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- package indieauth
- import (
- "math/rand"
- "time"
- "unsafe"
- )
- const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
- const (
- letterIdxBits = 6 // 6 bits to represent a letter index
- letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
- letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
- )
- var src = rand.NewSource(time.Now().UnixNano())
- func randString(n int) string {
- b := make([]byte, n)
- // A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
- for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
- if remain == 0 {
- cache, remain = src.Int63(), letterIdxMax
- }
- if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
- b[i] = letterBytes[idx]
- i--
- }
- cache >>= letterIdxBits
- remain--
- }
- return *(*string)(unsafe.Pointer(&b)) // nolint:gosec
- }
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