bitball

A simple, efficient, and easy-to-use Node.js module for working with individual bits.

npm i --save bitball

Documentation.

Example.

'use strict'

var bitball
var flagSet

bitball = require('bitball')

flagSet = new bitball.BitSet(18) // Defaults to 8 bits if a size isn't provided.

console.log('flagSet{0}: ' + ((flagSet.get(0) === true) ? '1' : '0'))
console.log('flagSet{17}: ' + ((flagSet.get(17) === true) ? '1' : '0'))
flagSet.set(17, true)
console.log('flagSet{17}: ' + ((flagSet.get(17) === true) ? '1' : '0'))
flagSet.flip(17)
console.log('flagSet{17}: ' + ((flagSet.get(17) === true) ? '1' : '0'))

// Take a look at the tests.

API.

new bitball.BitSet(numberOfBits : Number = 8) -> bitball.BitSet

Constructs a new BitSet object to hold your fancy bits. Allocates as few bytes as possible. numberOfBits defaults to 8 bits.

bitball.BitSet.prototype.flip(bitIndex : Number, allowIndexOverflow : Boolean) -> undefined

Flips the bit at bitIndex.

The allowIndexOverflow boolean allows you to control what happens if bitIndex is bigger than the number of bits you specified during construction.

• If allowIndexOverflow is true, then .flip(...) will fail silently.
• If allowIndexOverflow is false, then an exception will be thrown.

bitball.BitSet.prototype.get(bitIndex : Number, dontThrow : Boolean) -> Boolean|null

Gets the value of the bit at bitIndex.

The dontThrow boolean allows you to control what happens if bitIndex is bigger than the number of bits you specified during construction.

• If dontThrow is true, then .get(...) will return null.
• If dontThrow is false, then an exception will be thrown.

bitball.BitSet.prototype.resize(numberOfBits : Number) -> undefined

Resizes the BitSet as necessary to make sure it can hold numberOfBits bits.

bitball.BitSet.prototype.set(bitIndex : Number, bitValue : Boolean, forceResize : Boolean) -> undefined

Sets the value of the bit at bitIndex to bitValue.

The forceResize boolean allows you to control what happens if bitIndex is bigger than the number of bits you specified during construction.

• If forceResize is true, then .set(...) will call .resize(bitIndex + 1).
• If forceResize is false, then an exception will be thrown.

bitball.BitSet.prototype.length -> Number

Returns the number of bits this BitSet object can hold (i.e., the biggest index + 1).

Tests.

npm test

Author.

Jonathan Barronville <jonathan@belairlabs.com>

License.

Copyright 2015 Jonathan Barronville <jonathan@belairlabs.com>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.