mirror of
https://github.com/koreader/koreader
synced 2024-11-04 12:00:25 +00:00
34 lines
955 B
Lua
34 lines
955 B
Lua
--- A set of functions to extend math.random and math.randomseed.
|
|
|
|
local random = {}
|
|
|
|
--- Uses current time as seed to randomize.
|
|
function random.seed()
|
|
math.randomseed(os.time())
|
|
end
|
|
|
|
random.seed()
|
|
|
|
--- Returns a UUID (v4, random).
|
|
function random.uuid(with_dash)
|
|
local array = {}
|
|
for i = 1, 16 do
|
|
table.insert(array, math.random(256) - 1)
|
|
end
|
|
-- The 13th character should be 4.
|
|
array[7] = bit.band(array[7], 79)
|
|
array[7] = bit.bor(array[7], 64)
|
|
-- The 17th character should be 8 / 9 / a / b.
|
|
array[9] = bit.band(array[9], 191)
|
|
array[9] = bit.bor(array[9], 128)
|
|
if with_dash then
|
|
return string.format("%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
|
|
unpack(array))
|
|
else
|
|
return string.format("%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",
|
|
unpack(array))
|
|
end
|
|
end
|
|
|
|
return random
|