BitSetJS

Library to create and deal with a BitSet in ES6. BitSet creates a bit array, which allows us to store a big amount of binary flags in a very memory-wise efficient manner.

This library supports these operations:

• getting, setting and toggling of individual bits
• counting how many 1s bits are in the array
• serialization to and from strings (001101 binary format)
• serialization to and from arrays
• Use in the Browser, or as a CommonJS module

Usage

a = new BitArray(6);
a.set(0);
a.set(3);
a.stringify(); // "001001"
a.get(1); // false
a.get(3); // true

Internally, the library stores the bit array, into 32 bits integers objects. So, if you create a 64 bits array, the library will internally hold an array of 2 integers. You can call bitset.getData() to get this private array of integers, and transfer this array in client-server communications.

API

You can initialiaze a BitSet with threee different constructors:

BitSet(size=32 :int, value=0 :boolean)

Creates a new bit array with the given size and the selected value as default. Value can be 0 or 1. Ex: new Bitset(3, 1).stringify() == '111'

BitSet(binary : string)

Takes a binary number 0101, and converts it to the correspondent bits in the array. The rightmost carachter is the bit 0.

BitSet(ints : array[int])

Sets the the array of integers as the backing stored data of the bitset. Ex: new BitSet([3]).stringify() == '00000000000000000000000000000011';

The operations supported by the BitSet:

length

This property contains the number of bits in the bitset.

set(N)

Sets the N bit to 1. Returns true if the operation was succesful.

get(N)

Returns the value of the bit at N (boolean)

toggle(N)

Toggles (inverts) the bit at N index.

toString()

Returns "[object BitSet]" in order to identify the object as a Bitset.

stringify()

Returns the binary representation of the bitSet.

getData()

Gets the data with the integers holding the bits information. Ex: new BitSet("101").getData() // [5]

count()

Returns the total number of bits set to 1 in this BitSet.

invert()

Inverts this BitSet.

How to include

This library has been writen in ES6. However, an ES5 version (compiled by babel 5) is also distributed.

Also, by npm:

> npm install bit-set-js

Licence

GNU GENERAL PUBLIC LICENSE