Struct stack_dst::value::Value

pub struct Value<T: ?Sized, D: DataBuf> { /* private fields */ }

Stack-allocated dynamically sized type

T is the unsized type contained. D is the buffer used to hold the unsized type (both data and metadata).

let val = Value::<dyn Display, ::stack_dst::buffers::Ptr2>::new_stable(123456, |v| v as _).expect("Insufficient size");
assert_eq!( format!("{}", val), "123456" );

Implementations

impl<T: ?Sized, D: DataBuf> Value<T, D>

pub fn new<U: Unsize<T>>(val: U) -> Result<Value<T, D>, U>where (U, D::Inner): AlignmentValid, D: Default,

Construct a stack-based DST

Returns Ok(dst) if the allocation was successful, or Err(val) if it failed

let val = Value::<dyn Display, ::stack_dst::buffers::Ptr2>::new(1234).expect("Insufficient size");
assert_eq!( format!("{}", val), "1234" );

pub fn in_buffer<U: Unsize<T>>(buffer: D, val: U) -> Result<Value<T, D>, U>where (U, D::Inner): AlignmentValid,

Construct a stack-based DST using a pre-constructed buffer

Returns Ok(dst) if the allocation was successful, or Err(val) if it failed

let val = Value::<dyn Display, _>::in_buffer([MaybeUninit::new(0u64); 2], 1234).expect("Insufficient size");
assert_eq!( format!("{}", val), "1234" );

pub fn new_stable<U, F: FnOnce(&U) -> &T>( val: U, get_ref: F ) -> Result<Value<T, D>, U>where (U, D::Inner): AlignmentValid, D: Default,

Construct a stack-based DST (without needing Unsize). The closure get_ref must just convert &U to &U (if the pointers don’t match, an assertion triggers)

Returns Ok(dst) if the allocation was successful, or Err(val) if it failed

let val = Value::<dyn Display, ::stack_dst::buffers::Ptr2>::new_stable(1234, |v| v as _).expect("Insufficient size");
assert_eq!( format!("{}", val), "1234" );

pub fn in_buffer_stable<U, F: FnOnce(&U) -> &T>( buffer: D, val: U, get_ref: F ) -> Result<Value<T, D>, U>where (U, D::Inner): AlignmentValid,

Construct a stack-based DST (without needing Unsize) using a provided buffer. See new_stable for requirements on the get_ref closure.

Returns Ok(dst) if the allocation was successful, or Err(val) if it failed

let val = Value::<dyn Display, _>::in_buffer_stable([MaybeUninit::new(0u64); 2], 1234, |v| v as _).expect("Insufficient size");
assert_eq!( format!("{}", val), "1234" );

pub fn new_or_boxed<U>(val: U) -> Value<T, D> where (U, D::Inner): AlignmentValid, U: Unsize<T>, Box<U>: Unsize<T>, D: Default,

Construct a stack-based DST, falling back on boxing if the value doesn’t fit

let val = [1usize, 2, 3, 4];
assert!( Value::<dyn Debug, ::stack_dst::buffers::Ptr2>::new(val).is_err() );
let v = Value::<dyn Debug, ::stack_dst::buffers::Ptr2>::new_or_boxed(val);
println!("v = {:?}", v);

pub unsafe fn new_raw( info: &[usize], data: *mut (), size: usize, buffer: D ) -> Option<Value<T, D>>

UNSAFE: data must point to size bytes, which shouldn’t be freed if Some is returned

pub fn replace_stable<U>( &mut self, val: U, get_ref: impl Fn(&U) -> &T ) -> Result<(), U>where (U, D::Inner): AlignmentValid,

Replace the contents without dropping the backing allocation

let mut value = Value::<dyn Display, ::stack_dst::buffers::Ptr2>::new_stable(1234, |v| v).unwrap();
assert_eq!(format!("{}", value), "1234");
value.replace_stable(1.234, |v| v).unwrap();
assert_eq!(format!("{}", value), "1.234");

pub fn replace<U>(&mut self, val: U) -> Result<(), U>where (U, D::Inner): AlignmentValid, U: Unsize<T>,

Replace the contents without dropping the backing allocation

let mut value = Value::<dyn Display, ::stack_dst::buffers::Ptr2>::new(1234).unwrap();
assert_eq!(format!("{}", value), "1234");
value.replace(1.234).unwrap();
assert_eq!(format!("{}", value), "1.234");

impl<D: DataBuf> Value<str, D>

Specialisations for str (allowing storage of strings with single-byte alignment)

pub fn empty_str() -> Result<Self, ()>where D: Default,

Create a new empty string with a default buffer

pub fn empty_str_in_buffer(buffer: D) -> Result<Self, ()>

Create a new empty string with a provided buffer

pub fn new_str(v: &str) -> Result<Self, &str>where D: Default,

Construct from a str using a default-constructed buffer

let val = Value::<str, stack_dst::buffers::U8_32>::new_str("Hello, World").expect("Insufficient size");
assert_eq!( &val[..], "Hello, World" );

pub fn new_str_in_buffer(buffer: D, val: &str) -> Result<Self, &str>

Construct from a str using a provided buffer

let val = Value::new_str_in_buffer([MaybeUninit::new(0u8); 32], "Hello, World").expect("Insufficient size");
assert_eq!( &val[..], "Hello, World" );

pub fn append_str(&mut self, val: &str) -> Result<(), ()>

Add a string to the end of a string

let mut s = Value::<str, stack_dst::buffers::Ptr8>::new_str("Foo").unwrap();
s.append_str("Bar").unwrap();
assert_eq!(&s[..], "FooBar");

