OC-PsychOS2/lib/libmtar.lua

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local mtar = {}
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
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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", string.pack(">I2",fname:len()), fname, string.pack(">I2",len))
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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 = string.unpack(">I2", stream:read(2) or "\0\0")
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if nlen == 0 then
return
end
local name = cleanPath(stream:read(nlen))
local fsize = string.unpack(">I2", stream:read(2))
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remain = fsize
return name, read, fsize
end
end
return mtar