if not modules then modules = { } end modules ['l-os'] = {
    version   = 1.001,
    comment   = "companion to luat-lib.mkiv",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

-- maybe build io.flush in os.execute

local find, format = string.find, string.format
local random, ceil = math.random, math.ceil

local execute, spawn, exec, ioflush = os.execute, os.spawn or os.execute, os.exec or os.execute, io.flush

function os.execute(...) ioflush() return execute(...) end
function os.spawn  (...) ioflush() return spawn  (...) end
function os.exec   (...) ioflush() return exec   (...) end

function os.resultof(command)
    ioflush() -- else messed up logging
    local handle = io.popen(command,"r")
    if not handle then
    --  print("unknown command '".. command .. "' in os.resultof")
        return ""
    else
        return handle:read("*all") or ""
    end
end

--~ os.type     : windows | unix (new, we already guessed os.platform)
--~ os.name     : windows | msdos | linux | macosx | solaris | .. | generic (new)
--~ os.platform : extended os.name with architecture

if not io.fileseparator then
    if find(os.getenv("PATH"),";") then
        io.fileseparator, io.pathseparator, os.type = "\\", ";", os.type or "mswin"
    else
        io.fileseparator, io.pathseparator, os.type = "/" , ":", os.type or "unix"
    end
end

os.type = os.type or (io.pathseparator == ";"       and "windows") or "unix"
os.name = os.name or (os.type          == "windows" and "mswin"  ) or "linux"

function os.launch(str)
    if os.type == "windows" then
        os.execute("start " .. str) -- os.spawn ?
    else
        os.execute(str .. " &")     -- os.spawn ?
    end
end

if not os.setenv then
    function os.setenv() return false end
end

if not os.times then
    -- utime  = user time
    -- stime  = system time
    -- cutime = children user time
    -- cstime = children system time
    function os.times()
        return {
            utime  = os.gettimeofday(), -- user
            stime  = 0,                 -- system
            cutime = 0,                 -- children user
            cstime = 0,                 -- children system
        }
    end
end

os.gettimeofday = os.gettimeofday or os.clock

local startuptime = os.gettimeofday()

function os.runtime()
    return os.gettimeofday() - startuptime
end

--~ print(os.gettimeofday()-os.time())
--~ os.sleep(1.234)
--~ print (">>",os.runtime())
--~ print(os.date("%H:%M:%S",os.gettimeofday()))
--~ print(os.date("%H:%M:%S",os.time()))

-- no need for function anymore as we have more clever code and helpers now

os.platform  = os.name or os.type or "linux"
os.libsuffix = 'so'
os.binsuffix = ''

local name = os.name

if name == "windows" or name == "mswin" or name == "win32" or name == "msdos" or os.type == "windows" then
    if os.getenv("PROCESSOR_ARCHITECTURE") == "AMD64" then
        os.platform = "mswin-64"
    else
        os.platform = "mswin"
    end
    os.libsuffix = 'dll'
    os.binsuffix = 'exe'
else
    local architecture = os.getenv("HOSTTYPE") or ""
    if architecture == "" then
        architecture = os.resultof("uname -m") or ""
    end
    if architecture == "" then
        local architecture = os.resultof("echo $HOSTTYPE")
    end
    if name == "linux" then
        if find(architecture,"x86_64") then
            os.platform = "linux-64"
        elseif find(architecture,"ppc") then
            os.platform = "linux-ppc"
        else
            os.platform = "linux"
        end
    elseif name == "macosx" then
        if find(architecture,"i386") then
            os.platform = "osx-intel"
        elseif find(architecture,"x86_64") then
            os.platform = "osx-64"
        else
            os.platform = "osx-ppc"
        end
    elseif name == "sunos" then
        if find(architecture,"sparc") then
            os.platform = "solaris-sparc"
        else -- if architecture == 'i86pc'
            os.platform = "solaris-intel"
        end
    elseif name == "freebsd" then
        if find(architecture,"amd64") then
            os.platform = "freebsd-amd64"
        else
            os.platform = "freebsd"
        end
    else
        os.platform = 'linux'
    end
end

-- beware, we set the randomseed
--

-- from wikipedia: Version 4 UUIDs use a scheme relying only on random numbers. This algorithm sets the
-- version number as well as two reserved bits. All other bits are set using a random or pseudorandom
-- data source. Version 4 UUIDs have the form xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx with hexadecimal
-- digits x and hexadecimal digits 8, 9, A, or B for y. e.g. f47ac10b-58cc-4372-a567-0e02b2c3d479.
--
-- as we don't call this function too often there is not so much risk on repetition


local t = { 8, 9, "a", "b" }

function os.uuid()
    return format("%04x%04x-4%03x-%s%03x-%04x-%04x%04x%04x",
        random(0xFFFF),random(0xFFFF),
        random(0x0FFF),
        t[ceil(random(4))] or 8,random(0x0FFF),
        random(0xFFFF),
        random(0xFFFF),random(0xFFFF),random(0xFFFF)
    )
end