A small class for generating and validating Universal Product Codes (UPCs), the 12 digit codes found on many older US products.

gem install upc

UPC.new("632737715836").valid?
=> true

UPC.valid?("632737715836")
=> true

UPC.valid?("632737715837")
=> false

UPC.complete("63273771583")
=> "632737715836"

UPC.new("632737715836").to_ean
=> "0632737715836"

• http://en.wikipedia.org/wiki/Universal_Product_Code

Source code is publicly available @ http://github.com/yob/upc. Patches welcome, preferably via a git repo I can pull from.