util.go

package m3u8

import (
	"bytes"
	"crypto/aes"
	"crypto/cipher"
	"fmt"
	"os"
	"os/exec"
)

// ============================== shell相关 ==============================
// 判断文件是否存在
func pathExists(path string) (bool, error) {
	_, err := os.Stat(path)
	if err == nil {
		return true, nil
	}
	if os.IsNotExist(err) {
		return false, nil
	}
	return false, err
}

// 执行 shell
func execUnixShell(s string) {
	cmd := exec.Command("/bin/bash", "-c", s)
	var out bytes.Buffer
	cmd.Stdout = &out
	err := cmd.Run()
	if err != nil {
		panic(err)
	}
	fmt.Printf("%s", out.String())
}

func execWinShell(s string) error {
	cmd := exec.Command("cmd", "/C", s)
	var out bytes.Buffer
	cmd.Stdout = &out
	err := cmd.Run()
	if err != nil {
		return err
	}
	fmt.Printf("%s", out.String())
	return nil
}

// windows 合并文件
func win_merge_file(path string) {
	os.Chdir(path)
	execWinShell("copy /b *.ts merge.tmp")
	execWinShell("del /Q *.ts")
	os.Rename("merge.tmp", "merge.mp4")
}

// unix 合并文件
func unix_merge_file(path string) {
	os.Chdir(path)
	//cmd := `ls  *.ts |sort -t "\." -k 1 -n |awk '{print $0}' |xargs -n 1 -I {} bash -c "cat {} >> new.tmp"`
	cmd := `cat *.ts >> merge.tmp`
	execUnixShell(cmd)
	execUnixShell("rm -rf *.ts")
	os.Rename("merge.tmp", "merge.mp4")
}

// ============================== 加解密相关 ==============================

func PKCS7Padding(ciphertext []byte, blockSize int) []byte {
	padding := blockSize - len(ciphertext)%blockSize
	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
	return append(ciphertext, padtext...)
}

func PKCS7UnPadding(origData []byte) []byte {
	length := len(origData)
	unpadding := int(origData[length-1])
	return origData[:(length - unpadding)]
}

func AesEncrypt(origData, key []byte, ivs ...[]byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}
	blockSize := block.BlockSize()
	var iv []byte
	if len(ivs) == 0 {
		iv = key
	} else {
		iv = ivs[0]
	}
	origData = PKCS7Padding(origData, blockSize)
	blockMode := cipher.NewCBCEncrypter(block, iv[:blockSize])
	crypted := make([]byte, len(origData))
	blockMode.CryptBlocks(crypted, origData)
	return crypted, nil
}

func AesDecrypt(crypted, key []byte, ivs ...[]byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}
	blockSize := block.BlockSize()
	var iv []byte
	if len(ivs) == 0 {
		iv = key
	} else {
		iv = ivs[0]
	}
	blockMode := cipher.NewCBCDecrypter(block, iv[:blockSize])
	origData := make([]byte, len(crypted))
	blockMode.CryptBlocks(origData, crypted)
	origData = PKCS7UnPadding(origData)
	return origData, nil
}

func checkErr(e error) {
	if e != nil {
		logger.Panic(e)
	}
}