Thrust

std::collections::hashset (v0.2.2)

Hash set of keys.

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Overview

std::collections::hashset stores a set of unique keys with insert, contains, and remove.

insert returns true when the key was new; dropHashSet releases the storage.

Source: thrustc/std/v0.2.2/collections/hashset.thrust

Public Signatures

Exported declarations for this module snapshot.

const HASHSET_INITIAL_CAPACITY: usize @public = 8;
struct HashSetEntry @public {
struct HashSet [K] @public {
fn newHashSet [K] () HashSet[K] @public;
fn withCapacity [K] (capacity: usize) HashSet[K] @public;
fn dropHashSet [K] (set: ptr[HashSet[K]]) void @public @deallocator;
fn getLength [K] (set: ptr[HashSet[K]]) usize @public;
fn getCapacity [K] (set: ptr[HashSet[K]]) usize @public;
fn isEmpty [K] (set: ptr[HashSet[K]]) bool @public;
fn contains [K] (set: ptr[HashSet[K]], key: ptr) bool @public;
fn insert [K] (set: ptr[HashSet[K]], key: ptr) bool @public;
fn remove [K] (set: ptr[HashSet[K]], key: ptr) bool @public;
fn clear [K] (set: ptr[HashSet[K]]) void @public;
fn reserveCapacity [K] (set: ptr[HashSet[K]], requestedCapacity: usize) void @public;

Behavior and Use

insert returns true when the key was new; contains reports presence; remove deletes a key.

Call dropHashSet when the set is no longer needed to release the backing storage.

Examples

import std::collections::hashset;
import std::io;

// Keep track of which feature flags are enabled.
fn main() s32 @public {
    var enabled := hashset::newHashSet[s32]();

    var flagA: s32 = 7;

    hashset::insert[s32](ref enabled, ref flagA);

    if hashset::contains[s32](ref enabled, ref flagA) {
        io::print("flag A is enabled\n");
    }

    hashset::dropHashSet[s32](ref enabled);

    return 0;
}
import std::collections::hashset;
import std::io;

// Revoke a guest tag from the allowed set and report what remains.
fn main() s32 @public {
    var tags := hashset::newHashSet[s32]();

    var admin: s32 = 1;
    var guest: s32 = 2;

    hashset::insert[s32](ref tags, ref admin);
    hashset::insert[s32](ref tags, ref guest);

    hashset::remove[s32](ref tags, ref guest);

    io::print("remaining tags: %d\n", hashset::getLength[s32](ref tags));

    hashset::dropHashSet[s32](ref tags);

    return 0;
}
import std::collections::hashset;
import std::io;

// Pre-size a set of known VIP ids, then check membership.
fn main() s32 @public {
    var vips := hashset::withCapacity[s32](8);

    var id: s32 = 5;

    hashset::insert[s32](ref vips, ref id);

    if hashset::contains[s32](ref vips, ref id) {
        io::print("welcome, VIP\n");
    }

    hashset::dropHashSet[s32](ref vips);

    return 0;
}

Notes

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