comparison: util/random.lua
util/random.lua
- changeset 401
- 7be4ebefd1f4
- parent 388
- d963c8a5d89c
equal
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| 399:82ad158714e5 | 401:7be4ebefd1f4 |
|---|---|
| 4 -- | 4 -- |
| 5 -- This project is MIT/X11 licensed. Please see the | 5 -- This project is MIT/X11 licensed. Please see the |
| 6 -- COPYING file in the source package for more information. | 6 -- COPYING file in the source package for more information. |
| 7 -- | 7 -- |
| 8 | 8 |
| 9 local tostring = tostring; | 9 local urandom = io.open("/dev/urandom", "r"); |
| 10 local os_time = os.time; | |
| 11 local os_clock = os.clock; | |
| 12 local ceil = math.ceil; | |
| 13 local H = require "util.hashes".sha1; | |
| 14 | 10 |
| 15 local last_uniq_time = 0; | 11 if urandom then |
| 16 local function uniq_time() | 12 return { |
| 17 local new_uniq_time = os_time(); | 13 seed = function () end; |
| 18 if last_uniq_time >= new_uniq_time then new_uniq_time = last_uniq_time + 1; end | 14 bytes = function (n) return urandom:read(n); end |
| 19 last_uniq_time = new_uniq_time; | 15 }; |
| 20 return new_uniq_time; | |
| 21 end | 16 end |
| 22 | 17 |
| 23 local function new_random(x) | 18 local crypto = require "crypto" |
| 24 return H(x..os_clock()..tostring({})); | 19 return crypto.rand; |
| 25 end | |
| 26 | |
| 27 local buffer = new_random(uniq_time()); | |
| 28 | |
| 29 local function seed(x) | |
| 30 buffer = new_random(buffer..x); | |
| 31 end | |
| 32 | |
| 33 local function bytes(n) | |
| 34 if #buffer < n+4 then seed(uniq_time()); end | |
| 35 local r = buffer:sub(1, n); | |
| 36 buffer = buffer:sub(n+1); | |
| 37 return r; | |
| 38 end | |
| 39 | |
| 40 return { | |
| 41 seed = seed; | |
| 42 bytes = bytes; | |
| 43 }; |
