// Beego (http://beego.me/)
// @description beego is an open-source, high-performance web framework for the Go programming language.
// @link        http://github.com/astaxie/beego for the canonical source repository
// @license     http://github.com/astaxie/beego/blob/master/LICENSE
// @authors     astaxie

package utils

import (
	"crypto/rand"
)

// RandomCreateBytes generate random []byte by specify chars.
func RandomCreateBytes(n int, alphabets ...byte) []byte {
	const alphanum = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
	var bytes = make([]byte, n)
	rand.Read(bytes)
	for i, b := range bytes {
		if len(alphabets) == 0 {
			bytes[i] = alphanum[b%byte(len(alphanum))]
		} else {
			bytes[i] = alphabets[b%byte(len(alphabets))]
		}
	}
	return bytes
}