1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
var toString = Object.prototype.toString
var isModern = (
typeof Buffer.alloc === 'function' &&
typeof Buffer.allocUnsafe === 'function' &&
typeof Buffer.from === 'function'
)
function isArrayBuffer (input) {
return toString.call(input).slice(8, -1) === 'ArrayBuffer'
}
function fromArrayBuffer (obj, byteOffset, length) {
byteOffset >>>= 0
var maxLength = obj.byteLength - byteOffset
if (maxLength < 0) {
throw new RangeError("'offset' is out of bounds")
}
if (length === undefined) {
length = maxLength
} else {
length >>>= 0
if (length > maxLength) {
throw new RangeError("'length' is out of bounds")
}
}
return isModern
? Buffer.from(obj.slice(byteOffset, byteOffset + length))
: new Buffer(new Uint8Array(obj.slice(byteOffset, byteOffset + length)))
}
function fromString (string, encoding) {
if (typeof encoding !== 'string' || encoding === '') {
encoding = 'utf8'
}
if (!Buffer.isEncoding(encoding)) {
throw new TypeError('"encoding" must be a valid string encoding')
}
return isModern
? Buffer.from(string, encoding)
: new Buffer(string, encoding)
}
function bufferFrom (value, encodingOrOffset, length) {
if (typeof value === 'number') {
throw new TypeError('"value" argument must not be a number')
}
if (isArrayBuffer(value)) {
return fromArrayBuffer(value, encodingOrOffset, length)
}
if (typeof value === 'string') {
return fromString(value, encodingOrOffset)
}
return isModern
? Buffer.from(value)
: new Buffer(value)
}
module.exports = bufferFrom
|
