一个用go写的模拟mp3文字界面播放程序

这里的技巧在于学习如何定义数据结构，更新数据结构，在哪里用指针或是地址来更新。

manger.go

package library

import "errors"

type MusicEntry struct {
	Id     string
	Name   string
	Artist string
	Source string
	Type   string
}

type MusicManager struct {
	musics []MusicEntry
}

func NewMusicManager() *MusicManager {
	return &MusicManager{make([]MusicEntry, 0)}
}

func (m *MusicManager) Len() int {
	return len(m.musics)
}

func (m *MusicManager) Get(index int) (music *MusicEntry, err error) {
	if index < 0 || index >= len(m.musics) {
		return nil, errors.New("Index out of range.")
	}
	return &m.musics[index], nil
}

func (m *MusicManager) Find(name string) *MusicEntry {
	if len(m.musics) == 0 {
		return nil
	}

	for _, m := range m.musics {
		if m.Name == name {
			return &m
		}
	}
	return nil
}

func (m *MusicManager) Add(music *MusicEntry) {
	m.musics = append(m.musics, *music)
}

func (m *MusicManager) Remove(index int) *MusicEntry {
	if index < 0 || index >= len(m.musics) {
		return nil
	}

	removedMusic := &m.musics[index]

	if index < len(m.musics)-1 {
		m.musics = append(m.musics[:index-1], m.musics[index+1:]...)
	} else if index == 0 {
		m.musics = make([]MusicEntry, 0)
	} else {
		m.musics = m.musics[:index-1]
	}

	return removedMusic
}

func (m *MusicManager) RemoveByName(name string) *MusicEntry {
	if len(m.musics) == 0 {
		return nil
	}

	for _, m := range m.musics {
		if m.Name == name {
			return &m
		}
	}
	return nil
}

　　play.go

package mp

import "fmt"

type Player interface {
	Play(source string)
}

func Play(source, mtype string) {
	var p Player

	switch mtype {
	case "MP3":
		p = &MP3Player{}
	case "WAV":
		p = &WAVPlayer{}
	default:
		fmt.Println("Unsupported music type", mtype)
		return
	}
	p.Play(source)
}

　　mp3.go

package mp

import (
	"fmt"
	"time"
)

type MP3Player struct {
	stat     int
	progress int
}

func (p *MP3Player) Play(source string) {
	fmt.Println("Playing MP3 music", source)

	p.progress = 0

	for p.progress < 100 {
		time.Sleep(100 * time.Millisecond)
		fmt.Print(".")
		p.progress += 10
	}

	fmt.Println("\nFinished playing", source)
}

　　mplayer.go

// SMP project main.go
package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"

	"SMP/mlib"
	"SMP/mp"
)

var lib *library.MusicManager
var id int = 1
var ctrl, signal chan int

func handleLibCommands(tokens []string) {
	switch tokens[1] {
	case "list":
		for i := 0; i < lib.Len(); i++ {
			e, _ := lib.Get(i)
			fmt.Println(i+1, ":", e.Name, e.Artist, e.Source, e.Type)
		}
	case "add":
		{
			if len(tokens) == 6 {
				id++
				lib.Add(&library.MusicEntry{strconv.Itoa(id),
					tokens[2], tokens[3], tokens[4], tokens[5]})
			} else {
				fmt.Println("USAGE: lib add <name><artist><source><type>")
			}
		}
	case "remove":
		if len(tokens) == 3 {
			lib.RemoveByName(tokens[2])
		} else {
			fmt.Println("USAGE: lib remove <name>")
		}
	default:
		fmt.Println("Unrecognized lib command: ", tokens[1])
	}
}

func handlePlayCommand(tokens []string) {
	if len(tokens) != 2 {
		fmt.Println("USAGE: play <name>")
		return
	}

	e := lib.Find(tokens[1])
	if e == nil {
		fmt.Println("The music ", tokens[1], " does not exist.")
		return
	}

	mp.Play(e.Source, e.Type)
}

func main() {
	fmt.Println(`
		Enter following commands to control the player:
		lib list -- View the existing music lib
		lib add <name><artist><source><type> -- Add a music to the music lib
		lib remove <name> -- Remove the specified music from the lib
		play <name> -- Play the specified music
	`)

	lib = library.NewMusicManager()
	r := bufio.NewReader(os.Stdin)

	for {
		fmt.Print("Enter command-> ")
		rawLine, _, _ := r.ReadLine()
		line := string(rawLine)
		if line == "q" || line == "e" {
			break
		}
		tokens := strings.Split(line, " ")
		if tokens[0] == "lib" {
			handleLibCommands(tokens)
		} else if tokens[0] == "play" {
			handlePlayCommand(tokens)
		} else {
			fmt.Println("Unrecognized command: ", tokens[0])
		}
	}
}