Reorganize directory structures

Signed-off-by: Sean Du <do4suki@gmail.com>

pkg/utils/utils.go

@@ -0,0 +1,61 @@
+// Copyright (C) 2021-2023 YumeMichi
+//
+// SPDX-License-Identifier: Apache-2.0
+package utils
+
+import (
+	"encoding/hex"
+	"math/rand"
+	"os"
+	"sync"
+	"time"
+)
+
+var (
+	rwMutex sync.RWMutex
+)
+
+func PathExists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil || os.IsExist(err)
+}
+
+func ReadAllText(path string) string {
+	rwMutex.RLock()
+	defer rwMutex.RUnlock()
+
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return ""
+	}
+	return string(b)
+}
+
+func WriteAllText(path, text string) {
+	rwMutex.Lock()
+	defer rwMutex.Unlock()
+
+	_ = os.WriteFile(path, []byte(text), 0644)
+}
+
+func SliceXor(s1, s2 []byte) (res []byte) {
+	for k, b := range s1 {
+		newBt := b ^ s2[k]
+		res = append(res, newBt)
+	}
+
+	return
+}
+
+func Sub16(str []byte) []byte {
+	return str[16:]
+}
+
+func RandomStr(len int) string {
+	rand.Seed(time.Now().UnixNano())
+	mRand := make([]byte, len)
+	rand.Read(mRand)
+	mRandStr := hex.EncodeToString(mRand)[0:len]
+
+	return mRandStr
+}