--[[ base64 -- v1.5.3 public domain Lua base64 encoder/decoder no warranty implied; use at your own risk Needs bit32.extract function. If not present it's implemented using BitOp or Lua 5.3 native bit operators. For Lua 5.1 fallbacks to pure Lua implementation inspired by Rici Lake's post: http://ricilake.blogspot.co.uk/2007/10/iterating-bits-in-lua.html author: Ilya Kolbin (iskolbin@gmail.com) url: github.com/iskolbin/lbase64 COMPATIBILITY Lua 5.1+, LuaJIT LICENSE See end of file for license information. --]] local base64 = {} local extract = _G.bit32 and _G.bit32.extract -- Lua 5.2/Lua 5.3 in compatibility mode if not extract then if _G.bit then -- LuaJIT local shl, shr, band = _G.bit.lshift, _G.bit.rshift, _G.bit.band extract = function( v, from, width ) return band( shr( v, from ), shl( 1, width ) - 1 ) end elseif _G._VERSION == "Lua 5.1" then extract = function( v, from, width ) local w = 0 local flag = 2^from for i = 0, width-1 do local flag2 = flag + flag if v % flag2 >= flag then w = w + 2^i end flag = flag2 end return w end else -- Lua 5.3+ extract = load[[return function( v, from, width ) return ( v >> from ) & ((1 << width) - 1) end]]() end end function base64.makeencoder( s62, s63, spad ) local encoder = {} for b64code, char in pairs{[0]='A','B','C','D','E','F','G','H','I','J', 'K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y', 'Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n', 'o','p','q','r','s','t','u','v','w','x','y','z','0','1','2', '3','4','5','6','7','8','9',s62 or '+',s63 or'/',spad or'='} do encoder[b64code] = char:byte() end return encoder end function base64.makedecoder( s62, s63, spad ) local decoder = {} for b64code, charcode in pairs( base64.makeencoder( s62, s63, spad )) do decoder[charcode] = b64code end return decoder end local DEFAULT_ENCODER = base64.makeencoder() local DEFAULT_DECODER = base64.makedecoder() local char, concat = string.char, table.concat function base64.encode( str, encoder, usecaching ) encoder = encoder or DEFAULT_ENCODER local t, k, n = {}, 1, #str local lastn = n % 3 local cache = {} for i = 1, n-lastn, 3 do local a, b, c = str:byte( i, i+2 ) local v = a*0x10000 + b*0x100 + c local s if usecaching then s = cache[v] if not s then s = char(encoder[extract(v,18,6)], encoder[extract(v,12,6)], encoder[extract(v,6,6)], encoder[extract(v,0,6)]) cache[v] = s end else s = char(encoder[extract(v,18,6)], encoder[extract(v,12,6)], encoder[extract(v,6,6)], encoder[extract(v,0,6)]) end t[k] = s k = k + 1 end if lastn == 2 then local a, b = str:byte( n-1, n ) local v = a*0x10000 + b*0x100 t[k] = char(encoder[extract(v,18,6)], encoder[extract(v,12,6)], encoder[extract(v,6,6)], encoder[64]) elseif lastn == 1 then local v = str:byte( n )*0x10000 t[k] = char(encoder[extract(v,18,6)], encoder[extract(v,12,6)], encoder[64], encoder[64]) end return concat( t ) end function base64.decode( b64, decoder, usecaching ) decoder = decoder or DEFAULT_DECODER local pattern = '[^%w%+%/%=]' if decoder then local s62, s63 for charcode, b64code in pairs( decoder ) do if b64code == 62 then s62 = charcode elseif b64code == 63 then s63 = charcode end end pattern = ('[^%%w%%%s%%%s%%=]'):format( char(s62), char(s63) ) end b64 = b64:gsub( pattern, '' ) local cache = usecaching and {} local t, k = {}, 1 local n = #b64 local padding = b64:sub(-2) == '==' and 2 or b64:sub(-1) == '=' and 1 or 0 for i = 1, padding > 0 and n-4 or n, 4 do local a, b, c, d = b64:byte( i, i+3 ) local s if usecaching then local v0 = a*0x1000000 + b*0x10000 + c*0x100 + d s = cache[v0] if not s then local v = decoder[a]*0x40000 + decoder[b]*0x1000 + decoder[c]*0x40 + decoder[d] s = char( extract(v,16,8), extract(v,8,8), extract(v,0,8)) cache[v0] = s end else local v = decoder[a]*0x40000 + decoder[b]*0x1000 + decoder[c]*0x40 + decoder[d] s = char( extract(v,16,8), extract(v,8,8), extract(v,0,8)) end t[k] = s k = k + 1 end if padding == 1 then local a, b, c = b64:byte( n-3, n-1 ) local v = decoder[a]*0x40000 + decoder[b]*0x1000 + decoder[c]*0x40 t[k] = char( extract(v,16,8), extract(v,8,8)) elseif padding == 2 then local a, b = b64:byte( n-3, n-2 ) local v = decoder[a]*0x40000 + decoder[b]*0x1000 t[k] = char( extract(v,16,8)) end return concat( t ) end return base64 --[[ ------------------------------------------------------------------------------ This software is available under 2 licenses -- choose whichever you prefer. ------------------------------------------------------------------------------ ALTERNATIVE A - MIT License Copyright (c) 2018 Ilya Kolbin Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ------------------------------------------------------------------------------ ALTERNATIVE B - Public Domain (www.unlicense.org) This is free and unencumbered software released into the public domain. Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a compiled binary, for any purpose, commercial or non-commercial, and by any means. In jurisdictions that recognize copyright laws, the author or authors of this software dedicate any and all copyright interest in the software to the public domain. We make this dedication for the benefit of the public at large and to the detriment of our heirs and successors. We intend this dedication to be an overt act of relinquishment in perpetuity of all present and future rights to this software under copyright law. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ------------------------------------------------------------------------------ --]]