RosettaCodeData/Task/Base64-decode-data/Lua/base64-decode-data.lua

27 lines
889 B
Lua

-- Start taken from https://stackoverflow.com/a/35303321
local b='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/' -- You will need this for encoding/decoding
-- decoding
function 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^(8-i) or 0) end
return string.char(c)
end))
end
-- end of copy
local data = "VG8gZXJyIGlzIGh1bWFuLCBidXQgdG8gcmVhbGx5IGZvdWwgdGhpbmdzIHVwIHlvdSBuZWVkIGEgY29tcHV0ZXIuCiAgICAtLVBhdWwgUi5FaHJsaWNo"
print(data)
print()
local decoded = dec(data)
print(decoded)