mirror of
https://github.com/duke-git/lancet.git
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117 lines
2.8 KiB
Go
117 lines
2.8 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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const (
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Numeral = "0123456789"
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LowwerLetters = "abcdefghijklmnopqrstuvwxyz"
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UpperLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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Letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
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)
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func init() {
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rand.Seed(time.Now().UnixNano())
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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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// Play: https://go.dev/play/p/pXyyAAI5YxD
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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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// fix: https://github.com/duke-git/lancet/issues/75
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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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return rand.Intn(max-min) + min
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}
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// RandBytes generate random byte slice.
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// Play: https://go.dev/play/p/EkiLESeXf8d
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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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// RandString generate random string of specified length.
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// Play: https://go.dev/play/p/W2xvRUXA7Mi
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func RandString(length int) string {
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return random(Letters, length)
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}
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// RandUpper generate a random upper case string.
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// Play: https://go.dev/play/p/29QfOh0DVuh
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func RandUpper(length int) string {
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return random(UpperLetters, length)
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}
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// RandLower generate a random lower case string.
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// Play: https://go.dev/play/p/XJtZ471cmtI
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func RandLower(length int) string {
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return random(LowwerLetters, length)
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}
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// RandNumeral generate a random numeral string of specified length.
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// Play: https://go.dev/play/p/g4JWVpHsJcf
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func RandNumeral(length int) string {
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return random(Numeral, length)
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}
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// RandNumeralOrLetter generate a random numeral or letter string.
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// Play: https://go.dev/play/p/19CEQvpx2jD
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func RandNumeralOrLetter(length int) string {
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return random(Numeral+Letters, length)
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}
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// random generate a random string based on given string range.
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func random(s string, length int) string {
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b := make([]byte, length)
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// fix: https://github.com/duke-git/lancet/issues/75
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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] = s[rand.Int63()%int64(len(s))]
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}
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return string(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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// Play: https://go.dev/play/p/_Z9SFmr28ft
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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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