Merge pull request #23 from unlock-music/feature/qmc-v2

Feature: QMC Decoder v2

algo/common/dispatch.go

@@ -12,15 +12,15 @@ type decoderItem struct {
 	decoder NewDecoderFunc
 }
 
-var decoderRegistry = make(map[string][]decoderItem)
+var DecoderRegistry = make(map[string][]decoderItem)
 
 func RegisterDecoder(ext string, noop bool, dispatchFunc NewDecoderFunc) {
-	decoderRegistry[ext] = append(decoderRegistry[ext],
+	DecoderRegistry[ext] = append(DecoderRegistry[ext],
 		decoderItem{noop: noop, decoder: dispatchFunc})
 }
 func GetDecoder(filename string, skipNoop bool) (rs []NewDecoderFunc) {
 	ext := strings.ToLower(strings.TrimLeft(filepath.Ext(filename), "."))
-	for _, dec := range decoderRegistry[ext] {
+	for _, dec := range DecoderRegistry[ext] {
 		if skipNoop && dec.noop {
 			continue
 		}

algo/qmc/cipher.go

@@ -0,0 +1,5 @@
+package qmc
+
+type streamCipher interface {
+	Decrypt(buf []byte, offset int)
+}

algo/qmc/cipher_map.go

@@ -0,0 +1,39 @@
+package qmc
+
+import "errors"
+
+type mapCipher struct {
+	key  []byte
+	box  []byte
+	size int
+}
+
+func NewMapCipher(key []byte) (*mapCipher, error) {
+	if len(key) == 0 {
+		return nil, errors.New("qmc/cipher_map: invalid key size")
+	}
+	c := &mapCipher{key: key, size: len(key)}
+	c.box = make([]byte, c.size)
+	return c, nil
+}
+
+func (c *mapCipher) getMask(offset int) byte {
+	if offset > 0x7FFF {
+		offset %= 0x7FFF
+	}
+	idx := (offset*offset + 71214) % c.size
+	return c.rotate(c.key[idx], byte(idx)&0x7)
+}
+
+func (c *mapCipher) rotate(value byte, bits byte) byte {
+	rotate := (bits + 4) % 8
+	left := value << rotate
+	right := value >> rotate
+	return left | right
+}
+
+func (c *mapCipher) Decrypt(buf []byte, offset int) {
+	for i := 0; i < len(buf); i++ {
+		buf[i] ^= c.getMask(offset + i)
+	}
+}

algo/qmc/cipher_map_test.go

@@ -0,0 +1,53 @@
+package qmc
+
+import (
+	"fmt"
+	"os"
+	"reflect"
+	"testing"
+)
+
+func loadTestDataMapCipher(name string) ([]byte, []byte, []byte, error) {
+	key, err := os.ReadFile(fmt.Sprintf("./testdata/%s_key.bin", name))
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	raw, err := os.ReadFile(fmt.Sprintf("./testdata/%s_raw.bin", name))
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	target, err := os.ReadFile(fmt.Sprintf("./testdata/%s_target.bin", name))
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	return key, raw, target, nil
+}
+func Test_mapCipher_Decrypt(t *testing.T) {
+
+	tests := []struct {
+		name    string
+		wantErr bool
+	}{
+		{"mflac_map", false},
+		{"mgg_map", false},
+	}
+
+	for _, tt := range tests {
+
+		t.Run(tt.name, func(t *testing.T) {
+			key, raw, target, err := loadTestDataMapCipher(tt.name)
+			if err != nil {
+				t.Fatalf("load testing data failed: %s", err)
+			}
+			c, err := NewMapCipher(key)
+			if err != nil {
+				t.Errorf("init mapCipher failed: %s", err)
+				return
+			}
+			c.Decrypt(raw, 0)
+			if !reflect.DeepEqual(raw, target) {
+				t.Error("overall")
+			}
+		})
+	}
+}

algo/qmc/cipher_rc4.go

@@ -0,0 +1,133 @@
+package qmc
+
+import (
+	"errors"
+)
+
+// A rc4Cipher is an instance of RC4 using a particular key.
+type rc4Cipher struct {
+	box    []byte
+	key    []byte
+	hash   uint32
+	boxTmp []byte
+}
+
+// NewRC4Cipher creates and returns a new rc4Cipher. The key argument should be the
+// RC4 key, at least 1 byte and at most 256 bytes.
+func NewRC4Cipher(key []byte) (*rc4Cipher, error) {
+	n := len(key)
+	if n == 0 {
+		return nil, errors.New("qmc/cipher_rc4: invalid key size")
+	}
+
+	var c = rc4Cipher{key: key}
+	c.box = make([]byte, n)
+	c.boxTmp = make([]byte, n)
+
+	for i := 0; i < n; i++ {
+		c.box[i] = byte(i)
+	}
+
+	var j = 0
+	for i := 0; i < n; i++ {
+		j = (j + int(c.box[i]) + int(key[i%n])) % n
+		c.box[i], c.box[j] = c.box[j], c.box[i]
+	}
+	c.getHashBase()
+	return &c, nil
+}
+
+func (c *rc4Cipher) getHashBase() {
+	c.hash = 1
+	for i := 0; i < len(c.key); i++ {
+		v := uint32(c.key[i])
+		if v == 0 {
+			continue
+		}
+		nextHash := c.hash * v
+		if nextHash == 0 || nextHash <= c.hash {
+			break
+		}
+		c.hash = nextHash
+	}
+}
+
+const rc4SegmentSize = 5120
+
+func (c *rc4Cipher) Decrypt(src []byte, offset int) {
+	toProcess := len(src)
+	processed := 0
+	markProcess := func(p int) (finished bool) {
+		offset += p
+		toProcess -= p
+		processed += p
+		return toProcess == 0
+	}
+
+	if offset < 128 {
+		blockSize := toProcess
+		if blockSize > 128-offset {
+			blockSize = 128 - offset
+		}
+		c.encFirstSegment(src[:blockSize], offset)
+		if markProcess(blockSize) {
+			return
+		}
+	}
+
+	if offset%rc4SegmentSize != 0 {
+		blockSize := toProcess
+		if blockSize > rc4SegmentSize-offset%rc4SegmentSize {
+			blockSize = rc4SegmentSize - offset%rc4SegmentSize
+		}
+		k := src[processed : processed+blockSize]
+		c.encASegment(k, offset)
+		if markProcess(blockSize) {
+			return
+		}
+	}
+	for toProcess > rc4SegmentSize {
+		c.encASegment(src[processed:processed+rc4SegmentSize], offset)
+		markProcess(rc4SegmentSize)
+	}
+
+	if toProcess > 0 {
+		c.encASegment(src[processed:], offset)
+	}
+}
+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]
+	}
+}
+
+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))
+
+	j, k := 0, 0
+
+	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]
+		if i >= 0 {
+			buf[i] ^= c.boxTmp[int(c.boxTmp[j])+int(c.boxTmp[k])%n]
+		}
+	}
+}

