|
1
|
|
|
const ID3Util = require('./ID3Util') |
|
2
|
|
|
const ID3Definitions = require("./ID3Definitions") |
|
3
|
|
|
|
|
4
|
|
|
class ID3FrameHeader { |
|
5
|
|
|
constructor(identifier, frameSize, flags = {}) { |
|
6
|
|
|
this.identifier = identifier |
|
7
|
|
|
this.frameSize = frameSize |
|
8
|
|
|
this.flags = flags |
|
9
|
|
|
} |
|
10
|
|
|
|
|
11
|
|
|
static createFromBuffer(headerBuffer, version) { |
|
12
|
|
|
const identifierSize = (version === 2) ? 3 : 4 |
|
13
|
|
|
let identifier = headerBuffer.toString('utf8', 0, identifierSize) |
|
14
|
|
|
const frameSize = this.getFrameSizeFromBuffer(headerBuffer, version) |
|
15
|
|
|
const flags = this.getFlagsFromBytes(headerBuffer[8], headerBuffer[9], version) |
|
16
|
|
|
|
|
17
|
|
|
// Try to convert identifier for older versions |
|
18
|
|
|
if(version === 2) { |
|
19
|
|
|
const alias = ID3Definitions.FRAME_INTERNAL_IDENTIFIERS.v2[identifier] |
|
20
|
|
|
if(alias) { |
|
21
|
|
|
identifier = ID3Definitions.FRAME_IDENTIFIERS.v3[alias] |
|
22
|
|
|
} |
|
23
|
|
|
} |
|
24
|
|
|
|
|
25
|
|
|
return new ID3FrameHeader(identifier, frameSize, flags) |
|
26
|
|
|
} |
|
27
|
|
|
|
|
28
|
|
|
getBuffer() { |
|
29
|
|
|
const buffer = Buffer.alloc(10) |
|
30
|
|
|
buffer.write(this.identifier, 0) |
|
31
|
|
|
buffer.writeUInt32BE(this.frameSize, 4) |
|
32
|
|
|
return buffer |
|
33
|
|
|
} |
|
34
|
|
|
|
|
35
|
|
|
static getSizeByVersion(version) { |
|
36
|
|
|
return (version === 2) ? 6 : 10 |
|
37
|
|
|
} |
|
38
|
|
|
|
|
39
|
|
|
static getFrameSizeFromBuffer(headerBuffer, version) { |
|
40
|
|
|
const isDecoded = version === 4 |
|
41
|
|
|
let bytes |
|
42
|
|
|
if(version === 2) { |
|
43
|
|
|
bytes = [headerBuffer[3], headerBuffer[4], headerBuffer[5]] |
|
44
|
|
|
} else { |
|
45
|
|
|
bytes = [headerBuffer[4], headerBuffer[5], headerBuffer[6], headerBuffer[7]] |
|
46
|
|
|
} |
|
47
|
|
|
if(isDecoded) { |
|
48
|
|
|
return ID3Util.decodeSize(Buffer.from(bytes)) |
|
49
|
|
|
} |
|
50
|
|
|
|
|
51
|
|
|
return Buffer.from(bytes).readUIntBE(0, bytes.length) |
|
52
|
|
|
} |
|
53
|
|
|
|
|
54
|
|
|
static getFlagsFromBytes(statusFlag, encodingFlag, version) { |
|
55
|
|
|
if(version === 2) { |
|
56
|
|
|
return {} |
|
57
|
|
|
} |
|
58
|
|
|
|
|
59
|
|
View Code Duplication |
if(version === 3) { |
|
|
|
|
|
|
60
|
|
|
return { |
|
61
|
|
|
tagAlterPreservation: !!(statusFlag & 128), |
|
62
|
|
|
fileAlterPreservation: !!(statusFlag & 64), |
|
63
|
|
|
readOnly: !!(statusFlag & 32), |
|
64
|
|
|
compression: !!(encodingFlag & 128), |
|
65
|
|
|
encryption: !!(encodingFlag & 64), |
|
66
|
|
|
groupingIdentity: !!(encodingFlag & 32), |
|
67
|
|
|
dataLengthIndicator: !!(encodingFlag & 128) |
|
68
|
|
|
} |
|
69
|
|
|
} |
|
70
|
|
|
|
|
71
|
|
View Code Duplication |
if(version === 4) { |
|
|
|
|
|
|
72
|
|
|
return { |
|
73
|
|
|
tagAlterPreservation: !!(statusFlag & 64), |
|
74
|
|
|
fileAlterPreservation: !!(statusFlag & 32), |
|
75
|
|
|
readOnly: !!(statusFlag & 16), |
|
76
|
|
|
groupingIdentity: !!(encodingFlag & 64), |
|
77
|
|
|
compression: !!(encodingFlag & 8), |
|
78
|
|
|
encryption: !!(encodingFlag & 4), |
|
79
|
|
|
unsynchronisation: !!(encodingFlag & 2), |
|
80
|
|
|
dataLengthIndicator: !!(encodingFlag & 1) |
|
81
|
|
|
} |
|
82
|
|
|
} |
|
83
|
|
|
|
|
84
|
|
|
return {} |
|
85
|
|
|
} |
|
86
|
|
|
} |
|
87
|
|
|
|
|
88
|
|
|
module.exports = ID3FrameHeader |
Zazama /
node-id3
Loading history...