Created
February 5, 2016 08:17
-
-
Save loneops/6de4709bc0ec7a343b81 to your computer and use it in GitHub Desktop.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| local M = {} | |
| ----- | |
| local nix_uuid, tmp1, dec_random_seed | |
| nix_uuid = io.open("/proc/sys/kernel/random/uuid"):read() -- Read uuid from proc | |
| io.close() | |
| tmp1 = nix_uuid:gsub('%W','') -- Remove hyphens | |
| tmp1 = tmp1:sub(1, 9) -- Chop-off extra numbers | |
| dec_random_seed = tonumber(tmp1, 16) -- Convert to decimal base | |
| math.randomseed( os.time() + dec_random_seed ) -- Add to current time and seed the randomizer | |
| math.random() | |
| ----- | |
| local function num2bs(num) | |
| local _mod = math.fmod or math.mod | |
| local _floor = math.floor | |
| -- | |
| local result = "" | |
| if(num == 0) then return "0" end | |
| while(num > 0) do | |
| result = _mod(num,2) .. result | |
| num = _floor(num*0.5) | |
| end | |
| return result | |
| end | |
| -- | |
| local function bs2num(num) | |
| local _sub = string.sub | |
| local index, result = 0, 0 | |
| if(num == "0") then return 0; end | |
| for p=#num,1,-1 do | |
| local this_val = _sub( num, p,p ) | |
| if this_val == "1" then | |
| result = result + ( 2^index ) | |
| end | |
| index=index+1 | |
| end | |
| return result | |
| end | |
| -- | |
| local function padbits(num,bits) | |
| if #num == bits then return num end | |
| if #num > bits then print("too many bits") end | |
| local pad = bits - #num | |
| for i=1,pad do | |
| num = "0" .. num | |
| end | |
| return num | |
| end | |
| -- | |
| local function getUUID() | |
| local _rnd = math.random | |
| local _fmt = string.format | |
| -- | |
| _rnd() | |
| -- | |
| local time_low_a = _rnd(0, 65535) | |
| local time_low_b = _rnd(0, 65535) | |
| -- | |
| local time_mid = _rnd(0, 65535) | |
| -- | |
| local time_hi = _rnd(0, 4095 ) | |
| time_hi = padbits( num2bs(time_hi), 12 ) | |
| local time_hi_and_version = bs2num( "0100" .. time_hi ) | |
| -- | |
| local clock_seq_hi_res = _rnd(0,63) | |
| clock_seq_hi_res = padbits( num2bs(clock_seq_hi_res), 6 ) | |
| clock_seq_hi_res = "10" .. clock_seq_hi_res | |
| -- | |
| local clock_seq_low = _rnd(0,255) | |
| clock_seq_low = padbits( num2bs(clock_seq_low), 8 ) | |
| -- | |
| local clock_seq = bs2num(clock_seq_hi_res .. clock_seq_low) | |
| -- | |
| local node = {} | |
| for i=1,6 do | |
| node[i] = _rnd(0,255) | |
| end | |
| -- | |
| local guid = "" | |
| guid = guid .. padbits(_fmt("%X",time_low_a), 4) | |
| guid = guid .. padbits(_fmt("%X",time_low_b), 4) .. "-" | |
| guid = guid .. padbits(_fmt("%X",time_mid), 4) .. "-" | |
| guid = guid .. padbits(_fmt("%X",time_hi_and_version), 4) .. "-" | |
| guid = guid .. padbits(_fmt("%X",clock_seq), 4) .. "-" | |
| -- | |
| for i=1,6 do | |
| guid = guid .. padbits(_fmt("%X",node[i]), 2) | |
| end | |
| -- | |
| return guid | |
| end | |
| -- | |
| M.getUUID = getUUID | |
| return M |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
os.time()has only seconds precision, it will generate the same UUID when invoked during one second.