algo/qmc/cipher_rc4_test.go

@@ -0,0 +1,90 @@
+package qmc
+
+import (
+	"os"
+	"reflect"
+	"testing"
+)
+
+func loadTestRC4CipherData() ([]byte, []byte, []byte, error) {
+	key, err := os.ReadFile("./testdata/mflac0_rc4_key.bin")
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	raw, err := os.ReadFile("./testdata/mflac0_rc4_raw.bin")
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	target, err := os.ReadFile("./testdata/mflac0_rc4_target.bin")
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	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)
+	}
+	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 Test_rc4Cipher_encFirstSegment(t *testing.T) {
+	key, raw, target, err := loadTestRC4CipherData()
+	if err != nil {
+		t.Fatalf("load testing data failed: %s", err)
+	}
+	t.Run("first-block(0~128)", func(t *testing.T) {
+		c, err := NewRC4Cipher(key)
+		if err != nil {
+			t.Errorf("init rc4Cipher failed: %s", err)
+			return
+		}
+		c.Decrypt(raw[:128], 0)
+		if !reflect.DeepEqual(raw[:128], target[:128]) {
+			t.Error("first-block(0~128)")
+		}
+	})
+}
+
+func Test_rc4Cipher_encASegment(t *testing.T) {
+	key, raw, target, err := loadTestRC4CipherData()
+	if err != nil {
+		t.Fatalf("load testing data failed: %s", err)
+	}
+
+	t.Run("align-block(128~5120)", func(t *testing.T) {
+		c, err := NewRC4Cipher(key)
+		if err != nil {
+			t.Errorf("init rc4Cipher failed: %s", err)
+			return
+		}
+		c.Decrypt(raw[128:5120], 128)
+		if !reflect.DeepEqual(raw[128:5120], target[128:5120]) {
+			t.Error("align-block(128~5120)")
+		}
+	})
+	t.Run("simple-block(5120~10240)", func(t *testing.T) {
+		c, err := NewRC4Cipher(key)
+		if err != nil {
+			t.Errorf("init rc4Cipher failed: %s", err)
+			return
+		}
+		c.Decrypt(raw[5120:10240], 5120)
+		if !reflect.DeepEqual(raw[5120:10240], target[5120:10240]) {
+			t.Error("align-block(128~5120)")
+		}
+	})
+}

algo/qmc/cipher_static.go

@@ -0,0 +1,57 @@
+package qmc
+
+func NewStaticCipher() *staticCipher {
+	return &defaultStaticCipher
+}
+
+var defaultStaticCipher = staticCipher{}
+
+type staticCipher struct{}
+
+func (c *staticCipher) Decrypt(buf []byte, offset int) {
+	for i := 0; i < len(buf); i++ {
+		buf[i] ^= c.getMask(offset + i)
+	}
+}
+func (c *staticCipher) getMask(offset int) byte {
+	if offset > 0x7FFF {
+		offset %= 0x7FFF
+	}
+	idx := (offset*offset + 27) & 0xff
+	return staticCipherBox[idx]
+}
+
+var staticCipherBox = [...]byte{
+	0x77, 0x48, 0x32, 0x73, 0xDE, 0xF2, 0xC0, 0xC8, //0x00
+	0x95, 0xEC, 0x30, 0xB2, 0x51, 0xC3, 0xE1, 0xA0, //0x08
+	0x9E, 0xE6, 0x9D, 0xCF, 0xFA, 0x7F, 0x14, 0xD1, //0x10
+	0xCE, 0xB8, 0xDC, 0xC3, 0x4A, 0x67, 0x93, 0xD6, //0x18
+	0x28, 0xC2, 0x91, 0x70, 0xCA, 0x8D, 0xA2, 0xA4, //0x20
+	0xF0, 0x08, 0x61, 0x90, 0x7E, 0x6F, 0xA2, 0xE0, //0x28
+	0xEB, 0xAE, 0x3E, 0xB6, 0x67, 0xC7, 0x92, 0xF4, //0x30
+	0x91, 0xB5, 0xF6, 0x6C, 0x5E, 0x84, 0x40, 0xF7, //0x38
+	0xF3, 0x1B, 0x02, 0x7F, 0xD5, 0xAB, 0x41, 0x89, //0x40
+	0x28, 0xF4, 0x25, 0xCC, 0x52, 0x11, 0xAD, 0x43, //0x48
+	0x68, 0xA6, 0x41, 0x8B, 0x84, 0xB5, 0xFF, 0x2C, //0x50
+	0x92, 0x4A, 0x26, 0xD8, 0x47, 0x6A, 0x7C, 0x95, //0x58
+	0x61, 0xCC, 0xE6, 0xCB, 0xBB, 0x3F, 0x47, 0x58, //0x60
+	0x89, 0x75, 0xC3, 0x75, 0xA1, 0xD9, 0xAF, 0xCC, //0x68
+	0x08, 0x73, 0x17, 0xDC, 0xAA, 0x9A, 0xA2, 0x16, //0x70
+	0x41, 0xD8, 0xA2, 0x06, 0xC6, 0x8B, 0xFC, 0x66, //0x78
+	0x34, 0x9F, 0xCF, 0x18, 0x23, 0xA0, 0x0A, 0x74, //0x80
+	0xE7, 0x2B, 0x27, 0x70, 0x92, 0xE9, 0xAF, 0x37, //0x88
+	0xE6, 0x8C, 0xA7, 0xBC, 0x62, 0x65, 0x9C, 0xC2, //0x90
+	0x08, 0xC9, 0x88, 0xB3, 0xF3, 0x43, 0xAC, 0x74, //0x98
+	0x2C, 0x0F, 0xD4, 0xAF, 0xA1, 0xC3, 0x01, 0x64, //0xA0
+	0x95, 0x4E, 0x48, 0x9F, 0xF4, 0x35, 0x78, 0x95, //0xA8
+	0x7A, 0x39, 0xD6, 0x6A, 0xA0, 0x6D, 0x40, 0xE8, //0xB0
+	0x4F, 0xA8, 0xEF, 0x11, 0x1D, 0xF3, 0x1B, 0x3F, //0xB8
+	0x3F, 0x07, 0xDD, 0x6F, 0x5B, 0x19, 0x30, 0x19, //0xC0
+	0xFB, 0xEF, 0x0E, 0x37, 0xF0, 0x0E, 0xCD, 0x16, //0xC8
+	0x49, 0xFE, 0x53, 0x47, 0x13, 0x1A, 0xBD, 0xA4, //0xD0
+	0xF1, 0x40, 0x19, 0x60, 0x0E, 0xED, 0x68, 0x09, //0xD8
+	0x06, 0x5F, 0x4D, 0xCF, 0x3D, 0x1A, 0xFE, 0x20, //0xE0
+	0x77, 0xE4, 0xD9, 0xDA, 0xF9, 0xA4, 0x2B, 0x76, //0xE8
+	0x1C, 0x71, 0xDB, 0x00, 0xBC, 0xFD, 0x0C, 0x6C, //0xF0
+	0xA5, 0x47, 0xF7, 0xF6, 0x00, 0x79, 0x4A, 0x11, //0xF8
+}

