feat: allow reuse of random source

cli/random-data/main.go

@@ -6,7 +6,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"math/rand"
 	"os"
 
 	random "github.com/ipfs/go-test/random"
@@ -29,11 +28,11 @@ OPTIONS:
 
 	var (
 		b64  bool
-		seed int64
+		seed uint64
 		size int64
 	)
 	flag.BoolVar(&b64, "b64", false, "base-64 encode output")
-	flag.Int64Var(&seed, "seed", 0, "random seed, 0 or unset for current time")
+	flag.Uint64Var(&seed, "seed", 0, "random seed, 0 or unset for current time")
 	flag.Int64Var(&size, "size", 0, "number of bytes to generate")
 	flag.Parse()
 
@@ -54,12 +53,12 @@ OPTIONS:
 	}
 }
 
-func writeData(seed, size int64, b64 bool) error {
-	var rnd *rand.Rand
+func writeData(seed uint64, size int64, b64 bool) error {
+	var rnd *random.Random
 	if seed == 0 {
-		rnd = random.NewRand()
+		rnd = random.New()
 	} else {
-		rnd = random.NewSeededRand(seed)
+		rnd = random.NewSeeded(random.MakeSeed(seed))
 	}
 
 	var w io.Writer

cli/random-files/main.go

@@ -26,6 +26,7 @@ OPTIONS:
 	var (
 		quiet bool
 		paths []string
+		seed  string
 	)
 
 	cfg := files.DefaultConfig()
@@ -38,7 +39,7 @@ OPTIONS:
 	flag.BoolVar(&cfg.RandomDirs, "random-dirs", cfg.RandomDirs, "randomize number of subdirectories, from 1 to -dirs")
 	flag.BoolVar(&cfg.RandomFiles, "random-files", cfg.RandomFiles, "randomize number of files, from 1 to -files")
 	flag.BoolVar(&cfg.RandomSize, "random-size", cfg.RandomSize, "randomize file size, from 1 to -filesize")
-	flag.Int64Var(&cfg.Seed, "seed", cfg.Seed, "random seed, 0 for current time")
+	flag.StringVar(&seed, "seed", "", "random seed, leave empty to use random value")
 	flag.Parse()
 
 	paths = flag.Args()
@@ -47,6 +48,10 @@ OPTIONS:
 		cfg.Out = os.Stdout
 	}
 
+	if len(seed) != 0 {
+		cfg.Seed = []byte(seed)
+	}
+
 	err := files.Create(cfg, paths...)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "error:", err)

random/files/files.go

@@ -4,16 +4,15 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"math/rand"
 	"os"
 	"path/filepath"
 
 	"github.com/ipfs/go-test/random"
 )
 
 const (
-	MinimumNameSize = 4
-	fileNameAlpha   = "abcdefghijklmnopqrstuvwxyz01234567890-_"
+	MinimumNameSize  = 4
+	fileNameAlphabet = "abcdefghijklmnopqrstuvwxyz0123456789-_"
 )
 
 // Config contains settings for creating random files and directories.
@@ -42,9 +41,9 @@ type Config struct {
 	// RandomSize specifies whether or not to randomize the file size from 1 to
 	// the value configured by FileSize.
 	RandomSize bool
-	// Seed sets the seen for the random number generator when set to a
-	// non-zero value.
-	Seed int64
+	// Seed sets the seed for the random number generator when set to a
+	// non-empty value.
+	Seed []byte
 }
 
 // DefaultConfig returns default settings for creating random files and
@@ -75,11 +74,13 @@ func Create(cfg Config, roots ...string) error {
 		return err
 	}
 
-	var rnd *rand.Rand
-	if cfg.Seed == 0 {
-		rnd = random.NewRand()
+	var rnd *random.Random
+	if len(cfg.Seed) == 0 {
+		rnd = random.New()
 	} else {
-		rnd = random.NewSeededRand(cfg.Seed)
+		var seed [32]byte
+		copy(seed[:], cfg.Seed)
+		rnd = random.NewSeeded(seed)
 	}
 
 	for _, root := range roots {
@@ -128,7 +129,7 @@ func RandomName(sizes ...int) string {
 		cfg = DefaultConfig()
 	}
 
