52 lines
1.5 KiB
Go
52 lines
1.5 KiB
Go
// Copyright 2016 Google Inc. All rights reserved.
|
||
// Use of this source code is governed by a BSD-style
|
||
// license that can be found in the LICENSE file.
|
||
|
||
package uuid
|
||
|
||
import "io"
|
||
|
||
// New creates a new random UUID or panics. New is equivalent to
|
||
// the expression
|
||
//
|
||
// uuid.Must(uuid.NewRandom())
|
||
func New() UUID {
|
||
return Must(NewRandom())
|
||
}
|
||
|
||
// NewString creates a new random UUID and returns it as a string or panics.
|
||
// NewString is equivalent to the expression
|
||
//
|
||
// uuid.New().String()
|
||
func NewString() string {
|
||
return Must(NewRandom()).String()
|
||
}
|
||
|
||
// NewRandom returns a Random (Version 4) UUID.
|
||
//
|
||
// The strength of the UUIDs is based on the strength of the crypto/rand
|
||
// package.
|
||
//
|
||
// A note about uniqueness derived from the UUID Wikipedia entry:
|
||
//
|
||
// Randomly generated UUIDs have 122 random bits. One's annual risk of being
|
||
// hit by a meteorite is estimated to be one chance in 17 billion, that
|
||
// means the probability is about 0.00000000006 (6 × 10−11),
|
||
// equivalent to the odds of creating a few tens of trillions of UUIDs in a
|
||
// year and having one duplicate.
|
||
func NewRandom() (UUID, error) {
|
||
return NewRandomFromReader(rander)
|
||
}
|
||
|
||
// NewRandomFromReader returns a UUID based on bytes read from a given io.Reader.
|
||
func NewRandomFromReader(r io.Reader) (UUID, error) {
|
||
var uuid UUID
|
||
_, err := io.ReadFull(r, uuid[:])
|
||
if err != nil {
|
||
return Nil, err
|
||
}
|
||
uuid[6] = (uuid[6] & 0x0f) | 0x40 // Version 4
|
||
uuid[8] = (uuid[8] & 0x3f) | 0x80 // Variant is 10
|
||
return uuid, nil
|
||
}
|