init: dec-music 项目初始化

This commit is contained in:
2026-05-23 12:55:48 +08:00
commit 21045d0aad
50 changed files with 3662 additions and 0 deletions
+33
View File
@@ -0,0 +1,33 @@
package crypto
import "crypto/aes"
// PKCS7UnPadding removes PKCS#7 padding.
func PKCS7UnPadding(encrypt []byte) []byte {
length := len(encrypt)
if length == 0 {
return encrypt
}
unPadding := int(encrypt[length-1])
if unPadding <= 0 || unPadding > length {
return encrypt
}
return encrypt[:length-unPadding]
}
// DecryptAES128ECB decrypts data with AES-128 ECB (block size 16).
func DecryptAES128ECB(data, key []byte) []byte {
cipher, err := aes.NewCipher(key)
if err != nil {
return nil
}
decrypted := make([]byte, len(data))
size := aes.BlockSize
for bs, be := 0, size; bs < len(data); bs, be = bs+size, be+size {
if be > len(data) {
break
}
cipher.Decrypt(decrypted[bs:be], data[bs:be])
}
return decrypted
}
+50
View File
@@ -0,0 +1,50 @@
package fileutil
import (
"os"
"path/filepath"
"strings"
)
var (
standardMediaExts = map[string]struct{}{
".mp3": {}, ".flac": {}, ".wav": {}, ".m4a": {},
".ogg": {}, ".opus": {}, ".aac": {}, ".wma": {},
".ape": {}, ".alac": {}, ".dsf": {}, ".dff": {},
}
encryptedMediaExts = map[string]struct{}{
".kgma": {}, ".kgm": {},
".ncm": {},
".qmc": {}, ".qmc0": {}, ".qmc3": {}, ".qmcflac": {}, ".qmcogg": {},
".mgg": {}, ".mflac": {},
".tm": {}, ".tkm": {},
".xiami": {}, ".xm": {},
".ximalaya": {}, ".xmly": {},
".x2m": {}, ".x3m": {},
".kwm": {},
}
videoMediaExts = map[string]struct{}{
".mp4": {}, ".mkv": {}, ".avi": {}, ".mov": {}, ".flv": {},
}
)
// IsMediaFile reports whether the file name looks like a media file this tool handles.
func IsMediaFile(fileName string) bool {
ext := strings.ToLower(filepath.Ext(fileName))
if _, ok := standardMediaExts[ext]; ok {
return true
}
if _, ok := encryptedMediaExts[ext]; ok {
return true
}
if _, ok := videoMediaExts[ext]; ok {
return true
}
return false
}
// FileExist reports whether path exists.
func FileExist(path string) bool {
_, err := os.Stat(path)
return err == nil
}
+105
View File
@@ -0,0 +1,105 @@
package sniff
import (
"bytes"
"encoding/binary"
"slices"
)
type Sniffer interface {
Sniff(header []byte) bool
}
var audioExtensions = map[string]Sniffer{
// ref: https://mimesniff.spec.whatwg.org
".mp3": prefixSniffer("ID3"), // todo: check mp3 without ID3v2 tag
".ogg": prefixSniffer("OggS"),
".wav": prefixSniffer("RIFF"),
// ref: https://www.loc.gov/preservation/digital/formats/fdd/fdd000027.shtml
".wma": prefixSniffer{
0x30, 0x26, 0xb2, 0x75, 0x8e, 0x66, 0xcf, 0x11,
0xa6, 0xd9, 0x00, 0xaa, 0x00, 0x62, 0xce, 0x6c,
},
// ref: https://www.garykessler.net/library/file_sigs.html
".m4a": m4aSniffer{}, // MPEG-4 container, Apple Lossless Audio Codec
".mp4": &mpeg4Sniffer{}, // MPEG-4 container, other fallback
".flac": prefixSniffer("fLaC"), // ref: https://xiph.org/flac/format.html
".dff": prefixSniffer("FRM8"), // DSDIFF, ref: https://www.sonicstudio.com/pdf/dsd/DSDIFF_1.5_Spec.pdf
}
// AudioExtension sniffs the known audio types, and returns the file extension.
// header is recommended to at least 16 bytes.
func AudioExtension(header []byte) (string, bool) {
for ext, sniffer := range audioExtensions {
if sniffer.Sniff(header) {
return ext, true
}
}
return "", false
}
// AudioExtensionWithFallback is equivalent to AudioExtension, but returns fallback
// most likely to use .mp3 as fallback, because mp3 files may not have ID3v2 tag.
