mirror of
https://git.shadowkat.net/izaya/OC-PsychOS2.git
synced 2024-11-25 20:48:43 -05:00
59 lines
1.4 KiB
Lua
59 lines
1.4 KiB
Lua
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()
|
|
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
|
|
|
|
return mtar
|