cli/algo/ximalaya/ximalaya.go

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package ximalaya
import (
"bytes"
"fmt"
"io"
"unlock-music.dev/cli/algo/common"
"unlock-music.dev/cli/internal/sniff"
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)
type Decoder struct {
rd io.ReadSeeker
offset int
audio io.Reader
}
func NewDecoder(rd io.ReadSeeker) common.Decoder {
return &Decoder{rd: rd}
}
func (d *Decoder) Validate() error {
encryptedHeader := make([]byte, x2mHeaderSize)
if _, err := io.ReadFull(d.rd, encryptedHeader); err != nil {
return fmt.Errorf("ximalaya read header: %w", err)
}
{ // try to decode with x2m
header := decryptX2MHeader(encryptedHeader)
if _, ok := sniff.AudioExtension(header); ok {
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d.audio = io.MultiReader(bytes.NewReader(header), d.rd)
return nil
}
}
{ // try to decode with x3m
// not read file again, since x2m and x3m have the same header size
header := decryptX3MHeader(encryptedHeader)
if _, ok := sniff.AudioExtension(header); ok {
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d.audio = io.MultiReader(bytes.NewReader(header), d.rd)
return nil
}
}
return fmt.Errorf("ximalaya: unknown format")
}
func (d *Decoder) Read(p []byte) (n int, err error) {
return d.audio.Read(p)
}
func init() {
common.RegisterDecoder("x2m", false, NewDecoder)
common.RegisterDecoder("x3m", false, NewDecoder)
common.RegisterDecoder("xm", false, NewDecoder)
}