ducky/devices
2015-11-20
Parent:b6494e1a499e
ducky/devices/vendor/code.google.com/p/go-uuid/uuid/version4.go
Separate out StorerFactory into its own interface. We had previously included a Factory and Destroy method in the Storer interface, but it makes more sense to separate those out into a StorerFactory interface. This lets us avoid the impression that we're using the same instance of a Storer for every test, separates the test methods away from the methods that are actually used in prod, and hides them from Godoc. What's not to like?
| paddy@0 | 1 // Copyright 2011 Google Inc. All rights reserved. |
| paddy@0 | 2 // Use of this source code is governed by a BSD-style |
| paddy@0 | 3 // license that can be found in the LICENSE file. |
| paddy@0 | 4 |
| paddy@0 | 5 package uuid |
| paddy@0 | 6 |
| paddy@0 | 7 // Random returns a Random (Version 4) UUID or panics. |
| paddy@0 | 8 // |
| paddy@0 | 9 // The strength of the UUIDs is based on the strength of the crypto/rand |
| paddy@0 | 10 // package. |
| paddy@0 | 11 // |
| paddy@0 | 12 // A note about uniqueness derived from from the UUID Wikipedia entry: |
| paddy@0 | 13 // |
| paddy@0 | 14 // Randomly generated UUIDs have 122 random bits. One's annual risk of being |
| paddy@0 | 15 // hit by a meteorite is estimated to be one chance in 17 billion, that |
| paddy@0 | 16 // means the probability is about 0.00000000006 (6 × 10−11), |
| paddy@0 | 17 // equivalent to the odds of creating a few tens of trillions of UUIDs in a |
| paddy@0 | 18 // year and having one duplicate. |
| paddy@0 | 19 func NewRandom() UUID { |
| paddy@0 | 20 uuid := make([]byte, 16) |
| paddy@0 | 21 randomBits([]byte(uuid)) |
| paddy@0 | 22 uuid[6] = (uuid[6] & 0x0f) | 0x40 // Version 4 |
| paddy@0 | 23 uuid[8] = (uuid[8] & 0x3f) | 0x80 // Variant is 10 |
| paddy@0 | 24 return uuid |
| paddy@0 | 25 } |