_as_ptr<T>(t: Option<&T>) -> *const T {
25	0	match t {
26	0	Some(t) => t,
27	0	None => null(),
28		}
29	0	}
30
31		/// Convert an `Option<&mut T>` into a possibly-null `*mut T`.
32		#[inline]
33	0	pub(crate) fn option_as_mut_ptr<T>(t: Option<&mut T>) -> *mut T {
34	0	match t {
35	0	Some(t) => t,
36	0	None => null_mut(),
37		}
38	0	}
39
40		/// Convert a `mut c_void` to a `mut T`, checking that it is not null,
41		/// misaligned, or pointing to a region of memory that wraps around the address
42		/// space.
43	0	pub(crate) fn check_raw_pointer<T>(value: *mut c_void) -> Option<NonNull<T>> {
44	0	if (value as usize).checked_add(size_of::<T>()).is_none()
45	0	\|\| (value as usize) % align_of::<T>() != 0
46		{
47	0	return None;
48	0	}
49
50	0	NonNull::new(value.cast())
51	0	}
52
53		/// Create a union value containing a default value in one of its arms.
54		///
55		/// The field names a union field which must have the same size as the union
56		/// itself.
57		macro_rules! default_union {
58		($union:ident, $field:ident) => {{
59		let u = $union {
60		$field: Default::default(),
61		};
62
63		// Assert that the given field initializes the whole union.
64		#[cfg(test)]
65		unsafe {
66		let field_value = u.$field;
67		assert_eq!(
68		core::mem::size_of_val(&u),
69		core::mem::size_of_val(&field_value)
70		);
71		const_assert_eq!(memoffset::offset_of_union!($union, $field), 0);
72		}
73
74		u
75		}};
76		}

Coverage Report

Created: 2025-12-31 06:16