Struct bump_scope::BumpScope

pub struct BumpScope<'a, A = Global, const MIN_ALIGN: usize = 1, const UP: bool = true, const GUARANTEED_ALLOCATED: bool = true> { /* private fields */ }

A bump allocation scope whose allocations are valid for the lifetime of its associated BumpScopeGuard or closure.

Alternatively a Bump can be turned into a BumpScope with as_scope, as_mut_scope and into.

You can see examples in the crate documentation.

Implementations

impl<'a, A, const MIN_ALIGN: usize, const UP: bool> BumpScope<'a, A, MIN_ALIGN, UP>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<true>,

These functions are only available if the BumpScope is guaranteed allocated.

pub fn scoped<R>( &mut self, f: impl FnOnce(BumpScope<'_, A, MIN_ALIGN, UP>) -> R, ) -> R

Calls f with a new child scope.

Examples

let mut bump: Bump = Bump::new();

bump.scoped(|bump| {
    bump.alloc_str("Hello world!");
    assert_eq!(bump.stats().allocated(), 12);
});

assert_eq!(bump.stats().allocated(), 0);

pub fn scoped_aligned<const NEW_MIN_ALIGN: usize, R>( &mut self, f: impl FnOnce(BumpScope<'_, A, MIN_ALIGN, UP>) -> R, ) -> R

where MinimumAlignment<NEW_MIN_ALIGN>: SupportedMinimumAlignment,

Calls f with a new child scope of a new minimum alignment.

pub fn scope_guard(&mut self) -> BumpScopeGuard<'_, A, MIN_ALIGN, UP>

Creates a new BumpScopeGuard. This allows for creation of child scopes.

Examples

let mut bump: Bump = Bump::new();

{
    let mut guard = bump.scope_guard();
    let bump = guard.scope();
    bump.alloc_str("Hello world!");
    assert_eq!(bump.stats().allocated(), 12);
}

assert_eq!(bump.stats().allocated(), 0);

pub fn aligned<const NEW_MIN_ALIGN: usize, R>( &mut self, f: impl FnOnce(BumpScope<'_, A, NEW_MIN_ALIGN, UP>) -> R, ) -> R

where MinimumAlignment<NEW_MIN_ALIGN>: SupportedMinimumAlignment,

Calls f with this scope but with a new minimum alignment.

pub fn checkpoint(&self) -> Checkpoint

Creates a checkpoint of the current bump position.

Examples

let checkpoint = bump.checkpoint();

{
    let hello = bump.alloc_str("hello");
    assert_eq!(bump.stats().allocated(), 5);
}

unsafe { bump.reset_to(checkpoint); }
assert_eq!(bump.stats().allocated(), 0);

pub unsafe fn reset_to(&self, checkpoint: Checkpoint)

Resets the bump position to a previously created checkpoint. The memory that has been allocated since then will be reused by future allocations.

Safety

• the checkpoint must have been created by this bump allocator
• the bump allocator must not have been reset since creation of this checkpoint
• there must be no references to allocations made since creation of this checkpoint

pub fn guaranteed_allocated_stats(&self) -> GuaranteedAllocatedStats<'a, UP>

Returns a type which provides statistics about the memory usage of the bump allocator.

impl<'a, A, const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool> BumpScope<'a, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED>,

pub fn stats(&self) -> Stats<'a, UP>

Returns a type which provides statistics about the memory usage of the bump allocator.

pub fn allocator(&self) -> &A

Returns a reference to the base allocator.

pub fn without_dealloc(&self) -> WithoutDealloc<&Self>

Wraps &self in WithoutDealloc so that deallocate becomes a no-op.

pub fn without_shrink(&self) -> WithoutShrink<&Self>

Wraps &self in WithoutShrink so that shrink becomes a no-op.

pub fn as_scope(&self) -> &Self

Returns &self as is. This is useful for macros that support both Bump and BumpScope, like bump_vec!.

pub fn as_mut_scope(&mut self) -> &mut Self

Returns &mut self as is. This is useful for macros that support both Bump and BumpScope, like mut_bump_vec!.

pub fn into_aligned<const NEW_MIN_ALIGN: usize>( self, ) -> BumpScope<'a, A, NEW_MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<NEW_MIN_ALIGN>: SupportedMinimumAlignment,

Converts this BumpScope into a BumpScope with a new minimum alignment.

