Trait repr_offset::ext::ROExtRawOps

pub unsafe trait ROExtRawOps<A>: ROExtRawAcc {
    // Required methods
    unsafe fn f_read_copy<F>(self, offset: FieldOffset<Self::Target, F, A>) -> F
       where F: Copy;
    unsafe fn f_read<F>(self, offset: FieldOffset<Self::Target, F, A>) -> F;
}

Extension trait for raw pointers to do generic field operations, where the field is determined by a FieldOffset parameter.

Safety

This trait must not to be implemented outside the repr_offset crate.

Alignment

The A type parameter is the Alignment of the field, used to implement methods differently depending on whether the field is Aligned or Unaligned.

Required Methods

unsafe fn f_read_copy<F>(self, offset: FieldOffset<Self::Target, F, A>) -> F

where F: Copy,

Copies a field (determined by offset) from self.

Safety

You must ensure these properties about the pointed-to value:

• The value must be in an allocated object (this includes the stack) allocated at least up to the field (inclusive).

• The field must be initialized

• If the passed in offset is a FieldOffset<_, _, Aligned> (because it is for an aligned field), self must be an aligned pointer.

Example

use repr_offset::{
    for_examples::ReprPacked,
    ROExtRawOps, off,
};

use std::cmp::Ordering;

let mut value = ReprPacked {
    a: 3,
    b: Some(5),
    c: Ordering::Less,
    d: (),
};

let ptr: *const _ = &value;
unsafe {
    assert_eq!(ptr.f_read_copy(off!(a)), 3);
    assert_eq!(ptr.f_read_copy(off!(b)), Some(5));
    assert_eq!(ptr.f_read_copy(off!(c)), Ordering::Less);
}

unsafe fn f_read<F>(self, offset: FieldOffset<Self::Target, F, A>) -> F

Reads a copy of a field (determined by offset) from self, without mutating or moving the field.

Safety

You must ensure these properties about the pointed-to value:

• The value must be in an allocated object (this includes the stack) allocated at least up to the field (inclusive).

• The field must be initialized

• If the passed in offset is a FieldOffset<_, _, Aligned> (because it is for an aligned field), self must be an aligned pointer.

Example

use repr_offset::{
    for_examples::ReprPacked,
    ROExtRawOps, off,
};

use std::{cmp::Ordering, mem::ManuallyDrop};

let mut value = ManuallyDrop::new(ReprPacked {
    a: 3,
    b: Some(5),
    c: "hello".to_string(),
    d: vec![0, 1, 2],
});

let ptr: *const ReprPacked<_, _, _, _> = &*value;
unsafe {
    assert_eq!(ptr.f_read(off!(a)), 3);
    assert_eq!(ptr.f_read(off!(b)), Some(5));
    assert_eq!(ptr.f_read(off!(c)), "hello".to_string());
    assert_eq!(ptr.f_read(off!(d)), vec![0, 1, 2]);
}

Object Safety

This trait is not object safe.

Implementations on Foreign Types

impl<S> ROExtRawOps<Aligned> for *const S

unsafe fn f_read_copy<F>( self, offset: FieldOffset<Self::Target, F, Aligned>, ) -> F

where F: Copy,

unsafe fn f_read<F>(self, offset: FieldOffset<Self::Target, F, Aligned>) -> F

impl<S> ROExtRawOps<Aligned> for *mut S

unsafe fn f_read_copy<F>( self, offset: FieldOffset<Self::Target, F, Aligned>, ) -> F

where F: Copy,

unsafe fn f_read<F>(self, offset: FieldOffset<Self::Target, F, Aligned>) -> F

impl<S> ROExtRawOps<Unaligned> for *const S

unsafe fn f_read_copy<F>( self, offset: FieldOffset<Self::Target, F, Unaligned>, ) -> F

where F: Copy,

unsafe fn f_read<F>(self, offset: FieldOffset<Self::Target, F, Unaligned>) -> F

impl<S> ROExtRawOps<Unaligned> for *mut S

unsafe fn f_read_copy<F>( self, offset: FieldOffset<Self::Target, F, Unaligned>, ) -> F

where F: Copy,

unsafe fn f_read<F>(self, offset: FieldOffset<Self::Target, F, Unaligned>) -> F

Implementors