GO语言练习:第二个工程--模拟音乐播放器

 1 $ tree
 2 .
 3 ├── mplayer.go
 4 └── src
 5  ├── mlib
 6  │  ├── manager.go
 7  │  └── manager_test.go
 8  └── mp
 9  ├── mp3.go
10 └── play.go

 1 package library
 2 
 3 import "errors"
 4 
 5 type MusicEntry struct {
 6  Id string
 7  Name string
 8  Artist string
 9  Genre string
10  Source string
11  Type string
12 }
13 
14 type MusicManager struct {
15  musics []MusicEntry
16 }
17 
18 func NewMusicManager() * MusicManager {
19 return &MusicManager {make( []MusicEntry, 0)}
20 }
21 
22 func (m * MusicManager) Len() int {
23 return len(m.musics);
24 }
25 
26 func (m* MusicManager ) Get(index int) (music * MusicEntry, err error) {
27 if index < 0 || index >= len(m.musics) {
28 return nil, errors.New("Index out of range.")
29  }
30 
31 return &m.musics[index], nil
32 }
33 
34 func (m * MusicManager) Find (name string) * MusicEntry {
35 if len(m.musics) == 0 {
36 return nil
37  }
38 
39 for _,m := range m.musics {
40 if m.Name == name {
41 return &m
42  }
43  }
44 return nil
45 }
46 
47 func (m * MusicManager) Add (music * MusicEntry) {
48 m.musics = append(m.musics, * music)
49 }
50 
51 func (m * MusicManager) Remove (index int) * MusicEntry {
52 if index < 0 || index >= len(m.musics) {
53 return nil
54  }
55 removedMusic := &m.musics[index]
56 
57 if index < len(m.musics) - 1 {
58 m.musics = append(m.musics[:index - 1], m.musics[index + 1:]...)
59 }else if index == 0 {
60 m.musics = make([]MusicEntry, 0)
61 } else {
62 m.musics = m.musics[:index - 1]
63  }
64 
65 return removedMusic
66 }
67 
68 func (m * MusicManager) RemoveByName (name string) * MusicEntry {
69 var removedMusic * MusicEntry = nil
70 var iPos int = -1
71 for i := 0; i < m.Len(); i++ {
72 if m.musics[i].Name == name {
73 iPos = i
74 break
75  }
76  }
77 
78 if iPos < 0 {
79 return nil
80  }
81 
82 removedMusic = m.Remove(iPos)
83 
84 return removedMusic
85 }

 1 package library
 2 
 3 import (
 4 "testing"
 5 )
 6 
 7 func TestOps(t * testing.T) {
 8 mm := NewMusicManager()
 9 if mm == nil {
10 t.Error("NewMusicManager faild.");
11  }
12 if mm.Len() != 0 {
13 t.Error("NewMusicManager faild, not empty")
14  }
15 m0 := &MusicEntry { "1", "My Heart Will Go On", "Celion Dion", "Pop", "http://qbox.me/24501234", "MP3" }
16  mm.Add(m0)
17 
18 if mm.Len() != 1 {
19 t.Error("MusicManager.Add faild.")
20  }
21 
22 m := mm.Find(m0.Name)
23 if m == nil {
24 t.Error("MusicManager.Find faild")
25  }
26 
27 if m.Id != m0.Id ||
28 m.Name != m0.Name ||
29 m.Artist != m0.Artist ||
30 m.Genre != m0.Genre ||
31 m.Source != m0.Source ||
32 m.Type != m0.Type {
33 t.Error("MusicManager.Find() faild. Found item mismatch.")
34  }
35 
36 m, err := mm.Get(0)
37 if m == nil {
38 t.Error("MusicManager.Get() faild.", err)
39  }
40 
41 m = mm.Remove(0)
42 if m == nil || mm.Len() != 0 {
43 t.Error("MusicManager.Remove() faild.", err)
44  }
45 }

 1 package mp
 2 
 3 import (
 4 "fmt"
 5 "time"
 6 )
 7 
 8 type MP3Player struct {
 9 stat int
10 progress int
11 }
12 
13 type WAVPlayer struct {
14 stat int
15 progress int
16 }
17 
18 func (p * MP3Player) Play (source string) {
19 fmt.Println("Playing MP3 music", source)
20 
21 p.progress = 0
22 
23 for p.progress < 100 {
24 time.Sleep(100 * time.Millisecond)
25 fmt.Print(".")
26 p.progress += 10
27  }
28 fmt.Println("\nFinished playing", source)
29 }
30 
31 func (p * WAVPlayer) Play (source string) {
32 fmt.Println("Playing WAV music", source)
33 
34 p.progress = 0
35 
36 for p.progress < 100 {
37 time.Sleep(100 * time.Millisecond)
38 fmt.Print(".")
39 p.progress += 10
40  }
41 fmt.Println("\nFinished playing", source)
42 }

