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package crypto
import (
"io"
"github.com/gotd/td/bin"
)
// RandInt64n returns random int64 from randSource in [0; n).
func RandInt64n(randSource io.Reader, n int64) (int64, error) {
v, err := RandInt64(randSource)
if err != nil {
return 0, err
}
if v < 0 {
v *= -1
}
return v % n, nil
}
// RandInt64 returns random int64 from randSource.
func RandInt64(randSource io.Reader) (int64, error) {
var buf [bin.Word * 2]byte
if _, err := io.ReadFull(randSource, buf[:]); err != nil {
return 0, err
}
b := &bin.Buffer{Buf: buf[:]}
return b.Long()
}
// RandInt128 generates and returns new random 128-bit integer.
//
// Use crypto/rand.Reader as randSource in production.
func RandInt128(randSource io.Reader) (bin.Int128, error) {
var buf [bin.Word * 4]byte
if _, err := io.ReadFull(randSource, buf[:]); err != nil {
return bin.Int128{}, err
}
b := &bin.Buffer{Buf: buf[:]}
return b.Int128()
}
// RandInt256 generates and returns new random 256-bit integer.
//
// Use crypto/rand.Reader as randSource in production.
func RandInt256(randSource io.Reader) (bin.Int256, error) {
var buf [bin.Word * 8]byte
if _, err := io.ReadFull(randSource, buf[:]); err != nil {
return bin.Int256{}, err
}
b := &bin.Buffer{Buf: buf[:]}
return b.Int256()
}