This can not decrease the alignment. Trying to decrease alignment will result in a compile error. You can use aligned or scoped_aligned to decrease the alignment.

This mustn't decrease alignment because otherwise you could do this:

let mut bump: Bump<Global, 8, true> = Bump::new();
let mut guard = bump.scope_guard();

{
    let scope = guard.scope().into_aligned::<1>();
    scope.alloc(0u8);
}

{
    let scope = guard.scope();
    // scope is not aligned to `MIN_ALIGN`!!
}

pub fn as_aligned_mut<const NEW_MIN_ALIGN: usize>( &mut self, ) -> &mut BumpScope<'a, A, NEW_MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<NEW_MIN_ALIGN>: SupportedMinimumAlignment,

Mutably borrows BumpScope with a new minimum alignment.

This can not decrease the alignment. Trying to decrease alignment will result in a compile error. You can use aligned or scoped_aligned to decrease the alignment.

pub fn into_guaranteed_allocated(self) -> BumpScope<'a, A, MIN_ALIGN, UP>

Converts this BumpScope into a guaranteed allocated BumpScope.

Panics

Panics if the allocation fails.

pub fn try_into_guaranteed_allocated( self, ) -> Result<BumpScope<'a, A, MIN_ALIGN, UP>, AllocError>

Converts this BumpScope into a guaranteed allocated BumpScope.

Errors

Errors if the allocation fails.

pub fn as_guaranteed_allocated(&self) -> &BumpScope<'a, A, MIN_ALIGN, UP>

Borrows BumpScope in a guaranteed allocated state.

Panics

Panics if the allocation fails.

pub fn try_as_guaranteed_allocated( &self, ) -> Result<&BumpScope<'a, A, MIN_ALIGN, UP>, AllocError>

Borrows BumpScope in a guaranteed allocated state.

Errors

Errors if the allocation fails.

pub fn as_guaranteed_allocated_mut( &mut self, ) -> &mut BumpScope<'a, A, MIN_ALIGN, UP>

Mutably borrows BumpScope in a guaranteed allocated state.

Panics

Panics if the allocation fails.

pub fn try_as_guaranteed_allocated_mut( &mut self, ) -> Result<&mut BumpScope<'a, A, MIN_ALIGN, UP>, AllocError>

Mutably borrows BumpScope in a guaranteed allocated state.

Errors

Errors if the allocation fails.

pub fn into_raw(self) -> NonNull<()>

Converts this BumpScope into a raw pointer.

pub unsafe fn from_raw(ptr: NonNull<()>) -> Self

Converts the raw pointer that was created with into_raw back into a BumpScope.

Safety

This is highly unsafe, due to the number of invariants that aren’t checked:

• ptr must have been created with Self::into_raw.
• This function must only be called once with this ptr.
• The lifetime must be the original one.
• Nothing must have been allocated since then.

impl<'a, A, const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool> BumpScope<'a, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED>,

pub fn alloc_zeroed<T>(&self) -> BumpBox<'a, T>

where T: FromZeroes,

Available on crate feature zerocopy only.

Allocate a zeroed object.

Panics

Panics if the allocation fails.

Examples

let mut bump: Bump = Bump::new();
let zero = bump.alloc_zeroed::<i32>();
assert_eq!(*zero, 0);

pub fn alloc_zeroed_slice<T>(&self, len: usize) -> BumpBox<'a, [T]>

where T: FromZeroes,

Available on crate feature zerocopy only.

Allocate a zeroed object slice.

Panics

Panics if the allocation fails.

Examples

let mut bump: Bump = Bump::new();
let zeroes = bump.alloc_zeroed_slice::<i32>(3);
assert_eq!(*zeroes, [0; 3]);

pub fn try_alloc_zeroed<T>(&self) -> Result<BumpBox<'a, T>, AllocError>

where T: FromZeroes,

Available on crate feature zerocopy only.

Allocate a zeroed object.

Errors

Errors if the allocation fails.

Examples

let mut bump: Bump = Bump::try_new()?;
let zero = bump.try_alloc_zeroed::<i32>()?;
assert_eq!(*zero, 0);

pub fn try_alloc_zeroed_slice<T>( &self, len: usize, ) -> Result<BumpBox<'a, [T]>, AllocError>

where T: FromZeroes,

Available on crate feature zerocopy only.

