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--[[ | |
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 ([email protected]) | |
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. | |
------------------------------------------------------------------------------ | |
--]] |