 1 package mp
 2 
 3 import "fmt"
 4 
 5 type Player interface {
 6  Play(source string)
 7 }
 8 
 9 func Play(source, mtype string) {
10  var p Player
11 
12 switch mtype {
13 case "MP3" :
14 p = &MP3Player{}
15 case "WAV" :
16 p = &WAVPlayer{}
17 default :
18 fmt.Println("Unsupported music type", mtype)
19 return
20  }
21  p.Play(source)
22 }

 1 package main
 2 
 3 import (
 4 "bufio"
 5 "fmt"
 6 "os"
 7 "strconv"
 8 "strings"
 9 
10 "mlib"
11 "mp"
12 )
13 
14 var lib * library.MusicManager
15 var id int = 1
16 var ctrl, signal chan int
17 
18 func handleLibCommands(tokens []string) {
19 switch tokens[1] {
20 case "list" :
21 for i := 0; i < lib.Len(); i++ {
22 e, _ := lib.Get(i)
23 fmt.Println(i + 1, ":", e.Name, e.Artist, e.Source, e.Type)
24  }
25 case "add" :
26 if len(tokens) == 7 {
27 id++
28 lib.Add(&library.MusicEntry { strconv.Itoa(id), tokens[2], tokens[3], tokens[4], tokens[5], tokens[6] })
29 } else {
30 fmt.Println("USAGE : lib add <name><artist><genre><source><type> (7 argv)")
31  }
32 case "remove" :
33 if len(tokens) == 3 {
34 lib.RemoveByName(tokens[2])
35 } else {
36 fmt.Println("USAGE: lib remove <name>")
37  }
38 default :
39 fmt.Println("Unrecogized lib command: ", tokens[1])
40  }
41 }
42 
43 func handlePlayCommands(tokens []string) {
44 if len(tokens) != 2 {
45 fmt.Println("USAGE : play <name>")
46 return
47  }
48 
49 e := lib.Find(tokens[1])
50 if e == nil {
51 fmt.Println("The music", tokens[1], "does not exist.")
52 return
53  }
54 
55  mp.Play(e.Source, e.Type)
56 }
57 
58 func main() {
59  fmt.Println(`
60  Enter following commands to control the player:
61 lib list --View the existing music lib
62 lib add <name><artist><genre><source><type> -- Add a music to the music lib
63 lib remove <name> --Remove the specified music from the lib
64 play <name> -- Play the specified music
65  `)
66 lib = library.NewMusicManager()
67 
68 r := bufio.NewReader(os.Stdin)
69 
70 for i := 0; i <= 100; i++ {
71 fmt.Print("Enter command-> ")
72 rawLine, _, _ := r.ReadLine()
73 
74 line := string(rawLine)
75 if line == "q" || line == "e" {
76 break
77  }
78 tokens := strings.Split(line, " ")
79 
80 if tokens[0] == "lib" {
81  handleLibCommands(tokens)
82 } else if tokens[0] == "play" {
83  handlePlayCommands(tokens)
84 } else {
85 fmt.Println("Unrecognized command :", tokens[0])
86  }
87  }
88 }

$ export GOPATH="/home/normal/musicplayer"

1 $ go build

 1 .
 2 ├── mplayer.go
 3 ├── musicplayer
 4 └── src
 5  ├── mlib
 6  │  ├── manager.go
 7  │  └── manager_test.go
 8  └── mp
 9  ├── mp3.go
10 └── play.go

$ ./musicplayer 
 Enter following commands to control the player:
 lib list --View the existing music lib
 lib add <name><artist><genre><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
 
Enter command-> lib add a b c d e
Enter command-> lib list
1 : a b d e
Enter command-> play a
Unsupported music type e
Enter command-> lib remove a
Enter command-> lib add a b c d e MP3
USAGE : lib add <name><artist><genre><source><type> (7 argv)
Enter command-> lib add a b c d MP3
Enter command-> lib list
1 : a b d MP3
Enter command-> play a
Playing MP3 music d
..........
Finished playing d
Enter command-> q

有疑问加站长微信联系(非本文作者)

• 请尽量让自己的回复能够对别人有帮助
• 支持 Markdown 格式, **粗体**、~~删除线~~、`单行代码`
• 支持 @ 本站用户;支持表情(输入 : 提示),见 Emoji cheat sheet
• 图片支持拖拽、截图粘贴等方式上传