IBM MOD 11 Algorithm

Post a clever/fast/short implementation of this algorithm

http://en.wikipedia.org/wiki/MSI_Barcode#Mod_11_Check_Digit (IBM version)

¡In any programming language you want!

Skill level: 1 of 10

INB4: Check my Anus

>>9
Who said I wanted fast?

Size optimisation is more important 99% of the time, in code that is run after the program is waiting for something from the user. Speed only in the 1% or so where it really matters. I loathe things like a memcpy() that takes 2KB to implement but is maybe only 50% faster than the simple one that's under a dozen bytes. 200x increase in size for 50% or even 100% increase in speed is NOT efficient. (And in the future, architectural enhancements will make the simple one faster, making the complex one a waste of bytes.)

>>12
GNUfag.