letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
	letterIdxMax  = 63 / letterIdxBits   // # of letter indices fitting in 63 bits
)

// Random number state.
// We generate random temporary file names so that there's a good
// chance the file doesn't exist yet.
var (
	randN  uint32
	randmu sync.Mutex
)

// Temp files created in default Tmp dir

	// FileNameFunc must ensure collisions in filenames do not occur.
	// Do not rely on timestamps to be unique, high throughput writes
	// may fall on the same timestamp.
	// Eg.
	// 	2020-03-28_15-00-945-<random-hash>.log
	// When FileNameFunc is not specified, DefaultFilenameFunc will be used.
	FileNameFunc func() string

	// Compress specify if you want the logs to be compressed after rotation.
	Compress bool
}

func testPostPolicyBucketHandler(obj ObjectLayer, instanceType string, t TestErrHandler) {
	if err := newTestConfig(globalMinioDefaultRegion, obj); err != nil {
		t.Fatalf("Initializing config.json failed")
	}

	// get random bucket name.
	bucketName := getRandomBucketName()

	var opts ObjectOptions
	// Register the API end points with Erasure/FS object layer.
	apiRouter := initTestAPIEndPoints(obj, []string{"PostPolicy"})

		panic("unit cannot exceed one hour")
	}
	return func(attempt uint) time.Duration {
		if attempt > 16 {
			// Protect against integer overflow
			attempt = 16
		}
		// sleep = random_between(unit, min(cap, base * 2 ** attempt))
		sleep := unit * time.Duration(1<<attempt)
		if sleep > cap {
			sleep = cap
		}
		sleep -= time.Duration(r.Float64() * float64(sleep-unit))
		return sleep
	}

			mu.Unlock()
		}()
	}
	wg.Wait()
	return newDisks
}

func (er erasureObjects) getOnlineLocalDisks() (newDisks []StorageAPI) {
	disks := er.getOnlineDisks()

	// Based on the random shuffling return back randomized disks.
	r := rand.New(rand.NewSource(time.Now().UnixNano()))

	for _, i := range r.Perm(len(disks)) {
		if disks[i] != nil && disks[i].IsLocal() {
			newDisks = append(newDisks, disks[i])

	// independently picks a (uniformly distributed) random time in an interval
	// of size = baseInterval.
	//
	// For example:
	//
	//    - if baseInterval=10s, then 5s <= waitInterval() < 15s
	//
	//    - if baseInterval=10m, then 5m <= waitInterval() < 15m
	waitInterval := func() time.Duration {
		// Calculate a random value such that 0 <= value < baseInterval

			UseIdleTimeout(globalServerCtxt.IdleTimeout).
			UseReadHeaderTimeout(globalServerCtxt.ReadHeaderTimeout).
			UseBaseContext(GlobalContext).
			UseCustomLogger(log.New(io.Discard, "", 0)). // Turn-off random logging by Go stdlib
			UseTCPOptions(globalTCPOptions)

		httpServer.TCPOptions.Trace = bootstrapTraceMsg
		go func() {
			serveFn, err := httpServer.Init(GlobalContext, func(listenAddr string, err error) {

	// Need a unique name for the part being written in minioMetaBucket to
	// accommodate concurrent PutObjectPart requests

	partSuffix := fmt.Sprintf("part.%d", partID)
	// Random UUID and timestamp for temporary part file.
	tmpPart := fmt.Sprintf("%sx%d", mustGetUUID(), time.Now().UnixNano())
	tmpPartPath := pathJoin(tmpPart, partSuffix)

// the given io.Reader. If random is nil, crypto/rand.Reader is used.
// If length <= 0, the access key length is chosen automatically.
//
// GenerateAccessKey returns an error if length is too small for a valid
// access key.
func GenerateAccessKey(length int, random io.Reader) (string, error) {
	if random == nil {
		random = rand.Reader
	}
	if length <= 0 {
		length = accessKeyMaxLen

func preloadEntryPoint(db *gorm.DB, joins []string, relationships *schema.Relationships, preloads map[string][]interface{}, associationsConds []interface{}) error {
	preloadMap := parsePreloadMap(db.Statement.Schema, preloads)

	// avoid random traversal of the map
	preloadNames := make([]string, 0, len(preloadMap))
	for key := range preloadMap {
		preloadNames = append(preloadNames, key)
	}
	sort.Strings(preloadNames)