rand.go•690 B
package rand
import (
"crypto/rand"
"fmt"
"io"
"math/big"
)
func init() {
Reader = rand.Reader
}
// Reader provides a random reader that can reset during testing.
var Reader io.Reader
// Int63n returns a int64 between zero and value of max, read from an io.Reader source.
func Int63n(reader io.Reader, max int64) (int64, error) {
bi, err := rand.Int(reader, big.NewInt(max))
if err != nil {
return 0, fmt.Errorf("failed to read random value, %w", err)
}
return bi.Int64(), nil
}
// CryptoRandInt63n returns a random int64 between zero and value of max
// obtained from the crypto rand source.
func CryptoRandInt63n(max int64) (int64, error) {
return Int63n(Reader, max)
}