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|
//go:build testtools
// +build testtools
package main
import (
"crypto/rand"
"encoding/base64"
"encoding/binary"
"fmt"
"os"
"strconv"
)
const usageFmt = "Usage: %s [--base64|--base64url] [<size>]\n"
func main() {
offset := 1
b64 := false
b64url := false
if len(os.Args) > offset && (os.Args[offset] == "--base64" || os.Args[offset] == "--base64url") {
b64 = true
b64url = os.Args[offset] == "--base64url"
offset += 1
}
if len(os.Args) > offset+1 {
fmt.Fprintf(os.Stderr, usageFmt, os.Args[0])
os.Exit(2)
}
var count uint64 = ^uint64(0)
if len(os.Args) == offset+1 {
var err error
if count, err = strconv.ParseUint(os.Args[offset], 10, 64); err != nil {
fmt.Fprintf(os.Stderr, "Error reading size: %s, %v\n", os.Args[offset], err)
os.Exit(3)
}
}
b := make([]byte, 32)
bb := make([]byte, max(base64.RawStdEncoding.EncodedLen(len(b)), base64.RawURLEncoding.EncodedLen(len(b))))
for count > 0 {
n, err := rand.Read(b)
if err != nil {
fmt.Fprintf(os.Stderr, "Error reading random bytes: %v\n", err)
os.Exit(4)
}
if b64 {
if b64url {
base64.RawURLEncoding.Encode(bb, b[:n])
n = base64.RawURLEncoding.EncodedLen(n)
} else {
base64.RawStdEncoding.Encode(bb, b[:n])
n = base64.RawStdEncoding.EncodedLen(n)
}
}
num := min(uint64(n), count)
if b64 {
err = binary.Write(os.Stdout, binary.LittleEndian, bb[:num])
} else {
err = binary.Write(os.Stdout, binary.LittleEndian, b[:num])
}
if err != nil {
fmt.Fprintf(os.Stderr, "Error writing random bytes: %v\n", err)
os.Exit(5)
}
count -= num
}
}
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