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67 lines
1.4 KiB
67 lines
1.4 KiB
package utils
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import (
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"encoding/json"
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"fmt"
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"math/rand"
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"strings"
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"time"
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)
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const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
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const (
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letterIdxBits = 6 // 6 bits to represent a letter index
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letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
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letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
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)
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func RandString(n int) string {
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var src = rand.NewSource(time.Now().UnixNano())
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sb := strings.Builder{}
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sb.Grow(n)
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// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
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for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
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if remain == 0 {
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cache, remain = src.Int63(), letterIdxMax
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}
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if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
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sb.WriteByte(letterBytes[idx])
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i--
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}
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cache >>= letterIdxBits
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remain--
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}
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return sb.String()
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}
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func RandInt(s int, e int) int {
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var integer int
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for {
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integer = rand.Intn(e)
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if integer > s {
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break
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}
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}
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return integer
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}
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func PrettyPrintJSON(s interface{}) {
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switch v := s.(type) {
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case string:
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var j map[string]interface{}
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if err := json.Unmarshal([]byte(v), &j); err != nil {
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panic(err)
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}
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jsonString, err := json.Marshal(j)
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if err != nil {
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panic(err)
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}
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fmt.Println(string(jsonString))
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default:
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jsonString, err := json.MarshalIndent(s, "", " ")
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if err != nil {
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panic(err)
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}
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fmt.Println(string(jsonString))
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}
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}
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