转换网易云音乐缓存文件uc，转换成mp3

changeUc2Mp3.go

package main

import (
	"bufio"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"strings"
	"time"
)

// 转换网易云 缓存到mp3
func main() {

	cachePath := "C:\\\\Users\\Administrator\\AppData\\Local\\Netease\\CloudMusic\\Cache\\Cache"
	targetPath := "F:\\\\CloudMusic"
	files, _ := ioutil.ReadDir(cachePath)
	// 启动多少个 goroutine
	ch := make(chan string, 20)
	startTime := time.Now()
	count := 0
	for _, file := range files {
		if !file.IsDir() && strings.HasSuffix(file.Name(), ".uc") {
			ch <- file.Name()
			go func(fileName string) {
				fmt.Println("parse :", fileName)
				err := decodeFile(cachePath, fileName, targetPath, fileName+".mp3")
				//err := decodeFileStream(cachePath, fileName, targetPath, fileName+".mp3")
				count++
				fmt.Println("parse end:", <-ch, " err:", err)
			}(file.Name())
		}
	}

	fmt.Println("all end", time.Since(startTime), "count:", count)

}

func decodeFile(dirName, fileName, newDirName, newName string) error {
	bytes, err := ioutil.ReadFile(dirName + "\\" + fileName)
	if err != nil {
		return err
	}
	for i := 0; i < len(bytes); i++ {
		bytes[i] ^= 0xa3
	}
	return ioutil.WriteFile(newDirName+"\\"+newName, bytes, 0777)
}


// too slower
func decodeFileStream(dirName, fileName, newDirName, newName string) error {
	fs, err := os.OpenFile(dirName+"\\"+fileName, os.O_RDONLY, 0777)
	if err != nil {
		return err
	}
	defer fs.Close()
	fsw, err := os.OpenFile(newDirName+"\\"+newName, os.O_RDWR|os.O_CREATE, 0777)
	if err != nil {
		return err
	}
	nr := bufio.NewReader(fs)
	nw := bufio.NewWriter(fsw)

	defer fsw.Close()
	bytes := [30 * 1024]byte{}
	for {
		n, err := nr.Read(bytes[:])
		if err != nil {
			if err == io.EOF {
				break
			}
			return err
		}
		if n == 0 {
			break
		}
		for i := 0; i < n; i++ {
			bytes[i] ^= 0xa3
		}
		_, err = nw.Write(bytes[:n])
		if err != nil {
			return err
		}
	}
	return nil
}