algo/qmc/consts.go

@@ -1,70 +0,0 @@
-package qmc
-
-var oggPublicHeader1 = []byte{
-	0x4f, 0x67, 0x67, 0x53, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff,
-	0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0x01, 0x1e, 0x01, 0x76, 0x6f, 0x72,
-	0x62, 0x69, 0x73, 0x00, 0x00, 0x00, 0x00, 0x02, 0x44, 0xac, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-	0x00, 0xee, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0xb8, 0x01, 0x4f, 0x67, 0x67, 0x53, 0x00, 0x00,
-	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0x01, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff}
-
-var oggPublicHeader2 = []byte{
-	0x03, 0x76, 0x6f, 0x72, 0x62, 0x69, 0x73, 0x2c, 0x00, 0x00, 0x00, 0x58, 0x69, 0x70, 0x68, 0x2e,
-	0x4f, 0x72, 0x67, 0x20, 0x6c, 0x69, 0x62, 0x56, 0x6f, 0x72, 0x62, 0x69, 0x73, 0x20, 0x49, 0x20,
-	0x32, 0x30, 0x31, 0x35, 0x30, 0x31, 0x30, 0x35, 0x20, 0x28, 0xe2, 0x9b, 0x84, 0xe2, 0x9b, 0x84,
-	0xe2, 0x9b, 0x84, 0xe2, 0x9b, 0x84, 0x29, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0x54,
-	0x49, 0x54, 0x4c, 0x45, 0x3d}
-
-var oggPublicConfidence1 = []uint{
-	9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 0, 0,
-	0, 0, 9, 9, 9, 9, 0, 0, 0, 0, 9, 9, 9, 9, 9, 9,
-	9, 9, 9, 9, 9, 9, 9, 6, 3, 3, 3, 3, 6, 6, 6, 6,
-	3, 3, 3, 3, 6, 6, 6, 6, 6, 9, 9, 9, 9, 9, 9, 9,
-	9, 9, 9, 9, 9, 9, 9, 9, 0, 0, 0, 0, 9, 9, 9, 9,
-	0, 0, 0, 0}
-
-var oggPublicConfidence2 = []uint{
-	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
-	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
-	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
-	3, 3, 3, 3, 3, 3, 3, 0, 1, 3, 3, 0, 1, 3, 3, 3,
-	3, 3, 3, 3, 3}
-
-var (
-	defaultKey256Mask44 = []byte{
-		0xde, 0x51, 0xfa, 0xc3, 0x4a, 0xd6, 0xca, 0x90,
-		0x7e, 0x67, 0x5e, 0xf7, 0xd5, 0x52, 0x84, 0xd8,
-		0x47, 0x95, 0xbb, 0xa1, 0xaa, 0xc6, 0x66, 0x23,
-		0x92, 0x62, 0xf3, 0x74, 0xa1, 0x9f, 0xf4, 0xa0,
-		0x1d, 0x3f, 0x5b, 0xf0, 0x13, 0x0e, 0x09, 0x3d,
-		0xf9, 0xbc, 0x00, 0x11}
-)
-var key256MappingAll [][]int //[idx256][idx128]idx44
-var key256Mapping128to44 map[int]int
-
-func init() {
-	{ // init all mapping
-		key256MappingAll = make([][]int, 256)
-		for i := 0; i < 128; i++ {
-			realIdx := (i*i + 27) % 256
-			if key256MappingAll[realIdx] == nil {
-				key256MappingAll[realIdx] = []int{i}
-			} else {
-				key256MappingAll[realIdx] = append(key256MappingAll[realIdx], i)
-			}
-		}
-	}
-	{ // init
-		key256Mapping128to44 = make(map[int]int, 128)
-		idx44 := 0
-		for _, all128 := range key256MappingAll {
-			if all128 != nil {
-				for _, _i128 := range all128 {
-					key256Mapping128to44[_i128] = idx44
-				}
-				idx44++
-			}
-		}
-	}
-
-}

algo/qmc/key_dec.go

@@ -0,0 +1,115 @@
+package qmc
+
+import (
+	"encoding/base64"
+	"errors"
+	"math"
+
+	"golang.org/x/crypto/tea"
+)
+
+func simpleMakeKey(salt byte, length int) []byte {
+	keyBuf := make([]byte, length)
+	for i := 0; i < length; i++ {
+		tmp := math.Tan(float64(salt) + float64(i)*0.1)
+		keyBuf[i] = byte(math.Abs(tmp) * 100.0)
+	}
+	return keyBuf
+}
+func DecryptKey(rawKey []byte) ([]byte, error) {
+	rawKeyDec := make([]byte, base64.StdEncoding.DecodedLen(len(rawKey)))
+	n, err := base64.StdEncoding.Decode(rawKeyDec, rawKey)
+	if err != nil {
+		return nil, err
+	}
+	if n < 16 {
+		return nil, errors.New("key length is too short")
+	}
+	rawKeyDec = rawKeyDec[:n]
+
+	simpleKey := simpleMakeKey(106, 8)
+	teaKey := make([]byte, 16)
+	for i := 0; i < 8; i++ {
+		teaKey[i<<1] = simpleKey[i]
+		teaKey[i<<1+1] = rawKeyDec[i]
+	}
+
+	rs, err := decryptTencentTea(rawKeyDec[8:], teaKey)
+	if err != nil {
+		return nil, err
+	}
+	return append(rawKeyDec[:8], rs...), nil
+}
+func decryptTencentTea(inBuf []byte, key []byte) ([]byte, error) {
+	const saltLen = 2
+	const zeroLen = 7
+	if len(inBuf)%8 != 0 {
+		return nil, errors.New("inBuf size not a multiple of the block size")
+	}
+	if len(inBuf) < 16 {
+		return nil, errors.New("inBuf size too small")
+	}
+
+	blk, err := tea.NewCipherWithRounds(key, 32)
+	if err != nil {
+		return nil, err
+	}
+
+	destBuf := make([]byte, 8)
+	blk.Decrypt(destBuf, inBuf)
+	padLen := int(destBuf[0] & 0x7)
+	outLen := len(inBuf) - 1 - padLen - saltLen - zeroLen
+	if padLen+saltLen != 8 {
+		return nil, errors.New("invalid pad len")
+	}
+	out := make([]byte, outLen)
+
+	ivPrev := make([]byte, 8)
+	ivCur := inBuf[:8]
+
+	inBufPos := 8
+
+	destIdx := 1 + padLen
+	cryptBlock := func() {
+		ivPrev = ivCur
+		ivCur = inBuf[inBufPos : inBufPos+8]
+
+		xor8Bytes(destBuf, destBuf, inBuf[inBufPos:inBufPos+8])
+		blk.Decrypt(destBuf, destBuf)
+
+		inBufPos += 8
+		destIdx = 0
+	}
+	for i := 1; i <= saltLen; {
+		if destIdx < 8 {
+			destIdx++
+			i++
+		} else if destIdx == 8 {
+			cryptBlock()
+		}
+	}
+
+	outPos := 0
+	for outPos < outLen {
+		if destIdx < 8 {
+			out[outPos] = destBuf[destIdx] ^ ivPrev[destIdx]
+			destIdx++
+			outPos++
+		} else if destIdx == 8 {
+			cryptBlock()
+		}
+	}
+
+	for i := 1; i <= zeroLen; i++ {
+		if destBuf[destIdx] != ivPrev[destIdx] {
+			return nil, errors.New("zero check failed")
+		}
+	}
+
+	return out, nil
+}
+func xor8Bytes(dst, a, b []byte) {
+	for i := 0; i < 8; i++ {
+		dst[i] = a[i] ^ b[i]
+	}
+}