func AudioExtensionWithFallback(header []byte, fallback string) string {
ext, ok := AudioExtension(header)
if !ok {
return fallback
}
return ext
}
type prefixSniffer []byte
func (s prefixSniffer) Sniff(header []byte) bool {
return bytes.HasPrefix(header, s)
}
type m4aSniffer struct{}
func (m4aSniffer) Sniff(header []byte) bool {
box := readMpeg4FtypBox(header)
if box == nil {
return false
}
return box.majorBrand == "M4A " || slices.Contains(box.compatibleBrands, "M4A ")
}
type mpeg4Sniffer struct{}
func (s *mpeg4Sniffer) Sniff(header []byte) bool {
return readMpeg4FtypBox(header) != nil
}
type mpeg4FtpyBox struct {
majorBrand string
minorVersion uint32
compatibleBrands []string
}
func readMpeg4FtypBox(header []byte) *mpeg4FtpyBox {
if (len(header) < 8) || !bytes.Equal([]byte("ftyp"), header[4:8]) {
return nil // not a valid ftyp box
}
size := binary.BigEndian.Uint32(header[0:4]) // size
if size < 16 || size%4 != 0 {
return nil // invalid ftyp box
}
box := mpeg4FtpyBox{
majorBrand: string(header[8:12]),
minorVersion: binary.BigEndian.Uint32(header[12:16]),
}
// compatible brands
for i := 16; i < int(size) && i+4 < len(header); i += 4 {
box.compatibleBrands = append(box.compatibleBrands, string(header[i:i+4]))
}
return &box
}
+116
View File
@@ -0,0 +1,116 @@
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package tea implements the TEA algorithm, as defined in Needham and
// Wheeler's 1994 technical report, “TEA, a Tiny Encryption Algorithm”. See
// http://www.cix.co.uk/~klockstone/tea.pdf for details.
//
// TEA is a legacy cipher and its short block size makes it vulnerable to
// birthday bound attacks (see https://sweet32.info). It should only be used
// where compatibility with legacy systems, not security, is the goal.
//
// Deprecated: any new system should use AES (from crypto/aes, if necessary in
// an AEAD mode like crypto/cipher.NewGCM) or XChaCha20-Poly1305 (from
// golang.org/x/crypto/chacha20poly1305).
package tea
import (
"crypto/cipher"
"encoding/binary"
"errors"
)
const (
// BlockSize is the size of a TEA block, in bytes.
BlockSize = 8
// KeySize is the size of a TEA key, in bytes.
KeySize = 16
// delta is the TEA key schedule constant.
delta = 0x9e3779b9
// numRounds is the standard number of rounds in TEA.
numRounds = 64
)
// tea is an instance of the TEA cipher with a particular key.
type tea struct {
key [16]byte
rounds int
}
// NewCipher returns an instance of the TEA cipher with the standard number of
// rounds. The key argument must be 16 bytes long.
func NewCipher(key []byte) (cipher.Block, error) {
return NewCipherWithRounds(key, numRounds)
}
// NewCipherWithRounds returns an instance of the TEA cipher with a given
// number of rounds, which must be even. The key argument must be 16 bytes
// long.
func NewCipherWithRounds(key []byte, rounds int) (cipher.Block, error) {
if len(key) != 16 {
return nil, errors.New("tea: incorrect key size")
}
if rounds&1 != 0 {
return nil, errors.New("tea: odd number of rounds specified")
}
c := &tea{
rounds: rounds,
}
copy(c.key[:], key)
return c, nil
}
// BlockSize returns the TEA block size, which is eight bytes. It is necessary
// to satisfy the Block interface in the package "crypto/cipher".
func (*tea) BlockSize() int {
return BlockSize
}
// Encrypt encrypts the 8 byte buffer src using the key in t and stores the
// result in dst. Note that for amounts of data larger than a block, it is not
// safe to just call Encrypt on successive blocks; instead, use an encryption
// mode like CBC (see crypto/cipher/cbc.go).
func (t *tea) Encrypt(dst, src []byte) {
e := binary.BigEndian
v0, v1 := e.Uint32(src), e.Uint32(src[4:])
k0, k1, k2, k3 := e.Uint32(t.key[0:]), e.Uint32(t.key[4:]), e.Uint32(t.key[8:]), e.Uint32(t.key[12:])
sum := uint32(0)
delta := uint32(delta)
for i := 0; i < t.rounds/2; i++ {
sum += delta
v0 += ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1)
v1 += ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3)
}
e.PutUint32(dst, v0)
e.PutUint32(dst[4:], v1)
}
// Decrypt decrypts the 8 byte buffer src using the key in t and stores the
// result in dst.
func (t *tea) Decrypt(dst, src []byte) {
e := binary.BigEndian
v0, v1 := e.Uint32(src), e.Uint32(src[4:])
k0, k1, k2, k3 := e.Uint32(t.key[0:]), e.Uint32(t.key[4:]), e.Uint32(t.key[8:]), e.Uint32(t.key[12:])
delta := uint32(delta)
sum := delta * uint32(t.rounds/2) // in general, sum = delta * n
for i := 0; i < t.rounds/2; i++ {
v1 -= ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3)
v0 -= ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1)
sum -= delta
}
e.PutUint32(dst, v0)
e.PutUint32(dst[4:], v1)
}