mirror of
https://github.com/koreader/koreader
synced 2024-11-11 19:11:14 +00:00
34 lines
955 B
Lua
34 lines
955 B
Lua
--- A set of functions to extend math.random and math.randomseed.
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local random = {}
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--- Uses current time as seed to randomize.
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function random.seed()
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math.randomseed(os.time())
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end
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random.seed()
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--- Returns a UUID (v4, random).
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function random.uuid(with_dash)
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local array = {}
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for i = 1, 16 do
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table.insert(array, math.random(256) - 1)
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end
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-- The 13th character should be 4.
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array[7] = bit.band(array[7], 79)
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array[7] = bit.bor(array[7], 64)
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-- The 17th character should be 8 / 9 / a / b.
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array[9] = bit.band(array[9], 191)
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array[9] = bit.bor(array[9], 128)
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if with_dash then
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return string.format("%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
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unpack(array))
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else
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return string.format("%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",
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unpack(array))
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end
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end
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return random
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