DEFINE
shl == 2 *;
shr == 2 /;
and63 == [64 / 64 *] nullary -;
b64enc1 == ord 16 [shl] times [ord 8 [shl] times] dip + [ord] dip +;
b64enc2 == "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" swap [] [
		[18 [shr] times and63 at]
		[12 [shr] times and63 at]
		[6  [shr] times and63 at]
		[and63 at]
	      ] construct "" cons cons cons cons [pop] dip;

s2l == [null]  [pop []]  [uncons]  [cons]  linrec;
b64enc ==
	s2l
	"" swap
	# pad with null bytes
	# calculate how many bytes to pad
	[size 3 rem 3 swap - 3 rem] nullary
	# i cant use null bytes in strings (hence s2l)
	[0 chr [] cons concat] times
	# len(s)/3 times
	[size 3 /] nullary
	[[3 take] nullary s2l [b64enc1 b64enc2] infra first rollup [swap concat] dip 3 drop] times
	# remove the now-empty string
	pop
	"\n" concat
END
stdin [feof not] [fgets b64enc putchars] while fclose.