1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
#############################################################################
#
# File: base64.icn
#
# Subject: Procedures for base64 encodings for MIME (RFC 2045)
#
# Author: David A. Gamey
#
# Date: May 2, 2001
#
#############################################################################
#
# This file is in the public domain.
#
#############################################################################
#
# Descriptions:
#
# base64encode( s1 ) : s2
#
# returns the base64 encoding of a string s1
#
# base64decode( s1 ) : s2
#
# returns the base64 decoding of a string s1
# fails if s1 isn't base64 encoded
#
# references: MIME encoding Internet RFC 2045
#
#############################################################################
procedure base64encode(s) #: encode a string into base 64 (MIME)
local pad, t, i, j, k
static b64
initial b64 := &ucase || &lcase || &digits || "+/"
i := (3 - (*s % 3)) % 3
s ||:= repl("\x00",i)
pad := repl("=",i)
t := ""
s ? while ( i := ord(move(1)), j := ord(move(1)), k := ord(move(1)) ) do {
t ||:= b64[ 1 + ishift(i,-2) ]
t ||:= b64[ 1 + ior( ishift(iand(i,3),4), ishift(j,-4) ) ]
t ||:= b64[ 1 + ior( ishift(iand(j,15),2), ishift(k,-6) ) ]
t ||:= b64[ 1 + iand(k,63) ]
}
t[ 0 -: *pad ] := pad
return t
end
procedure base64decode(s) #: decode a string from base 64 (MIME)
local t, w, x, y, z
static b64, c64, n64
initial {
b64 := &ucase || &lcase || &digits || "+/"
c64 := cset(b64)
n64 := string(&cset)[1+:64]
}
if not s ? ( tab(many(c64)), =("===" | "==" | "=" | ""), pos(0)) then fail
if ( *s % 4 ) ~= 0 then fail
s := map(s,"=","\x00")
s := map(s,b64,n64)
t := ""
s ? while ( w := ord(move(1)), x := ord(move(1)),
y := ord(move(1)), z := ord(move(1)) ) do {
t ||:= char( ior( ishift(w,2), ishift(x,-4) ) )
t ||:= char( ior( iand(ishift(x,4),255), ishift(y,-2) ) )
t ||:= char( ior( iand(ishift(y,6),255), z ) )
}
return trim(t,'\x00')
end
|