Allocate a zeroed object slice.

Errors

Errors if the allocation fails.

Examples

let mut bump: Bump = Bump::try_new()?;
let zeroes = bump.try_alloc_zeroed_slice::<i32>(3)?;
assert_eq!(*zeroes, [0; 3]);

impl<'a, A, const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool> BumpScope<'a, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED>,

Functions to allocate. Available as fallible or infallible.

pub fn alloc<T>(&self, value: T) -> BumpBox<'a, T>

Allocate an object.

Panics

Panics if the allocation fails.

Examples

let allocated = bump.alloc(123);
assert_eq!(allocated, 123);

pub fn alloc_with<T>(&self, f: impl FnOnce() -> T) -> BumpBox<'a, T>

Pre-allocate space for an object. Once space is allocated f will be called to create the value to be put at that place. In some situations this can help the compiler realize that T can be constructed at the allocated space instead of having to copy it over.

Panics

Panics if the allocation fails.

Examples

let allocated = bump.alloc_with(|| 123);
assert_eq!(allocated, 123);

pub fn alloc_default<T: Default>(&self) -> BumpBox<'a, T>

Allocate an object with its default value. This is equivalent to alloc_with(T::default).

Panics

Panics if the allocation fails.

Examples

let allocated = bump.alloc_default::<i32>();
assert_eq!(allocated, 0);

pub fn alloc_slice_copy<T: Copy>(&self, slice: &[T]) -> BumpBox<'a, [T]>

Allocate a slice and Copy elements from an existing slice.

Panics

Panics if the allocation fails.

Examples

let allocated = bump.alloc_slice_copy(&[1, 2, 3]);
assert_eq!(allocated, [1, 2, 3]);

pub fn alloc_slice_clone<T: Clone>(&self, slice: &[T]) -> BumpBox<'a, [T]>

Allocate a slice and Clone elements from an existing slice.

Panics

Panics if the allocation fails.

Examples

let allocated = bump.alloc_slice_clone(&[String::from("a"), String::from("b")]);
assert_eq!(allocated, [String::from("a"), String::from("b")]);

pub fn alloc_slice_fill<T: Clone>( &self, len: usize, value: T, ) -> BumpBox<'a, [T]>

Allocate a slice and fill it with elements by cloning value.

Panics

Panics if the allocation fails.

Examples

let allocated = bump.alloc_slice_fill(3, "ho");
assert_eq!(allocated, ["ho", "ho", "ho"]);

pub fn alloc_slice_fill_with<T>( &self, len: usize, f: impl FnMut() -> T, ) -> BumpBox<'a, [T]>

Allocates a slice by fill it with elements returned by calling a closure repeatedly.

This method uses a closure to create new values. If you’d rather Clone a given value, use (try_)alloc_slice_fill. If you want to use the Default trait to generate values, you can pass Default::default as the argument.

Panics

Panics if the allocation fails.

Examples

let allocated = bump.alloc_slice_fill_with::<i32>(3, Default::default);
assert_eq!(allocated, [0, 0, 0]);

pub fn alloc_str(&self, src: &str) -> BumpBox<'a, str>

Allocate a str.

Panics

Panics if the allocation fails.

Examples

let allocated = bump.alloc_str("Hello world!");
assert_eq!(allocated, "Hello world!");

pub fn alloc_fmt(&self, args: Arguments<'_>) -> BumpBox<'a, str>

Allocate a str from format arguments. For better performance prefer alloc_fmt_mut.

Panics

Panics if the allocation fails.

Panics if a formatting trait implementation returned an error.

Examples

let one = 1;
let two = 2;
let string = bump.alloc_fmt(format_args!("{one} + {two} = {}", one + two));

assert_eq!(string, "1 + 2 = 3");

pub fn alloc_fmt_mut(&mut self, args: Arguments<'_>) -> BumpBox<'a, str>

Allocate a str from format arguments. Unlike alloc_fmt, this function requires a mutable Bump(Scope).

Panics

Panics if the allocation fails.

Panics if a formatting trait implementation returned an error.