algo/qmc/key_dec_test.go

@@ -0,0 +1,56 @@
+package qmc
+
+import (
+	"fmt"
+	"os"
+	"reflect"
+	"testing"
+)
+
+func TestSimpleMakeKey(t *testing.T) {
+	expect := []byte{0x69, 0x56, 0x46, 0x38, 0x2b, 0x20, 0x15, 0x0b}
+	t.Run("106,8", func(t *testing.T) {
+		if got := simpleMakeKey(106, 8); !reflect.DeepEqual(got, expect) {
+			t.Errorf("simpleMakeKey() = %v, want %v", got, expect)
+		}
+	})
+}
+func loadDecryptKeyData(name string) ([]byte, []byte, error) {
+	keyRaw, err := os.ReadFile(fmt.Sprintf("./testdata/%s_key_raw.bin", name))
+	if err != nil {
+		return nil, nil, err
+	}
+	keyDec, err := os.ReadFile(fmt.Sprintf("./testdata/%s_key.bin", name))
+	if err != nil {
+		return nil, nil, err
+	}
+	return keyRaw, keyDec, nil
+}
+func TestDecryptKey(t *testing.T) {
+
+	tests := []struct {
+		name     string
+		filename string
+		wantErr  bool
+	}{
+		{"mflac0_rc4(512)", "mflac0_rc4", false},
+		{"mflac_map(256)", "mflac_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) {
+			got, err := DecryptKey(raw)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("DecryptKey() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, want) {
+				t.Errorf("DecryptKey() got = %v..., want %v...",
+					string(got[:32]), string(want[:32]))
+			}
+		})
+	}
+}

algo/qmc/mask_key256.go

@@ -1,212 +0,0 @@
-package qmc
-
-import (
-	"bytes"
-	"errors"
-	"github.com/unlock-music/cli/algo/common"
-	"github.com/unlock-music/cli/internal/logging"
-	"go.uber.org/zap"
-)
-
-var (
-	ErrFailToMatchMask = errors.New("can not match at least one key")
-	ErrTestDataLength  = errors.New("invalid length of test file")
-	ErrMaskLength128   = errors.New("incorrect mask length 128")
-	ErrMaskLength44    = errors.New("incorrect mask length 44")
-	ErrMaskDecode      = errors.New("decode mask-128 to mask-58 failed")
-	ErrDetectFlacMask  = errors.New("can not detect mflac mask")
-	ErrDetectMggMask   = errors.New("can not detect mgg mask")
-)
-
-type Key256Mask struct {
-	matrix []byte // Mask 128
-}
-
-func NewKey256FromMask128(mask128 []byte) (*Key256Mask, error) {
-	if len(mask128) != 128 {
-		return nil, ErrMaskLength128
-	}
-	q := &Key256Mask{matrix: mask128}
-	return q, nil
-}
-
-func NewKey256FromMask44(mask44 []byte) (*Key256Mask, error) {
-	mask128, err := convertKey256Mask44to128(mask44)
-	if err != nil {
-		return nil, err
-	}
-	q := &Key256Mask{matrix: mask128}
-	return q, nil
-}
-
-func (q *Key256Mask) GetMatrix44() ([]byte, error) {
-	if len(q.matrix) != 128 {
-		return nil, ErrMaskLength128
-	}
-	matrix44 := make([]byte, 44)
-	idx44 := 0
-	for _, it256 := range key256MappingAll {
-		if it256 != nil {
-			it256Len := len(it256)
-			for i := 1; i < it256Len; i++ {
-				if q.matrix[it256[0]] != q.matrix[it256[i]] {
-					return nil, ErrMaskDecode
-				}
-			}
-			matrix44[idx44] = q.matrix[it256[0]]
-			idx44++
-		}
-	}
-	return matrix44, nil
-}
-
-func (q *Key256Mask) Decrypt(data []byte) []byte {
-	dst := make([]byte, len(data))
-	index := -1
-	maskIdx := -1
-	for cur := 0; cur < len(data); cur++ {
-		index++
-		maskIdx++
-		if index == 0x8000 || (index > 0x8000 && (index+1)%0x8000 == 0) {
-			index++
-			maskIdx++
-		}
-		if maskIdx >= 128 {
-			maskIdx -= 128
-		}
-		dst[cur] = data[cur] ^ q.matrix[maskIdx]
-	}
-	return dst
-}
-
-func convertKey256Mask44to128(mask44 []byte) ([]byte, error) {
-	if len(mask44) != 44 {
-		return nil, ErrMaskLength44
-	}
-	mask128 := make([]byte, 128)
-	idx44 := 0
-	for _, it256 := range key256MappingAll {
-		if it256 != nil {
-			for _, idx128 := range it256 {
-				mask128[idx128] = mask44[idx44]
-			}
-			idx44++
-		}
-	}
-	return mask128, nil
-}
-
-func getDefaultMask() *Key256Mask {
-	y, _ := NewKey256FromMask44(defaultKey256Mask44)
-	return y
-}
-
-func detectMflac256Mask(input []byte) (*Key256Mask, error) {
-	var q *Key256Mask
-	var rtErr = ErrDetectFlacMask
-
-	lenData := len(input)
-	lenTest := 0x8000
-	if lenData < 0x8000 {
-		lenTest = lenData
-	}
-
-	for blockIdx := 0; blockIdx < lenTest; blockIdx += 128 {
-		var err error
-		q, err = NewKey256FromMask128(input[blockIdx : blockIdx+128])
-		if err != nil {
-			continue
-		}
-		if common.SnifferFLAC(q.Decrypt(input[:4])) {
-			rtErr = nil
-			break
-		}
-	}
-	return q, rtErr
-}
-
-func detectMgg256Mask(input []byte) (*Key256Mask, error) {
-	if len(input) < 0x100 {
-		return nil, ErrTestDataLength
-	}
-
-	matrixConf := make([]map[uint8]uint, 44) //meaning: [idx58][value]confidence
-	for i := uint(0); i < 44; i++ {
-		matrixConf[i] = make(map[uint8]uint)
-	}
-
-	page2size := input[0x54] ^ input[0xC] ^ oggPublicHeader1[0xC]
-	spHeader, spConf := generateOggFullHeader(int(page2size))
-	lenTest := len(spHeader)
-
-	for idx128 := 0; idx128 < lenTest; idx128++ {
-		confidence := spConf[idx128]
-		if confidence > 0 {
-			mask := input[idx128] ^ spHeader[idx128]
-
-			idx44 := key256Mapping128to44[idx128&0x7f] // equals: [idx128 % 128]
-			if _, ok2 := matrixConf[idx44][mask]; ok2 {
-				matrixConf[idx44][mask] += confidence
-			} else {
-				matrixConf[idx44][mask] = confidence
-			}
-		}
-	}
-
-	matrix := make([]uint8, 44)
-	var err error
-	for i := uint(0); i < 44; i++ {
-		matrix[i], err = decideMgg256MaskItemConf(matrixConf[i])
-		if err != nil {
-			return nil, err
-		}
-	}
-	q, err := NewKey256FromMask44(matrix)
-	if err != nil {
-		return nil, err
-	}
-	if common.SnifferOGG(q.Decrypt(input[:4])) {
-		return q, nil
-	}
-	return nil, ErrDetectMggMask
-}
-
-func generateOggFullHeader(pageSize int) ([]byte, []uint) {
-	spec := make([]byte, pageSize+1)
-
-	spec[0], spec[1], spec[pageSize] = uint8(pageSize), 0xFF, 0xFF
-	for i := 2; i < pageSize; i++ {
-		spec[i] = 0xFF
-	}
-	specConf := make([]uint, pageSize+1)
-	specConf[0], specConf[1], specConf[pageSize] = 6, 0, 0
-	for i := 2; i < pageSize; i++ {
-		specConf[i] = 4
-	}
-	allConf := append(oggPublicConfidence1, specConf...)
-	allConf = append(allConf, oggPublicConfidence2...)
-
-	allHeader := bytes.Join(
-		[][]byte{oggPublicHeader1, spec, oggPublicHeader2},
-		[]byte{},
-	)
-	return allHeader, allConf
-}
-
-func decideMgg256MaskItemConf(confidence map[uint8]uint) (uint8, error) {
-	lenConf := len(confidence)
-	if lenConf == 0 {
-		return 0xff, ErrFailToMatchMask
-	} else if lenConf > 1 {
-		logging.Log().Warn("there are 2 potential value for the mask", zap.Any("confidence", confidence))
-	}
-	result := uint8(0)
-	conf := uint(0)
-	for idx, item := range confidence {
-		if item > conf {
-			result = idx
-			conf = item
-		}
-	}
-	return result, nil
-}

