Struct frame_support::storage::bounded_btree_set::BoundedBTreeSet[][src]

pub struct BoundedBTreeSet<T, S>(_, _);
Expand description

A bounded set based on a B-Tree.

B-Trees represent a fundamental compromise between cache-efficiency and actually minimizing the amount of work performed in a search. See BTreeSet for more details.

Unlike a standard BTreeSet, there is an enforced upper limit to the number of items in the set. All internal operations ensure this bound is respected.

Implementations

Get the bound of the type in usize.

Create a new BoundedBTreeSet.

Does not allocate.

Consume self, and return the inner BTreeSet.

This is useful when a mutating API of the inner type is desired, and closure-based mutation such as provided by try_mutate is inconvenient.

Consumes self and mutates self via the given mutate function.

If the outcome of mutation is within bounds, Some(Self) is returned. Else, None is returned.

This is essentially a consuming shorthand Self::into_inner -> ... -> Self::try_from.

Exactly the same semantics as BTreeSet::insert, but returns an Err (and is a noop) if the new length of the set exceeds S.

In the Err case, returns the inserted item so it can be further used without cloning.

Remove an item from the set, returning whether it was previously in the set.

The item may be any borrowed form of the set’s item type, but the ordering on the borrowed form must match the ordering on the item type.

Removes and returns the value in the set, if any, that is equal to the given one.

The value may be any borrowed form of the set’s value type, but the ordering on the borrowed form must match the ordering on the value type.

Methods from Deref<Target = BTreeSet<T>>

Constructs a double-ended iterator over a sub-range of elements in the set. The simplest way is to use the range syntax min..max, thus range(min..max) will yield elements from min (inclusive) to max (exclusive). The range may also be entered as (Bound<T>, Bound<T>), so for example range((Excluded(4), Included(10))) will yield a left-exclusive, right-inclusive range from 4 to 10.

Examples
use std::collections::BTreeSet;
use std::ops::Bound::Included;

let mut set = BTreeSet::new();
set.insert(3);
set.insert(5);
set.insert(8);
for &elem in set.range((Included(&4), Included(&8))) {
    println!("{}", elem);
}
assert_eq!(Some(&5), set.range(4..).next());

Visits the values representing the difference, i.e., the values that are in self but not in other, in ascending order.

Examples
use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);
a.insert(2);

let mut b = BTreeSet::new();
b.insert(2);
b.insert(3);

let diff: Vec<_> = a.difference(&b).cloned().collect();
assert_eq!(diff, [1]);

Visits the values representing the symmetric difference, i.e., the values that are in self or in other but not in both, in ascending order.

Examples
use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);
a.insert(2);

let mut b = BTreeSet::new();
b.insert(2);
b.insert(3);

let sym_diff: Vec<_> = a.symmetric_difference(&b).cloned().collect();
assert_eq!(sym_diff, [1, 3]);

Visits the values representing the intersection, i.e., the values that are both in self and other, in ascending order.

Examples
use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);
a.insert(2);

let mut b = BTreeSet::new();
b.insert(2);
b.insert(3);

let intersection: Vec<_> = a.intersection(&b).cloned().collect();
assert_eq!(intersection, [2]);

Visits the values representing the union, i.e., all the values in self or other, without duplicates, in ascending order.

Examples
use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);

let mut b = BTreeSet::new();
b.insert(2);

let union: Vec<_> = a.union(&b).cloned().collect();
assert_eq!(union, [1, 2]);

Returns true if the set contains a value.

The value may be any borrowed form of the set’s value type, but the ordering on the borrowed form must match the ordering on the value type.

Examples
use std::collections::BTreeSet;

let set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
assert_eq!(set.contains(&1), true);
assert_eq!(set.contains(&4), false);

Returns a reference to the value in the set, if any, that is equal to the given value.

The value may be any borrowed form of the set’s value type, but the ordering on the borrowed form must match the ordering on the value type.

Examples
use std::collections::BTreeSet;

let set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
assert_eq!(set.get(&2), Some(&2));
assert_eq!(set.get(&4), None);

Returns true if self has no elements in common with other. This is equivalent to checking for an empty intersection.

Examples
use std::collections::BTreeSet;

let a: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
let mut b = BTreeSet::new();

assert_eq!(a.is_disjoint(&b), true);
b.insert(4);
assert_eq!(a.is_disjoint(&b), true);
b.insert(1);
assert_eq!(a.is_disjoint(&b), false);

Returns true if the set is a subset of another, i.e., other contains at least all the values in self.

Examples
use std::collections::BTreeSet;

let sup: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
let mut set = BTreeSet::new();

assert_eq!(set.is_subset(&sup), true);
set.insert(2);
assert_eq!(set.is_subset(&sup), true);
set.insert(4);
assert_eq!(set.is_subset(&sup), false);

Returns true if the set is a superset of another, i.e., self contains at least all the values in other.

