nodemcu-firmware/lua_modules/base64/base64_v2.lua

36 lines
817 B
Lua

--this version actually works
local tab = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
base64 = {
enc = function(data)
local l,out = 0,''
local d = data..string.rep('\0',(3-data:len()%3)%3)
for i=1,d:len() do
l = bit.lshift(l,8)
l = l+d:byte(i,i)
if i%3==0 then
for j=1,4 do
local a = bit.rshift(l,18)+1
out = out..tab:sub(a,a)
l = bit.band(bit.lshift(l,6),0xFFFFFF)
end
end
end
return out..({'','==','='})[data:len()%3+1]
end,
dec = function(data)
local a,b = data:gsub('=','A')
local out = ''
local l = 0
for i=1,a:len() do
l=l+tab:find(a:sub(i,i))-1
if i%4==0 then
out=out..string.char(bit.rshift(l,16),bit.band(bit.rshift(l,8),255),bit.band(l,255))
l=0
end
l=bit.lshift(l,6)
end
return out:sub(1,-b-1)
end
}