uuid.go

package util

import (
	"crypto/rand"
	"encoding/hex"
	"io"
)

//see https://github.com/google/uuid
var (
	rander = rand.Reader
)

type UUID [16]byte

// NewRandomUUID returns a UUID based on bytes read from crypto.Rand

func NewRandomUUID() UUID {
	var uuid UUID
	_, err := io.ReadFull(rander, uuid[:])
	if err != nil {
		return UUID{}
	}
	uuid[6] = (uuid[6] & 0x0f) | 0x40 // Version 4
	uuid[8] = (uuid[8] & 0x3f) | 0x80 // Variant is 10
	return uuid
}

// String returns the string form of uuid, xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
// , or "" if uuid is invalid.
func (uuid UUID) String() string {
	var buf [36]byte
	encodeHex(buf[:], uuid)
	return string(buf[:])
}
func encodeHex(dst []byte, uuid UUID) {
	hex.Encode(dst, uuid[:4])
	dst[8] = '-'
	hex.Encode(dst[9:13], uuid[4:6])
	dst[13] = '-'
	hex.Encode(dst[14:18], uuid[6:8])
	dst[18] = '-'
	hex.Encode(dst[19:23], uuid[8:10])
	dst[23] = '-'
	hex.Encode(dst[24:], uuid[10:])
}