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Base64 encode data: Difference between revisions
added Ol
(added Ol) |
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val enc : string =
"AAABAAIAEBAAAAAAAABoBQAAJgAAACAgAAAAAAAAqAgAAI4F"... (* string length 4852; truncated *)
</pre>
=={{header|Ol}}==
<lang scheme>
(define base64-codes "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
(define kernel (alist->ff (map cons (iota (string-length base64-codes)) (string->bytes base64-codes))))
; returns n bits from input binary stream
(define (bits n hold)
(let loop ((hold hold))
(vector-apply hold (lambda (v i l)
(cond
; usual case
((pair? l)
(if (not (less? i n))
(values (>> v (- i n)) (vector (band v (- (<< 1 (- i n)) 1)) (- i n) l))
(loop (vector
(bor (<< v 8) (car l))
(+ i 8)
(cdr l)))))
; special case - no more characters in input stream
((null? l)
(cond
((= i 0)
(values #false #false)) ; done
((< i n)
(values (<< v (- n i)) (vector 0 0 #null)))
(else
(values (>> v (- i n)) (vector (band v (- (<< 1 (- i n)) 1)) (- i n) #null)))))
; just stream processing
(else
(loop (vector v i (force l)))))))))
; decoder.
(define (encode str)
(case (mod
(let loop ((hold [0 0 (str-iter str)]) (n 0))
(let*((bit hold (bits 6 hold)))
(when bit (display (string (kernel bit))))
(if (not hold)
n
(loop hold (+ n 1)))))
4)
(2 (print "=="))
(3 (print "="))
(else (print))))
(encode "Hello, Lisp!")
(encode "To err is human, but to really foul things up you need a computer.\n -- Paul R. Ehrlich")
(encode "Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure.")
</lang>
{{Out}}
<pre>
SGVsbG8sIExpc3Ah
MDEyMzQ=
VG8gZXJyIGlzIGh1bWFuLCBidXQgdG8gcmVhbGx5IGZvdWwgdGhpbmdzIHVwIHlvdSBuZWVkIGEgY29tcHV0ZXIuCiAgICAtLSBQYXVsIFIuIEVocmxpY2g=
TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCBieSB0aGlzIHNpbmd1bGFyIHBhc3Npb24gZnJvbSBvdGhlciBhbmltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2YgdGhlIG1pbmQsIHRoYXQgYnkgYSBwZXJzZXZlcmFuY2Ugb2YgZGVsaWdodCBpbiB0aGUgY29udGludWVkIGFuZCBpbmRlZmF0aWdhYmxlIGdlbmVyYXRpb24gb2Yga25vd2xlZGdlLCBleGNlZWRzIHRoZSBzaG9ydCB2ZWhlbWVuY2Ugb2YgYW55IGNhcm5hbCBwbGVhc3VyZS4=</pre>
The rosettacode icon:
<lang scheme>
(define icon (runes->string (bytevector->list (file->bytevector "favicon.ico"))))
(encode icon)
</lang>
<pre>
AAABAAIAEBAAAAAAAABoBQAAJgAAACAgAAAAAAAAqAgAAI4FAAAoAAAAEAAAACAAAAABAAgAAAAAAEABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP///wCG
...
AABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAE=
</pre>
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