mirror of
https://github.com/mjl-/mox.git
synced 2024-12-28 01:13:47 +03:00
de435fceba
this allows removing some ugly instantiations of an rng based on the current time. Intn is now IntN for our concurrency-safe prng wrapper to match the randv2 api. v2 exists since go1.22, which we already require.
46 lines
919 B
Go
46 lines
919 B
Go
package mox
|
|
|
|
import (
|
|
cryptorand "crypto/rand"
|
|
"encoding/binary"
|
|
"fmt"
|
|
mathrand2 "math/rand/v2"
|
|
"sync"
|
|
)
|
|
|
|
type rand struct {
|
|
rand *mathrand2.Rand
|
|
sync.Mutex
|
|
}
|
|
|
|
// NewPseudoRand returns a new PRNG seeded with random bytes from crypto/rand. Its
|
|
// functions can be called concurrently.
|
|
func NewPseudoRand() *rand {
|
|
var seed [32]byte
|
|
if _, err := cryptorand.Read(seed[:]); err != nil {
|
|
panic(err)
|
|
}
|
|
return &rand{rand: mathrand2.New(mathrand2.NewChaCha8(seed))}
|
|
}
|
|
|
|
func (r *rand) Float64() float64 {
|
|
r.Lock()
|
|
defer r.Unlock()
|
|
return r.rand.Float64()
|
|
}
|
|
|
|
func (r *rand) IntN(n int) int {
|
|
r.Lock()
|
|
defer r.Unlock()
|
|
return r.rand.IntN(n)
|
|
}
|
|
|
|
// CryptoRandInt returns a cryptographically random number.
|
|
func CryptoRandInt() int64 {
|
|
buf := make([]byte, 8)
|
|
_, err := cryptorand.Read(buf)
|
|
if err != nil {
|
|
panic(fmt.Errorf("reading random bytes: %v", err))
|
|
}
|
|
return int64(binary.LittleEndian.Uint64(buf))
|
|
}
|