Examples

let one = 1;
let two = 2;
let string = bump.alloc_fmt_mut(format_args!("{one} + {two} = {}", one + two));

assert_eq!(string, "1 + 2 = 3");

pub fn alloc_iter<T>( &self, iter: impl IntoIterator<Item = T>, ) -> BumpBox<'a, [T]>

Allocate elements of an iterator into a slice. For better performance prefer alloc_iter_exact or alloc_iter_mut.

Panics

Panics if the allocation fails.

Examples

let slice = bump.alloc_iter([1, 2, 3]);
assert_eq!(slice, [1, 2, 3]);

pub fn alloc_iter_exact<T, I>( &self, iter: impl IntoIterator<Item = T, IntoIter = I>, ) -> BumpBox<'a, [T]>

where I: ExactSizeIterator<Item = T>,

Allocate elements of an ExactSizeIterator into a slice.

Panics

Panics if the allocation fails.

Panics if the supplied iterator returns fewer elements than it promised.

Examples

let slice = bump.alloc_iter_exact([1, 2, 3]);
assert_eq!(slice, [1, 2, 3]);

pub fn alloc_iter_mut<T>( &mut self, iter: impl IntoIterator<Item = T>, ) -> BumpBox<'a, [T]>

Allocate elements of an iterator into a slice. Unlike alloc_iter, this function requires a mutable Bump(Scope).

When bumping downwards, prefer alloc_iter_mut_rev or alloc_iter_exact to avoid a shift of the slice.

Panics

Panics if the allocation fails.

Examples

let slice = bump.alloc_iter_mut([1, 2, 3]);
assert_eq!(slice, [1, 2, 3]);

pub fn alloc_iter_mut_rev<T>( &mut self, iter: impl IntoIterator<Item = T>, ) -> BumpBox<'a, [T]>

Allocate elements of an iterator into a slice in reverse order.

When bumping upwards, prefer alloc_iter_mut or alloc_iter_exact to avoid a shift of the slice.

Panics

Panics if the allocation fails.

Examples

let slice = bump.alloc_iter_mut_rev([1, 2, 3]);
assert_eq!(slice, [3, 2, 1]);

pub fn alloc_uninit<T>(&self) -> BumpBox<'a, MaybeUninit<T>>

Allocate an unitialized object.

You can safely initialize the object with init or unsafely with assume_init.

Panics

Panics if the allocation fails.

Examples

Safely:

let five = bump.alloc_uninit();

let five = five.init(5);

assert_eq!(*five, 5)

Unsafely:

let mut five = bump.alloc_uninit();

let five = unsafe {
    five.write(5);
    five.assume_init()
};

assert_eq!(*five, 5)

pub fn alloc_uninit_slice<T>(&self, len: usize) -> BumpBox<'a, [MaybeUninit<T>]>

Allocate an unitialized object slice.

You can safely initialize the object with init_fill, init_fill_with, init_copy, init_clone or unsafely with assume_init.

Panics

Panics if the allocation fails.

Examples

Safely:

let values = bump.alloc_uninit_slice(3);

let values = values.init_copy(&[1, 2, 3]);

assert_eq!(values, [1, 2, 3])

Unsafely:

let mut values = bump.alloc_uninit_slice(3);

let values = unsafe {
    values[0].write(1);
    values[1].write(2);
    values[2].write(3);

    values.assume_init()
};

assert_eq!(values, [1, 2, 3]);

pub fn alloc_uninit_slice_for<T>( &self, slice: &[T], ) -> BumpBox<'a, [MaybeUninit<T>]>

Allocate an unitialized object slice.

You can safely initialize the object with init_fill, init_fill_with, init_copy, init_clone or unsafely with assume_init.

This is just like alloc_uninit_slice but uses a slice to provide the len. This avoids a check for a valid layout. The elements of slice are irrelevant.

Panics

Panics if the allocation fails.

Examples

let slice = &[1, 2, 3];
let other_slice = bump.alloc_uninit_slice_for(slice);
assert_eq!(other_slice.len(), 3);

pub fn alloc_fixed_vec<T>(&self, capacity: usize) -> FixedBumpVec<'a, T>

Allocate a FixedBumpVec with the given capacity.

Panics

Panics if the allocation fails.

Examples

let mut values = bump.alloc_fixed_vec(3);
values.push(1);
values.push(2);
values.push(3);
assert_eq!(values, [1, 2, 3])

pub fn alloc_fixed_string(&self, capacity: usize) -> FixedBumpString<'a>

Allocate a FixedBumpString with the given capacity in bytes.

