54 lines
1.1 KiB
Go
54 lines
1.1 KiB
Go
// Copyright © 2016 Abcum Ltd
|
|
//
|
|
// 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,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package rand
|
|
|
|
import (
|
|
"crypto/rand"
|
|
)
|
|
|
|
var chars = []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789")
|
|
|
|
// New produces a random string of length n
|
|
func New(l int) []byte {
|
|
|
|
if l == 0 {
|
|
return nil
|
|
}
|
|
|
|
i := 0
|
|
t := len(chars)
|
|
m := 255 - (256 % t)
|
|
b := make([]byte, l)
|
|
r := make([]byte, l+(l/4))
|
|
|
|
for {
|
|
|
|
rand.Read(r)
|
|
|
|
for _, rb := range r {
|
|
c := int(rb)
|
|
if c > m {
|
|
continue
|
|
}
|
|
b[i] = chars[c%t]
|
|
i++
|
|
if i == l {
|
|
return b
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
}
|