Struct thincollections::thin_set::ThinSet

pub struct ThinSet<T: ThinSentinel + Eq + Hash, S: BuildHasher = OneFieldHasherBuilder> { /* private fields */ }

A hash set implemented as a ThinMap where the value is ().

As with the ThinMap type, a ThinSet requires that the elements implement the Eq and Hash and [‘ThinSentinel’] traits. Eq and Hash can frequently be achieved by using #[derive(PartialEq, Eq, Hash)]. If you implement these yourself, it is important that the following property holds:

k1 == k2 -> hash(k1) == hash(k2)

In other words, if two keys are equal, their hashes must be equal.

It is a logic error for an item to be modified in such a way that the item’s hash, as determined by the Hash trait, or its equality, as determined by the Eq trait, changes while it is in the set. This is normally only possible through Cell, RefCell, global state, I/O, or unsafe code.

Examples

use thincollections::thin_set::ThinSet;
// Type inference lets us omit an explicit type signature (which
// would be `ThinSet<String>` in this example).
let mut nums = ThinSet::new();

// Add some nums.
nums.insert(17);
nums.insert(42);
nums.insert(225);
nums.insert(-5);

// Check for a specific one.
if !nums.contains(&44) {
    println!("We have {} nums, but 44 ain't one.",
             nums.len());
}

// Remove a num.
nums.remove(&225);

// Iterate over everything.
for n in &nums {
    println!("{}", n);
}

The easiest way to use ThinSet with a custom type is to derive Eq and Hash and then implement ThinSentinel. We must also derive PartialEq, this will in the future be implied by Eq.

use thincollections::thin_set::ThinSet;
use thincollections::thin_sentinel::ThinSentinel;
 
#[derive(Hash, Eq, PartialEq, Debug)]
struct Color {
    r: u8, g: u8, b: u8
}
 
impl ThinSentinel for Color {
    fn thin_sentinel_zero() -> Self {
        Color {r: 0, g: 0, b: 0}
    }

    fn thin_sentinel_one() -> Self {
        Color {r : 0, g: 0, b: 1}
    }
}

let mut colors = ThinSet::new();

colors.insert(Color { r: 255, g: 255, b: 255 });
colors.insert(Color { r: 255, g: 255, b: 0 });
colors.insert(Color { r: 255, g: 0, b: 255 });
colors.insert(Color { r: 0, g: 255, b: 255 });

// Use derived implementation to print the colors.
for x in &colors {
    println!("{:?}", x);
}

A ThinSet with fixed list of elements can be initialized from an array:

use thincollections::thin_set::ThinSet;

fn main() {
    let nums: ThinSet<i32> =
        [ 2, 4, 6, 8 ].iter().cloned().collect();
    // use the values stored in the set
}

Implementations

impl<T: Hash + Eq + ThinSentinel> ThinSet<T, OneFieldHasherBuilder>

pub fn new() -> ThinSet<T, OneFieldHasherBuilder>

Creates an empty ThinSet.

The hash set is initially created with a capacity of 0, so it will not allocate until it is first inserted into.

Examples

use thincollections::thin_set::ThinSet;
let set: ThinSet<i32> = ThinSet::new();

pub fn with_capacity(capacity: usize) -> ThinSet<T, OneFieldHasherBuilder>

Creates an empty ThinSet with the specified capacity.

The hash set will be able to hold at least capacity elements without reallocating. If capacity is 0, the hash set will not allocate.

Examples

use thincollections::thin_set::ThinSet;
let set: ThinSet<i32> = ThinSet::with_capacity(10);
assert!(set.capacity() >= 10);

impl<T, S> ThinSet<T, S>where
    T: Eq + Hash + ThinSentinel,
    S: BuildHasher,

pub fn with_hasher(hasher: S) -> ThinSet<T, S>

Creates a new empty hash set which will use the given hasher to hash keys.

The hash set is also created with the default initial capacity.

Examples

use thincollections::thin_set::ThinSet;
use thincollections::thin_hasher::OneFieldHasherBuilder;

let s = OneFieldHasherBuilder::new();
let mut set = ThinSet::with_hasher(s);
set.insert(2);

pub fn with_capacity_and_hasher(capacity: usize, hasher: S) -> ThinSet<T, S>

Creates an empty ThinSet with with the specified capacity, using hasher to hash the keys.

The hash set will be able to hold at least capacity elements without reallocating. If capacity is 0, the hash set will not allocate.

Warning: hasher is normally randomly generated, and is designed to allow ThinSets to be resistant to attacks that cause many collisions and very poor performance. Setting it manually using this function can expose a DoS attack vector.