Panics

Panics if the allocation fails.

Examples

let mut string = bump.alloc_fixed_string(12);
string.push_str("Hello");
string.push_str(" world!");
assert_eq!(string, "Hello world!");

pub fn alloc_layout(&self, layout: Layout) -> NonNull<u8>

Allocates memory as described by the given Layout.

Panics

Panics if the allocation fails.

pub fn reserve_bytes(&self, additional: usize)

Reserves capacity for at least additional more bytes to be bump allocated. The bump allocator may reserve more space to avoid frequent reallocations. After calling reserve_bytes, self.stats().remaining() will be greater than or equal to additional. Does nothing if the capacity is already sufficient.

Panics

Panics if the allocation fails.

Examples

let bump: Bump = Bump::new();
assert!(bump.stats().capacity() < 4096);

bump.reserve_bytes(4096);
assert!(bump.stats().capacity() > 4096);

pub fn try_alloc<T>(&self, value: T) -> Result<BumpBox<'a, T>, AllocError>

Allocate an object.

Errors

Errors if the allocation fails.

Examples

let allocated = bump.try_alloc(123)?;
assert_eq!(allocated, 123);

pub fn try_alloc_with<T>( &self, f: impl FnOnce() -> T, ) -> Result<BumpBox<'a, T>, AllocError>

Pre-allocate space for an object. Once space is allocated f will be called to create the value to be put at that place. In some situations this can help the compiler realize that T can be constructed at the allocated space instead of having to copy it over.

Errors

Errors if the allocation fails.

Examples

let allocated = bump.try_alloc_with(|| 123)?;
assert_eq!(allocated, 123);

pub fn try_alloc_default<T: Default>( &self, ) -> Result<BumpBox<'a, T>, AllocError>

Allocate an object with its default value. This is equivalent to try_alloc_with(T::default).

Errors

Errors if the allocation fails.

Examples

let allocated = bump.try_alloc_default()?;
assert_eq!(allocated, 0);

pub fn try_alloc_slice_copy<T: Copy>( &self, slice: &[T], ) -> Result<BumpBox<'a, [T]>, AllocError>

Allocate a slice and Copy elements from an existing slice.

Errors

Errors if the allocation fails.

Examples

let allocated = bump.alloc_slice_copy(&[1, 2, 3]);
assert_eq!(allocated, [1, 2, 3]);

pub fn try_alloc_slice_clone<T: Clone>( &self, slice: &[T], ) -> Result<BumpBox<'a, [T]>, AllocError>

Allocate a slice and Clone elements from an existing slice.

Errors

Errors if the allocation fails.

Examples

let allocated = bump.try_alloc_slice_clone(&[String::from("a"), String::from("b")])?;
assert_eq!(allocated, [String::from("a"), String::from("b")]);

pub fn try_alloc_slice_fill<T: Clone>( &self, len: usize, value: T, ) -> Result<BumpBox<'a, [T]>, AllocError>

Allocate a slice and fill it with elements by cloning value.

Errors

Errors if the allocation fails.

Examples

let allocated = bump.try_alloc_slice_fill(3, "ho")?;
assert_eq!(allocated, ["ho", "ho", "ho"]);

pub fn try_alloc_slice_fill_with<T>( &self, len: usize, f: impl FnMut() -> T, ) -> Result<BumpBox<'a, [T]>, AllocError>

Allocates a slice by fill it with elements returned by calling a closure repeatedly.

This method uses a closure to create new values. If you’d rather Clone a given value, use (try_)alloc_slice_fill. If you want to use the Default trait to generate values, you can pass Default::default as the argument.

Errors

Errors if the allocation fails.

Examples

let allocated = bump.try_alloc_slice_fill_with::<i32>(3, Default::default)?;
assert_eq!(allocated, [0, 0, 0]);

pub fn try_alloc_str(&self, src: &str) -> Result<BumpBox<'a, str>, AllocError>

Allocate a str.

Errors

Errors if the allocation fails.

Examples

let allocated = bump.try_alloc_str("Hello world!")?;
assert_eq!(allocated, "Hello world!");

pub fn try_alloc_fmt( &self, args: Arguments<'_>, ) -> Result<BumpBox<'a, str>, AllocError>

Allocate a str from format arguments. For better performance prefer try_alloc_fmt_mut.

