mirror of
https://github.com/Adorable-Catgirl/Zorya-NEO.git
synced 2024-09-29 07:01:00 +10:00
40 lines
978 B
Lua
40 lines
978 B
Lua
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local s, t = string, table
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local ss = s.sub
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--------------------------------------------------------------------------------
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local POS_BITS = 12
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local LEN_BITS = 16 - POS_BITS
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local POS_SIZE = 1 << POS_BITS
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local LEN_SIZE = 1 << LEN_BITS
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local LEN_MIN = 3
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local function lzss_decompress(input)
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local offset, output = 1, {}
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local window = ''
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while offset <= #input do
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local flags = s.byte(input, offset)
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offset = offset + 1
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for i = 1, 8 do
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local str = nil
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if (flags & 1) ~= 0 and offset <= #input then
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str = ss(input, offset, offset)
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offset = offset + 1
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elseif offset + 1 <= #input then
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local tmp = s.unpack('>I2', input, offset)
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offset = offset + 2
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local pos = (tmp >> LEN_BITS) + 1
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local len = (tmp & (LEN_SIZE - 1)) + LEN_MIN
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str = ss(window, pos, pos + len - 1)
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end
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flags = flags >> 1
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if str then
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output[#output + 1] = str
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window = ss(window .. str, -POS_SIZE)
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end
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end
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end
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return t.concat(output)
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end
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