// Copyright 2017 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

package util

import (
	"math/rand"
)

// RandomBuf generates a random string using ASCII characters but avoid separator character.
// See https://github.com/mysql/mysql-server/blob/5.7/mysys_ssl/crypt_genhash_impl.cc#L435
func RandomBuf(size int) []byte {
	buf := make([]byte, size)
	for i := 0; i < size; i++ {
		buf[i] = byte(rand.Intn(127))
		if buf[i] == 0 || buf[i] == byte('$') {
			buf[i]++
		}
	}
	return buf
}