Errors

Errors if the allocation fails.

Errors if a formatting trait implementation returned an error.

Examples

let one = 1;
let two = 2;
let string = bump.try_alloc_fmt(format_args!("{one} + {two} = {}", one + two))?;

assert_eq!(string, "1 + 2 = 3");

pub fn try_alloc_fmt_mut( &mut self, args: Arguments<'_>, ) -> Result<BumpBox<'a, str>, AllocError>

Allocate a str from format arguments. Unlike try_alloc_fmt, this function requires a mutable Bump(Scope).

Errors

Errors if the allocation fails.

Errors if a formatting trait implementation returned an error.

Examples

let one = 1;
let two = 2;
let string = bump.try_alloc_fmt_mut(format_args!("{one} + {two} = {}", one + two))?;

assert_eq!(string, "1 + 2 = 3");

pub fn try_alloc_iter<T>( &self, iter: impl IntoIterator<Item = T>, ) -> Result<BumpBox<'a, [T]>, AllocError>

Allocate elements of an iterator into a slice. For better performance prefer try_alloc_iter_exact or try_alloc_iter_mut.

Errors

Errors if the allocation fails.

Examples

let slice = bump.try_alloc_iter([1, 2, 3])?;
assert_eq!(slice, [1, 2, 3]);

pub fn try_alloc_iter_exact<T, I>( &self, iter: impl IntoIterator<Item = T, IntoIter = I>, ) -> Result<BumpBox<'a, [T]>, AllocError>

where I: ExactSizeIterator<Item = T>,

Allocate elements of an ExactSizeIterator into a slice.

Panics

Panics if the supplied iterator returns fewer elements than it promised.

Errors

Errors if the allocation fails.

Examples

let slice = bump.try_alloc_iter_exact([1, 2, 3])?;
assert_eq!(slice, [1, 2, 3]);

pub fn try_alloc_iter_mut<T>( &mut self, iter: impl IntoIterator<Item = T>, ) -> Result<BumpBox<'a, [T]>, AllocError>

Allocate elements of an iterator into a slice. Unlike try_alloc_iter, this function requires a mutable Bump(Scope).

When bumping downwards, prefer try_alloc_iter_mut_rev or try_alloc_iter_exact to avoid a shift of the slice.

Errors

Errors if the allocation fails.

Examples

let slice = bump.try_alloc_iter_mut([1, 2, 3])?;
assert_eq!(slice, [1, 2, 3]);

pub fn try_alloc_iter_mut_rev<T>( &mut self, iter: impl IntoIterator<Item = T>, ) -> Result<BumpBox<'a, [T]>, AllocError>

Allocate elements of an iterator into a slice in reverse order.

When bumping upwards, prefer try_alloc_iter_mut or try_alloc_iter_exact to avoid a shift of the slice.

Errors

Errors if the allocation fails.

Examples

let slice = bump.try_alloc_iter_mut_rev([1, 2, 3])?;
assert_eq!(slice, [3, 2, 1]);

pub fn try_alloc_uninit<T>( &self, ) -> Result<BumpBox<'a, MaybeUninit<T>>, AllocError>

Allocate an unitialized object.

You can safely initialize the object with init or unsafely with assume_init.

Errors

Errors if the allocation fails.

Examples

Safely:

let five = bump.try_alloc_uninit()?;

let five = five.init(5);

assert_eq!(*five, 5);

Unsafely:

let mut five = bump.try_alloc_uninit()?;

let five = unsafe {
    five.write(5);
    five.assume_init()
};

assert_eq!(*five, 5);

pub fn try_alloc_uninit_slice<T>( &self, len: usize, ) -> Result<BumpBox<'a, [MaybeUninit<T>]>, AllocError>

Allocate an unitialized object slice.

You can safely initialize the object with init_fill, init_fill_with, init_copy, init_clone or unsafely with assume_init.

Errors

Errors if the allocation fails.

