Array mapping each character code back to its associated value.
This is the main lookup table used for decoding. It covers every character code from 0...255. Codes for characters that aren't part of the Base64 alphabet are mapped to NIL.
Definition:
(defconst *b64-vals-from-codes-array* (compress1 '*b64-vals-from-codes-array* (cons (list :header :dimensions (list 256) :maximum-length 257 :default nil :name '*b64-vals-from-codes-array*) (pairlis$ (char-code-list (strip-cdrs *b64-chars-from-vals-alist*)) (strip-cars *b64-chars-from-vals-alist*)))))