Examples

use thincollections::thin_set::ThinSet;
use thincollections::thin_hasher::OneFieldHasherBuilder;

let s = OneFieldHasherBuilder::new();
let mut set = ThinSet::with_capacity_and_hasher(10, s);
set.insert(1);

pub fn hasher(&self) -> &S

Returns a reference to the set’s BuildHasher.

Examples

use thincollections::thin_set::ThinSet;
use thincollections::thin_hasher::OneFieldHasherBuilder;

let hasher = OneFieldHasherBuilder::new();
let set: ThinSet<i32> = ThinSet::with_hasher(hasher);
let hasher: &OneFieldHasherBuilder = set.hasher();

pub fn capacity(&self) -> usize

Returns the number of elements the set can hold without reallocating.

Examples

use thincollections::thin_set::ThinSet;
let set: ThinSet<i32> = ThinSet::with_capacity(100);
assert!(set.capacity() >= 100);

pub fn reserve(&mut self, additional: usize)

Reserves capacity for at least additional more elements to be inserted in the ThinSet. The collection may reserve more space to avoid frequent reallocations.

Panics

Panics if the new allocation size overflows usize.

Examples

use thincollections::thin_set::ThinSet;
let mut set: ThinSet<i32> = ThinSet::new();
set.reserve(10);
assert!(set.capacity() >= 10);

pub fn shrink_to_fit(&mut self)

Shrinks the capacity of the set as much as possible. It will drop down as much as possible while maintaining the internal rules and possibly leaving some space in accordance with the resize policy.

Examples

use thincollections::thin_set::ThinSet;

let mut set = ThinSet::with_capacity(100);
set.insert(1);
set.insert(2);
assert!(set.capacity() >= 100);
set.shrink_to_fit();
assert!(set.capacity() < 100);

pub fn iter(&self) -> Iter<'_, T>

An iterator visiting all elements in arbitrary order. The iterator element type is &'a T.

Examples

use thincollections::thin_set::ThinSet;
let mut set = ThinSet::new();
set.insert(7);
set.insert(22);

// Will print in an arbitrary order.
for x in set.iter() {
    println!("{}", x);
}

pub fn difference<'a>(&'a self, other: &'a ThinSet<T, S>) -> Difference<'a, T, S>

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

Examples

use thincollections::thin_set::ThinSet;
let a: ThinSet<i32> = [1, 2, 3].iter().cloned().collect();
let b: ThinSet<i32> = [4, 2, 3, 4].iter().cloned().collect();

// Can be seen as `a - b`.
for x in a.difference(&b) {
    println!("{}", x); // Print 1
}

let diff: ThinSet<i32> = a.difference(&b).cloned().collect();
assert_eq!(diff, [1].iter().cloned().collect());

// Note that difference is not symmetric,
// and `b - a` means something else:
let diff: ThinSet<_> = b.difference(&a).cloned().collect();
let diff: ThinSet<_> = b.difference(&a).cloned().collect();
assert_eq!(diff, [4].iter().cloned().collect());

pub fn symmetric_difference<'a>(
    &'a self,
    other: &'a ThinSet<T, S>
) -> SymmetricDifference<'a, T, S>

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

Examples

use thincollections::thin_set::ThinSet;
let a: ThinSet<_> = [1, 2, 3].iter().cloned().collect();
let b: ThinSet<_> = [4, 2, 3, 4].iter().cloned().collect();

// Print 1, 4 in arbitrary order.
for x in a.symmetric_difference(&b) {
    println!("{}", x);
}

let diff1: ThinSet<_> = a.symmetric_difference(&b).cloned().collect();
let diff2: ThinSet<_> = b.symmetric_difference(&a).cloned().collect();

assert_eq!(diff1, diff2);
assert_eq!(diff1, [1, 4].iter().cloned().collect());

pub fn intersection<'a>(
    &'a self,
    other: &'a ThinSet<T, S>
) -> Intersection<'a, T, S>

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

Examples

use thincollections::thin_set::ThinSet;
let a: ThinSet<_> = [1, 2, 3].iter().cloned().collect();
let b: ThinSet<_> = [4, 2, 3, 4].iter().cloned().collect();

// Print 2, 3 in arbitrary order.
for x in a.intersection(&b) {
    println!("{}", x);
}

let intersection: ThinSet<_> = a.intersection(&b).cloned().collect();
assert_eq!(intersection, [2, 3].iter().cloned().collect());

pub fn union<'a>(&'a self, other: &'a ThinSet<T, S>) -> Union<'a, T, S>

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

Examples

use thincollections::thin_set::ThinSet;
let a: ThinSet<_> = [1, 2, 3].iter().cloned().collect();
let b: ThinSet<_> = [4, 2, 3, 4].iter().cloned().collect();

// Print 1, 2, 3, 4 in arbitrary order.
for x in a.union(&b) {
    println!("{}", x);
}

let union: ThinSet<_> = a.union(&b).cloned().collect();
assert_eq!(union, [1, 2, 3, 4].iter().cloned().collect());

pub fn len(&self) -> usize

Returns the number of elements in the set.

