forked from izaya/OC-PsychOS2
72 lines
1.3 KiB
Lua
72 lines
1.3 KiB
Lua
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local lz = require "lzss"
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local buffer = require "buffer"
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lz16 = {}
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local function cint(n,l)
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local t={}
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for i = 0, 7 do
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t[i+1] = (n >> (i * 8)) & 0xFF
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end
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return string.reverse(string.char(table.unpack(t)):sub(1,l))
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end
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local function toint(s)
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local n = 0
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local i = 1
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for p in s:gmatch(".") do
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n = n << 8
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n = n | string.byte(p)
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i=i+1
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end
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return n
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end
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local function readBuffer(fi)
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local stream = {}
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if fi:read(4) ~= "lz16" then
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return false, "not an lz16 archive"
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end
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function stream.read()
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local len = toint(fi:read(2) or "\0\0")
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if len < 1 then
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return nil
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end
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coroutine.yield()
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return lz.decompress(fi:read(len))
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end
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function stream.close()
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fi:close()
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end
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return buffer.new("rb",stream)
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end
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local function writeBuffer(fo)
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local stream = {}
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function stream:write(data)
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local cblock = lz.compress(data)
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fo:write(cint(cblock:len(),2)..cblock)
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return cblock:len()+2
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end
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function stream.close()
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fo:close()
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end
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fo:write("lz16") -- write header
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return buffer.new("wb",stream)
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end
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function lz16.buffer(stream)
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if stream.mode.w then
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return writeBuffer(stream)
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end
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return readBuffer(stream)
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end
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function lz16.open(fname, mode)
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local f = io.open(fname, mode)
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if not f then return false end
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f.mode.b = true
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return lz16.buffer(f)
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end
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return lz16
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