[−][src]Struct static_alloc::bump::Level
Specifies an amount of consumed space of a slab.
Each allocation of the Bump
increases the current level as they must not be empty. By
ensuring that an allocation is performed at a specific level it is thus possible to check that
multiple allocations happened in succession without other intermediate allocations. This
ability in turns makes it possible to group allocations together, for example to initialize a
#[repr(C)]
struct member-by-member or to extend a slice.
Usage
The main use is successively allocating a slice without requiring all data to be present at
once. Other similar interface often require an internal locking mechanism but Level
leaves
the choice to the user. This is not yet encapsulate in a safe API yet Level
makes it easy to
reason about.
static BUMP: Bump<[u64; 4]> = Bump::uninit(); /// Gathers as much data as possible. /// /// An arbitrary amount of data, can't stack allocate! fn gather_data(mut iter: impl Iterator<Item=u64>) -> &'static mut [u64] { let first = match iter.next() { Some(item) => item, None => return &mut [], }; let mut level: Level = BUMP.level(); let mut begin: *mut u64; let mut count; match BUMP.leak_at(first, level) { Ok((first, first_level)) => { begin = first; level = first_level; count = 1; }, _ => return &mut [], } let _ = iter.try_for_each(|value: u64| { match BUMP.leak_at(value, level) { Err(err) => return Err(err), Ok((_, new_level)) => level = new_level, }; count += 1; Ok(()) }); unsafe { // SAFETY: all `count` allocations are contiguous, begin is well aligned and no // reference is currently pointing at any of the values. The lifetime is `'static` as // the BUMP itself is static. slice::from_raw_parts_mut(begin, count) } } fn main() { // There is no other thread running, so this succeeds. let slice = gather_data(0..=3); assert_eq!(slice, [0, 1, 2, 3]); }
Trait Implementations
impl Clone for Level
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fn clone(&self) -> Level
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fn clone_from(&mut self, source: &Self)
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impl Copy for Level
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impl Debug for Level
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impl Eq for Level
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impl Hash for Level
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fn hash<__H: Hasher>(&self, state: &mut __H)
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fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
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H: Hasher,
impl Ord for Level
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fn cmp(&self, other: &Level) -> Ordering
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fn max(self, other: Self) -> Self
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fn min(self, other: Self) -> Self
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fn clamp(self, min: Self, max: Self) -> Self
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impl PartialEq<Level> for Level
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impl PartialOrd<Level> for Level
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fn partial_cmp(&self, other: &Level) -> Option<Ordering>
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fn lt(&self, other: &Level) -> bool
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fn le(&self, other: &Level) -> bool
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fn gt(&self, other: &Level) -> bool
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fn ge(&self, other: &Level) -> bool
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impl StructuralEq for Level
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impl StructuralPartialEq for Level
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Auto Trait Implementations
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,