Examples

use thincollections::thin_set::ThinSet;

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

pub fn is_empty(&self) -> bool

Returns true if the set contains no elements.

Examples

use thincollections::thin_set::ThinSet;

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

pub fn drain(&mut self) -> Drain<'_, T>

Clears the set, returning all elements in an iterator.

Examples

use thincollections::thin_set::ThinSet;

let mut set: ThinSet<_> = [1, 2, 3].iter().cloned().collect();
assert!(!set.is_empty());

// print 1, 2, 3 in an arbitrary order
for i in set.drain() {
    println!("{}", i);
}

assert!(set.is_empty());

pub fn clear(&mut self)

Clears the set, removing all values.

Examples

use thincollections::thin_set::ThinSet;

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

pub fn contains(&self, value: &T) -> bool

Returns true if the set contains a value.

Examples

use thincollections::thin_set::ThinSet;

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

pub fn get(&self, value: &T) -> Option<&T>

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

Examples

use thincollections::thin_set::ThinSet;

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

pub fn is_disjoint(&self, other: &ThinSet<T, S>) -> bool

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

Examples

use thincollections::thin_set::ThinSet;

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

pub fn is_subset(&self, other: &ThinSet<T, S>) -> bool

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

Examples

use thincollections::thin_set::ThinSet;

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

pub fn is_superset(&self, other: &ThinSet<T, S>) -> bool

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

Examples

use thincollections::thin_set::ThinSet;

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

pub fn insert(&mut self, value: T) -> bool

Adds a value to the set.

If the set did not have this value present, true is returned.

If the set did have this value present, false is returned.

Examples

use thincollections::thin_set::ThinSet;

let mut set = ThinSet::new();

assert_eq!(set.insert(2), true);
assert_eq!(set.insert(2), false);
assert_eq!(set.len(), 1);

pub fn remove(&mut self, value: &T) -> bool

Removes a value from the set. Returns true if the value was present in the set.

Examples

use thincollections::thin_set::ThinSet;

let mut set = ThinSet::new();

set.insert(2);
assert_eq!(set.remove(&2), true);
assert_eq!(set.remove(&2), false);

pub fn take(&mut self, value: &T) -> Option<T>

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

Examples

use thincollections::thin_set::ThinSet;

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

pub fn retain<F>(&mut self, f: F)where
    F: FnMut(&T) -> bool,

Retains only the elements specified by the predicate.

In other words, remove all elements e such that f(&e) returns false.

Examples

use thincollections::thin_set::ThinSet;

let xs = [1,2,3,4,5,6];
let mut set: ThinSet<i32> = xs.iter().cloned().collect();
set.retain(|&k| k % 2 == 0);
assert_eq!(set.len(), 3);

Trait Implementations

impl<'a, 'b, T, S> BitAnd<&'b ThinSet<T, S>> for &'a ThinSet<T, S>where
    T: Eq + Hash + Clone + ThinSentinel,
    S: BuildHasher + Default,

fn bitand(self, rhs: &ThinSet<T, S>) -> ThinSet<T, S>

Returns the intersection of self and rhs as a new ThinSet<T, S>.

Examples

use thincollections::thin_set::ThinSet;

let a: ThinSet<_> = vec![1, 2, 3].into_iter().collect();
let b: ThinSet<_> = vec![2, 3, 4].into_iter().collect();

let set = &a & &b;

let mut i = 0;
let expected = [2, 3];
for x in &set {
    assert!(expected.contains(x));
    i += 1;
}
assert_eq!(i, expected.len());

type Output = ThinSet<T, S>

The resulting type after applying the & operator.

impl<'a, 'b, T, S> BitOr<&'b ThinSet<T, S>> for &'a ThinSet<T, S>where
    T: Eq + Hash + Clone + ThinSentinel,
    S: BuildHasher + Default,

fn bitor(self, rhs: &ThinSet<T, S>) -> ThinSet<T, S>

Returns the union of self and rhs as a new ThinSet<T, S>.

