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- local mtar = {}
-
- -- detect OS hopefully
- if _OSVERSION then
- if _OSVERSION:sub(1,8) == "OpenOS" then
- OPENOS = true
- elseif _OSVERSION:sub(1,9) == "PsychOS" then
- PSYCHOS = true
- end
- else
- LINUX = true
- end
-
- local function mkdir(dir)
- if OPENOS or LINUX then
- os.execute("mkdir "..dest.."/"..dir.." &> /dev/null")
- elseif PSYCHOS then
- -- todo: write PsychOS support
- end
- end
-
- local function toint(s)
- local n = 0
- local i = 1
- for p in s:gmatch(".") do
- n = n << 8
- n = n | string.byte(p)
- i=i+1
- end
- return n
- end
-
- local function cint(n,l)
- local t={}
- for i = 0, 7 do
- t[i+1] = (n >> (i * 8)) & 0xFF
- end
- return string.reverse(string.char(table.unpack(t)):sub(1,l))
- end
-
- local function cleanPath(path)
- local pt = {}
- for segment in path:gmatch("[^/]+") do
- if segment == ".." then
- pt[#pt] = nil
- elseif segment ~= "." then
- pt[#pt+1] = segment
- end
- end
- return table.concat(pt,"/")
- end
-
- function mtar.genHeader(fname,len) -- generate a header for file *fname* when provided with file length *len*
- return string.format("%s%s%s",cint(fname:len(),2),fname,cint(len,2))
- end
-
- function mtar.iter(stream) -- table -- function -- Given buffer *stream*, returns an iterator suitable for use with *for* that returns, for each iteration, the file name, a function to read from the file, and the length of the file.
- local remain = 0
- local function read(n)
- local rb = stream:read(math.min(n,remain))
- remain = remain - rb:len()
- return rb
- end
- return function()
- stream:read(remain)
- local nlen = toint(stream:read(2) or "\0\0")
- if nlen == 0 then
- return
- end
- local name = cleanPath(stream:read(nlen))
- local fsize = toint(stream:read(2))
- remain = fsize
- return name, read, fsize
- end
- end
-
- function mtar.unarchive(stream,dest,verbose) -- Extract mtar archive read from *stream* to *dest*. If *verbose*, print status.
- dest = dest or "."
- while true do
- local nlen = toint(stream:read(2) or "\0\0")
- if nlen == 0 then
- break
- end
- local name = cleanPath(stream:read(nlen))
- local fsize = toint(stream:read(2))
- if verbose then
- io.write(name.." "..tostring(fsize).."... ")
- end
- local dir = name:match("(.+)/.*%.?.+")
- if (dir) then
- mkdir(dir)
- end
- local f = io.open(dest.."/"..name,"wb")
- local rsize,buf = fsize, ""
- if f then
- repeat
- buf = stream:read(math.min(rsize,2048))
- f:write(buf)
- rsize = rsize - buf:len()
- if verbose then
- io.write(tostring(rsize).." ")
- end
- until rsize <= 1
- f:close()
- end
- if verbose then
- print("done.")
- end
- end
- end
-
- return mtar
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