algo/qmc/qmc.go

@@ -1,128 +1,263 @@
 package qmc
 
 import (
-	"encoding/base64"
+	"bytes"
 	"encoding/binary"
 	"errors"
+	"io"
+	"strconv"
+	"strings"
+
 	"github.com/unlock-music/cli/algo/common"
 )
 
-var (
-	ErrQmcFileLength      = errors.New("invalid qmc file length")
-	ErrQmcKeyDecodeFailed = errors.New("base64 decode qmc key failed")
-	ErrQmcKeyLength       = errors.New("unexpected decoded qmc key length")
-)
-
 type Decoder struct {
-	file         []byte
-	maskDetector func(encodedData []byte) (*Key256Mask, error)
-	mask         *Key256Mask
-	audioExt     string
-	key          []byte
-	audio        []byte
+	r       io.ReadSeeker
+	fileExt string
+
+	audioLen   int
+	decodedKey []byte
+	cipher     streamCipher
+	offset     int
+
+	rawMetaExtra1 int
+	rawMetaExtra2 int
 }
 
-func NewMflac256Decoder(data []byte) common.Decoder {
-	return &Decoder{file: data, maskDetector: detectMflac256Mask, audioExt: "flac"}
+// Read implements io.Reader, offer the decrypted audio data.
+// Validate should call before Read to check if the file is valid.
+func (d *Decoder) Read(p []byte) (int, error) {
+	n := len(p)
+	if d.audioLen-d.offset <= 0 {
+		return 0, io.EOF
+	} else if d.audioLen-d.offset < n {
+		n = d.audioLen - d.offset
+	}
+	m, err := d.r.Read(p[:n])
+	if m == 0 {
+		return 0, err
+	}
+
+	d.cipher.Decrypt(p[:m], d.offset)
+	d.offset += m
+	return m, err
 }
 
-func NewMgg256Decoder(data []byte) common.Decoder {
-	return &Decoder{file: data, maskDetector: detectMgg256Mask, audioExt: "ogg"}
+func NewDecoder(r io.ReadSeeker) (*Decoder, error) {
+	d := &Decoder{r: r}
+	err := d.searchKey()
+	if err != nil {
+		return nil, err
+	}
+
+	if len(d.decodedKey) > 300 {
+		d.cipher, err = NewRC4Cipher(d.decodedKey)
+		if err != nil {
+			return nil, err
+		}
+	} else if len(d.decodedKey) != 0 {
+		d.cipher, err = NewMapCipher(d.decodedKey)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		d.cipher = NewStaticCipher()
+	}
+
+	_, err = d.r.Seek(0, io.SeekStart)
+	if err != nil {
+		return nil, err
+	}
+
+	return d, nil
 }
 
 func (d *Decoder) Validate() error {
-	if nil != d.mask {
-		return nil
-	}
-	if nil != d.maskDetector {
-		if err := d.validateKey(); err != nil {
+	buf := make([]byte, 16)
+	if _, err := io.ReadFull(d.r, buf); err != nil {
 		return err
 	}
-		var err error
-		d.mask, err = d.maskDetector(d.file)
-		return err
-	}
-	return errors.New("no mask or mask detector found")
-}
-
-func (d *Decoder) validateKey() error {
-	lenData := len(d.file)
-	if lenData < 4 {
-		return ErrQmcFileLength
-	}
-
-	keyLen := binary.LittleEndian.Uint32(d.file[lenData-4:])
-	if lenData < int(keyLen+4) {
-		return ErrQmcFileLength
-	}
-	var err error
-	d.key, err = base64.StdEncoding.DecodeString(
-		string(d.file[lenData-4-int(keyLen) : lenData-4]))
+	_, err := d.r.Seek(0, io.SeekStart)
 	if err != nil {
-		return ErrQmcKeyDecodeFailed
+		return err
 	}
 
