kopia lustrzana https://github.com/jcs/id3-go
108 wiersze
2.0 KiB
Go
108 wiersze
2.0 KiB
Go
// Copyright 2013 Michael Yang. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package id3
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import (
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"errors"
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"github.com/jcs/id3-go/v1"
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"github.com/jcs/id3-go/v2"
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"os"
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)
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const (
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LatestVersion = 3
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)
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// Tagger represents the metadata of a tag
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type Tagger interface {
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Title() string
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Artist() string
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Album() string
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Year() string
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Genre() string
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Comments() []string
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SetTitle(string)
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SetArtist(string)
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SetAlbum(string)
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SetYear(string)
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SetGenre(string)
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AllFrames() []v2.Framer
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Frames(string) []v2.Framer
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Frame(string) v2.Framer
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DeleteFrame(v2.Framer) []v2.Framer
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DeleteFrames(string) []v2.Framer
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AddFrames(...v2.Framer)
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Bytes() []byte
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Dirty() bool
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Padding() uint
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Size() int
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Version() string
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}
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// File represents the tagged file
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type File struct {
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Tagger
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originalSize int
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file *os.File
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}
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// Opens a new tagged file
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func Open(name string) (*File, error) {
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fi, err := os.OpenFile(name, os.O_RDWR, 0666)
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if err != nil {
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return nil, err
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}
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file := &File{file: fi}
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if v2Tag := v2.ParseTag(fi); v2Tag != nil {
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file.Tagger = v2Tag
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file.originalSize = v2Tag.Size()
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} else if v1Tag := v1.ParseTag(fi); v1Tag != nil {
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file.Tagger = v1Tag
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} else {
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// Add a new tag if none exists
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file.Tagger = v2.NewTag(LatestVersion)
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}
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return file, nil
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}
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// Saves any edits to the tagged file
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func (f *File) Close() error {
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defer f.file.Close()
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if !f.Dirty() {
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return nil
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}
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switch f.Tagger.(type) {
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case (*v1.Tag):
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if _, err := f.file.Seek(-v1.TagSize, os.SEEK_END); err != nil {
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return err
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}
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case (*v2.Tag):
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if f.Size() > f.originalSize {
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start := int64(f.originalSize + v2.HeaderSize)
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offset := int64(f.Tagger.Size() - f.originalSize)
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if err := shiftBytesBack(f.file, start, offset); err != nil {
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return err
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}
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}
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if _, err := f.file.Seek(0, os.SEEK_SET); err != nil {
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return err
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}
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default:
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return errors.New("Close: unknown tag version")
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}
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if _, err := f.file.Write(f.Tagger.Bytes()); err != nil {
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return err
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}
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return nil
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}
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