feat(QMCv2): support .mggl and .bkc*

`.mggl`: QQ Music MacOS Ogg (fix https://github.com/unlock-music/cli/issues/25)
`.bkc*` (".bkc" + {"mp3", "m4a", "flac", "wav", "ape", "ogg", "wma"}): Moo Music

algo/qmc/cipher_rc4.go

@@ -6,10 +6,10 @@ import (
 
 // A rc4Cipher is an instance of RC4 using a particular key.
 type rc4Cipher struct {
-	box    []byte
-	key    []byte
-	hash   uint32
-	boxTmp []byte
+	box  []byte
+	key  []byte
+	hash uint32
+	n    int
 }
 
 // NewRC4Cipher creates and returns a new rc4Cipher. The key argument should be the
@@ -20,9 +20,8 @@ func NewRC4Cipher(key []byte) (*rc4Cipher, error) {
 		return nil, errors.New("qmc/cipher_rc4: invalid key size")
 	}
 
-	var c = rc4Cipher{key: key}
+	var c = rc4Cipher{key: key, n: n}
 	c.box = make([]byte, n)
-	c.boxTmp = make([]byte, n)
 
 	for i := 0; i < n; i++ {
 		c.box[i] = byte(i)
@@ -39,7 +38,7 @@ func NewRC4Cipher(key []byte) (*rc4Cipher, error) {
 
 func (c *rc4Cipher) getHashBase() {
 	c.hash = 1
-	for i := 0; i < len(c.key); i++ {
+	for i := 0; i < c.n; i++ {
 		v := uint32(c.key[i])
 		if v == 0 {
 			continue
@@ -52,7 +51,10 @@ func (c *rc4Cipher) getHashBase() {
 	}
 }
 
-const rc4SegmentSize = 5120
+const (
+	rc4SegmentSize      = 5120
+	rc4FirstSegmentSize = 128
+)
 
 func (c *rc4Cipher) Decrypt(src []byte, offset int) {
 	toProcess := len(src)
@@ -64,10 +66,10 @@ func (c *rc4Cipher) Decrypt(src []byte, offset int) {
 		return toProcess == 0
 	}
 
-	if offset < 128 {
+	if offset < rc4FirstSegmentSize {
 		blockSize := toProcess
-		if blockSize > 128-offset {
-			blockSize = 128 - offset
+		if blockSize > rc4FirstSegmentSize-offset {
+			blockSize = rc4FirstSegmentSize - offset
 		}
 		c.encFirstSegment(src[:blockSize], offset)
 		if markProcess(blockSize) {
@@ -80,8 +82,7 @@ func (c *rc4Cipher) Decrypt(src []byte, offset int) {
 		if blockSize > rc4SegmentSize-offset%rc4SegmentSize {
 			blockSize = rc4SegmentSize - offset%rc4SegmentSize
 		}
-		k := src[processed : processed+blockSize]
-		c.encASegment(k, offset)
+		c.encASegment(src[processed:processed+blockSize], offset)
 		if markProcess(blockSize) {
 			return
 		}
@@ -96,38 +97,28 @@ func (c *rc4Cipher) Decrypt(src []byte, offset int) {
 	}
 }
 func (c *rc4Cipher) encFirstSegment(buf []byte, offset int) {
-	n := len(c.box)
 	for i := 0; i < len(buf); i++ {
-		idx1 := offset + i
-		segmentID := int(c.key[idx1%n])
-		idx2 := int(float64(c.hash) / float64((idx1+1)*segmentID) * 100.0)
-		buf[i] ^= c.key[idx2%n]
+		buf[i] ^= c.key[c.getSegmentSkip(offset+i)]
 	}
 }
 
 func (c *rc4Cipher) encASegment(buf []byte, offset int) {
-	n := len(c.box)
-	copy(c.boxTmp, c.box)
-
-	segmentID := (offset / rc4SegmentSize) & 0x1FF
-
-	if n <= segmentID {
-		return
-	}
-
-	idx2 := int64(float64(c.hash) /
-		float64((offset/rc4SegmentSize+1)*int(c.key[segmentID])) *
-		100.0)
-	skipLen := int((idx2 & 0x1FF) + int64(offset%rc4SegmentSize))
-
+	box := make([]byte, c.n)
+	copy(box, c.box)
 	j, k := 0, 0
 
