services

services/tiktak/vendor/github.com/thanhpk/randstr/randstr.go

@@ -0,0 +1,57 @@
+// Package randstr provides basic functions for generating random bytes, string
+package randstr
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+	"encoding/hex"
+)
+
+// Bytes generates n random bytes
+func Bytes(n int) []byte {
+	b := make([]byte, n)
+	_, err := rand.Read(b)
+	if err != nil {
+		panic(err)
+	}
+	return b
+}
+
+// Base64 generates a random base64 string with length of n
+func Base64(n int) string {
+	return String(n, "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/")
+}
+
+// Base64 generates a random base62 string with length of n
+func Base62(s int) string {
+	return String(s, "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+}
+
+// Hex generates a random hex string with length of n
+// e.g: 67aab2d956bd7cc621af22cfb169cba8
+func Hex(n int) string { return hex.EncodeToString(Bytes(n)) }
+
+// list of default letters that can be used to make a random string when calling String
+// function with no letters provided
+var defLetters = []rune("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+// String generates a random string using only letters provided in the letters parameter
+// if user ommit letters parameters, this function will use defLetters instead
+func String(n int, letters ...string) string {
+	var letterRunes []rune
+	if len(letters) == 0 {
+		letterRunes = defLetters
+	} else {
+		letterRunes = []rune(letters[0])
+	}
+
+	var bb bytes.Buffer
+	bb.Grow(n)
+	l := uint32(len(letterRunes))
+	// on each loop, generate one random rune and append to output
+	for i := 0; i < n; i++ {
+		bb.WriteRune(letterRunes[binary.BigEndian.Uint32(Bytes(4))%l])
+	}
+	return bb.String()
+}