eancheck - check digit validator for EAN, PLU and UPC barcode numbers
[EAN code, PLU code or UPC prefixed with 0]
eancheck takes a 13 digit EAN (European Article Number, aka a barcode number) or
a 4 digit PLU code and runs some simple maths upon it to discover the
"check digit". It then compares this against the last number of the
inputted EAN to check whether that code; if they match, then the EAN/PLU is
valid. If they do not, then the opposite applies.
Right now UPC codes need to be prefixed with a zero (i.e turned into EAN codes)
to be properly checked.
Joe Baldwin <firstname.lastname@example.org>