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