bit-set-js v0.1.0

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 : arrayint)

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.

Licence

GNU GENERAL PUBLIC LICENSE