/
util.go
76 lines (63 loc) · 1.45 KB
/
util.go
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package util
import (
crand "crypto/rand"
"fmt"
"math/rand"
"sync"
"time"
)
var guidTracker map[string]int
var lock *sync.Mutex
var R *rand.Rand
func init() {
ResetGuids()
lock = &sync.Mutex{}
R = rand.New(&lockedSource{src: rand.NewSource(time.Now().UnixNano())})
}
func ResetGuids() {
guidTracker = map[string]int{}
}
func NewGuid(prefix string) string {
guidTracker[prefix] = guidTracker[prefix] + 1
return fmt.Sprintf("%s-%d", prefix, guidTracker[prefix])
}
func NewGrayscaleGuid(prefix string) string {
guidTracker[prefix] = guidTracker[prefix] + 1
col := R.Intn(200)
return fmt.Sprintf("%s-%d-%s", prefix, guidTracker[prefix], rgb(col, col, col))
}
func rgb(r int, g int, b int) string {
return fmt.Sprintf("rgb(%d,%d,%d)", r, g, b)
}
func RandomIntIn(min, max int) int {
return R.Intn(max-min+1) + min
}
func RandomSleep(minMilliseconds, maxMilliseconds int) {
milliseconds := RandomIntIn(minMilliseconds, maxMilliseconds)
time.Sleep(time.Duration(milliseconds) * time.Millisecond)
}
func RandomGuid() string {
b := make([]byte, 8)
lock.Lock()
_, err := crand.Read(b)
lock.Unlock()
if err != nil {
return ""
}
return fmt.Sprintf("%x-%x-%x-%x", b[0:2], b[2:4], b[4:6], b[6:8])
}
type lockedSource struct {
lock sync.Mutex
src rand.Source
}
func (r *lockedSource) Int63() (n int64) {
r.lock.Lock()
n = r.src.Int63()
r.lock.Unlock()
return
}
func (r *lockedSource) Seed(seed int64) {
r.lock.Lock()
r.src.Seed(seed)
r.lock.Unlock()
}