Examples

Safely:

let values = bump.try_alloc_uninit_slice(3)?;

let values = values.init_copy(&[1, 2, 3]);

assert_eq!(values, [1, 2, 3]);

Unsafely:

let mut values = bump.try_alloc_uninit_slice(3)?;

let values = unsafe {
    values[0].write(1);
    values[1].write(2);
    values[2].write(3);

    values.assume_init()
};

assert_eq!(values, [1, 2, 3]);

pub fn try_alloc_uninit_slice_for<T>( &self, slice: &[T], ) -> Result<BumpBox<'a, [MaybeUninit<T>]>, AllocError>

Allocate an unitialized object slice.

You can safely initialize the object with init_fill, init_fill_with, init_copy, init_clone or unsafely with assume_init.

This is just like try_alloc_uninit_slice but uses a slice to provide the len. This avoids a check for a valid layout. The elements of slice are irrelevant.

Errors

Errors if the allocation fails.

Examples

let slice = &[1, 2, 3];
let other_slice = bump.try_alloc_uninit_slice_for(slice)?;
assert_eq!(other_slice.len(), 3);

pub fn try_alloc_fixed_vec<T>( &self, capacity: usize, ) -> Result<FixedBumpVec<'a, T>, AllocError>

Allocate a FixedBumpVec with the given capacity.

Errors

Errors if the allocation fails.

Examples

let mut values = bump.try_alloc_fixed_vec(3)?;
values.push(1);
values.push(2);
values.push(3);
assert_eq!(values, [1, 2, 3]);

pub fn try_alloc_fixed_string( &self, capacity: usize, ) -> Result<FixedBumpString<'a>, AllocError>

Allocate a FixedBumpString with the given capacity in bytes.

Errors

Errors if the allocation fails.

Examples

let mut string = bump.try_alloc_fixed_string(12)?;
string.push_str("Hello");
string.push_str(" world!");
assert_eq!(string, "Hello world!");

pub fn try_alloc_layout( &self, layout: Layout, ) -> Result<NonNull<u8>, AllocError>

Allocates memory as described by the given Layout.

Errors

Errors if the allocation fails.

pub fn try_reserve_bytes(&self, additional: usize) -> Result<(), AllocError>

Reserves capacity for at least additional more bytes to be bump allocated. The bump allocator may reserve more space to avoid frequent reallocations. After calling reserve_bytes, self.stats().remaining() will be greater than or equal to additional. Does nothing if the capacity is already sufficient.

Errors

Errors if the allocation fails.

Examples

let bump: Bump = Bump::try_new()?;
assert!(bump.stats().capacity() < 4096);

bump.try_reserve_bytes(4096)?;
assert!(bump.stats().capacity() > 4096);

impl<'a, A, const MIN_ALIGN: usize, const UP: bool> BumpScope<'a, A, MIN_ALIGN, UP>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator,

Functions to allocate. Available as fallible or infallible.

pub fn alloc_try_with<T, E>( &self, f: impl FnOnce() -> Result<T, E>, ) -> Result<BumpBox<'a, T>, E>

Allocates the result of f in the bump allocator, then moves E out of it and deallocates the space it took up.

This can be more performant than allocating T after the fact, as Result<T, E> may be constructed in the bump allocators memory instead of on the stack and then copied over.

There is also alloc_try_with_mut, optimized for a mutable reference.

Panics

Panics if the allocation fails.

Examples

let result = bump.alloc_try_with(|| -> Result<i32, i32> { Ok(123) });
assert_eq!(result.unwrap(), 123);
assert_eq!(bump.stats().allocated(), offset_of!(Result<i32, i32>, Ok.0) + size_of::<i32>());

let result = bump.alloc_try_with(|| -> Result<i32, i32> { Err(123) });
assert_eq!(result.unwrap_err(), 123);
assert_eq!(bump.stats().allocated(), 0);

pub fn alloc_try_with_mut<T, E>( &mut self, f: impl FnOnce() -> Result<T, E>, ) -> Result<BumpBox<'a, T>, E>

Allocates the result of f in the bump allocator, then moves E out of it and deallocates the space it took up.

This can be more performant than allocating T after the fact, as Result<T, E> may be constructed in the bump allocators memory instead of on the stack and then copied over.

This is just like alloc_try_with, but optimized for a mutable reference.

Panics

Panics if the allocation fails.

