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- local mtar = {}
-
- 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) -- string number -- string -- 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()
- while remain > 0 do
- remain=remain-#stream:read(math.min(remain,2048))
- end
- 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
-
- return mtar
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