73 lines
1.6 KiB
Lua
73 lines
1.6 KiB
Lua
local base91={}
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local b91enc={[0]=
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
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'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
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'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
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'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
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'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '!', '#', '$',
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'%', '&', '(', ')', '*', '+', ',', '.', '/', ':', ';', '<', '=',
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'>', '?', '@', '[', ']', '^', '_', '`', '{', '|', '}', '~', '"'
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}
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local b91dec=table.flip(b91enc)
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function base91.decode(d)
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local l,v,o,b,n = #d,-1,"",0,0
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for i in d:gmatch(".") do
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local c=b91dec[i]
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if not(c) then
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-- Continue
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else
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if v < 0 then
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v = c
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else
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v = v+c*91
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b = bit.bor(b, bit.lshift(v,n))
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if bit.band(v,8191) then
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n = n + 13
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else
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n = n + 14
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end
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while true do
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o=o..string.char(bit.band(b,255))
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b=bit.rshift(b,8)
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n=n-8
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if not (n>7) then
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break
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end
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end
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v=-1
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end
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end
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end
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if v + 1>0 then
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o=o..string.char(bit.band(bit.bor(b,bit.lshift(v,n)),255))
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end
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return o
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end
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function base91.encode(d)
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local b,n,o,l=0,0,"",#d
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for i in d:gmatch(".") do
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b=bit.bor(b,bit.lshift(string.byte(i),n))
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n=n+8
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if n>13 then
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v=bit.band(b,8191)
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if v>88 then
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b=bit.rshift(b,13)
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n=n-13
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else
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v=bit.band(b,16383)
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b=bit.rshift(b,14)
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n=n-14
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end
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o=o..b91enc[v % 91] .. b91enc[math.floor(v / 91)]
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end
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end
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if n>0 then
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o=o..b91enc[b % 91]
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if n>7 or b>90 then
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o=o .. b91enc[math.floor(b / 91)]
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end
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end
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return o
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end
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return base91
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