Struct base::VolatileSlice

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#[repr(transparent)]
pub struct VolatileSlice<'a>(IoBufMut<'a>);

Expand description

A slice of raw memory that supports volatile access. Like std::io::IoSliceMut, this type is guaranteed to be ABI-compatible with libc::iovec but unlike IoSliceMut, it doesn’t automatically deref to &mut [u8].

Tuple Fields§

§0: IoBufMut<'a>

Implementations§

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impl<'a> VolatileSlice<'a>

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pub fn new(buf: &mut [u8]) -> VolatileSlice<'_> ⓘ

Creates a slice of raw memory that must support volatile access.

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pub unsafe fn from_raw_parts(addr: *mut u8, len: usize) -> VolatileSlice<'a> ⓘ

Creates a VolatileSlice from a pointer and a length.

§Safety

In order to use this method safely, addr must be valid for reads and writes of len bytes and should live for the entire duration of lifetime 'a.

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pub fn as_ptr(&self) -> *const u8

Gets a const pointer to this slice’s memory.

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pub fn as_mut_ptr(&self) -> *mut u8

Gets a mutable pointer to this slice’s memory.

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pub fn size(&self) -> usize

Gets the size of this slice.

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pub fn advance(&mut self, count: usize)

Advance the starting position of this slice.

Panics if count > self.size().

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pub fn truncate(&mut self, len: usize)

Shorten the length of the slice.

Has no effect if len > self.size().

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pub fn as_iobuf(&self) -> &IoBufMut<'_>

Returns this VolatileSlice as an IoBufMut.

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pub fn as_iobufs<'mem, 'slice>( iovs: &'slice [VolatileSlice<'mem>] ) -> &'slice [IoBufMut<'mem>]

Converts a slice of VolatileSlices into a slice of IoBufMuts

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pub fn as_iobufs_mut<'mem, 'slice>( iovs: &'slice mut [VolatileSlice<'mem>] ) -> &'slice mut [IoBufMut<'mem>]

Converts a mutable slice of VolatileSlices into a mutable slice of IoBufMuts

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pub fn offset(self, count: usize) -> VolatileMemoryResult<VolatileSlice<'a>>

Creates a copy of this slice with the address increased by count bytes, and the size reduced by count bytes.

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pub fn sub_slice( self, offset: usize, count: usize ) -> VolatileMemoryResult<VolatileSlice<'a>>

Similar to get_slice but the returned slice outlives this slice.

The returned slice’s lifetime is still limited by the underlying data’s lifetime.

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pub fn write_bytes(&self, value: u8)

Sets each byte of this slice with the given byte, similar to memset.

The bytes of this slice are accessed in an arbitray order.

§Examples

let mut mem = [0u8; 32];
let vslice = VolatileSlice::new(&mut mem[..]);
vslice.write_bytes(45);
for &v in &mem[..] {
    assert_eq!(v, 45);
}

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pub fn copy_to<T>(&self, buf: &mut [T])
where T: FromBytes + AsBytes + Copy,

Copies self.size() or buf.len() times the size of T bytes, whichever is smaller, to buf.

The copy happens from smallest to largest address in T sized chunks using volatile reads.

§Examples

let mut mem = [0u8; 32];
let vslice = VolatileSlice::new(&mut mem[..]);
let mut buf = [5u8; 16];
vslice.copy_to(&mut buf[..]);
for v in &buf[..] {
    assert_eq!(buf[0], 0);
}

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pub fn copy_to_volatile_slice(&self, slice: VolatileSlice<'_>)

Copies self.size() or slice.size() bytes, whichever is smaller, to slice.

The copies happen in an undefined order.

§Examples

let mut mem = [0u8; 32];
let vslice = VolatileSlice::new(&mut mem[..]);
vslice.copy_to_volatile_slice(vslice.get_slice(16, 16).map_err(|_| ())?);

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pub fn copy_from<T>(&self, buf: &[T])
where T: FromBytes + AsBytes,

Copies self.size() or buf.len() times the size of T bytes, whichever is smaller, to this slice’s memory.

The copy happens from smallest to largest address in T sized chunks using volatile writes.

§Examples

let mut mem = [0u8; 32];
let vslice = VolatileSlice::new(&mut mem[..]);
let buf = [5u8; 64];
vslice.copy_from(&buf[..]);
let mut copy_buf = [0u32; 4];
vslice.copy_to(&mut copy_buf);
for i in 0..4 {
    assert_eq!(copy_buf[i], 0x05050505);
}