mirror of
https://gitee.com/johng/gf
synced 2026-06-07 02:12:11 +08:00
118 lines
3.3 KiB
Go
118 lines
3.3 KiB
Go
// Copyright 2017 gf Author(https://github.com/gogf/gf). All Rights Reserved.
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//
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// This Source Code Form is subject to the terms of the MIT License.
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// If a copy of the MIT was not distributed with this file,
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// You can obtain one at https://github.com/gogf/gf.
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// Package grand provides high performance random string generation functionality.
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package grand
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import (
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"unsafe"
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)
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var (
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letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" // 52
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symbols = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~" // 32
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digits = "0123456789" // 10
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characters = letters + digits + symbols // 94
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)
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// Meet randomly calculate whether the given probability <num>/<total> is met.
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func Meet(num, total int) bool {
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return Intn(total) < num
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}
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// MeetProb randomly calculate whether the given probability is met.
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func MeetProb(prob float32) bool {
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return Intn(1e7) < int(prob*1e7)
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}
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// N returns a random int between min and max: [min, max].
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// The <min> and <max> also support negative numbers.
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func N(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 min >= 0 {
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// Because Intn dose not support negative number,
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// so we should first shift the value to left,
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// then call Intn to produce the random number,
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// and finally shift the result back to right.
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return Intn(max-(min-0)+1) + (min - 0)
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}
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if min < 0 {
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// Because Intn dose not support negative number,
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// so we should first shift the value to right,
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// then call Intn to produce the random number,
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// and finally shift the result back to left.
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return Intn(max+(0-min)+1) - (0 - min)
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}
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return 0
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}
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// S returns a random string which contains digits and letters, and its length is <n>.
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// The optional parameter <symbols> specifies whether the result could contain symbols,
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// which is false in default.
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func S(n int, symbols ...bool) string {
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b := make([]byte, n)
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for i := range b {
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if len(symbols) > 0 && symbols[0] {
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b[i] = characters[Intn(94)]
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} else {
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b[i] = characters[Intn(62)]
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}
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}
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return *(*string)(unsafe.Pointer(&b))
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}
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// Str randomly picks and returns <n> count of chars from given string <s>.
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// It also supports unicode string like Chinese/Russian/Japanese, etc.
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func Str(s string, n int) string {
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b := make([]rune, n)
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runes := []rune(s)
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for i := range b {
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b[i] = runes[Intn(len(runes))]
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}
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return string(b)
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}
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// Digits returns a random string which contains only digits, and its length is <n>.
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func Digits(n int) string {
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b := make([]byte, n)
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for i := range b {
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b[i] = digits[Intn(10)]
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}
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return *(*string)(unsafe.Pointer(&b))
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}
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// Letters returns a random string which contains only letters, and its length is <n>.
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func Letters(n int) string {
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b := make([]byte, n)
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for i := range b {
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b[i] = letters[Intn(52)]
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}
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return *(*string)(unsafe.Pointer(&b))
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}
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// Symbols returns a random string which contains only symbols, and its length is <n>.
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func Symbols(n int) string {
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b := make([]byte, n)
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for i := range b {
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b[i] = symbols[Intn(52)]
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}
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return *(*string)(unsafe.Pointer(&b))
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}
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// Perm returns, as a slice of n int numbers, a pseudo-random permutation of the integers [0,n).
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// TODO performance improving for large slice producing.
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func Perm(n int) []int {
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m := make([]int, n)
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for i := 0; i < n; i++ {
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j := Intn(i + 1)
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m[i] = m[j]
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m[j] = i
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}
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return m
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}
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