Short String Packer

Implement a simple but effective compression scheme for short, simple strings

Setup

Make sure you have a Github account, and setup your public and private SSH keys for password-less authentication from your local machine to Github.

1. Fork this Github project to your your own account. Then, clone your fork to your local machine.

git clone git@github.com:[your-github-username]/hw-data_packer.git

2. Set your local ruby version for the project folder using rbenv

e.g., for Ruby 3.4.2:

rbenv local 3.4.2

This creates a .ruby-version file in the root of your project directory.

3. Run bundle install to install the package dependencies listed in Gemfile. After bundling, you should see a Gemfile.lock file appear in your project directory.

Overview

In this assignment, you must write the code needed within two methods found in the file short_string_packer.rb:

• The pack(str) method must take a string called str and return an Integer
• The unpack(packed) method must take an Integer called packed, decompress it and return the string that was originally compressed

Details

Types:

• str: A short String that only contains lowercase characters 'a' - 'z' (no spaces, digits, uppercase, symbols, etc.)
• packed: An integer of type Integer

Methods:

• pack(str): Realize that the 26 letters 'a'-'z' don't need to use all the bits available in a UTF-8 character. You can use this to compress a string by packing the bits of each character together:
  • take each letter of str, convert it to a number from 1-26
  • take the bits of each number have created and shift them appropriately, and use a binary operation to pack them together into a single Integer called packed
• unpack(packed): Reverse the process above by accepting a packed Integer and returning the reproduced String

Coding rules

• Do not use any external libraries (gems)
• Do not write code anywhere outside of the two methods of short_string_packer.rb
• Do not use any for/while loops. ONLY use functional iterators: .map, .each, .reduce etc.
• Run rubocop on your code to ensure that it is formatted correctly

Testing

Test your solution by running the test specification file:

ruby packer_spec.rb

Your final solution should see all tests passing:

$ ruby packer_spec.rb
Run options:

# Running:

.......

Finished in 0.001401s

7 runs, 7 assertions, 0 failures, 0 errors, 0 skips

Submission

On Canvas, submit a URL to your git repository.