pkg: added random string, peer
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4 changed files with 173 additions and 0 deletions
74
pkg/random/peer.go
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74
pkg/random/peer.go
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// Copyright 2016 The Chihaya Authors. All rights reserved.
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// Use of this source code is governed by the BSD 2-Clause license,
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// which can be found in the LICENSE file.
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package random
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import (
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"math/rand"
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"net"
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"github.com/chihaya/chihaya"
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)
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// Peer generates a random chihaya.Peer.
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//
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// prefix is the prefix to use for the peer ID. If len(prefix) > 20, it will be
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// truncated to 20 characters. If len(prefix) < 20, it will be padded with an
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// alphanumeric random string to have 20 characters.
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//
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// v6 indicates whether an IPv6 address should be generated.
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// Regardless of the length of the generated IP address, its bytes will have
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// values in [1,254].
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//
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// minPort and maxPort describe the range for the randomly generated port, where
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// minPort <= port < maxPort.
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// minPort and maxPort will be checked and altered so that
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// 1 <= minPort <= maxPort <= 65536.
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// If minPort == maxPort, port will be set to minPort.
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func Peer(r *rand.Rand, prefix string, v6 bool, minPort, maxPort int) chihaya.Peer {
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var (
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port uint16
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ip net.IP
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)
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if minPort <= 0 {
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minPort = 1
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}
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if maxPort > 65536 {
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maxPort = 65536
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}
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if maxPort < minPort {
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maxPort = minPort
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}
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if len(prefix) > 20 {
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prefix = prefix[:20]
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}
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if minPort == maxPort {
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port = uint16(minPort)
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} else {
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port = uint16(r.Int63()%int64(maxPort-minPort)) + uint16(minPort)
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}
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if v6 {
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b := make([]byte, 16)
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ip = net.IP(b)
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} else {
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b := make([]byte, 4)
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ip = net.IP(b)
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}
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for i := range ip {
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b := r.Intn(254) + 1
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ip[i] = byte(b)
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}
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prefix = prefix + AlphaNumericString(r, 20-len(prefix))
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return chihaya.Peer{
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ID: chihaya.PeerID(prefix),
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Port: port,
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IP: ip,
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}
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}
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43
pkg/random/peer_test.go
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43
pkg/random/peer_test.go
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// Copyright 2016 The Chihaya Authors. All rights reserved.
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// Use of this source code is governed by the BSD 2-Clause license,
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// which can be found in the LICENSE file.
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package random
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import (
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"math/rand"
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"net"
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"testing"
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"github.com/stretchr/testify/assert"
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)
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func TestPeer(t *testing.T) {
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r := rand.New(rand.NewSource(0))
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for i := 0; i < 100; i++ {
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minPort := 2000
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maxPort := 2010
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p := Peer(r, "", false, minPort, maxPort)
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assert.Equal(t, 20, len(p.ID))
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assert.True(t, p.Port >= uint16(minPort) && p.Port < uint16(maxPort))
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assert.NotNil(t, p.IP.To4())
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}
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for i := 0; i < 100; i++ {
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minPort := 2000
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maxPort := 2010
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p := Peer(r, "", true, minPort, maxPort)
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assert.Equal(t, 20, len(p.ID))
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assert.True(t, p.Port >= uint16(minPort) && p.Port < uint16(maxPort))
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assert.True(t, len(p.IP) == net.IPv6len)
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}
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p := Peer(r, "abcdefghijklmnopqrst", false, 2000, 2000)
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assert.Equal(t, "abcdefghijklmnopqrst", string(p.ID))
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assert.Equal(t, uint16(2000), p.Port)
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p = Peer(r, "abcdefghijklmnopqrstUVWXYZ", true, -10, -5)
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assert.Equal(t, "abcdefghijklmnopqrst", string(p.ID))
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assert.True(t, p.Port >= uint16(1) && p.Port <= uint16(65535))
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}
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26
pkg/random/string.go
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26
pkg/random/string.go
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// Copyright 2016 The Chihaya Authors. All rights reserved.
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// Use of this source code is governed by the BSD 2-Clause license,
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// which can be found in the LICENSE file.
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package random
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import "math/rand"
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// AlphaNumeric is an alphabet with all lower- and uppercase letters and
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// numbers.
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const AlphaNumeric = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
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// AlphaNumericString is a shorthand for String(r, l, AlphaNumeric).
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func AlphaNumericString(r rand.Source, l int) string {
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return String(r, l, AlphaNumeric)
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}
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// String generates a random string of length l, containing only runes from
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// the alphabet using the random source r.
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func String(r rand.Source, l int, alphabet string) string {
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b := make([]byte, l)
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for i := range b {
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b[i] = alphabet[r.Int63()%int64(len(alphabet))]
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}
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return string(b)
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}
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30
pkg/random/string_test.go
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30
pkg/random/string_test.go
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// Copyright 2016 The Chihaya Authors. All rights reserved.
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// Use of this source code is governed by the BSD 2-Clause license,
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// which can be found in the LICENSE file.
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package random
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import (
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"math/rand"
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"strings"
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"testing"
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"github.com/stretchr/testify/assert"
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)
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func TestAlphaNumericString(t *testing.T) {
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r := rand.NewSource(0)
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s := AlphaNumericString(r, 0)
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assert.Equal(t, 0, len(s))
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s = AlphaNumericString(r, 10)
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assert.Equal(t, 10, len(s))
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for i := 0; i < 100; i++ {
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s := AlphaNumericString(r, 10)
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for _, c := range s {
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assert.True(t, strings.Contains(AlphaNumeric, string(c)))
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}
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}
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}
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