BinaryKata

Kata for the Hamburg-Elixir Usergroup by Julius Beckmann (@h4cc).

Contents

This kata contains tasks for a few simple binary pattern matching functions like:

• Has a content a UTF-8 BOM?
• Remove a UTF-8 BOM from content.
• Add a UTF-8 BOM to content.
• Detect JPG/PNG/GIF images.
• Read width and height from a GIF image.
• Parsing a ARP packet.

Have fun!

Hints

• Have a look out for binary values and magic constants.
• Also check for endianess which can be little or big.
• Make sure you use byte and bits correctly.
• Use IO.inspect to "see" the stuff you are working with.
• Use the iex -S mix shell to try stuff out.

Get yourself a HEX Editor to "see" the binary stuff in a file.

• Ubuntu: https://wiki.ubuntuusers.de/GHex/
• Mac: http://ridiculousfish.com/hexfiend/

Resources

Elixir getting started with binaries: http://elixir-lang.org/getting-started/binaries-strings-and-char-lists.html

Resource for learning binary pattern matching: http://www.zohaib.me/binary-pattern-matching-in-elixir/