-	if len(d.key) != 272 {
-		return ErrQmcKeyLength
+	d.cipher.Decrypt(buf, 0)
+	fileExt, ok := common.SniffAll(buf)
+	if !ok {
+		return errors.New("detect file type failed")
 	}
-	d.file = d.file[:lenData-4-int(keyLen)]
-	return nil
-
-}
-
-func (d *Decoder) Decode() error {
-	d.audio = d.mask.Decrypt(d.file)
+	d.fileExt = fileExt
 	return nil
 }
 
-func (d Decoder) GetCoverImage() []byte {
+func (d Decoder) GetFileExt() string {
+	return d.fileExt
+}
+
+func (d *Decoder) searchKey() error {
+	fileSizeM4, err := d.r.Seek(-4, io.SeekEnd)
+	if err != nil {
+		return err
+	}
+	buf, err := io.ReadAll(io.LimitReader(d.r, 4))
+	if err != nil {
+		return err
+	}
+	if string(buf) == "QTag" {
+		if err := d.readRawMetaQTag(); err != nil {
+			return err
+		}
+	} else {
+		size := binary.LittleEndian.Uint32(buf)
+		if size < 0x300 && size != 0 {
+			return d.readRawKey(int64(size))
+		} else {
+			// try to use default static cipher
+			d.audioLen = int(fileSizeM4 + 4)
+			return nil
+		}
+	}
 	return nil
 }
 
-func (d Decoder) GetAudioData() []byte {
-	return d.audio
-}
-
-func (d Decoder) GetAudioExt() string {
-	if d.audioExt != "" {
-		return "." + d.audioExt
+func (d *Decoder) readRawKey(rawKeyLen int64) error {
+	audioLen, err := d.r.Seek(-(4 + rawKeyLen), io.SeekEnd)
+	if err != nil {
+		return err
+	}
+	d.audioLen = int(audioLen)
+
+	rawKeyData, err := io.ReadAll(io.LimitReader(d.r, rawKeyLen))
+	if err != nil {
+		return err
+	}
+
+	d.decodedKey, err = DecryptKey(rawKeyData)
+	if err != nil {
+		return err
 	}
-	return ""
-}
 
-func (d Decoder) GetMeta() common.Meta {
 	return nil
 }
 
-func DecoderFuncWithExt(ext string) common.NewDecoderFunc {
-	return func(file []byte) common.Decoder {
-		return &Decoder{file: file, audioExt: ext, mask: getDefaultMask()}
+func (d *Decoder) readRawMetaQTag() error {
+	// get raw meta data len
+	if _, err := d.r.Seek(-8, io.SeekEnd); err != nil {
+		return err
 	}
+	buf, err := io.ReadAll(io.LimitReader(d.r, 4))
+	if err != nil {
+		return err
+	}
+	rawMetaLen := int64(binary.BigEndian.Uint32(buf))
+
+	// read raw meta data
+	audioLen, err := d.r.Seek(-(8 + rawMetaLen), io.SeekEnd)
+	if err != nil {
+		return err
+	}
+	d.audioLen = int(audioLen)
+	rawMetaData, err := io.ReadAll(io.LimitReader(d.r, rawMetaLen))
+	if err != nil {
+		return err
+	}
+
+	items := strings.Split(string(rawMetaData), ",")
+	if len(items) != 3 {
+		return errors.New("invalid raw meta data")
+	}
+
+	d.decodedKey, err = DecryptKey([]byte(items[0]))
+	if err != nil {
+		return err
+	}
+
+	d.rawMetaExtra1, err = strconv.Atoi(items[1])
+	if err != nil {
+		return err
+	}
+	d.rawMetaExtra2, err = strconv.Atoi(items[2])
+	if err != nil {
+		return err
+	}
+
+	return nil
 }
 
 //goland:noinspection SpellCheckingInspection
 func init() {
-	common.RegisterDecoder("qmc0", false, DecoderFuncWithExt("mp3")) //QQ Music Mp3
-	common.RegisterDecoder("qmc3", false, DecoderFuncWithExt("mp3")) //QQ Music Mp3
+	supportedExts := []string{
+		"qmc0", "qmc3", //QQ Music MP3
+		"qmc2", "qmc4", "qmc6", "qmc8", //QQ Music M4A
+		"qmcflac", //QQ Music FLAC
+		"qmcogg",  //QQ Music OGG
 
-	common.RegisterDecoder("qmc2", false, DecoderFuncWithExt("m4a")) //QQ Music M4A
-	common.RegisterDecoder("qmc4", false, DecoderFuncWithExt("m4a")) //QQ Music M4A
-	common.RegisterDecoder("qmc6", false, DecoderFuncWithExt("m4a")) //QQ Music M4A
-	common.RegisterDecoder("qmc8", false, DecoderFuncWithExt("m4a")) //QQ Music M4A
+		"tkm",     //QQ Music Accompaniment M4A
+		"bkcmp3",  //Moo Music Mp3
+		"bkcflac", //Moo Music Flac
 
-	common.RegisterDecoder("qmcflac", false, DecoderFuncWithExt("flac")) //QQ Music Flac
-	common.RegisterDecoder("qmcogg", false, DecoderFuncWithExt("ogg"))   //QQ Music Ogg
-	common.RegisterDecoder("tkm", false, DecoderFuncWithExt("m4a"))      //QQ Music Accompaniment M4a
+		"666c6163", //QQ Music Weiyun Flac
+		"6d7033",   //QQ Music Weiyun Mp3
+		"6f6767",   //QQ Music Weiyun Ogg
+		"6d3461",   //QQ Music Weiyun M4a
+		"776176",   //QQ Music Weiyun Wav
 
