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51 lines
1.2 KiB
51 lines
1.2 KiB
package rand
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import (
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mrand "math/rand"
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)
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const (
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strChars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" // 62 characters
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)
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// Str constructs a random alphanumeric string of given length
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// from math/rand's global default Source.
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func Str(length int) string { return buildString(length, mrand.Int63) }
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// StrFromSource produces a random string of a specified length from
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// the specified random source.
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func StrFromSource(r *mrand.Rand, length int) string { return buildString(length, r.Int63) }
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func buildString(length int, picker func() int64) string {
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if length <= 0 {
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return ""
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}
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chars := make([]byte, 0, length)
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for {
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val := picker()
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for i := 0; i < 10; i++ {
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v := int(val & 0x3f) // rightmost 6 bits
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if v >= 62 { // only 62 characters in strChars
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val >>= 6
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continue
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} else {
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chars = append(chars, strChars[v])
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if len(chars) == length {
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return string(chars)
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}
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val >>= 6
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}
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}
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}
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}
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// Bytes returns n random bytes generated from math/rand's global default Source.
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func Bytes(n int) []byte {
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bs := make([]byte, n)
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for i := 0; i < len(bs); i++ {
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// nolint:gosec // G404: Use of weak random number generator
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bs[i] = byte(mrand.Int() & 0xFF)
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}
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return bs
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}
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