Examples
use std::collections::BTreeSet;

let sub: BTreeSet<_> = [1, 2].iter().cloned().collect();
let mut set = BTreeSet::new();

assert_eq!(set.is_superset(&sub), false);

set.insert(0);
set.insert(1);
assert_eq!(set.is_superset(&sub), false);

set.insert(2);
assert_eq!(set.is_superset(&sub), true);
🔬 This is a nightly-only experimental API. (map_first_last)

Returns a reference to the first value in the set, if any. This value is always the minimum of all values in the set.

Examples

Basic usage:

#![feature(map_first_last)]
use std::collections::BTreeSet;

let mut set = BTreeSet::new();
assert_eq!(set.first(), None);
set.insert(1);
assert_eq!(set.first(), Some(&1));
set.insert(2);
assert_eq!(set.first(), Some(&1));
🔬 This is a nightly-only experimental API. (map_first_last)

Returns a reference to the last value in the set, if any. This value is always the maximum of all values in the set.

Examples

Basic usage:

#![feature(map_first_last)]
use std::collections::BTreeSet;

let mut set = BTreeSet::new();
assert_eq!(set.last(), None);
set.insert(1);
assert_eq!(set.last(), Some(&1));
set.insert(2);
assert_eq!(set.last(), Some(&2));

Gets an iterator that visits the values in the BTreeSet in ascending order.

Examples
use std::collections::BTreeSet;

let set: BTreeSet<usize> = [1, 2, 3].iter().cloned().collect();
let mut set_iter = set.iter();
assert_eq!(set_iter.next(), Some(&1));
assert_eq!(set_iter.next(), Some(&2));
assert_eq!(set_iter.next(), Some(&3));
assert_eq!(set_iter.next(), None);

Values returned by the iterator are returned in ascending order:

use std::collections::BTreeSet;

let set: BTreeSet<usize> = [3, 1, 2].iter().cloned().collect();
let mut set_iter = set.iter();
assert_eq!(set_iter.next(), Some(&1));
assert_eq!(set_iter.next(), Some(&2));
assert_eq!(set_iter.next(), Some(&3));
assert_eq!(set_iter.next(), None);

Returns the number of elements in the set.

Examples
use std::collections::BTreeSet;

let mut v = BTreeSet::new();
assert_eq!(v.len(), 0);
v.insert(1);
assert_eq!(v.len(), 1);

Returns true if the set contains no elements.

Examples
use std::collections::BTreeSet;

let mut v = BTreeSet::new();
assert!(v.is_empty());
v.insert(1);
assert!(!v.is_empty());

Trait Implementations

Performs the conversion.

Returns a copy of the value. Read more

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Formats the value using the given formatter. Read more

Attempt to deserialise the value from input.

Attempt to skip the encoded value from input. Read more

Returns the fixed encoded size of the type. Read more

Return the number of elements in self_encoded.

Returns the “default value” for a type. Read more

The resulting type after dereferencing.

Dereferences the value.

Convert self to a slice and append it to the destination.

If possible give a hint of expected size of the encoding. Read more

Convert self to an owned vector.

Convert self to a slice and then invoke the given closure with it.

Calculates the encoded size. Read more

Performs the conversion.

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

Creates an iterator from a value. Read more

Upper bound, in bytes, of the maximum encoded size of this item.

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Decode the length of the storage value at key. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type identifying for which type info is provided. Read more

Returns the static type identifier for Self.

Auto Trait Implementations

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True iff no bits are set.

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Performs the conversion.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

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Performs the conversion.

Get a reference to the inner from the outer.

Get a mutable reference to the inner from the outer.

Return an encoding of Self prepended by given slice.

Pipes by value. This is generally the method you want to use. Read more

Borrows self and passes that borrow into the pipe function. Read more

Mutably borrows self and passes that borrow into the pipe function. Read more

Borrows self, then passes self.borrow() into the pipe function. Read more

Mutably borrows self, then passes self.borrow_mut() into the pipe function. Read more

Borrows self, then passes self.as_ref() into the pipe function.

Mutably borrows self, then passes self.as_mut() into the pipe function. Read more

Borrows self, then passes self.deref() into the pipe function.

Mutably borrows self, then passes self.deref_mut() into the pipe function. Read more

Pipes a value into a function that cannot ordinarily be called in suffix position. Read more

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Should always be Self

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Calls .tap() only in debug builds, and is erased in release builds.

Calls .tap_mut() only in debug builds, and is erased in release builds. Read more

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Calls tap in debug builds, and does nothing in release builds.

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Provides mutable access to the reference for modification.

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Calls tap_borrow_mut in debug builds, and does nothing in release builds. Read more

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Calls tap_deref_mut in debug builds, and does nothing in release builds. Read more

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

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

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

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The type returned in the event of a conversion error.

Performs the conversion.

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Performs the conversion.

The counterpart to unchecked_from.

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