GoCourse - Exercise18

analyze_mp3.go

package main

import (
	"fmt"
	"log"
	"os"
)

func check(e error) {
	if e != nil {
		log.Fatal(e)
	}
}

func main() {
	//Check for program arguments
	args := os.Args
	numArgs := len(args)
	if numArgs != 2 {
		log.Fatal("You must provide the mp3 file name")
	}

	//Get the .mp3 file name provided
	mp3filename := args[1]

	//Get the statistics on the file
	file, err := os.Open(mp3filename)
	check(err)

	defer file.Close()

	// get the file size
	stat, err := file.Stat()
	check(err)

	//Read the last 128 bytes. Seek from the end
	_, err = file.Seek(stat.Size()-128, 0)
	check(err)

	Tag_Slice := make([]byte, 3)
	_, err = file.Read(Tag_Slice)
	check(err)

	if string(Tag_Slice) == "TAG" {
		Artist := make([]byte, 30)
		_, err = file.Read(Artist)
		fmt.Println(string(Artist))
		Song := make([]byte, 30)
		_, err = file.Read(Song)
		fmt.Println(string(Song))
	} else {
		fmt.Println("Does not look like an MP3 file.")
	}
}