Examples

use thincollections::thin_set::ThinSet;

let a: ThinSet<_> = vec![1, 2, 3].into_iter().collect();
let b: ThinSet<_> = vec![3, 4, 5].into_iter().collect();

let set = &a | &b;

let mut i = 0;
let expected = [1, 2, 3, 4, 5];
for x in &set {
    assert!(expected.contains(x));
    i += 1;
}
assert_eq!(i, expected.len());

type Output = ThinSet<T, S>

The resulting type after applying the | operator.

impl<'a, 'b, T, S> BitXor<&'b ThinSet<T, S>> for &'a ThinSet<T, S>where
    T: Eq + Hash + Clone + ThinSentinel,
    S: BuildHasher + Default,

fn bitxor(self, rhs: &ThinSet<T, S>) -> ThinSet<T, S>

Returns the symmetric difference of self and rhs as a new ThinSet<T, S>.

Examples

use thincollections::thin_set::ThinSet;

let a: ThinSet<_> = vec![1, 2, 3].into_iter().collect();
let b: ThinSet<_> = vec![3, 4, 5].into_iter().collect();

let set = &a ^ &b;

let mut i = 0;
let expected = [1, 2, 4, 5];
for x in &set {
    assert!(expected.contains(x));
    i += 1;
}
assert_eq!(i, expected.len());

type Output = ThinSet<T, S>

The resulting type after applying the ^ operator.

impl<T: Clone + ThinSentinel + Eq + Hash, S: Clone + BuildHasher> Clone for ThinSet<T, S>

fn clone(&self) -> ThinSet<T, S>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T, S> Debug for ThinSet<T, S>where
    T: Eq + Hash + Debug + ThinSentinel,
    S: BuildHasher,

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

Formats the value using the given formatter.

impl<T, S> Default for ThinSet<T, S>where
    T: Eq + Hash + ThinSentinel,
    S: BuildHasher + Default,

fn default() -> ThinSet<T, S>

Creates an empty ThinSet<T, S> with the Default value for the hasher.

impl<'a, T, S> Extend<&'a T> for ThinSet<T, S>where
    T: 'a + Eq + Hash + Copy + ThinSentinel,
    S: BuildHasher,

fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

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

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

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

Reserves capacity in a collection for the given number of additional elements.

impl<T, S> Extend<T> for ThinSet<T, S>where
    T: Eq + Hash + ThinSentinel,
    S: BuildHasher,

fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

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

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

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

Reserves capacity in a collection for the given number of additional elements.

impl<T, S> FromIterator<T> for ThinSet<T, S>where
    T: Eq + Hash + ThinSentinel,
    S: BuildHasher + Default,

fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> ThinSet<T, S>

Creates a value from an iterator.

impl<'a, T, S> IntoIterator for &'a ThinSet<T, S>where
    T: Eq + Hash + ThinSentinel,
    S: BuildHasher,

type Item = &'a T

The type of the elements being iterated over.

type IntoIter = Iter<'a, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Iter<'a, T>

Creates an iterator from a value.

impl<T, S> IntoIterator for ThinSet<T, S>where
    T: Eq + Hash + ThinSentinel,
    S: BuildHasher,

fn into_iter(self) -> IntoIter<T>

Creates a consuming iterator, that is, one that moves each value out of the set in arbitrary order. The set cannot be used after calling this.

Examples

use thincollections::thin_set::ThinSet;
let mut set = ThinSet::new();
set.insert(1_000_000);
set.insert(200_000);

// Not possible to collect to a Vec<u32> with a regular `.iter()`.
let v: Vec<u32> = set.into_iter().collect();

// Will print in an arbitrary order.
for x in &v {
    println!("{}", x);
}

type Item = T

The type of the elements being iterated over.

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?

impl<T, S> PartialEq<ThinSet<T, S>> for ThinSet<T, S>where
    T: Eq + Hash + ThinSentinel,
    S: BuildHasher,

fn eq(&self, other: &ThinSet<T, S>) -> bool

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

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a, 'b, T, S> Sub<&'b ThinSet<T, S>> for &'a ThinSet<T, S>where
    T: Eq + Hash + Clone + ThinSentinel,
    S: BuildHasher + Default,

fn sub(self, rhs: &ThinSet<T, S>) -> ThinSet<T, S>

Returns the difference of self and rhs as a new ThinSet<T, S>.

Examples

use thincollections::thin_set::ThinSet;

let a: ThinSet<_> = vec![1, 2, 3].into_iter().collect();
let b: ThinSet<_> = vec![3, 4, 5].into_iter().collect();

let set = &a - &b;

let mut i = 0;
let expected = [1, 2];
for x in &set {
    assert!(expected.contains(x));
    i += 1;
}
assert_eq!(i, expected.len());

type Output = ThinSet<T, S>

The resulting type after applying the - operator.

impl<T, S> Eq for ThinSet<T, S>where
    T: Eq + Hash + ThinSentinel,
    S: BuildHasher,