-	return cfg.randomName(random.NewRand())
+	return cfg.randomName(random.New())
 }
 
 func (cfg *Config) validate() error {
@@ -165,11 +166,11 @@ func validateNameSize(minSize, maxSize int) error {
 	return nil
 }
 
-func (cfg *Config) writeTree(rnd *rand.Rand, root string, depth int) error {
+func (cfg *Config) writeTree(rnd *random.Random, root string, depth int) error {
 	nFiles := cfg.Files
 	if nFiles != 0 {
 		if cfg.RandomFiles && nFiles > 1 {
-			nFiles = rnd.Intn(nFiles) + 1
+			nFiles = rnd.IntN(nFiles) + 1
 		}
 
 		for i := 0; i < nFiles; i++ {
@@ -182,15 +183,15 @@ func (cfg *Config) writeTree(rnd *rand.Rand, root string, depth int) error {
 	return cfg.writeSubdirs(rnd, root, depth)
 }
 
-func (cfg *Config) writeSubdirs(rnd *rand.Rand, root string, depth int) error {
+func (cfg *Config) writeSubdirs(rnd *random.Random, root string, depth int) error {
 	if depth == cfg.Depth {
 		return nil
 	}
 	depth++
 
 	nDirs := cfg.Dirs
 	if cfg.RandomDirs && nDirs > 1 {
-		nDirs = rnd.Intn(nDirs) + 1
+		nDirs = rnd.IntN(nDirs) + 1
 	}
 
 	for i := 0; i < nDirs; i++ {
@@ -202,7 +203,7 @@ func (cfg *Config) writeSubdirs(rnd *rand.Rand, root string, depth int) error {
 	return nil
 }
 
-func (cfg *Config) writeSubdir(rnd *rand.Rand, root string, depth int) error {
+func (cfg *Config) writeSubdir(rnd *random.Random, root string, depth int) error {
 	name := cfg.randomName(rnd)
 	root = filepath.Join(root, name)
 	if err := os.MkdirAll(root, 0755); err != nil {
@@ -216,20 +217,24 @@ func (cfg *Config) writeSubdir(rnd *rand.Rand, root string, depth int) error {
 	return cfg.writeTree(rnd, root, depth)
 }
 
-func (cfg *Config) randomName(rnd *rand.Rand) string {
+func (cfg *Config) randomName(rnd *random.Random) string {
 	sizeDiff := cfg.NameMaxSize - cfg.NameMinSize
-	n := cfg.NameMinSize
+	size := cfg.NameMinSize
 	if sizeDiff != 0 {
-		n += rnd.Intn(sizeDiff)
+		size += rnd.IntN(sizeDiff + 1)
 	}
-	b := make([]byte, n)
-	for i := 0; i < n; i++ {
-		b[i] = fileNameAlpha[rnd.Intn(len(fileNameAlpha))]
+	if size <= 0 {
+		return ""
 	}
-	return string(b)
+	src := make([]byte, size)
+	rnd.Read(src)
+	for i := range src {
+		src[i] = fileNameAlphabet[src[i]%byte(len(fileNameAlphabet))]
+	}
+	return string(src)
 }
 
-func (cfg *Config) writeFile(rnd *rand.Rand, root string) error {
+func (cfg *Config) writeFile(rnd *random.Random, root string) error {
 	name := cfg.randomName(rnd)
 	filePath := filepath.Join(root, name)
 	f, err := os.Create(filePath)
@@ -240,7 +245,7 @@ func (cfg *Config) writeFile(rnd *rand.Rand, root string) error {
 	if cfg.FileSize > 0 {
 		fileSize := cfg.FileSize
 		if cfg.RandomSize && fileSize > 1 {
-			fileSize = rnd.Int63n(fileSize) + 1
+			fileSize = rnd.Int64N(fileSize) + 1
 		}
 
 		if _, err := io.CopyN(f, rnd, fileSize); err != nil {