1 ! Copyright (C) 2008 Doug Coleman.
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: kernel math sequences io.binary splitting grouping ;
8 : count-end ( seq quot -- count )
9 >r [ length ] keep r> find-last drop dup [ - 1- ] [ 2drop 0 ] if ; inline
11 : ch>base64 ( ch -- ch )
12 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" nth ;
14 : base64>ch ( ch -- ch )
16 f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f
17 f f f f f f f f f f 62 f f f 63 52 53 54 55 56 57 58 59 60 61 f f
18 f 0 f f f 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
19 22 23 24 25 f f f f f f 26 27 28 29 30 31 32 33 34 35 36 37 38 39
20 40 41 42 43 44 45 46 47 48 49 50 51
23 : encode3 ( seq -- seq )
24 be> 4 <reversed> [ -6 * shift HEX: 3f bitand ch>base64 ] with B{ } map-as ;
26 : decode4 ( str -- str )
27 0 [ base64>ch swap 6 shift bitor ] reduce 3 >be ;
29 : >base64-rem ( str -- str )
30 [ 3 0 pad-right encode3 ] [ length 1+ ] bi head 4 CHAR: = pad-right ;
34 : >base64 ( seq -- base64 )
35 #! cut string into two pieces, convert 3 bytes at a time
36 #! pad string with = when not enough bits
37 dup length dup 3 mod - cut
38 [ 3 <groups> [ encode3 ] map concat ]
39 [ [ "" ] [ >base64-rem ] if-empty ]
42 : base64> ( base64 -- str )
43 #! input length must be a multiple of 4
44 [ 4 <groups> [ decode4 ] map concat ]
45 [ [ CHAR: = = not ] count-end ]