-	common.RegisterDecoder("bkcmp3", false, DecoderFuncWithExt("mp3"))   //Moo Music Mp3
-	common.RegisterDecoder("bkcflac", false, DecoderFuncWithExt("flac")) //Moo Music Flac
-
-	common.RegisterDecoder("666c6163", false, DecoderFuncWithExt("flac")) //QQ Music Weiyun Flac
-	common.RegisterDecoder("6d7033", false, DecoderFuncWithExt("mp3"))    //QQ Music Weiyun Mp3
-	common.RegisterDecoder("6f6767", false, DecoderFuncWithExt("ogg"))    //QQ Music Weiyun Ogg
-	common.RegisterDecoder("6d3461", false, DecoderFuncWithExt("m4a"))    //QQ Music Weiyun M4a
-	common.RegisterDecoder("776176", false, DecoderFuncWithExt("wav"))    //QQ Music Weiyun Wav
-
-	common.RegisterDecoder("mgg", false, NewMgg256Decoder)     //QQ Music New Ogg
-	common.RegisterDecoder("mflac", false, NewMflac256Decoder) //QQ Music New Flac
+		"mgg", "mgg1", //QQ Music New Ogg
+		"mflac", "mflac0", //QQ Music New Flac
+	}
+	for _, ext := range supportedExts {
+		common.RegisterDecoder(ext, false, newCompactDecoder)
+	}
+}
+
+type compactDecoder struct {
+	decoder   *Decoder
+	createErr error
+	buf       *bytes.Buffer
+}
+
+func newCompactDecoder(p []byte) common.Decoder {
+	r := bytes.NewReader(p)
+	d, err := NewDecoder(r)
+	c := compactDecoder{
+		decoder:   d,
+		createErr: err,
+	}
+	return &c
+}
+
+func (c *compactDecoder) Validate() error {
+	if c.createErr != nil {
+		return c.createErr
+	}
+	return c.decoder.Validate()
+}
+
+func (c *compactDecoder) Decode() error {
+	if c.createErr != nil {
+		return c.createErr
+	}
+	c.buf = bytes.NewBuffer(nil)
+	_, err := io.Copy(c.buf, c.decoder)
+	return err
+}
+
+func (c *compactDecoder) GetCoverImage() []byte {
+	return nil
+}
+
+func (c *compactDecoder) GetAudioData() []byte {
+	return c.buf.Bytes()
+}
+
+func (c *compactDecoder) GetAudioExt() string {
+	if c.createErr != nil {
+		return ""
+	}
+	return c.decoder.GetFileExt()
+}
+
+func (c *compactDecoder) GetMeta() common.Meta {
+	return nil
 }

algo/qmc/qmc_test.go

@@ -0,0 +1,98 @@
+package qmc
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"reflect"
+	"testing"
+)
+
+func loadTestDataQmcDecoder(filename string) ([]byte, []byte, error) {
+	encBody, err := os.ReadFile(fmt.Sprintf("./testdata/%s_raw.bin", filename))
+	if err != nil {
+		return nil, nil, err
+	}
+	encSuffix, err := os.ReadFile(fmt.Sprintf("./testdata/%s_suffix.bin", filename))
+	if err != nil {
+		return nil, nil, err
+	}
+
+	target, err := os.ReadFile(fmt.Sprintf("./testdata/%s_target.bin", filename))
+	if err != nil {
+		return nil, nil, err
+	}
+	return bytes.Join([][]byte{encBody, encSuffix}, nil), target, nil
+
+}
+func TestMflac0Decoder_Read(t *testing.T) {
+	tests := []struct {
+		name    string
+		wantErr bool
+	}{
+		{"mflac0_rc4", false},
+		{"mflac_map", false},
+		{"mgg_map", false},
+		{"qmc0_static", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			raw, target, err := loadTestDataQmcDecoder(tt.name)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			d, err := NewDecoder(bytes.NewReader(raw))
+			if err != nil {
+				t.Error(err)
+				return
+			}
+			buf := make([]byte, len(target))
+			if _, err := io.ReadFull(d, buf); err != nil {
+				t.Errorf("read bytes from decoder error = %v", err)
+				return
+			}
+			if !reflect.DeepEqual(buf, target) {
+				t.Errorf("Decrypt() got = %v, want %v", buf[:32], target[:32])
+			}
+		})
+	}
+
+}
+
+func TestMflac0Decoder_Validate(t *testing.T) {
+	tests := []struct {
+		name    string
+		fileExt string
+		wantErr bool
+	}{
+		{"mflac0_rc4", ".flac", false},
+		{"mflac_map", ".flac", false},
+		{"mgg_map", ".ogg", false},
+		{"qmc0_static", ".mp3", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			raw, _, err := loadTestDataQmcDecoder(tt.name)
+			if err != nil {
+				t.Fatal(err)
+			}
+			d, err := NewDecoder(bytes.NewReader(raw))
+			if err != nil {
+				t.Error(err)
+				return
+			}
+
+			if err := d.Validate(); err != nil {
+				t.Errorf("read bytes from decoder error = %v", err)
+				return
+			}
+			if tt.fileExt != d.GetFileExt() {
+				t.Errorf("Decrypt() got = %v, want %v", d.GetFileExt(), tt.fileExt)
+			}
+		})
+	}
+}

algo/qmc/testdata/mflac0_rc4_key.bin

@@ -0,0 +1 @@
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

algo/qmc/testdata/mflac0_rc4_key_raw.bin

@@ -0,0 +1 @@
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

algo/qmc/testdata/mflac_map_key.bin

@@ -0,0 +1 @@
+yw7xWOyNQ8585Jwx3hjB49QLPKi38F89awnrQ0fq66NT9TDq1ppHNrFqhaDrU5AFk916D58I53h86304GqOFCCyFzBem68DqiXJ81bILEQwG3P3MOnoNzM820kNW9Lv9IJGNn9Xo497p82BLTm4hAX8JLBs0T2pilKvT429sK9jfg508GSk4d047Jxdz5Fou4aa33OkyFRBU3x430mgNBn04Lc9BzXUI2IGYXv3FGa9qE4Vb54kSjVv8ogbg47j3

algo/qmc/testdata/mflac_map_key_raw.bin

@@ -0,0 +1 @@
+eXc3eFdPeU6+3f7GVeF35bMpIEIQj5JWOWt7G+jsR68Hx3BUFBavkTQ8dpPdP0XBIwPe+OfdsnTGVQqPyg3GCtQSrkgA0mwSQdr4DPzKLkEZFX+Cf1V6ChyipOuC6KT37eAxWMdV1UHf9/OCvydr1dc6SWK1ijRUcP6IAHQhiB+mZLay7XXrSPo32WjdBkn9c9sa2SLtI48atj5kfZ4oOq6QGeld2JA3Z+3wwCe6uTHthKaEHY8ufDYodEe3qqrjYpzkdx55pCtxCQa1JiNqFmJigWm4m3CDzhuJ7YqnjbD+mXxLi7BP1+z4L6nccE2h+DGHVqpGjR9+4LBpe4WHB4DrAzVp2qQRRQJxeHd1v88=

algo/qmc/testdata/mgg_map_key.bin

@@ -0,0 +1 @@
+zGxNk54pKJ0hDkAo80wHE80ycSWQ7z4m4E846zVy2sqCn14F42Y5S7GqeR11WpOV75sDLbE5dFP992t88l0pHy1yAQ49YK6YX6c543drBYLo55Hc4Y0Fyic6LQPiGqu2bG31r8vaq9wS9v63kg0X5VbnOD6RhO4t0RRhk3ajrA7p0iIy027z0L70LZjtw6E18H0D41nz6ASTx71otdF9z1QNC0JmCl51xvnb39zPExEXyKkV47S6QsK5hFh884QJ

