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random.go
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random.go
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// Content managed by Project Forge, see [projectforge.md] for details.
package util
import (
"crypto/rand"
"fmt"
"io"
"math/big"
"time"
)
const charset = "abcdefghijklmnopqrstuvwxyz0123456789"
func RandomString(length int) string {
b := make([]byte, length)
for i := range b {
idx := RandomInt(len(charset))
b[i] = charset[idx]
}
return string(b)
}
func RandomInt(maxExclusive int) int {
max := big.NewInt(int64(maxExclusive))
ret, err := rand.Int(rand.Reader, max)
if err != nil {
panic(errMsg(err))
}
return int(ret.Int64())
}
func RandomFloat(maxExclusive int) float64 {
max := big.NewInt(int64(maxExclusive) * 1000)
ret, err := rand.Int(rand.Reader, max)
if err != nil {
panic(errMsg(err))
}
return float64(ret.Int64()) / 1000
}
func RandomBool() bool {
ret, err := rand.Int(rand.Reader, big.NewInt(1))
if err != nil {
panic(errMsg(err))
}
return ret.Int64() == 1
}
func RandomValueMap(keys int) ValueMap {
ret := ValueMap{}
for i := 0; i < keys; i++ {
ret[RandomString(4)] = RandomString(10)
}
return ret
}
func RandomBytes(size int) []byte {
b := make([]byte, size)
_, err := io.ReadFull(rand.Reader, b)
if err != nil {
panic(errMsg(err))
}
return b
}
func RandomDate() time.Time {
from := time.Now().Unix()
to := time.Now().AddDate(2, 0, 0).Unix()
rnd, err := rand.Int(rand.Reader, big.NewInt(to-from))
if err != nil {
panic(errMsg(err))
}
return time.Unix(from+rnd.Int64(), 0)
}
func RandomDiffs(size int) Diffs {
ret := make(Diffs, 0, size)
for i := 0; i < size; i++ {
ret = append(ret, &Diff{Path: RandomString(8), Old: RandomString(12), New: RandomString(12)})
}
return ret
}
func errMsg(err error) string {
return fmt.Sprintf("source of randomness unavailable: %+v", err.Error())
}