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

Resize the string (discarding trailing data)

let mut s = Value::<str, stack_dst::buffers::Ptr8>::new_str("FooBar").unwrap();
s.truncate(3);
assert_eq!(&s[..], "Foo");

impl<I, D: DataBuf> Value<[I], D>where (I, D::Inner): AlignmentValid,

Specialisation for slices (acting like an ArrayVec)

pub fn empty_slice() -> Result<Self, ()>where D: Default,

Create a new zero-sized slice (will error only if the metadata doesn’t fit)

pub fn empty_slice_with_buffer(buffer: D) -> Result<Self, ()>

Create a new zero-sized slice in the provided buffer (will error only if the metadata doesn’t fit)

pub fn append(&mut self, v: I) -> Result<(), I>

Append an item to the end of the slice (similar to Vec::push)

pub fn appended(self, v: I) -> Result<Self, (Self, I)>

Inline append an item (See Self::append)

pub fn extend<It: Iterator<Item = I>>( &mut self, iter: It ) -> Result<(), (I, It)>

Extend a slice with an iterator

pub fn extended<It: Iterator<Item = I>>( self, iter: It ) -> Result<Self, (Self, I, It)>

Helper to extend during construction (see Self::extend)

pub fn pop(&mut self) -> Option<I>

Remove the last item from the slice

Trait Implementations

impl<D: DataBuf, T> Debug for Value<T, D>where T: Debug + ?Sized,

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

Formats the value using the given formatter.

impl<T: ?Sized, D: DataBuf> Deref for Value<T, D>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T: ?Sized, D: DataBuf> DerefMut for Value<T, D>

fn deref_mut(&mut self) -> &mut T

Mutably dereferences the value.

impl<D: DataBuf, T> Display for Value<T, D>where T: Display + ?Sized,

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

Formats the value using the given formatter.

impl<D: DataBuf, T> DoubleEndedIterator for Value<T, D>where T: DoubleEndedIterator + ?Sized,

fn next_back(&mut self) -> Option<Self::Item>

Removes and returns an element from the end of the iterator.

fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize>

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

Advances the iterator from the back by n elements.

fn nth_back(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element from the end of the iterator.

fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> Rwhere Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

This is the reverse version of Iterator::try_fold(): it takes elements starting from the back of the iterator.

fn rfold<B, F>(self, init: B, f: F) -> Bwhere Self: Sized, F: FnMut(B, Self::Item) -> B,

An iterator method that reduces the iterator’s elements to a single, final value, starting from the back.

fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator from the back that satisfies a predicate.

impl<T: ?Sized, D: DataBuf> Drop for Value<T, D>

fn drop(&mut self)

Executes the destructor for this type.

impl<D: DataBuf, T> ExactSizeIterator for Value<T, D>where T: ExactSizeIterator + ?Sized,

fn len(&self) -> usize

Returns the exact remaining length of the iterator.

fn is_empty(&self) -> bool

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

Returns true if the iterator is empty.

impl<D: DataBuf, T> Future for Value<T, D>where T: Future + ?Sized,

type Output = <T as Future>::Output

The type of value produced on completion.

fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.

impl<D: DataBuf, T> Iterator for Value<T, D>where T: Iterator + ?Sized,

type Item = <T as Iterator>::Item

The type of the elements being iterated over.

fn next(&mut self) -> Option<Self::Item>

Advances the iterator and returns the next value.

fn next_chunk<const N: usize>( &mut self ) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where Self: Sized,

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

Advances the iterator and returns an array containing the next N values.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

fn count(self) -> usizewhere Self: Sized,

Consumes the iterator, counting the number of iterations and returning it.

fn last(self) -> Option<Self::Item>where Self: Sized,

Consumes the iterator, returning the last element.

fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize>

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

Advances the iterator by n elements.

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator.

fn step_by(self, step: usize) -> StepBy<Self>where Self: Sized,

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>where Self: Sized, U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence.

fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where Self: Sized, U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs.

