1 files changed, 43 insertions, 0 deletions
diff --git a/builtin/base64.lua b/builtin/base64.lua
new file mode 100644
index 0000000..5afa64a
--- /dev/null
+++ b/builtin/base64.lua
@@ -0,0 +1,43 @@
+--[[ builtin/base64.lua ]]--
+
+-- Taken from: http://lua-users.org/wiki/BaseSixtyFour with minor modifications
+
+-- Lua 5.1+ base64 v3.0 (c) 2009 by Alex Kloss <alexthkloss@web.de>
+-- licensed under the terms of the LGPL2
+
+local base64 = {}
+package.loaded.base64 = base64
+
+-- character table string
+local b='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
+
+-- encoding
+function base64.encode(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 base64.decode(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
+