70 lines
1.6 KiB
JavaScript
70 lines
1.6 KiB
JavaScript
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
|