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v2fly/common/dice/dice.go
2024-03-15 20:19:18 +00:00

69 lines
1.4 KiB
Go

// Package dice contains common functions to generate random number.
// It also initialize math/rand with the time in seconds at launch time.
package dice
import (
crand "crypto/rand"
"io"
"math/big"
"math/rand"
"time"
"github.com/v2fly/v2ray-core/v5/common"
)
// Roll returns a non-negative number between 0 (inclusive) and n (exclusive).
func Roll(n int) int {
if n == 1 {
return 0
}
return rand.Intn(n)
}
// RollWith returns a non-negative number between 0 (inclusive) and n (exclusive).
// Use random as the random source, if read fails, it panics.
func RollWith(n int, random io.Reader) int {
if n == 1 {
return 0
}
mrand, err := crand.Int(random, big.NewInt(int64(n)))
common.Must(err)
return int(mrand.Int64())
}
// Roll returns a non-negative number between 0 (inclusive) and n (exclusive).
func RollDeterministic(n int, seed int64) int {
if n == 1 {
return 0
}
return rand.New(rand.NewSource(seed)).Intn(n)
}
// RollUint16 returns a random uint16 value.
func RollUint16() uint16 {
return uint16(rand.Int63() >> 47)
}
func RollUint64() uint64 {
return rand.Uint64()
}
func NewDeterministicDice(seed int64) *DeterministicDice {
return &DeterministicDice{rand.New(rand.NewSource(seed))}
}
type DeterministicDice struct {
*rand.Rand
}
func (dd *DeterministicDice) Roll(n int) int {
if n == 1 {
return 0
}
return dd.Intn(n)
}
func init() {
rand.Seed(time.Now().Unix())
}