Examples

let result = bump.alloc_try_with_mut(|| -> Result<i32, i32> { Ok(123) });
assert_eq!(result.unwrap(), 123);
assert_eq!(bump.stats().allocated(), offset_of!(Result<i32, i32>, Ok.0) + size_of::<i32>());

let result = bump.alloc_try_with_mut(|| -> Result<i32, i32> { Err(123) });
assert_eq!(result.unwrap_err(), 123);
assert_eq!(bump.stats().allocated(), 0);

pub fn try_alloc_try_with<T, E>( &self, f: impl FnOnce() -> Result<T, E>, ) -> Result<Result<BumpBox<'a, T>, E>, AllocError>

Allocates the result of f in the bump allocator, then moves E out of it and deallocates the space it took up.

This can be more performant than allocating T after the fact, as Result<T, E> may be constructed in the bump allocators memory instead of on the stack and then copied over.

There is also try_alloc_try_with_mut, optimized for a mutable reference.

Errors

Errors if the allocation fails.

Examples

let result = bump.try_alloc_try_with(|| -> Result<i32, i32> { Ok(123) })?;
assert_eq!(result.unwrap(), 123);
assert_eq!(bump.stats().allocated(), offset_of!(Result<i32, i32>, Ok.0) + size_of::<i32>());

let result = bump.try_alloc_try_with(|| -> Result<i32, i32> { Err(123) })?;
assert_eq!(result.unwrap_err(), 123);
assert_eq!(bump.stats().allocated(), 0);

pub fn try_alloc_try_with_mut<T, E>( &mut self, f: impl FnOnce() -> Result<T, E>, ) -> Result<Result<BumpBox<'a, T>, E>, AllocError>

Allocates the result of f in the bump allocator, then moves E out of it and deallocates the space it took up.

This can be more performant than allocating T after the fact, as Result<T, E> may be constructed in the bump allocators memory instead of on the stack and then copied over.

This is just like try_alloc_try_with, but optimized for a mutable reference.

Errors

Errors if the allocation fails.

Examples

let result = bump.try_alloc_try_with_mut(|| -> Result<i32, i32> { Ok(123) })?;
assert_eq!(result.unwrap(), 123);
assert_eq!(bump.stats().allocated(), offset_of!(Result<i32, i32>, Ok.0) + size_of::<i32>());

let result = bump.try_alloc_try_with_mut(|| -> Result<i32, i32> { Err(123) })?;
assert_eq!(result.unwrap_err(), 123);
assert_eq!(bump.stats().allocated(), 0);

Trait Implementations

impl<A, const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool> Allocator for BumpScope<'_, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED>,

fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Attempts to allocate a block of memory.

unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout)

🔬This is a nightly-only experimental API. (allocator_api)

Deallocates the memory referenced by ptr.

unsafe fn grow( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Attempts to extend the memory block.

unsafe fn grow_zeroed( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Behaves like grow, but also ensures that the new contents are set to zero before being returned.

unsafe fn shrink( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Attempts to shrink the memory block.

fn allocate_zeroed(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Behaves like allocate, but also ensures that the returned memory is zero-initialized.

fn by_ref(&self) -> &Self

where Self: Sized,

🔬This is a nightly-only experimental API. (allocator_api)

Creates a “by reference” adapter for this instance of Allocator.

impl<A, const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool> Debug for BumpScope<'_, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED>,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'b, A, const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool> From<&'b Bump<A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>> for &'b BumpScope<'b, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED>,

fn from(value: &'b Bump<A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>) -> Self

Converts to this type from the input type.

impl<'b, A, const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool> From<&'b mut Bump<A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>> for &'b mut BumpScope<'b, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED>,

fn from(value: &'b mut Bump<A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>) -> Self

Converts to this type from the input type.

impl<A, const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool> BumpAllocator for BumpScope<'_, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED>,

impl<A, const MIN_ALIGN: usize, const UP: bool> NoDrop for BumpScope<'_, A, MIN_ALIGN, UP>

impl<const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool, A> RefUnwindSafe for BumpScope<'_, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED> + UnwindSafe,

impl<const MIN_ALIGN: usize, const UP: bool, const GUARANTEED_ALLOCATED: bool, A> UnwindSafe for BumpScope<'_, A, MIN_ALIGN, UP, GUARANTEED_ALLOCATED>

where MinimumAlignment<MIN_ALIGN>: SupportedMinimumAlignment, A: BaseAllocator<GUARANTEED_ALLOCATED> + UnwindSafe,