1*e7b1675dSTing-Kang Chang// Copyright 2018 Google LLC 2*e7b1675dSTing-Kang Chang// 3*e7b1675dSTing-Kang Chang// Licensed under the Apache License, Version 2.0 (the "License"); 4*e7b1675dSTing-Kang Chang// you may not use this file except in compliance with the License. 5*e7b1675dSTing-Kang Chang// You may obtain a copy of the License at 6*e7b1675dSTing-Kang Chang// 7*e7b1675dSTing-Kang Chang// http://www.apache.org/licenses/LICENSE-2.0 8*e7b1675dSTing-Kang Chang// 9*e7b1675dSTing-Kang Chang// Unless required by applicable law or agreed to in writing, software 10*e7b1675dSTing-Kang Chang// distributed under the License is distributed on an "AS IS" BASIS, 11*e7b1675dSTing-Kang Chang// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12*e7b1675dSTing-Kang Chang// See the License for the specific language governing permissions and 13*e7b1675dSTing-Kang Chang// limitations under the License. 14*e7b1675dSTing-Kang Chang// 15*e7b1675dSTing-Kang Chang//////////////////////////////////////////////////////////////////////////////// 16*e7b1675dSTing-Kang Chang 17*e7b1675dSTing-Kang Chang// Package random provides functions that generate random numbers or bytes. 18*e7b1675dSTing-Kang Changpackage random 19*e7b1675dSTing-Kang Chang 20*e7b1675dSTing-Kang Changimport ( 21*e7b1675dSTing-Kang Chang "crypto/rand" 22*e7b1675dSTing-Kang Chang "encoding/binary" 23*e7b1675dSTing-Kang Chang) 24*e7b1675dSTing-Kang Chang 25*e7b1675dSTing-Kang Chang// GetRandomBytes randomly generates n bytes. 26*e7b1675dSTing-Kang Changfunc GetRandomBytes(n uint32) []byte { 27*e7b1675dSTing-Kang Chang buf := make([]byte, n) 28*e7b1675dSTing-Kang Chang _, err := rand.Read(buf) 29*e7b1675dSTing-Kang Chang if err != nil { 30*e7b1675dSTing-Kang Chang panic(err) // out of randomness, should never happen 31*e7b1675dSTing-Kang Chang } 32*e7b1675dSTing-Kang Chang return buf 33*e7b1675dSTing-Kang Chang} 34*e7b1675dSTing-Kang Chang 35*e7b1675dSTing-Kang Chang// GetRandomUint32 randomly generates an unsigned 32-bit integer. 36*e7b1675dSTing-Kang Changfunc GetRandomUint32() uint32 { 37*e7b1675dSTing-Kang Chang b := GetRandomBytes(4) 38*e7b1675dSTing-Kang Chang return binary.BigEndian.Uint32(b) 39*e7b1675dSTing-Kang Chang} 40