|
1
|
|
|
import zlib = require('zlib') |
|
2
|
|
|
import { |
|
3
|
|
|
Flags, |
|
4
|
|
|
getHeaderSize, |
|
5
|
|
|
FrameHeader |
|
6
|
|
|
} from './FrameHeader' |
|
7
|
|
|
import * as Frames from './Frames' |
|
8
|
|
|
import * as ID3Util from './ID3Util' |
|
9
|
|
|
import { isKeyOf } from "./util" |
|
10
|
|
|
|
|
11
|
|
|
type HeaderInfo = { |
|
12
|
|
|
identifier: string |
|
13
|
|
|
headerSize: number |
|
14
|
|
|
bodySize: number |
|
15
|
|
|
flags: Flags |
|
16
|
|
|
} |
|
17
|
|
|
|
|
18
|
|
|
export class Frame { |
|
19
|
|
|
identifier: string |
|
20
|
|
|
private value: unknown |
|
21
|
|
|
flags: Flags |
|
22
|
|
|
|
|
23
|
|
|
constructor(identifier: string, value: unknown, flags: Flags = {}) { |
|
24
|
|
|
this.identifier = identifier |
|
25
|
|
|
this.value = value |
|
26
|
|
|
this.flags = flags |
|
27
|
|
|
} |
|
28
|
|
|
|
|
29
|
|
|
static createFromBuffer( |
|
30
|
|
|
frameBuffer: Buffer, |
|
31
|
|
|
version: number |
|
32
|
|
|
): Frame | null { |
|
33
|
|
|
const headerSize = getHeaderSize(version) |
|
34
|
|
|
// Specification requirement |
|
35
|
|
|
if (frameBuffer.length < headerSize + 1) { |
|
36
|
|
|
return null |
|
37
|
|
|
} |
|
38
|
|
|
const headerBuffer = frameBuffer.subarray(0, headerSize) |
|
39
|
|
|
const header: HeaderInfo = { |
|
40
|
|
|
headerSize, |
|
41
|
|
|
...FrameHeader.createFromBuffer(headerBuffer, version) |
|
42
|
|
|
} |
|
43
|
|
|
if (header.flags.encryption) { |
|
44
|
|
|
return null |
|
45
|
|
|
} |
|
46
|
|
|
|
|
47
|
|
|
const body = decompressBody( |
|
48
|
|
|
header.flags, |
|
49
|
|
|
getDataLength(header, frameBuffer), |
|
50
|
|
|
getBody(header, frameBuffer) |
|
51
|
|
|
) |
|
52
|
|
|
if (!body) { |
|
53
|
|
|
return null |
|
54
|
|
|
} |
|
55
|
|
|
|
|
56
|
|
|
const identifier = header.identifier |
|
57
|
|
|
let value = null |
|
58
|
|
|
if (isKeyOf(identifier, Frames.Frames)) { |
|
59
|
|
|
value = Frames.Frames[identifier].read(body, version) |
|
60
|
|
|
} else if (identifier.startsWith('T')) { |
|
61
|
|
|
value = Frames.GENERIC_TEXT.read(body) |
|
62
|
|
|
} else if (identifier.startsWith('W')) { |
|
63
|
|
|
value = Frames.GENERIC_URL.read(body) |
|
64
|
|
|
} else { |
|
65
|
|
|
return null |
|
66
|
|
|
} |
|
67
|
|
|
return new Frame(identifier, value, header.flags) |
|
68
|
|
|
} |
|
69
|
|
|
|
|
70
|
|
|
getBuffer() { |
|
71
|
|
|
if (isKeyOf(this.identifier, Frames.Frames)) { |
|
72
|
|
|
return Frames.Frames[this.identifier].create(this.value) |
|
73
|
|
|
} |
|
74
|
|
|
if (this.identifier.startsWith('T')) { |
|
75
|
|
|
return Frames.GENERIC_TEXT.create(this.identifier, this.value) |
|
76
|
|
|
} |
|
77
|
|
|
if (this.identifier.startsWith('W')) { |
