60 lines
1.8 KiB
Go
60 lines
1.8 KiB
Go
// Package randx contains math/rand extensions. The functions
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// exported by this package do not use a CSRNG so you SHOULD NOT
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// use these strings for, e.g., generating passwords.
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package randx
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import (
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"math/rand"
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"time"
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"unicode"
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)
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// These constants are used by lettersWithString.
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const (
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uppercase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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lowercase = "abcdefghijklmnopqrstuvwxyz"
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letters = uppercase + lowercase
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)
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// lettersWithString is a method for generating a random string
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// described at https://stackoverflow.com/questions/22892120.
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func lettersWithString(n int, letterBytes string) string {
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rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
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b := make([]byte, n)
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for i := range b {
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b[i] = letterBytes[rnd.Intn(len(letterBytes))]
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}
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return string(b)
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}
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// Letters return a string composed of random letters. Note that
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// this function uses a non-cryptographically-secure generator.
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func Letters(n int) string {
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return lettersWithString(n, letters)
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}
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// LettersUppercase return a string composed of random uppercase
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// letters. Note that this function uses a non-cryptographically-secure
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// generator. So, we SHOULD NOT use it for generating passwords.
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func LettersUppercase(n int) string {
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return lettersWithString(n, uppercase)
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}
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// ChangeCapitalization returns a new string where the capitalization
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// of each character is changed at random. Note that this function
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// uses a non-cryptographically-secure generator. So, we SHOULD NOT use
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// it for generating passwords.
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func ChangeCapitalization(source string) (dest string) {
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rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
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for _, chr := range source {
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if unicode.IsLower(chr) && rnd.Float64() <= 0.5 {
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dest += string(unicode.ToUpper(chr))
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} else if unicode.IsUpper(chr) && rnd.Float64() <= 0.5 {
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dest += string(unicode.ToLower(chr))
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} else {
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dest += string(chr)
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}
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}
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return
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}
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