+	skipLen := (offset % rc4SegmentSize) + c.getSegmentSkip(offset/rc4SegmentSize)
 	for i := -skipLen; i < len(buf); i++ {
-		j = (j + 1) % n
-		k = (int(c.boxTmp[j]) + k) % n
-		c.boxTmp[j], c.boxTmp[k] = c.boxTmp[k], c.boxTmp[j]
+		j = (j + 1) % c.n
+		k = (int(box[j]) + k) % c.n
+		box[j], box[k] = box[k], box[j]
 		if i >= 0 {
-			buf[i] ^= c.boxTmp[int(c.boxTmp[j])+int(c.boxTmp[k])%n]
+			buf[i] ^= box[(int(box[j])+int(box[k]))%c.n]
 		}
 	}
 }
+func (c *rc4Cipher) getSegmentSkip(id int) int {
+	seed := int(c.key[id%c.n])
+	idx := int64(float64(c.hash) / float64((id+1)*seed) * 100.0)
+	return int(idx % int64(c.n))
+}

algo/qmc/cipher_rc4_test.go

@@ -6,16 +6,17 @@ import (
 	"testing"
 )
 
-func loadTestRC4CipherData() ([]byte, []byte, []byte, error) {
-	key, err := os.ReadFile("./testdata/mflac0_rc4_key.bin")
+func loadTestRC4CipherData(name string) ([]byte, []byte, []byte, error) {
+	prefix := "./testdata/" + name
+	key, err := os.ReadFile(prefix + "_key.bin")
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	raw, err := os.ReadFile("./testdata/mflac0_rc4_raw.bin")
+	raw, err := os.ReadFile(prefix + "_raw.bin")
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	target, err := os.ReadFile("./testdata/mflac0_rc4_target.bin")
+	target, err := os.ReadFile(prefix + "_target.bin")
 	if err != nil {
 		return nil, nil, nil, err
 	}
@@ -23,26 +24,50 @@ func loadTestRC4CipherData() ([]byte, []byte, []byte, error) {
 	return key, raw, target, nil
 }
 func Test_rc4Cipher_Decrypt(t *testing.T) {
-	key, raw, target, err := loadTestRC4CipherData()
-	if err != nil {
-		t.Fatalf("load testing data failed: %s", err)
+	tests := []struct {
+		name    string
+		wantErr bool
+	}{
+		{"mflac0_rc4", false},
+		{"mflac_rc4", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			key, raw, target, err := loadTestRC4CipherData(tt.name)
+			if err != nil {
+				t.Fatalf("load testing data failed: %s", err)
+			}
+			c, err := NewRC4Cipher(key)
+			if err != nil {
+				t.Errorf("init rc4Cipher failed: %s", err)
+				return
+			}
+			c.Decrypt(raw, 0)
+			if !reflect.DeepEqual(raw, target) {
+				t.Error("overall")
+			}
+		})
 	}
-	t.Run("overall", func(t *testing.T) {
-		c, err := NewRC4Cipher(key)
-		if err != nil {
-			t.Errorf("init rc4Cipher failed: %s", err)
-			return
-		}
-		c.Decrypt(raw, 0)
-		if !reflect.DeepEqual(raw, target) {
-			t.Error("overall")
-		}
-	})
 
