Std::HashSet

An open-addressing hash set of integers.

Module: Std::HashSet

Struct

struct HashSet {
    data:  *uint8;
    cap:   uint;
    count: uint;
}

HashSet stores a collection of unique int keys with fast membership tests. It uses open addressing with linear probing and grows automatically as it fills. It's the value-less companion to HashMap.

A set must be initialized with Init before use and released with Free when done.

Lifecycle

Function	Description
Init	Initialize a set (optionally with capacity).
Free	Release the set's memory.
Clear	Remove all keys, keep the allocation.

Membership

Method	Description
Insert	Add a key.
Contains	Test whether a key is present.
Remove	Delete a key.

Inspection

Method	Description
Len	Number of keys.
Cap	Number of slots currently allocated.
Keys	Allocate an array of all keys.

Example

import Std::HashSet::*;
import Std::Io::PrintLine;

func Main() -> int {
    var seen: HashSet;
    Init(&seen);

    seen.Insert(10);
    seen.Insert(20);
    seen.Insert(10);             // duplicate ignored

    PrintLine(seen.Len());       // 2
    PrintLine(seen.Contains(20));// true

    seen.Free();
    return 0;
}