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https://github.com/duke-git/lancet.git
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67 lines
1.6 KiB
Go
67 lines
1.6 KiB
Go
// Copyright 2021 dudaodong@gmail.com. All rights reserved.
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// Use of this source code is governed by MIT license.
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// Package random implements some basic functions to generate random int and string.
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package random
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import (
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crand "crypto/rand"
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"fmt"
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"io"
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"math/rand"
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"time"
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)
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// RandString generate random string
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// see https://stackoverflow.com/questions/22892120/how-to-generate-a-random-string-of-a-fixed-length-in-go
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func RandString(length int) string {
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const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
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b := make([]byte, length)
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r := rand.New(rand.NewSource(time.Now().UnixNano()))
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for i := range b {
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b[i] = letters[r.Int63()%int64(len(letters))]
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}
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return string(b)
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}
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// RandInt generate random int between min and max, maybe min, not be max
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func RandInt(min, max int) int {
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if min == max {
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return min
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}
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if max < min {
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min, max = max, min
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}
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r := rand.New(rand.NewSource(time.Now().UnixNano()))
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return r.Intn(max-min) + min
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}
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// RandBytes generate random byte slice
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func RandBytes(length int) []byte {
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if length < 1 {
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return []byte{}
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}
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b := make([]byte, length)
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if _, err := io.ReadFull(crand.Reader, b); err != nil {
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return nil
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}
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return b
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}
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// UUIdV4 generate a random UUID of version 4 according to RFC 4122
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func UUIdV4() (string, error) {
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uuid := make([]byte, 16)
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n, err := io.ReadFull(crand.Reader, uuid)
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if n != len(uuid) || err != nil {
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return "", err
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}
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uuid[8] = uuid[8]&^0xc0 | 0x80
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uuid[6] = uuid[6]&^0xf0 | 0x40
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return fmt.Sprintf("%x-%x-%x-%x-%x", uuid[0:4], uuid[4:6], uuid[6:8], uuid[8:10], uuid[10:]), nil
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}
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