rclone/vendor/github.com/spacemonkeygo/monkit/v3/id.go
2020-05-12 15:56:50 +00:00

49 lines
1.3 KiB
Go

// Copyright (C) 2015 Space Monkey, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package monkit
import (
crand "crypto/rand"
"encoding/binary"
"math/rand"
"sync/atomic"
"github.com/spacemonkeygo/monkit/v3/monotime"
)
var (
idCounter uint64
inc uint64
)
func init() {
var buf [16]byte
if _, err := crand.Read(buf[:]); err == nil {
idCounter = binary.BigEndian.Uint64(buf[0:8]) >> 1
inc = binary.BigEndian.Uint64(buf[0:8])>>1 | 3
} else {
rng := rand.New(rand.NewSource(monotime.Now().UnixNano()))
idCounter = uint64(rng.Int63())
inc = uint64(rng.Int63() | 3)
}
}
// NewId returns a random integer intended for use when constructing new
// traces. See NewTrace.
func NewId() int64 {
id := atomic.AddUint64(&idCounter, inc)
return int64(id >> 1)
}