35 lines
1 KiB
Lua
35 lines
1 KiB
Lua
function to_base64(data)
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local b = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
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return ((data:gsub('.', function(x)
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local r,b='',x:byte()
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for i=8,1,-1 do r=r..(b%2^i-b%2^(i-1)>0 and '1' or '0') end
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return r;
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end)..'0000'):gsub('%d%d%d?%d?%d?%d?', function(x)
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if (#x < 6) then return '' end
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local c=0
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for i=1,6 do c=c+(x:sub(i,i)=='1' and 2^(6-i) or 0) end
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return b:sub(c+1,c+1)
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end)..({ '', '==', '=' })[#data%3+1])
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end
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function from_base64(data)
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local b = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
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data = string.gsub(data, '[^'..b..'=]', '')
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return (data:gsub('.', function(x)
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if (x == '=') then return '' end
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local r,f='',(b:find(x)-1)
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for i=6,1,-1 do r=r..(f%2^i-f%2^(i-1)>0 and '1' or '0') end
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return r;
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end):gsub('%d%d%d?%d?%d?%d?%d?%d?', function(x)
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if (#x ~= 8) then return '' end
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local c=0
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for i=1,8 do c=c+(x:sub(i,i)=='1' and 2^(8-i) or 0) end
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return string.char(c)
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end))
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end
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return {
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atob = from_base64,
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btoa = to_base64
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}
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