lua win 7zip binding

local M = {}
M.root = 'C:\\Program Files\\7-Zip\\7z.exe'

local function fmt(s)
    if s:find(' ') and s:sub(1, 1) ~= '"' then
        return '"' .. s .. '"'
    end
    return s
end

function M.command(...)
    local data = 'CALL'

    for i = 1, select('#', ...) do
        data = data .. ' ' .. fmt(select(i, ...))
    end
    print('COMMAND [' .. data .. ']')
    return data
end

local File = {}
File.__index = File

function File:new(o)
    return setmetatable(o or {}, self)
end

function File:extract(dst)
    return os.execute(M.command(M.root, "x", "-y", self.src, self.path, '-o' .. dst))
end

function File:read(dst)
    if self.data then return self.data end

    local f = io.popen(M.command(M.root, 'x', '-so', self.src, self.path), 'rb')
    self.data = f:read("*a")
    f:close()

    return self.data
end

function M.list(src, filter)
    local files = {}

    local command = M.command(M.root, 'l', src, filter or '*')
    local listing = io.popen(command, 'rb')

    local nextLine = listing:lines()

    local line = nextLine()
    while line:sub(1, 2) ~= '--' do
        line = nextLine()
    end
    line = nextLine()

    while line:sub(1, 2) ~= '--' do
        local key, value = line:match('(.-) = (.*)')
        if key and value then
            files[key:lower():gsub('%W', '_')] = tonumber(value) or value
        end
        line = nextLine()
    end

    line = nextLine()

    while line:sub(1, 2) ~= '--' do
        local o = {}
        o.src = src
        o.date, o.time, o.res, o.size, o.compressed, o.path = line:match('(.-)%s+(.-)%s+(.-)%s+(.-)%s+(.-)%s+(.*)')
        if o.date then
            table.insert(files, File:new(o))
        end
        line = nextLine()
    end

    listing:close()
    return files
end

function M.extract(src, dst, filter)
    filter = filter or '*'
    return os.execute(M.command(M.root, "x", "-y", src, filter, '-o' .. dst))
end

function M.read(src, filter)
    filter = filter or '*'

    local list = M.list(src, filter)

    local file = io.popen(M.command(M.root, 'x', '-so', src, filter), 'rb')
    local data = file:read("*a"); file:close()

    local pos = 1
    for i, v in ipairs(list) do
        --print(pos, v.size)
        local filedata = data:sub(pos, pos + v.size - 1)
        pos = pos + v.size
        v.data = filedata
    end

    return list
end

if not ... then return M end

function lines_iter(s, pos, d)
    print(s, pos, d)
    pos = pos + 1
    if pos > #s then return nil end

    local i, j = s:find('\n', pos)

    if not j then
        return #s, s:sub(pos)
    end

    local v = s:sub(pos, j - 1)
    return j, v
end

function string.lines(s)
    return lines_iter, s, 0
end



local time = os.clock()

local files = M.read('C:\\7-Zip\\processed.zip', '*')

local file = files[1004]
print(file.data)

print("Len", len, "Time", os.clock() - time)