A BitArray Implementation in CoffeeScript

BitArray.coffee

class BitArray
  width: 24

  constructor: (size=24, default_value = 0) ->
    @size = size
    initialElements = Math.floor(size / @width) + 1
    @field = []
    for i in [0...initialElements]
      @field[i] = 0

  # Set a bit (1/0)
  set: (position, value) ->
    position -= 1
    if value == 1
      @field[Math.floor(position / @width)] |= 1 << (position % @width)
    else if (@field[Math.floor(position / @width)]) & (1 << (position % @width)) != 0
      @field[Math.floor(position / @width)] |= 0 << (position % @width)
    return @

  get: (position) ->
    position -= 1
    return if (@field[Math.floor(position / @width)] & 1 << (position % @width)) > 0  then 1 else 0

  each: (callback) ->
    i=0
    while i < @size
      callback @getValue(i), i
      i++
    return @

  # Returns the field as a string like "0101010100111100," etc.
  toString: ->
    c = @
    localField = @field.map (n) ->
      val = n.toString(2)
      while val.length < c.width
        val = '0' + val;
      val

    str = localField.reverse().join('')
    str.substr(str.length - c.size)

  setFromString: (str) ->
    vals = str.split('').reverse()
    valCount = vals.length
    for i in [0...valCount]
      @set(i+1, parseInt(vals[i]))
    return @


  toArray: ->
    return @field.slice()