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package tracer
import (
cryptorand "crypto/rand"
"log"
"math"
"math/big"
"math/rand"
"sync"
"time"
)
// random holds a thread-safe source of random numbers.
var random *rand.Rand
func init() {
var seed int64
n, err := cryptorand.Int(cryptorand.Reader, big.NewInt(math.MaxInt64))
if err == nil {
seed = n.Int64()
} else {
log.Printf("%scannot generate random seed: %v; using current time\n", errorPrefix, err)
seed = time.Now().UnixNano()
}
random = rand.New(&safeSource{
source: rand.NewSource(seed),
})
}
// safeSource holds a thread-safe implementation of rand.Source64.
type safeSource struct {
source rand.Source
sync.Mutex
}
func (rs *safeSource) Int63() int64 {
rs.Lock()
n := rs.source.Int63()
rs.Unlock()
return n
}
func (rs *safeSource) Uint64() uint64 { return uint64(rs.Int63()) }
func (rs *safeSource) Seed(seed int64) {
rs.Lock()
rs.Seed(seed)
rs.Unlock()
}
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