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- -- Lua 5.1+ base64 v3.0 (c) 2009 by Alex Kloss <alexthkloss@web.de>
- -- licensed under the terms of the LGPL2
- local moduleName = ...
- local M = {}
- _G[moduleName] = M
- -- character table string
- local b='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
-
- -- encoding
- function M.enc(data)
- return ((data:gsub('.', function(x)
- local r,b='',x:byte()
- for i=8,1,-1 do r=r..(b%2^i-b%2^(i-1)>0 and '1' or '0') end
- return r;
- end)..'0000'):gsub('%d%d%d?%d?%d?%d?', function(x)
- if (#x < 6) then return '' end
- local c=0
- for i=1,6 do c=c+(x:sub(i,i)=='1' and 2^(6-i) or 0) end
- return b:sub(c+1,c+1)
- end)..({ '', '==', '=' })[#data%3+1])
- end
-
- -- decoding
- function M.dec(data)
- data = string.gsub(data, '[^'..b..'=]', '')
- return (data:gsub('.', function(x)
- if (x == '=') then return '' end
- local r,f='',(b:find(x)-1)
- for i=6,1,-1 do r=r..(f%2^i-f%2^(i-1)>0 and '1' or '0') end
- return r;
- end):gsub('%d%d%d?%d?%d?%d?%d?%d?', function(x)
- if (#x ~= 8) then return '' end
- local c=0
- for i=1,8 do c=c+(x:sub(i,i)=='1' and 2^(7-i) or 0) end
- return string.char(c)
- end))
- end
- return M
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