 }
+func BenchmarkRc4Cipher_Decrypt(b *testing.B) {
+	key, raw, _, err := loadTestRC4CipherData("mflac0_rc4")
+	if err != nil {
+		b.Fatalf("load testing data failed: %s", err)
+	}
+	c, err := NewRC4Cipher(key)
+	if err != nil {
+		b.Errorf("init rc4Cipher failed: %s", err)
+		return
+	}
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		c.Decrypt(raw, 0)
+	}
+}
 
 func Test_rc4Cipher_encFirstSegment(t *testing.T) {
-	key, raw, target, err := loadTestRC4CipherData()
+	key, raw, target, err := loadTestRC4CipherData("mflac0_rc4")
 	if err != nil {
 		t.Fatalf("load testing data failed: %s", err)
 	}
@@ -60,7 +85,7 @@ func Test_rc4Cipher_encFirstSegment(t *testing.T) {
 }
 
 func Test_rc4Cipher_encASegment(t *testing.T) {
-	key, raw, target, err := loadTestRC4CipherData()
+	key, raw, target, err := loadTestRC4CipherData("mflac0_rc4")
 	if err != nil {
 		t.Fatalf("load testing data failed: %s", err)
 	}

algo/qmc/key_dec_test.go

@@ -27,7 +27,6 @@ func loadDecryptKeyData(name string) ([]byte, []byte, error) {
 	return keyRaw, keyDec, nil
 }
 func TestDecryptKey(t *testing.T) {
-
 	tests := []struct {
 		name     string
 		filename string
@@ -35,13 +34,15 @@ func TestDecryptKey(t *testing.T) {
 	}{
 		{"mflac0_rc4(512)", "mflac0_rc4", false},
 		{"mflac_map(256)", "mflac_map", false},
+		{"mflac_rc4(256)", "mflac_rc4", false},
+		{"mgg_map(256)", "mgg_map", false},
 	}
 	for _, tt := range tests {
-		raw, want, err := loadDecryptKeyData(tt.filename)
-		if err != nil {
-			t.Fatalf("load test data failed: %s", err)
-		}
 		t.Run(tt.name, func(t *testing.T) {
+			raw, want, err := loadDecryptKeyData(tt.filename)
+			if err != nil {
+				t.Fatalf("load test data failed: %s", err)
+			}
 			got, err := DecryptKey(raw)
 			if (err != nil) != tt.wantErr {
 				t.Errorf("DecryptKey() error = %v, wantErr %v", err, tt.wantErr)

algo/qmc/qmc.go

@@ -193,9 +193,9 @@ func init() {
 		"qmcflac", //QQ Music FLAC
 		"qmcogg",  //QQ Music OGG
 
-		"tkm",     //QQ Music Accompaniment M4A
-		"bkcmp3",  //Moo Music Mp3
-		"bkcflac", //Moo Music Flac
+		"tkm", //QQ Music Accompaniment M4A
+
+		"bkcmp3", "bkcm4a", "bkcflac", "bkcwav", "bkcape", "bkcogg", "bkcwma", //Moo Music
 
 		"666c6163", //QQ Music Weiyun Flac
 		"6d7033",   //QQ Music Weiyun Mp3
@@ -203,7 +203,7 @@ func init() {
 		"6d3461",   //QQ Music Weiyun M4a
 		"776176",   //QQ Music Weiyun Wav
 
-		"mgg", "mgg1", //QQ Music New Ogg
+		"mgg", "mgg1", "mggl", //QQ Music New Ogg
 		"mflac", "mflac0", //QQ Music New Flac
 	}
 	for _, ext := range supportedExts {

algo/qmc/qmc_test.go

@@ -32,6 +32,7 @@ func TestMflac0Decoder_Read(t *testing.T) {
 		wantErr bool
 	}{
 		{"mflac0_rc4", false},
+		{"mflac_rc4", false},
 		{"mflac_map", false},
 		{"mgg_map", false},
 		{"qmc0_static", false},

algo/qmc/testdata/mflac_rc4_key.bin

@@ -0,0 +1 @@
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

algo/qmc/testdata/mflac_rc4_key_raw.bin

@@ -0,0 +1 @@
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