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where Self: Sized, G: FnMut() -> Self::Item,

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

Creates a new iterator which places an item generated by separator between adjacent items of the original iterator.

fn map<B, F>(self, f: F) -> Map<Self, F>where Self: Sized, F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each element.

fn for_each<F>(self, f: F)where Self: Sized, F: FnMut(Self::Item),

Calls a closure on each element of an iterator.

fn filter<P>(self, predicate: P) -> Filter<Self, P>where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element should be yielded.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate<Self>where Self: Sized,

Creates an iterator which gives the current iteration count as well as the next value.

fn peekable(self) -> Peekable<Self>where Self: Sized,

Creates an iterator which can use the peek and peek_mut methods to look at the next element of the iterator without consuming it. See their documentation for more information.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate.

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where Self: Sized, P: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both yields elements based on a predicate and maps.

fn skip(self, n: usize) -> Skip<Self>where Self: Sized,

Creates an iterator that skips the first n elements.

fn take(self, n: usize) -> Take<Self>where Self: Sized,

Creates an iterator that yields the first n elements, or fewer if the underlying iterator ends sooner.

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where Self: Sized, F: FnMut(&mut St, Self::Item) -> Option<B>,

An iterator adapter which, like fold, holds internal state, but unlike fold, produces a new iterator.

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where Self: Sized, U: IntoIterator, F: FnMut(Self::Item) -> U,

Creates an iterator that works like map, but flattens nested structure.

fn fuse(self) -> Fuse<Self>where Self: Sized,

Creates an iterator which ends after the first None.

fn inspect<F>(self, f: F) -> Inspect<Self, F>where Self: Sized, F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on.

fn by_ref(&mut self) -> &mut Selfwhere Self: Sized,

Borrows an iterator, rather than consuming it.

fn collect<B>(self) -> Bwhere B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection.

fn collect_into<E>(self, collection: &mut E) -> &mut Ewhere E: Extend<Self::Item>, Self: Sized,

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

Collects all the items from an iterator into a collection.

fn partition<B, F>(self, f: F) -> (B, B)where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it.

fn is_partitioned<P>(self, predicate: P) -> boolwhere Self: Sized, P: FnMut(Self::Item) -> bool,

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

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false.

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

fn try_for_each<F, R>(&mut self, f: F) -> Rwhere Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

fn fold<B, F>(self, init: B, f: F) -> Bwhere Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result.

fn reduce<F>(self, f: F) -> Option<Self::Item>where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation.

fn try_reduce<F, R>( &mut self, f: F ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere Self: Sized, F: FnMut(Self::Item, Self::Item) -> R, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

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

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately.

fn all<F>(&mut self, f: F) -> boolwhere Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate.

fn any<F>(&mut self, f: F) -> boolwhere Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate.

fn find<P>(&mut self, predicate: P) -> Option<Self::Item>where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate.

fn find_map<B, F>(&mut self, f: F) -> Option<B>where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Applies function to the elements of iterator and returns the first non-none result.

fn try_find<F, R>( &mut self, f: F ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere Self: Sized, F: FnMut(&Self::Item) -> R, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

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

Applies function to the elements of iterator and returns the first true result or the first error.

fn position<P>(&mut self, predicate: P) -> Option<usize>where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index.

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function.

fn max_by<F>(self, compare: F) -> Option<Self::Item>where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function.

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function.

fn min_by<F>(self, compare: F) -> Option<Self::Item>where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function.

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where FromA: Default + Extend<A>, FromB: Default + Extend<B>, Self: Sized + Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers.

fn copied<'a, T>(self) -> Copied<Self>where T: 'a + Copy, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements.

fn cloned<'a, T>(self) -> Cloned<Self>where T: 'a + Clone, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements.

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>where Self: Sized,

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

Returns an iterator over N elements of the iterator at a time.

fn sum<S>(self) -> Swhere Self: Sized, S: Sum<Self::Item>,

Sums the elements of an iterator.

fn product<P>(self) -> Pwhere Self: Sized, P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements

fn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,

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

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn partial_cmp<I>(self, other: I) -> Option<Ordering>where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Lexicographically compares the PartialOrd elements of this Iterator with those of another. The comparison works like short-circuit evaluation, returning a result without comparing the remaining elements. As soon as an order can be determined, the evaluation stops and a result is returned.

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,

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

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn eq<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are equal to those of another.

fn eq_by<I, F>(self, other: I, eq: F) -> boolwhere Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,

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

Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function.

fn ne<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are not equal to those of another.

fn lt<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less than those of another.

fn le<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

fn gt<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than those of another.

fn ge<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.

fn is_sorted_by<F>(self, compare: F) -> boolwhere Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,

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

Checks if the elements of this iterator are sorted using the given comparator function.

fn is_sorted_by_key<F, K>(self, f: F) -> boolwhere Self: Sized, F: FnMut(Self::Item) -> K, K: PartialOrd<K>,

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

Checks if the elements of this iterator are sorted using the given key extraction function.

impl<D: DataBuf, T> LowerHex for Value<T, D>where T: LowerHex + ?Sized,

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

Formats the value using the given formatter.

impl<D: DataBuf, T> UpperHex for Value<T, D>where T: UpperHex + ?Sized,

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

Formats the value using the given formatter.