bitarray

Memory efficient Boolean array implementation, very easy to use

Installation

  npm install  zo-bitarray --save

Usage

    const BitArray = require('zo-bitarray')  

    let ba = new BitArray('1010101010')
    ba.get(0)  //1
    ba.count() //5
    ba.set(3, 1) // ba.get(3) -> 1
    ba.not(3)   // ba.get(3) -> 0

    for(let v of ba){
     //v is assigned to  1,0,1,0,1,0,1,0,1,0  in order
    }
    
    ba.forExist(i => {
      ba.get(i) // always 1
    })

API

Constructor

• constructor(lenght, val=0)
• constructor(data)

  new BitArray(10)  //0000000000
  new BitArray(10, 1) //1111111111
  new BitArray([1,0,1,0,1,0,1,0,1,0]) // 1010101010
  let ba = new BitArray('1010101010') // 1010101010
  new BitArray(ba) // 1010101010


  let data = {  //Usually get from  rawData()
    length: 100,
    rawdata: [1227133513, 2454267026, 613566756, 9]
  }
  ba = new BitArray(data) // 100100100.....1001    100 bits  

  //string start with '@' from compactData()
  ba = new BitArray('@0001fnHfD-L1u=Zb$7!A00009') // 100100100.....1001    100 bits  

Attribute

• length
• count()
• blockSize()
• blockBitNum()

Traversing Data

• for of
• forEach(cb)
• forExist(cb)
• entries()

  let ba = new BitArray('1010101010')
  let s = ''
  for(let v of ba){
    s += v
  }  // s == '1010101010'

  s = ''
  ba.forEach((v, i) => {
    s += v
  })  // s == '1010101010'

  s = ''
  ba.forExist(i => {
    s += i
  }) // s == '02468'

  s = ''
  for (let [i, v] of ba.entries()) {
    s += i + ':' + v + ','
  } // s == '0:1,1:0,2:1,3:0,4:1,5:0,6:1,7:0,8:1,9:0,'

  assert(String(ba) == '1010101010')

Export Data

• toString()
• toArray()
• rawData()
• compactData()

  let ba = new BitArray('1010101010') 
  ba.toString() //'1010101010'
  ba.toArray() // [1,0,1,0,1,0,1,0,1,0]

  //More efficient data
  ba.rawData() // {length:10,rawdata:[341]}

  //More compact data 
  ba.compactData() //'@0000a00041'

Bit Operation

• get(index)
• set(index, val)
• and(other)
• and(index, val)
• or(other)
• or(index, val)
• not(index)
• not()
• xor(index, val)
• xor(other)

Other

• fill(val, begin, end)
• cover(other, begin, end)
• swap(other, begin, end)