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authorMatthew Wild <mwild1@gmail.com>2014-09-02 17:57:18 +0100
committerMatthew Wild <mwild1@gmail.com>2014-09-02 17:57:18 +0100
commit2716c4191dfe01af0f75dc7d4642f3a0e1494b31 (patch)
tree2ee28a3400a1281b64b5f7ace48ae827c7fa5f07 /util/random.lua
parent56b4c1c856f107e178aede2313d943022ad3c73d (diff)
downloadprosody-2716c4191dfe01af0f75dc7d4642f3a0e1494b31.tar.gz
prosody-2716c4191dfe01af0f75dc7d4642f3a0e1494b31.zip
util.random: Generic util lib for generating strings of random bytes
Diffstat (limited to 'util/random.lua')
-rw-r--r--util/random.lua43
1 files changed, 43 insertions, 0 deletions
diff --git a/util/random.lua b/util/random.lua
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+-- Prosody IM
+-- Copyright (C) 2008-2014 Matthew Wild
+-- Copyright (C) 2008-2014 Waqas Hussain
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+
+local tostring = tostring;
+local os_time = os.time;
+local os_clock = os.clock;
+local ceil = math.ceil;
+local sha1 = require "util.hashes".sha1;
+
+local last_uniq_time = 0;
+local function uniq_time()
+ local new_uniq_time = os_time();
+ if last_uniq_time >= new_uniq_time then new_uniq_time = last_uniq_time + 1; end
+ last_uniq_time = new_uniq_time;
+ return new_uniq_time;
+end
+
+local function new_random(x)
+ return sha1(x..os_clock()..tostring({}));
+end
+
+local buffer = new_random(uniq_time());
+
+local function seed(x)
+ buffer = new_random(buffer..x);
+end
+
+local function bytes(n)
+ if #buffer < n then seed(uniq_time()); end
+ local r = buffer:sub(0, n);
+ buffer = buffer:sub(n+1);
+ return r;
+end
+
+return {
+ seed = seed;
+ bytes = bytes;
+};