|
78
|
|
|
return Frames.GENERIC_URL.create(this.identifier, this.value) |
|
79
|
|
|
} |
|
80
|
|
|
return null |
|
81
|
|
|
} |
|
82
|
|
|
|
|
83
|
|
|
getValue() { |
|
84
|
|
|
return this.value |
|
85
|
|
|
} |
|
86
|
|
|
} |
|
87
|
|
|
|
|
88
|
|
|
function getBody({flags, headerSize, bodySize}: HeaderInfo, buffer: Buffer) { |
|
89
|
|
|
const bodyOffset = flags.dataLengthIndicator ? 4 : 0 |
|
90
|
|
|
const bodyStart = headerSize + bodyOffset |
|
91
|
|
|
const bodyEnd = bodyStart + bodySize - bodyOffset |
|
92
|
|
|
const body = buffer.subarray(bodyStart, bodyEnd) |
|
93
|
|
|
if (flags.unsynchronisation) { |
|
94
|
|
|
// This method should stay in ID3Util for now because it's also used in the Tag's header which we don't have a class for. |
|
95
|
|
|
return ID3Util.processUnsynchronisedBuffer(body) |
|
96
|
|
|
} |
|
97
|
|
|
return body |
|
98
|
|
|
} |
|
99
|
|
|
|
|
100
|
|
|
function getDataLength({flags, headerSize}: HeaderInfo, buffer: Buffer) { |
|
101
|
|
|
return flags.dataLengthIndicator ? buffer.readInt32BE(headerSize) : 0 |
|
102
|
|
|
} |
|
103
|
|
|
|
|
104
|
|
|
function decompressBody( |
|
105
|
|
|
{compression}: Flags, |
|
106
|
|
|
dataLength: number, |
|
107
|
|
|
body: Buffer |
|
108
|
|
|
) { |
|
109
|
|
|
return compression ? decompressBuffer(body, dataLength) : body |
|
110
|
|
|
} |
|
111
|
|
|
|
|
112
|
|
|
function decompressBuffer(buffer: Buffer, expectedDecompressedLength: number) { |
|
113
|
|
|
if (buffer.length < 5) { |
|
114
|
|
|
return null |
|
115
|
|
|
} |
|
116
|
|
|
|
|
117
|
|
|
// ID3 spec defines that compression is stored in ZLIB format, |
|
118
|
|
|
// but doesn't specify if header is present or not. |
|
119
|
|
|
// ZLIB has a 2-byte header. |
|
120
|
|
|
// 1. try if header + body decompression |
|
121
|
|
|
// 2. else try if header is not stored (assume that all content is deflated "body") |
|
122
|
|
|
// 3. else try if inflation works if the header is omitted (implementation dependent) |
|
123
|
|
|
const tryDecompress = () => { |
|
124
|
|
|
try { |
|
125
|
|
|
return zlib.inflateSync(buffer) |
|
126
|
|
|
} catch (error) { |
|
127
|
|
|
try { |
|
128
|
|
|
return zlib.inflateRawSync(buffer) |
|
129
|
|
|
} catch (error) { |
|
130
|
|
|
try { |
|
131
|
|
|
return zlib.inflateRawSync(buffer.subarray(2)) |
|
132
|
|
|
} catch (error) { |
|
133
|
|
|
return null |
|
134
|
|
|
} |
|
135
|
|
|
} |
|
136
|
|
|
} |
|
137
|
|
|
} |
|
138
|
|
|
const decompressed = tryDecompress() |
|
139
|
|
|
if (decompressed && decompressed.length === expectedDecompressedLength) { |
|
140
|
|
|
return decompressed |
|
141
|
|
|
} |
|
142
|
|
|
return null |
|
143
|
|
|
} |
|
144
|
|
|
|
Zazama /
node-id3
