github.com/uber/kraken@v0.1.4/utils/randutil/randutil.go (about)

     1  // Copyright (c) 2016-2019 Uber Technologies, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  package randutil
    15  
    16  import (
    17  	"fmt"
    18  	"io"
    19  	"io/ioutil"
    20  	"math/rand"
    21  	"time"
    22  )
    23  
    24  func init() {
    25  	rand.Seed(time.Now().UnixNano())
    26  }
    27  
    28  func choose(n uint64, choices string) []byte {
    29  	b := make([]byte, n)
    30  	for i := range b {
    31  		c := choices[rand.Intn(len(choices))]
    32  		b[i] = byte(c)
    33  	}
    34  	return b
    35  }
    36  
    37  const text = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    38  
    39  // Text returns randomly generated alphanumeric text of length n.
    40  func Text(n uint64) []byte {
    41  	return choose(n, text)
    42  }
    43  
    44  // Blob returns randomly generated blob data of length n.
    45  func Blob(n uint64) []byte {
    46  	r := rand.New(rand.NewSource(time.Now().UnixNano()))
    47  
    48  	lr := io.LimitReader(r, int64(n))
    49  	b, _ := ioutil.ReadAll(lr)
    50  
    51  	return b
    52  }
    53  
    54  const hex = "0123456789abcdef"
    55  
    56  // Hex returns randomly generated hexadecimal string of length n.
    57  func Hex(n uint64) string {
    58  	return string(choose(n, hex))
    59  }
    60  
    61  // IP returns a randomly generated ip address.
    62  func IP() string {
    63  	return fmt.Sprintf(
    64  		"%d.%d.%d.%d",
    65  		rand.Intn(256),
    66  		rand.Intn(256),
    67  		rand.Intn(256),
    68  		rand.Intn(256))
    69  }
    70  
    71  // Port returns a randomly generated port.
    72  func Port() int {
    73  	return rand.Intn(65535) + 1
    74  }
    75  
    76  // Addr returns a random address in ip:port format.
    77  func Addr() string {
    78  	return fmt.Sprintf("%s:%d", IP(), Port())
    79  }
    80  
    81  // ShuffleInts shuffles the values of xs in place.
    82  func ShuffleInts(xs []int) {
    83  	for i := range xs {
    84  		j := rand.Intn(i + 1)
    85  		xs[i], xs[j] = xs[j], xs[i]
    86  	}
    87  }
    88  
    89  // ShuffleInt64s shuffles the values of xs in place.
    90  func ShuffleInt64s(xs []int64) {
    91  	for i := range xs {
    92  		j := rand.Intn(i + 1)
    93  		xs[i], xs[j] = xs[j], xs[i]
    94  	}
    95  }
    96  
    97  // Bools returns a list of randomly generated bools of length n.
    98  func Bools(n int) []bool {
    99  	b := make([]bool, n)
   100  	for i := range b {
   101  		b[i] = rand.Intn(2) == 1
   102  	}
   103  	return b
   104  }
   105  
   106  // Duration returns a random duration below limit.
   107  func Duration(limit time.Duration) time.Duration {
   108  	return time.Duration(rand.Int63n(int64(limit)))
   109  }