algo/qmc/testdata/mgg_map_key_raw.bin

@@ -0,0 +1 @@
+ekd4Tms1NHC53JEDO/AKVyF+I0bj0hHB7CZeoLDGSApaQB9Oo/pJTBGA/RO+nk5RXLXdHsffLiY4e8kt3LNo6qMl7S89vkiSFxx4Uoq4bGDJ7Jc+bYL6lLsa3M4sBvXS4XcPChrMDz+LmrJMGG6ua2fYyIz1d6TCRUBf1JJgCIkBbDAEeMVYc13qApitiz/apGAPmAnveCaDhfD5GxWsF+RfQ2OcnvrnIXe80Feh/0jx763DlsOBI3eIede6t5zYHokWkZmVEF1jMrnlvsgbQK2EzUWMblmLMsTKNILyZazEoKUyulqmyLO/c/KYE+USPOXPcbjlYFmLhSGHK7sQB5aBR153Yp+xh61ooh2NGAA=

cmd/um/main.go

@@ -3,6 +3,15 @@ package main
 import (
 	"errors"
 	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strings"
+
+	"github.com/urfave/cli/v2"
+	"go.uber.org/zap"
+
 	"github.com/unlock-music/cli/algo/common"
 	_ "github.com/unlock-music/cli/algo/kgm"
 	_ "github.com/unlock-music/cli/algo/kwm"
@@ -11,12 +20,6 @@ import (
 	_ "github.com/unlock-music/cli/algo/tm"
 	_ "github.com/unlock-music/cli/algo/xm"
 	"github.com/unlock-music/cli/internal/logging"
-	"github.com/urfave/cli/v2"
-	"go.uber.org/zap"
-	"os"
-	"path/filepath"
-	"runtime"
-	"strings"
 )
 
 var AppVersion = "v0.0.6"
@@ -31,6 +34,7 @@ func main() {
 			&cli.StringFlag{Name: "input", Aliases: []string{"i"}, Usage: "path to input file or dir", Required: false},
 			&cli.StringFlag{Name: "output", Aliases: []string{"o"}, Usage: "path to output dir", Required: false},
 			&cli.BoolFlag{Name: "skip-noop", Aliases: []string{"n"}, Usage: "skip noop decoder", Required: false, Value: true},
+			&cli.BoolFlag{Name: "supported-ext", Usage: "Show supported file extensions and exit", Required: false, Value: false},
 		},
 
 		Action:          appMain,
@@ -43,8 +47,21 @@ func main() {
 		logging.Log().Fatal("run app failed", zap.Error(err))
 	}
 }
-
+func printSupportedExtensions() {
+	exts := []string{}
+	for ext := range common.DecoderRegistry {
+		exts = append(exts, ext)
+	}
+	sort.Strings(exts)
+	for _, ext := range exts {
+		fmt.Printf("%s: %d\n", ext, len(common.DecoderRegistry[ext]))
+	}
+}
 func appMain(c *cli.Context) (err error) {
+	if c.Bool("supported-ext") {
+		printSupportedExtensions()
+		return nil
+	}
 	input := c.String("input")
 	if input == "" {
 		switch c.Args().Len() {

go.mod

@@ -6,12 +6,12 @@ require (
 	github.com/ulikunitz/xz v0.5.10
 	github.com/urfave/cli/v2 v2.3.0
 	go.uber.org/zap v1.19.1
+	golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550
 )
 
 require (
-	github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d // indirect
-	github.com/russross/blackfriday/v2 v2.0.1 // indirect
-	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
-	go.uber.org/atomic v1.7.0 // indirect
-	go.uber.org/multierr v1.6.0 // indirect
+	github.com/cpuguy83/go-md2man/v2 v2.0.1 // indirect
+	github.com/russross/blackfriday/v2 v2.1.0 // indirect
+	go.uber.org/atomic v1.9.0 // indirect
+	go.uber.org/multierr v1.7.0 // indirect
 )

go.sum

@@ -1,8 +1,9 @@
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/benbjohnson/clock v1.1.0 h1:Q92kusRqC1XV2MjkWETPvjJVqKetz1OzxZB7mHJLju8=
 github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
-github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d h1:U+s90UTSYgptZMwQh2aRr3LuazLJIa+Pg3Kc1ylSYVY=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
+github.com/cpuguy83/go-md2man/v2 v2.0.1 h1:r/myEWzV9lfsM1tFLgDyu0atFtJ1fXn261LKYj/3DxU=
+github.com/cpuguy83/go-md2man/v2 v2.0.1/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -13,9 +14,9 @@ github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/russross/blackfriday/v2 v2.0.1 h1:lPqVAte+HuHNfhJ/0LC98ESWRz8afy9tM/0RK8m9o+Q=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
-github.com/shurcooL/sanitized_anchor_name v1.0.0 h1:PdmoCO6wvbs+7yrJyMORt4/BmY5IYyJwS/kOiWx8mHo=
+github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
+github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
@@ -26,15 +27,18 @@ github.com/ulikunitz/xz v0.5.10/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0o
 github.com/urfave/cli/v2 v2.3.0 h1:qph92Y649prgesehzOrQjdWyxFOp/QVM+6imKHad91M=
 github.com/urfave/cli/v2 v2.3.0/go.mod h1:LJmUH05zAU44vOAcrfzZQKsZbVcdbOG8rtL3/XcUArI=
 github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
-go.uber.org/atomic v1.7.0 h1:ADUqmZGgLDDfbSL9ZmPxKTybcoEYHgpYfELNoN+7hsw=
 go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
+go.uber.org/atomic v1.9.0 h1:ECmE8Bn/WFTYwEW/bpKD3M8VtR/zQVbavAoalC1PYyE=
+go.uber.org/atomic v1.9.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/goleak v1.1.11-0.20210813005559-691160354723 h1:sHOAIxRGBp443oHZIPB+HsUGaksVCXVQENPxwTfQdH4=
 go.uber.org/goleak v1.1.11-0.20210813005559-691160354723/go.mod h1:cwTWslyiVhfpKIDGSZEM2HlOvcqm+tG4zioyIeLoqMQ=
-go.uber.org/multierr v1.6.0 h1:y6IPFStTAIT5Ytl7/XYmHvzXQ7S3g/IeZW9hyZ5thw4=
 go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU=
+go.uber.org/multierr v1.7.0 h1:zaiO/rmgFjbmCXdSYJWQcdvOCsthmdaHfr3Gm2Kx4Ec=
+go.uber.org/multierr v1.7.0/go.mod h1:7EAYxJLBy9rStEaz58O2t4Uvip6FSURkq8/ppBp95ak=
 go.uber.org/zap v1.19.1 h1:ue41HOKd1vGURxrmeKIgELGb3jPW9DMUDGtsinblHwI=
 go.uber.org/zap v1.19.1/go.mod h1:j3DNczoxDZroyBnOT1L/Q79cfUMGZxlv/9dzN7SM1rI=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 h1:ObdrDkeb4kJdCP557AjRjq69pTHfNouLtWZG7j9rPN8=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=