short_string_packer.rb

short_string_packer.rb

# frozen_string_literal: true

# Packs/Unpacks a String to and from an Integer
class ShortStringPacker
  ## Packs a short string into a Integer
  # Arguments:
  #   str - String object
  # Returns: a Integer object
  def self.pack(str)
    # IMPLEMENT THIS METHOD
    mapping_hash = Hash[('a'..'z').to_a.zip(1..26)]
    chars = str.split('')
    bit_arr = chars.map do |char|
      mapping_hash[char].to_s(2).rjust(5, '0')
    end
    bit_arr.join('').to_i(2)
  end

  ## Unpacks a Integer from pack() method into a short string
  # Arguments:
  #   packed - a Integer object
  # Returns: a String object
  def self.unpack(packed)
    # IMPLEMENT THIS METHOD
    bit_arr = packed.to_s(2).reverse.scan(/.{1,5}/).join(',').reverse.split(',')
    mapping_hash = Hash[(1..26).to_a.zip('a'..'z')]
    str_arr = bit_arr.map do |ele|
      int = ele.to_i(2)
      mapping_hash[int]
    end
    str_arr.join('')
  end
end