|
1
|
|
|
import * as ID3Util from "./ID3Util" |
|
2
|
|
|
import { TextEncoding } from "./definitions/Encoding" |
|
3
|
|
|
|
|
4
|
|
|
type FrameReaderOptions = { |
|
5
|
|
|
consumeEncodingByte?: boolean |
|
6
|
|
|
} |
|
7
|
|
|
|
|
8
|
|
|
type Size = { |
|
9
|
|
|
size?: number |
|
10
|
|
|
} |
|
11
|
|
|
|
|
12
|
|
|
export class FrameReader { |
|
13
|
|
|
private _encoding: TextEncoding = TextEncoding.ISO_8859_1 |
|
14
|
|
|
private _buffer: Buffer |
|
15
|
|
|
|
|
16
|
|
|
constructor( |
|
17
|
|
|
buffer: Buffer, |
|
18
|
|
|
{ |
|
19
|
|
|
consumeEncodingByte = false |
|
20
|
|
|
}: FrameReaderOptions = {} |
|
21
|
|
|
) { |
|
22
|
|
|
this._buffer = buffer |
|
23
|
|
|
if (consumeEncodingByte) { |
|
24
|
|
|
const encoding = this.consumeBuffer({ size: 1 }) |
|
25
|
|
|
this._encoding = encoding[0] as TextEncoding |
|
26
|
|
|
} |
|
27
|
|
|
} |
|
28
|
|
|
|
|
29
|
|
|
isBufferEmpty() { |
|
30
|
|
|
return this._buffer.length === 0 |
|
31
|
|
|
} |
|
32
|
|
|
|
|
33
|
|
|
consumePossiblyEmptyBuffer( |
|
34
|
|
|
{ size = this._buffer.length }: Size = {} |
|
35
|
|
|
): Buffer { |
|
36
|
|
|
if (size > this._buffer.length) { |
|
37
|
|
|
throw new RangeError( |
|
38
|
|
|
`Requested size ${size} larger than the buffer size ${this._buffer.length}` |
|
39
|
|
|
) |
|
40
|
|
|
} |
|
41
|
|
|
const consumed = this._buffer.subarray(0, size) |
|
42
|
|
|
this._buffer = this._buffer.subarray(size) |
|
43
|
|
|
return consumed |
|
44
|
|
|
} |
|
45
|
|
|
|
|
46
|
|
|
consumeBuffer(size?: Size): Buffer { |
|
47
|
|
|
if (this._buffer.length === 0) { |
|
48
|
|
|
throw new RangeError("Buffer empty") |
|
49
|
|
|
} |
|
50
|
|
|
return this.consumePossiblyEmptyBuffer(size) |
|
51
|
|
|
} |
|
52
|
|
|
|
|
53
|
|
|
consumeNumber({ size }: { size: number }): number { |
|
54
|
|
|
const buffer = this.consumeBuffer({ size }) |
|
55
|
|
|
return parseInt(buffer.toString('hex'), 16) |
|
56
|
|
|
} |
|
57
|
|
|
|
|
58
|
|
|
consumeText({ size, encoding = TextEncoding.ISO_8859_1 }: { |
|
59
|
|
|
size?: number |
|
60
|
|
|
encoding?: TextEncoding |
|
61
|
|
|
} = {}): string { |
|
62
|
|
|
const buffer = this.consumeBuffer({ size }) |
|
63
|
|
|
return ID3Util.bufferToDecodedString(buffer, encoding) |
|
64
|
|
|
} |
|
65
|
|
|
|
|
66
|
|
|
consumeTextWithFrameEncoding(size: Size = {}): string { |
|
67
|
|
|
return this.consumeText({...size, encoding: this._encoding}) |
|
68
|
|
|
} |
|
69
|
|
|
|
|
70
|
|
|
consumeTerminatedText( |
|
71
|
|
|
encoding: TextEncoding = TextEncoding.ISO_8859_1 |
|
72
|
|
|
): string { |
|
73
|
|
|
const [consumed, remainder] = |
|
74
|
|
|
splitNullTerminatedBuffer(this._buffer, encoding) |
|
75
|
|
|
this._buffer = remainder |
|
76
|
|
|
return ID3Util.bufferToDecodedString(consumed, encoding) |
|
77
|
|
|
} |
|
78
|
|
|
|
|
79
|
|
|
consumeTerminatedTextWithFrameEncoding(): string { |
|
80
|
|
|
return this.consumeTerminatedText(this._encoding) |
|
81
|
|
|
} |
|
82
|
|
|
} |
|
83
|
|
|
|
|
84
|
|
|
/** |
|
85
|
|
|
* @param buffer A buffer starting with a null-terminated text string. |
|
86
|
|
|
* @param encoding The encoding type in which the text string is encoded. |
|
87
|
|
|
* @returns A split buffer containing the bytes before and after the null |
|
88
|
|
|
* termination. If no null termination is found, considers that |
|
89
|
|
|
* the buffer was not containing a text string and returns |
|
90
|
|
|
* the given buffer as the remainder in the split buffer. |
|
91
|
|
|
*/ |
|
92
|
|
|
export function splitNullTerminatedBuffer( |
|
93
|
|
|
buffer: Buffer, |
|
94
|
|
|
encoding: TextEncoding |
|
95
|
|
|
) { |
|
96
|
|
|
const charSize = ([ |
|
97
|
|
|
TextEncoding.UTF_16_WITH_BOM, |
|
98
|
|
|
TextEncoding.UTF_16_BE |
|
99
|
|
|
] as number[]).includes(encoding) ? 2 : 1 |
|
100
|
|
|
|
|
101
|
|
|
for (let pos = 0; pos <= buffer.length - charSize; pos += charSize) { |
|
102
|
|
|
if (buffer.readUIntBE(pos, charSize) === 0) { |
|
103
|
|
|
return [ |
|
104
|
|
|
buffer.subarray(0, pos), |
|
105
|
|
|
buffer.subarray(pos + charSize) |
|
106
|
|
|
] as const |
|
107
|
|
|
} |
|
108
|
|
|
} |
|
109
|
|
|
throw new RangeError("Terminating character not found") |
|
110
|
|
|
} |
|
111
|
|
|
|
Zazama /
node-id3
